Firefly 1.5W Tube Amp Build

[duhvoodooman]

Well, on to the next project! This is a cool one. Mentioned HERE (http://www.thefret.net/showthread.php?t=4114) back in Sept. by then-new-member Tunghaichuan, I was immediately smitten with the idea of building it. All the info you need is available on John Calhoun's website (http://web.mac.com/calhoun/PCB/Firefly_PCB.html), where you can also purchase the PCB for the amp build for a very reasonable $19. If you want to hear what this little sucker is capable of, check out THIS CLIP (http://annex.ax84.com/media/ax84_m277.mp3). Sounds like a mini-Marshall stack, no lie!

Between some spare components that Tung was generous enough to send me at no charge, and the rest of the parts order from the sources given in Calhoun's amazingly complete instructions, I've started construction, and finished the PCB fab tonight. Below are some pics, tubes & all. It uses two 12AX7's for the main preamp and a switchable boost stage, and the power tube is a 12AU7!! Now comes the hard part--drilling the chassis and putting all the hardware together. I'll post back here as I make further progress.

http://duhvoodooman.com/miscimages/musical/ffly/ffly_pcb_front1.jpg

http://duhvoodooman.com/miscimages/musical/ffly/ffly_pcb_angle.jpg

http://duhvoodooman.com/miscimages/musical/ffly/ffly_pcb_top.jpg

[Algonquin]

That sound clip is Killer DVM!

Good luck with the rest of the build... Would absolutely love to hear the completed project! :AOK:

Way Cool! :beer:

[Robert]

That looks cool! Imagine that thingy on top of a 4x12... what a sight, hehe... :D

At least you won't need rubber feet for it! :bravo:

[Tone2TheBone]

Or wheels. :D Heard that little sucker today and yeah it rocks heavy. I think I want one.

[sunvalleylaw]

What was that clip played through? Wow!

[duhvoodooman]

What was that clip played through? Wow!
A closed back 1x12 cabinet with a Celestion G12H30. Sounds bigger, doesn't it? :dude: :rockon:

[tot_Ou_tard]

Emminently cool Vood.

Was that your Goldtop straight in?

[duhvoodooman]

Was that your Goldtop straight in?
Oh, sorry if I was misleading! No, the clip isn't me (I wish!!), it's a clip posted on the Firefly project page at AX84.com (http://ax84.com/?pg=legacyprojects&project_id=firefly). Doesn't say who the player or the guitar is, though it certainly sounds like an LP or similar humbucker guitar.

[tot_Ou_tard]

Oh, sorry if I was misleading! No, the clip isn't me (I wish!!), it's a clip posted on the Firefly project page at AX84.com (http://ax84.com/?pg=legacyprojects&project_id=firefly). Doesn't say who the player or the guitar is, though it certainly sounds like an LP or similar humbucker guitar.
My bad. I do see now that you haven't built the dang thing yet!:thwap:!

That would'a be some trick, playing through a pile of tubes & bits n' bobs!

[duhvoodooman]

My bad. I do see now that you haven't built the dang thing yet!:thwap:!

That would'a be some trick, playing through a pile of tubes & bits n' bobs!
Yeah, they're kinda quiet without power and output transformers wired in! ;)

BTW, some more excellent clips can be found at the following link. Scroll way down the page to the "Amps" section of clips, and you'll see the Firefly listed there. There's a nice set of 3 clips that demo the clean, mid-gain and hi-gain sounds. Humbucker guitar, but it doesn't say what the cab was. There's also a clip by Doug Hammond (more on him below). Here's the link:


http://www.mrdwab.com/john/soundclipspage.html

A bit more "credit where credit is due":

The Firefly is the brainchild of Doug Hammond, a familiar name among DIY amp builders. It's one of several amp projects listed at the AX84.com (http://ax84.com/) website, a very cool DIY amp building site run by Chris Hurley, the proprietor of Doberman Music Products (http://shop.dobermanamps.com/). There are some nice bigger DIY tube amp projects there, too, if you're looking to build something with more muscle. What John Calhoun did was to take the project and design a very nice PCB to build it on, and then put together a really outstanding set of instructions, complete with a full bill of materials, sourcing/part # info (this saves hours!), chassis templates, and more. A big tip o' the hat to Doug, Chris & John! :AOK: :bravo: :dude:

[sunvalleylaw]

Hmm, what cab would you pick to run with it? Would one of those sale ones from a few months back do a good job?

[duhvoodooman]

I expect I'll use it extensively with both the 1x12 I assembled myself (http://www.thefret.net/showthread.php?t=4242) and the 2x12 Drive cab (http://www.thefret.net/showthread.php?p=49638#post49638) I bought during that insane Music123 close-out sale. A 4x12 would probably sound great, but it's getting a bit ridiculous to be playing a 1.5W through a cab that size! Not that it would stop Tone.... ;) :rockon:

[Tone2TheBone]

I wanna see what that circuit would like like in one of M29's amp head creations!

ps - you're right Bob nothing stops me moo ah ah ah

[abraxas]

Wow!!! :bravo:

That sounds great!!! :AOK:

[mrmudcat]

Not to thread hijack but after having god awful (still have) internet problems lately(upgrading system:whatever: ) I got to post fast no time for a big thread.:D You have given me the bug to do my own SKYDOG project.I think im going with package 2 all the parts just assemble.Im going to do a special cab:smile-us: Vood if I dont hear from ya or vice versa we are still on with book and pedal:beer:

http://www.ceriatone.com/productSubPages/BSPlexi50Bass/BSPlexi50BassKits.htm

[duhvoodooman]

WOO WOO WOO!!!! Finished the Firefly build and fired it up Saturday evening--worked the first time!! :dude: The chassis hasn't been painted yet, but it looks pretty cool just the same. Here are some pics, below. Haven't had much chance to play through it yet (out last night at a school function and at church this morning, and now my daughter's asleep on the family room couch!), but the little sucker screams, especially with the boost enabled (insert evil grin/maniacal laughter here). :rockon:

Looking across the front panel from left to right, it's the input jack, boost switch, boost gain, main gain, standby switch, power switch and power indicator light.The power transformer is the larger black one on the right, and the output tranformer is to its left. The tubes (l to r) are boost (12AX7), main preamp (12AX7), and power stage (12AU7).

Will post a clip or two when I have a chance....

http://duhvoodooman.com/miscimages/musical/ffly/ffly_assembled_front.jpg

http://duhvoodooman.com/miscimages/musical/ffly/ffly_assembled_top.jpg

http://duhvoodooman.com/miscimages/musical/ffly/ffly_assembled_under.jpg

[warren0728]

:drool: :bravo: :beer: :drool: :bravo: :beer:

[sunvalleylaw]

:drool: :bravo: :beer: :drool: :bravo: :beer:


Yeah, all of those, plus pancakes! I kinda like it all industrial and stainless looking. Kinda gives it a 50's tone scientist vibe!

[SuperSwede]

ooohhhhh! (and everything warren said)

[duhvoodooman]

Well, after spending a bit more time with this little dynamo, I must admit I'm pretty impressed. It can generate an unbelievable amount of volume considering it's power rating (I suspect that 1.5W is very conservative), and when you crank the boost gain, it has plenty of raunch on tap. And I haven't even really "opened it up" yet, because I haven't had the house to myself since I built it. But I will on Wed. night, and I'll try to record a demo clip then, too.

The only thing I don't particularly like is that it's a little dark sounding, at least at low volumes. The good news is that John Calhoun included an optional "brightness" capacitor spot on his PCB design, so I'm going to get two different value silver-mica caps and wire them to the board via an on-off-on DPDT switch. That'll give me three settings: normal, bright and brighter. That should cover it....

[oldguy]

Vood, that looks fantastic! You do nice work.
Thanks for the pics and updates, you are 'da MAN!!!:bravo:

[Jimi75]

Why didn't GOD give the talent to assemble small amps and pedals on my own?

This amp looks gergeous and the sound in the clip is killer. I can only look up to people like you - respect!

[duhvoodooman]

I can only look up to people like you - respect!
Funny, that's how I feel about you when I hear your guitar playing! Thanks for your generous comments, Jimi. Really--the building is easier than the playing!

[tot_Ou_tard]

I waited a bit to make sure that you really have built it now :D .

Looks beautiful as usual Vood!

Technically speaking, what makes the amp dark. Could you go into a little more detail about how a bright switch works?

You duh_man voodoo!

[duhvoodooman]

Technically speaking, what makes the amp dark. Could you go into a little more detail about how a bright switch works?

As I understand these things, and amp will sound dark if the circuit is laid out such that a large portion of the high frequencies are lost/bled off to ground during the course of amplifying the signal. This tends to be most pronounced at low volumes. Some amps are intrinsically dark sounding, while others are bright, or somewhere in between. Dark sounding amps are often modified in some way to give them more top end, with the addition of the famous "Top Boost" stage to the Vox AC30 being a well-known example. (Interestingly, that circuit was copied directly from an old 50's Gibson amp, right down to an error in the bass pot design!)

However, this can be done in other ways, notably by adding judiciously chosen capacitors to locations in the circuit where they can act as a bypass around points where high frequencies would otherwise be bled off. This works because of the the fact that the impedance of a capacitor varies inversely with frequency, so that at very high frequencies, a capacitor becomes a short circuit, and at very low frequencies, an open circuit. Now, exactly how you decide what capacitance rating to use in what circuit is still a mystery to me, but John Calhoun suggests something in the 200 - 450 picofarad range for the optional brightness cap in the Firefly. So I've ordered several silver mica caps in that capacitance ballpark and will see which I like the sound of best.

Clear as mud?

[Jimi75]

Funny, that's how I feel about you when I hear your guitar playing! Thanks for your generous comments, Jimi. Really--the building is easier than the playing!

Thank you :-)

[Tone2TheBone]

Holy Moley Voo that's the coolest thing I've ever seen! Let us know how the cap mods do.

[aeolian]

Very nicely done. It must be cool to play through an amp you build yourself.

[tot_Ou_tard]

As I understand these things, and amp will sound dark if the circuit is laid out such that a large portion of the high frequencies are lost/bled off to ground during the course of amplifying the signal. This tends to be most pronounced at low volumes. Some amps are intrinsically dark sounding, while others are bright, or somewhere in between. Dark sounding amps are often modified in some way to give them more top end, with the addition of the famous "Top Boost" stage to the Vox AC30 being a well-known example. (Interestingly, that circuit was copied directly from an old 50's Gibson amp, right down to an error in the bass pot design!)

However, this can be done in other ways, notably by adding judiciously chosen capacitors to locations in the circuit where they can act as a bypass around points where high frequencies would otherwise be bled off. This works because of the the fact that the impedance of a capacitor varies inversely with frequency, so that at very high frequencies, a capacitor becomes a short circuit, and at very low frequencies, an open circuit. Now, exactly how you decide what capacitance rating to use in what circuit is still a mystery to me, but John Calhoun suggests something in the 200 - 450 picofarad range for the optional brightness cap in the Firefly. So I've ordered several silver mica caps in that capacitance ballpark and will see which I like the sound of best.

Clear as mud?

I think you need to mod the above with a clarity boost ;)

Thanks Vood, that did help some.

[duhvoodooman]

I think you need to mod the above with a clarity boost....
Got a schematic? I could use one of those! :D

[duhvoodooman]

OK, here's a little sample of what the Firefly can do. I came across a posting at the AX84.com Firefly forum that said if you swap a 12AT7 for the 12AU7 power tube, it drops the max. power output but brings on an earlier breakup with a huge bottom end. Since I'm not using close to the max. output of this little monster, that sounded like a pretty good tradeoff to me. So I tried it through my 1x12 cab using my LP Std. and--WHAM--instant mini-Marshall stack sounds! Couldn't think of anything better to ram through it than some vintage Zep. Now, I'll never be confused for Jimmy Page, but playing aside, this sounded pretty good to me. Mind you, this is with NO effects other than a bit of plate reverb from my DigiVerb pedal. All the crunch comes purely from the amp. Here's the link:


http://www.box.net/shared/12u35riuck

[stingx]

SWEET!

I have GOT to build me one of these!

[ted s]

Crunchy Vood !, nice playing !

[F_BSurfer]

oh yea I like that mini marshall!!!!

[tot_Ou_tard]

Sweet is right Vood!!!!

[Adrian30]

That's a truly sweet sounding amp!

[sunvalleylaw]

Wowza!

[duhvoodooman]

Two additional notes:


Though the Firefly is really about tube distortion, it's not purely a one-trick pony. Nobody's ever gonna confuse it with a Fender Twin, but if I put the 12AU7 tube back in and run just on the main preamp with the boost stage off, it will do a pretty nice clean tone, too. I'll record another clip with my Strat when I have some time, showing the cleaner side of the amp.


If you liked the sound of that 1x12 cab, it's got one of those $45 Warehouse Guitar Speakers "Veteran 30" models in it, a Celestion Vintage 30 clone. Unbelievable value at that price, IMO.

[Katastrophe]

Strange... I posted a reply, and now my post is missing.:confused:

[oldguy]

That little sucker sounds great, Voodoo. You may have just built the least expensive boutique mini stack in existence!
:D :D

[Robert]

That is awesome, vood! What a fun project that must be for you! :AOK:
Cool happening tones, dude! I didn't know Jimmy Page came over to play it for you?

[duhvoodooman]

Strange... I posted a reply, and now my post is missing.:confused:
What did you say?? :confused: ;)

[Katastrophe]

Repost:


Couldn't think of anything better to ram through it than some vintage Zep. Now, I'll never be confused for Jimmy Page, but playing aside, this sounded pretty good to me.

You're right... Page plays sloppier.:master: The tone you're getting from the amph sounds very warm, even through my little computer speakers. Great stuff, DVM!

Added:

I wish I had your talent with electronics. Put a soldering iron in my hand, and somebody better have a paramedic on standby, with a bed waiting at the nearest burn center.;)

[Tone2TheBone]

SWEET!

I have GOT to build me one of these!

Hell yeah buddy that's what I told him. This is my next amp! Great job Voo! It's inspirational stuff mang!

[duhvoodooman]

Anybody interested in tackling this DIY amp project, refer to the resource links back in posts #1 and #10 in this thread. John Calhoun's PCB and detailed instructions (with full BOM/source/part # info) really make it quite straightforward! If you have basic electrical knowledge, decent soldering skills and can follow directions, this really isn't that hard to do.... :AOK:

[warren0728]

can follow directions
man....i was so close... :thwap: :rotflmao:

ww

[Robert]

Me too, I get lost all the time when driving. :(

[tot_Ou_tard]

Anybody interested in tackling this DIY amp project, refer to the resource links back in posts #1 and #10 in this thread. John Calhoun's PCB and detailed instructions (with full BOM/source/part # info) really make it quite straightforward! If you have basic electrical knowledge, decent soldering skills and can follow directions, this really isn't that hard to do.... :AOK:
Jeez...I gotta look at previous posts & *then* what?!?

Hoo boy! I've got enough trouble trying to replace a speaker :D .

[SuperSwede]

Me too, I get lost all the time when driving. :(

Me too! I really need (ok want) a GPS.

[luvmyshiner]

DVM, I've been giving some serious thought to trying my hand at this little project. I've downloaded the guide and reviewed it. My biggest concern as far as tackling the project is with cutting out the chassis. I think I can get the round holes ok, but I have concerns about the hole for the IEC outlet. Could you explain how you tackled that one?

Also, did you make the chassis yourself or use something commercially available? Thanks for the input.

[duhvoodooman]

I used a Hammond 1444-16 aluminum chassis (http://www.mouser.com/search/ProductDetail.aspx?R=1444-16virtualkey54600000virtualkey546-1444-16) that I ordered from Mouser.com. John Calhoun includes a template for this chassis (10"x6"x2") in his instructions.

Re: the holes, I handled eveything on the chassis with a regular drill set, except for the tube holes (got some panel punches from our shop here at work for those; worked great) and the IEC connector, which one of our shop techs cut out for me with a jigsaw.

[Tone2TheBone]

Hey Voo how are you going to handle putting the chassis in a brain head ermm I mean amp head? Some plywood and finish? Some plywood covered in tolex? I can't wait to see that baby when it's finished.

[tunghaichuan]

Re: the holes, I handled eveything on the chassis with a regular drill set, except for the tube holes (got some panel punches from our shop here at work for those; worked great) and the IEC connector, which one of our shop techs cut out for me with a jigsaw.

I have a set of Irwin Unibit stepped drill bits. Home Depot and Lowe's sell a set that includes a #1, two #3s and a #4. The #1 goes up to 1/2", the #3s go up to 3/4" and the #4 goes up to 7/8". This will cover most of your drilling needs. I like the Unibit brand as they drill nice round holes. Some of the cheaper knock-offs don't do such a good job. The Vermont American bit I have, for example, drills triangular holes when using a hand drill.

I was thinking of having a machinist make me a template out of 1/2" aluminum plate for cutting IEC connector holes. The Greenlee punch is about $250 Yikes! I've had good luck with using a template with a laminate trimmer and a flush cutting bit with a roller bearing. Cuts through aluminum like butter. The downside: you have to clamp the open end of the chassis down as the bit throws little aluminum chips all over the place. Also, you can't cut ferrous materials with the bit/template.

I've used this method to cut 1 & 3/8" holes in aluminum chassis. I bored a 1 & 3/8" hole in a 1/2" thick piece of MDF and use that as a guide with my laminate trimmer and flush cutting bit. I'm too cheap to pony up the cash for yet another Greenlee punch (I already own 5).

tung

[luvmyshiner]

Thanks DVM and Tung. That gives me a plan of attack.

[duhvoodooman]

Hey Voo how are you going to handle putting the chassis in a brain head ermm I mean amp head? Some plywood and finish? Some plywood covered in tolex? I can't wait to see that baby when it's finished.
Really haven't decided yet. Either plywood with a tolex/vinyal finish, or maybe just a nice wood enclosure, stained & urethaned. I'm really in no hurry, because (1) I'm enjoying playing the little sucker too much, and (2) I don't lug my stuff around, so there's really no functional need for an enclosure at this point. I'll get around to it eventually, and you know I'll post it here, when I do....

[Dreadman]

Cool, very cool.

I'm ordering parts tonight!

[Dreadman]

On second thought..........

I made a spreadsheet for the parts and realized it's going to be $170 just for the electronics. Add a chassis, case, speaker & misc. and we're talking $250-$300 for a 1.5 watt amp - unassembled. Too much for me.

If anyone wants the spreadsheet email me (I can't attach an .xlr file here, can I?). Copying and pasting makes ordering parts easier.

[duhvoodooman]

I made a spreadsheet for the parts and realized it's going to be $170 just for the electronics. Add a chassis, case, speaker & misc. and we're talking $250-$300 for a 1.5 watt amp - unassembled. Too much for me.

If anyone wants the spreadsheet email me (I can't attach an .xlr file here, can I?). Copying and pasting makes ordering parts easier.
Yeah, buying individual parts "a la carte" is rather expensive, but a big part of a project like this is the enjoyment of building it and the satisfaction in having YOUR own amp, when it's done. Not to mention the little sucker sounds great and is very flexible, with all the tube types you can swap in and out. And let me tell you--1.5W or not, this puppy can still be deafeningly loud in a small room! I typically play it with the boost gain at 50% and the main preamp gain at about 15%! Going up to 20% gets me yelled at!

BTW, I have the bill of materials/source/part # info all spreadsheeted, too. If anybody wants it, just shoot me a PM. IMO, this is the ONLY way to go for orders of more than a few items at Mouser.com. They have a BOM import function that lets you just copy part #'s and quantities into their form, and it fills out the entire order for you. Huge time-saver.

[Dreadman]

I hear ya about the enjoyment and satisfaction part for sure and I know tube watts are big. I think I developed a "less than a hundred" mentality early on.

Who knows, I could revisit the idea again.

Any idea what kind of quantities one must meet to make a substantial dent in the cost? Has this been discussed at any point as a forum project?

[just strum]

Any idea what kind of quantities one must meet to make a substantial dent in the cost? Has this been discussed at any point as a forum project?

I can hear the gears grinding in that head of yours all the way here in Ohio;)

[Dreadman]

LOL

My gears never grind - they always mesh smoothly.

[F_BSurfer]

One way someone might think about in the saving part is look at different lower cost transformers a couple you might check are

http://www.edcorusa.com/products/transformers/single_ended.html
and
http://www.musicalpowersupplies.com/
MPS is out of his se output transformers but is soon to have more and a couple more choices

[luvmyshiner]

Hey DVM, I ordered everything for the amph build this morning. A few parts are on back order, which is actually ok because I also ordered the Veteran 30 from Warehouse Guitar Speakers, and I'd like to build the cab before I build the amph so I have something to test it on.

I'm looking forward to many hours of playing around with this project, and I'll do my best to post lots of pics.

[just strum]

Hey DVM, I ordered everything for the amph build this morning. A few parts are on back order, which is actually ok because I also ordered the Veteran 30 from Warehouse Guitar Speakers, and I'd like to build the cab before I build the amph so I have something to test it on.

I'm looking forward to many hours of playing around with this project, and I'll do my best to post lots of pics.

You are going to have to supply us with a pictorial of the process.

1) Because it will be entertaining and informative

2) It didn't happen, if you don't have pics.

[tot_Ou_tard]

Hey DVM, I ordered everything for the amph build this morning. A few parts are on back order, which is actually ok because I also ordered the Veteran 30 from Warehouse Guitar Speakers, and I'd like to build the cab before I build the amph so I have something to test it on.

I'm looking forward to many hours of playing around with this project, and I'll do my best to post lots of pics.
Excellent!!!

How experienced are you with soldering etc?

This is one amph which you'll be able to lift no matter how bad your back gets Shiner.

[luvmyshiner]

You know there will be lots of pics Strum.:beer:

Tot, in my younger days I had an amateur radio license and did a lot of soldering. The last major soldering job was when I rebuilt this beast about 4-5 years ago:

http://i103.photobucket.com/albums/m159/luvmyshiner/P2230001.jpg

She had a buttload of broken solders that I had to repair to get her working. However, that has been awhile back. I need to take a picture of the circuit board for the computer guys on the Fret. They'll laugh their tails off. It's like, 2' x 3'.:rotflmao:

This is my soldering iron:

http://i103.photobucket.com/albums/m159/luvmyshiner/P2230002.jpg

It hasn't been used in awhile so I'll have to clean the tip and re-tin it. But I think as long as I take my time I should be able to handle it. My biggest concern is that the soldering iron might be too powerful for this task. Do y'all think I should get something with lower wattage or will this work?

[duhvoodooman]

WHOA!! :eek: You really don't want to use that beast on the little Firefly PCB. W-a-a-a-y too much power. That's a soldering gun, not an iron. Get yourself a little Weller 25W job, or similar.

BTW, let me know what's backordered, and I may be able to point you to alternative sources or part #'s....

[luvmyshiner]

Thanks DVM, I was afraid that was the case. But any excuse to buy a new tool is a good one.:beer:

If I haven't received the back-ordered parts by the time I finish the cab and the rest of the build on Firefly, I'll pm you.:)

[tot_Ou_tard]

Nice beast!!!

I remember watching Soylent Green as a kid & whoever was the hero (Charleston Heston?) was wealthy & had a Pong game in his *HOUSE*!!!!

I thought

"Man, that's rich!"

It still brings me smiles to think about how far video games have come since those days.

[Dreadman]

I recently broke down and bought a "cold heat" soldering iron and much to my surprise it works very well. It's cordless (battery powered), , heats instantly, solders well and gets cool enough to touch in just a second or two. Here's the one I got:

http://www2.northerntool.com/product/200324393.htm

I can also personally recommend Northern Tool. I've done a ton of business with them and it's always been great.

[just strum]

http://www2.northerntool.com/product/200324393.htm

I can also personally recommend Northern Tool. I've done a ton of business with them and it's always been great.

+1 I started using them on a few items after Dreadman recommended them to me and I have been 100% satisfied.

[mrmudcat]

Maybe ill venture down the cold road again.I bought one of those cheapy tv specials and it stopped working its first guitar build:whatever:

Chalked it up as gimmicky,Dread how is the one you got!:poke:

[Dreadman]

It's a pretty good tool. Not for big stuff at all but very good on circuit boards and the like. Good quality and seems like it will last. I haven't tried to solder to the back of a pot yet and I don't know if it's got the power for that but for only $30 it's good to have around.

[Dreadman]

I just did a quick test and it will solder a jack terminal very easily but not quite enough power for tha back of a pot. Interestingly, I left it on the pot for about thirty seconds to see if would even come close and after that test the tip stayed very hot afterward for over thirty more seconds.

[Jipes]

Well, on to the next project! This is a cool one. Mentioned HERE (http://www.thefret.net/showthread.php?t=4114) back in Sept. by then-new-member Tunghaichuan, I was immediately smitten with the idea of building it. All the info you need is available on John Calhoun's website (http://web.mac.com/calhoun/PCB/Firefly_PCB.html), where you can also purchase the PCB for the amp build for a very reasonable $19. If you want to hear what this little sucker is capable of, check out THIS CLIP (http://annex.ax84.com/media/ax84_m277.mp3). Sounds like a mini-Marshall stack, no lie!



Sounds really great Warm tone and nice crunch :bravo:

[luvmyshiner]

I got my first shipment from Mouser today, and I'm just like a kid at candy store. It's going to take me awhile to put this project together, but I'm looking forward to every minute of it. Now tell me, how cool is this!:bravo:

http://i103.photobucket.com/albums/m159/luvmyshiner/P2260001.jpg

[just strum]

did you get a 20w soldering iron to replace that branding iron you have now?

[luvmyshiner]

Not yet, but it's on the list. Along with the Irwin Unibit stepped drill bits that Tung recommended. But I'm planning on picking those up locally.

[just strum]

Not yet, but it's on the list. Along with the Irwin Unibit stepped drill bits that Tung recommended. But I'm planning on picking those up locally.

boy, I would use this opportunity to put a list of "Tools I need for this project" that is a little longer than that. Don't you need a radial arm saw, table jointer, router, Craftsman 250 pc socket set, Fender Strat and Marshall amp? I don't see you finishing this project without these essentials.

[luvmyshiner]

boy, I would use this opportunity to put a list of "Tools I need for this project" that is a little longer than that. Don't you need a radial arm saw, table jointer, router, Craftsman 250 pc socket set, Fender Strat and Marshall amp? I don't see you finishing this project without these essentials.

Hmmm, good point Strummy. HEY, isnt' Father's day, or . . . um Easter or . . . something coming up??? I gotta get Baby Girl posting over here so she can get present ideas.:beer:

[duhvoodooman]

Now tell me, how cool is this!:bravo:

http://i103.photobucket.com/albums/m159/luvmyshiner/P2260001.jpg
Certainly a familiar sight at my house, Shiner! :dude:

[Kazz]

Get those damn parts off the pool table Shiner....you are committing sacrilege lmao.

Love the asteroids game...I am looking for a pacman or mrs pacman game or asteroids game for our basement game room....and a full sized air hockey table to go along with the pool table we already have down there.

[ted s]

Looking good Shiner ! looking forward to reading/seeing the progress !

[tot_Ou_tard]

I Now tell me, how cool is this!:bravo:


Answer: d@mned cool indeed! :AOK:

[Rocket]

Get those damn parts off the pool table Shiner....you are committing sacrilege lmao.
That's the Sunday-company fancy eatin' table... just drop yer chicken bones in the holes.

[duhvoodooman]

Just a brief resurrection of this old thread just to underscore again what a cool little amp--and DIY project--the Firefly is....

I just finished a small modification to the amp, adding a rotary switch to the rear of the chassis that lets me easily change the rating of the power tube cathode resistor to one of four discrete values. I've acquired four different pin-compatible tube types that can be used for the power tube in the Firefly, and this allows me to dial in the right bias on each to get them up in the range of 85 - 100% of their rated dissipation values, where they sound their best. The four tube types are the 12AU7 (the "stock" Firefly power tube), 12AT7, 6BH7 and ECC99, and their dissipation ratings vary from 2.5 to 5.0W. The four cathode resistors wired to the switch vary between 220 and 510 ohm, a pretty wide range. Sunday night, I wired up the switch, and last night I ran all four tube types in the amp and checked the actual dissipation values vs. what I'd expected to see (they were all very close).

Naturally, I didn't just conduct my testing with a DMM--I also played a few licks with my LP Std. through each type to see how they sounded. In a word, GREAT! Though it will do a cleaner tone, this little bugger's forte is crunch--that vintage Marshall stack kind of tone from a tiny little package. I dial the Boost stage gain up around 80% and then use the main Preamp control to set the overall volume. The thing just nails that early Zeppelin-AC/DC-Who tone. Lawdy mama--have mercy!!

So I just wanted to encourage you do-it-yourselfers with a bit of prior electronics experience to give this amp project a shot. While I wouldn't recommend it for a rank beginner, you don't need a lot of experience to tackle this one, especially if you use John Calhoun's super PCB and outstanding build documentation. It won't break the bank, either--you can get all the parts you'll need for under $200. So far, the only Fretter I've seen who seems to be serious about building one of these little monsters is Luvmyshiner--and don't be too surprised if he changes his ID to "Luvmyfirefly" after he does!

As always, let me interject the required safety warning here: Working inside a tube amplifier exposes you to potentially LETHAL levels of DC voltage, so follow all recommended safety practices and BE CAREFUL. If you don't know what these are, you're better off not attempting such a project.

But if you understand how to work safely with high voltages and you love that Marshall crunch, by all means give this one a try. I promise you--you won't be disappointed!

[luvmyshiner]

Well, here's what I got done today. All the soldering is done. Tomorrow I get to start cutting out the box. I've really learned a lot. The first dozen or so solders were pretty rough. But then I got the hang of things. I'll keep y'all updated.

http://i103.photobucket.com/albums/m159/luvmyshiner/Cab%20build/P5170001.jpg

[ET335]

Looks like you have done a nice job putting that amp together Shiner.
Looks Great to me!:AOK:

[warren0728]

looking great shiner! :bravo: :beer:

ww

[Tone2TheBone]

Wow Shiner that deserves a beer or two! Great job!

[Kazz]

Ah come on now Shine.....you can't be excellent at everything you do....your wood working skills most around here would take out a hit contract for.

Soldering is a developed skill and one that the term if you don't use it, you'll lose it is very true....I have tried a few small soldering projects in the last few weeks and lets just say it was not like riding a bike....it took some trial and error.....tinning wires is one thing, but not producing a cold solder joint is another.....it's not for the weak of stomach LOL.


Turn that board over and let's see your joints. Knowing you for the last 2 years or so, I will be they are far above average :-)

I will be following this with great anticipation, as when Shiner does something he goes all the way, and I love that about him.

I am really digging the idea of a diy Marshall tone, just wish I had an extra 200 to spend.....but then again if I did...I would probably have an Epiphone Valve Jr that has been heavily modded from a local member sitting next to me already :-)


I do have a project in the works tho.....I got a Vox Wah from another forum member that I plan on modding a little after I record some baseline stuff with it.

Probably looking to add a Fasel inductor and something to clean it up a bit in the hotzone. The one thing I can say...if you think your electric lead tone is missing something and you are not quite sure what it is, get a Vox Wah....click in on and nail the pedal down......it is pure hair metal a great lead boost.

I now return you to your regularly scheduled programming :-)

[marnold]

Aren't you just the cutest little amp? Yes, you are! Yes, you are!

[duhvoodooman]

Lookin' aces so far there, Shiner! :AOK:

BTW, where'd you get the tubes and what kind?

[Mark]

Excellent work man!!

[just strum]

Aren't you just the cutest little amp? Yes, you are! Yes, you are!

Hmmm, the latest batch of brew must be ready.:D

[luvmyshiner]

Aren't you just the cutest little amp? Yes, you are! Yes, you are!

Snicker.:rotflmao:

DVM, I just ordered the JJ Electronics tubes from tubesandmore.com. But I did pick up both the 12AT7 and the 12AU7 to swap out like you suggested.

OK, here's a picture of the bottom. Let me know if y'all see anything that looks like a problem.

http://i103.photobucket.com/albums/m159/luvmyshiner/Cab%20build/P5190001.jpg

[duhvoodooman]

Looks very good from here, Shiner. I'd need a higher resolution than that to see the individual solder point quality, but there aren't any ugly ones evident. NICE JOB!! :AOK: :bravo:

[luvmyshiner]

Thanks DVM. I had to take it outside to get enough light, and its getting dark now. But tomorrow I'll jack up the resolution on the camera and try to get another shot.

I'd especially appreciate it if you took a look at the wires. It appeared to me that the red wire stayed in the bottom holes until they got to the power at the far left, then red went top (yup, that's technical talk y'all). That's the way I wired it, but I'd feel more comfortable if you confirmed that.

[just strum]

If I did that you would say nice job, but it would be because you would think I made a silver platter - no green to be seen:D

Nice job Shiner.

[M29]

Fine job there luvmyshiner fine job indeed:AOK:

M29

[duhvoodooman]

I'd especially appreciate it if you took a look at the wires. It appeared to me that the red wire stayed in the bottom holes until they got to the power at the far left, then red went top (yup, that's technical talk y'all). That's the way I wired it, but I'd feel more comfortable if you confirmed that.
I'm not sure it makes any difference. I kept the green on one side throughout, and the red on the other, including the power hookup end. But these are only the 6.3V filament heater wires, so I really don't think current direction matters, or the instructions would make a point of that. When you power up the first time (main power switch on, but the standby switch still off), the filament heaters should energize and glow orange in all 3 tubes. If they don't, no harm done--you'd just have to rewire it.

[luvmyshiner]

Well it's been awhile since I posted my progress, but I didn't want y'all to think I had forgotten this little project. I ran into some problems drilling out the box, but my son brought his Dremel down this weekend and I was able to finish the box. I haven't finished the final wiring yet because I'd like to paint the box, but I put everything together just to make sure it all fit ok. I have to say this thing is a lot heavier then I thought it would be.

http://i103.photobucket.com/albums/m159/luvmyshiner/Cab%20build/P6150002.jpg

[duhvoodooman]

Looks good, Shiner! :AOK: And VERY familiar!! ;)

When will the electrons flow??

[Katastrophe]

Very cool, Shiner! Are you going to build a wooden surround for the head to match the speaker cabinet? If so, you'd only have to paint the front of the head.

[Kazz]

Very cool, Shiner! Are you going to build a wooden surround for the head to match the speaker cabinet? If so, you'd only have to paint the front of the head.



Great Point Kat.......Shine would only need to paint the control panel side and I think a head cabinet that matches his speaker cab would look sharp.

[tot_Ou_tard]

Screw the paint ;). Wire it up Shiner; we want clips!

[luvmyshiner]

Hey Kat, I was planning on building a matching cabinet for it, and your suggestion sounds great!:AOK:

DVM, CB's Grandmother is coming in for a visit this week, and my daughter is coming in for a visit next week, so that may slow me down on a few projects. But be patient with me, I'll finish it up eventually:beer:

[luvmyshiner]

Even with the kids in town, I managed to paint the amph. Kat, I was going to just paint the front, but I've never been happy with the lines I get from tape. So I figured what the hell, and went ahead and painted the whole thing.

DVM, with the long weekend coming up, I'm hoping we'll have electrons flowing (or exploding stuff), before next Monday.:bravo: Keep your fingers crossed.:beer:

I really wanted to paint it black, but I want to label the controls, and I remembered what DVM said about keeping the color light enough to see the letters. So I compromised. The red is still pretty dark, but it's better than black.:D

http://i103.photobucket.com/albums/m159/luvmyshiner/Cab%20build/P6300009.jpg

[warren0728]

i like the red...it looks great!! :AOK: :beer:

ww

[ted s]

pretty sweet shiner!

[duhvoodooman]

Looks GREAT, Shiner!! :AOK:

Now....how will it sound?? :confused: ;)

[luvmyshiner]

Looks GREAT, Shiner!! :AOK:

Now....how will it sound?? :confused: ;)

Well, it's either going to sound really great, or it's going to sound like . . . psssszzt . . . BANG . . . . (smoke).:messedup:

[warren0728]

Well, it's either going to sound really great, or it's going to sound like . . . psssszzt . . . BANG . . . . (smoke).:messedup:
sig material right there folks!! :beer:

ww

[duhvoodooman]

Well, it's either going to sound really great, or it's going to sound like . . . psssszzt . . . BANG . . . . (smoke).:messedup:
The former, I'm sure! :dude:

[sunvalleylaw]

Looking super good! I like its cold war science era look. It looks like it would be comfortable with a 50's style robot with glass dome on the head twiddling its controls.



I am sure it will sound great! If it doesn't the robot could yell:

"Help me Will Robinson!" :D

But I am sure it will sound really great!

[stingx]

That looks FANTASTIC, dude! Cmon now with the clips...video is all bettah too btw...

[tot_Ou_tard]

Shiner it looks incredible.

I'm with sting.

Video when you first fire her up so we can either hear your ohh & ahhs or ahh shits depending on which way she goes.

[warren0728]

Video when you first fire her up so we can either hear your ohh & ahhs or ahh shits depending on which way she goes.
that's a great idea!! :bravo:

ww

[Katastrophe]

Even with the kids in town, I managed to paint the amph. Kat, I was going to just paint the front, but I've never been happy with the lines I get from tape. So I figured what the hell, and went ahead and painted the whole thing.

DVM, with the long weekend coming up, I'm hoping we'll have electrons flowing (or exploding stuff), before next Monday.:bravo: Keep your fingers crossed.:beer:

I really wanted to paint it black, but I want to label the controls, and I remembered what DVM said about keeping the color light enough to see the letters. So I compromised. The red is still pretty dark, but it's better than black.:D

http://i103.photobucket.com/albums/m159/luvmyshiner/Cab%20build/P6300009.jpg

Shiner, that's awesome! I wouldn't bother with a cab for that head now, it looks cool as is. :rockon:

[tot_Ou_tard]

that's a great idea!! :bravo:

ww
That way it won't be a total loss if she screaches &

EXPLODES!

catching your work bench on fire.

Imagine all the sincere Fretter concern (read gut-busting laughter) as you run around like the proverbial headless chicken trying to put out the flames only to catch your t-shirt on fire.

The best part will be when CB runs into the garage from the kitchen to save your a$$, if not your amph, by dumping a pitcher of sweet iced-tea on you & your firefly. :rotflmao: :rotflmao: :rotflmao: :rotflmao:

In other words...break a leg ;).

[Rocket]

Looks great... very 50's sci-fi.
You might have some RFI probs. If so, try some copper or gold plated screen... could still see through it and would look pretty cool with the red:

http://www.twpinc.com/images/categories/category/TWPCAT_11.jpg

[warren0728]

That way it won't be a total loss if she screaches &

EXPLODES!

catching your work bench on fire.

Imagine all the sincere Fretter concern (read gut-busting laughter) as you run around like the proverbial headless chicken trying to put out the flames only to catch your t-shirt on fire.

The best part will be when CB runs into the garage from the kitchen to save your a$$, if not your amph, by dumping a pitcher of sweet iced-tea on you & your firefly. :rotflmao: :rotflmao: :rotflmao: :rotflmao:

In other words...break a leg ;).

now that's funny....i don't care who you are! :bravo: :beer: :rotflmao:

ww

[Steve206]

Shiner,,

Very impressive...

Now,,,what is next? Do you build some kind of cover for it? Attach it to the cabinet somehow? Look like it might even fit into one of those elementary school lunch boxes? You know with the Jetsons or some other hanna-barbera celebrity painted all over it.

Steve

[luvmyshiner]

Thanks for all the kind comments y'all. I haven't made my mind up yet about the cab, but I like Rocket's suggestion about using copper screen. If I made a cab, I could cover the inside with the screen, but I think it might look even cooler if I made sort of a box out of the screen to fit on the top of the amph. At any rate, I think I may have found something that would work at a local craft store, I just need to make sure it's made of the right material.

As much as I'd like to post a video of the opening ceremony, good or bad, I lack the technology folks. Sorry. In fact, CB got quite upset with me last week because we couldn't record our little jam sessions with BG. I guess I need to ask for a microphone for my birthday or something.

[sunvalleylaw]

Coupla guitar mavens like you and CB, and BG has a major in the music arena, plus you are a lawyer and are bound to have computers, . . . you can do it man! Or you can just old school it and use the video camera with built in mic! Hook that thing up to the computer with a cable and you can put it on youtube in a few minutes. You can do it!

I am not sure I could do the wood working or amph building you have done, but YOU can do this! :) :beer:

[Childbride]

The best part will be when CB runs into the garage from the kitchen to save your a$$, if not your amph, by dumping a pitcher of sweet iced-tea on you & your firefly. :rotflmao: :rotflmao: :rotflmao: :rotflmao:



[snicker] if you use a coldbeer, you get kicked out of the Brotherhood. :rotflmao:

[tot_Ou_tard]

[snicker] if you use a coldbeer, you get kicked out of the Brotherhood. :rotflmao:
Yeah, why waste a cold one?

[warren0728]

Thanks for all the kind comments y'all. I haven't made my mind up yet about the cab, but I like Rocket's suggestion about using copper screen. If I made a cab, I could cover the inside with the screen, but I think it might look even cooler if I made sort of a box out of the screen to fit on the top of the amph. At any rate, I think I may have found something that would work at a local craft store, I just need to make sure it's made of the right material.

As much as I'd like to post a video of the opening ceremony, good or bad, I lack the technology folks. Sorry. In fact, CB got quite upset with me last week because we couldn't record our little jam sessions with BG. I guess I need to ask for a microphone for my birthday or something.
i think the entire enclosure out of the screen would be really cool.... :beer:

as for video taping....do you have a digital point and shoot camera with a movie mode? that would work just fine for such an event!! :AOK:

ww

[sunvalleylaw]

A rounded arch type enclosure out of the wire might look really cool and bring out the sci fi, cold war, art deco look of the tops of the tubes sticking up.

[Tone2TheBone]

Finally get to see your project from home Shiner and it's coming out dang good neighbor. I love that painted chassis.:beer:

[Kazz]

Very nice Shiner......what are you going to use to label the control panel?

[tot_Ou_tard]

A rounded arch type enclosure out of the wire might look really cool and bring out the sci fi, cold war, art deco look of the tops of the tubes sticking up.
Or an off axis ovoid.

[warren0728]

Very nice Shiner......what are you going to use to label the control panel?
a sharpie... :poke: :rotflmao:

ww

[luvmyshiner]

Very nice Shiner......what are you going to use to label the control panel?

I'll either be using those "rub on" letters or a fire extinguisher.:AOK:

[Steve206]

Is that what y'all call decals, down in Waco?

Steve

[luvmyshiner]

Finished wiring up the Firefly last night.

http://i103.photobucket.com/albums/m159/luvmyshiner/Cab%20build/P7050001.jpg

In the process I realized I made a mistake. The screw terminals for connecting the wires to the pcb were supposed to be soldered on the bottom of the pcb so they could be accessed after it was installed in the chassis. I soldered them on the top. No big deal, it just meant I had to connect all the wires before installing the pcb in the chassis.

So last night, about 9:00 pm, I plugged her in, and flipped the switch. No bang, no smoke, no explosion . . . no hum, no sound, no screaming solos, no nothin'.:thwap:

So I wisely decided to call it a night and take a look at her today with a fresh set of eyes. Turns out the problem wasn't with the amp, I had wired the input jack to the speaker wrong. Ok, good, simple fix. Wired everything correctly, flipped her on, and WOW!

The first thing I have to say is this little sucker is LOUD! I only had it turned up about a quarter of the way and windows were rattling. CB came running in the room because she thought a plane had just crashed in our house. I haven't played around with it enough yet to see what she can really do, but Shiner is one happy man.

So if you'll excuse me, I'm going to crack a beer, borrow CB's Strat, and go crank out a few screaming solos on my new toy!:beer:

[Katastrophe]

Sweet, Shiner! You're gonna have to nickname the Firefly something like "The Red Beast," or something similar. :bravo: :beer: :D

[Steve206]

Have to say that I consider it a treat when I get another installment on this project. One of those everyman things done by one of our own. Causes me to think that I could do something close???

Now that you have finished the build and have a speaker cabinet waiting, it seems like a good time to hear what is going on down there??

Steve

[luvmyshiner]

Sweet, Shiner! You're gonna have to nickname the Firefly something like "The Red Beast," or something similar. :bravo: :beer: :D

"Shiner's Red Beast" . . . I kinda like that Kat.:bravo:

Sorry Steve, still can't post clips yet, but give me a little time.

And I'm still saying, if this thing is only 1.5 watts, I'll quit drinking.:rotflmao: CB's already getting very nervous about the neighbors calling the cops. I'm going to try one of the acoustics through it in a little bit and see what I get.

[tot_Ou_tard]

Call it

The Shining

All acoustic & no amph makes Jack a dull boy.

[ibanezjunkie]

wouldnt 2 x 12AX7s and a 12AU7 give out a higher wattage than 1.5 watts? this has more valves in it than my 5 watt.

[tunghaichuan]

wouldnt 2 x 12AX7s and a 12AU7 give out a higher wattage than 1.5 watts? this has more valves in it than my 5 watt.

Not necessarily. The power tube in the Firefly is a 12AU7, which is really more of a preamp tube. It is a dual triode like the 12AX7. The 12AU7 just happens to have some characteristics to allow it to be used as a power tube in this application. It only puts out 1.5 wattts in the circuit due to its characteristics.

tung

[ibanezjunkie]

Not necessarily. The power tube in the Firefly is a 12AU7, which is really more of a preamp tube. It is a dual triode like the 12AX7. The 12AU7 just happens to have some characteristics to allow it to be used as a power tube in this application. It only puts out 1.5 wattts in the circuit due to its characteristics.

tung

well using a preamp tube as a power tube wouldnt have come to me...but i guess its an idea that works:AOK:

[heatherd66]

Mesa Boogie Express 112 5:25 Tone demo Mic: http://play.kendincos.com/174562/Wrvnrdhjnvzvzrv-mesa-boogie-express-112-5-25-tone-demo-mic.html

[stingx]

:pancake

[Katastrophe]

Wow, there are quite a few members on this thread that don't post much anymore... since it was started four years ago. Stingx, wanna take bets that "heatherd66" is never heard from again?

[duhvoodooman]

Resurrecting this ANCIENT thread, since I finally got a proper cabinet to install this nifty little amp head into! Since I am totally lacking in woodworking skills, the "nekkid" chassis had been sitting in my man-cave for the past SIX YEARS getting minimal use, 'cuz you have to be VERY careful handling exposed high-voltage electronics! Somewhat serendipitously, I discovered that one of my fellow moderators at the BYOC forums makes a mean head cab! And when I asked him about getting one made, he said he had one he'd just finished for a Champ build that had the exact same chassis dimensions! And he was nice enough to sell it to me, instead! Check out the head mounted in this beautifully made little cabinet in the pics below. I still need to paint & decal the front & back panels, but at least the amp is fully usable now:

http://www.duhvoodooman.com/miscimages/musical/ffly/cab/ffly_cab_back_open.jpg

http://www.duhvoodooman.com/miscimages/musical/ffly/cab/ffly_cab_top_empty.jpg

http://www.duhvoodooman.com/miscimages/musical/ffly/cab/ffly_cab_front_mounted.jpg

http://www.duhvoodooman.com/miscimages/musical/ffly/cab/ffly_cab_back_mounted.jpg

[marnold]

Looks sharp, DVM!

[Monkus]

love it !

[Robert]

Cool, looks like an old Traynor or Garnet!

[Monkus]

that looks supremely vintage... good things come to those who wait?. :D

[Jipes]

Great little amp for recording !

[The Grand Vizier]

Cool amp no doubt.
I do not understand why more amp companies don't build one watt tube amps, they are such a great tool for bedroom players/practise, recording etc.

I have a Blackstar one watt head that I purchased a fair while back & find it to work well for most music genres that I am into.
I messaged TC Electronics recently & posed the same question & they replied & said they had passed it on to the "think tank"

Anyone own or played through one of these Palmer amps?
http://www.youtube.com/watch?v=0QRVUSa4-vo