Guess what I'm building....

[duhvoodooman]

....finally:

http://duhvoodooman.com/miscimages/musical/18W/18W_pop_board.jpg

[marnold]

I think I'm going to have a coronary! Forget the Mayans, this is a sure sign of the apocalypse! Repent, I tell you, repent!

[Tig]

About time!!!
:pancake

[Spudman]

Resistor test board?

[bcdon]

Resistor test board?

Far more than that, it also test capacitors!

[Ch0jin]

Cool! I actually got started on my JTM45 project over the weekend too! I received my transformers recently and over the weekend I stripped the old amp out of the chassis and started marking out all the new cuts.

Nice job on the board. Very neat and tidy.

[duhvoodooman]

Here's the loaded chassis. Now the long, tedious wiring process begins....

http://duhvoodooman.com/miscimages/musical/18W/18W_loaded_chassis.jpg

[Katastrophe]

I think I'm going to have a coronary! Forget the Mayans, this is a sure sign of the apocalypse! Repent, I tell you, repent!

+1.

Glad you're getting to it! I'm gonna enjoy the pics on this thread.

[Ch0jin]

I really can't get enough of amp building threads /me grabs cyberpopcorn

I might be able to help you feel better about the impending tedium of wiring too. I'm not going to thread hijack, but have a gander at what I've got as a starting point now I've all but gutted it. (need to drill out those octal sockets)

http://members.iinet.net.au/~ch0jin/stuff/IMG_8158.JPG

EVERY hole on this chassis is in the wrong spot for a JTM45 layout. Even the chassis mounts in the cab upside down compared to a Marshall. I already butchered the chassis once in the 90's, so by the time I'm done she'll be like Swiss cheese!

At least yours is beautiful and clean and shiny and all the holes are in the right spot :)

[kiteman]

Let me guess... you're building an amp! :cool:

[Commodore 64]

I started drilling out a Hammond 16x8x2 box (for a 5E3 based on the PPwatt PCB) yesterday, too. Amp building is in the air! I'm using MPS Transformers, so I'll be able to give you guys a good review of a reasonably priced OT and PT.

My biggest question now is whether to use Orange Drops or Mallory 150s. I've got plenty of both.

[duhvoodooman]

I'm not going to thread hijack, but have a gander at what I've got as a starting point now I've all but gutted it.
Start a thread on your build, too! Will be interesting to compare my "brand new" build and your "old amp transformation".


My biggest question now is whether to use Orange Drops or Mallory 150s.
Conventional wisdom says OD's for Fender circuits, Mallory's for Marshalls. Then again, what the heck do those convention guys know, anyway?!? ;)

[R_of_G]

It's amazing to me that you guys can build this stuff. I can barely play my guitar let alone build new gear for it. Keep the pics coming!

[tunghaichuan]

It's amazing to me that you guys can build this stuff. I can barely play my guitar let alone build new gear for it. Keep the pics coming!

I taught myself how to build this stuff to substitute for lack of musical ability. I never really got anywhere on the guitar when I practiced, so I went off into collecting stuff, and then building other stuff. It was easier than making myself sit down and practice on a regular basis.

[piebaldpython]

It's amazing to me that you guys can build this stuff. I can barely play my guitar let alone build new gear for it. Keep the pics coming!

+1........Oh yeah, I'm totally in awe. DVM built 4 or 5 pedals for me and I had occasion to look inside one of them and it was so nice and clean......and meticulous. Nothing but the utmost respect for you pedal/amp builder guys.

[Ch0jin]

Start a thread on your build, too! Will be interesting to compare my "brand new" build and your "old amp transformation".


Oh I absolutely will! All I have right now is chassis and iron. When the rest of my bits start arriving I'll get a build thread happening. Just wanted to make you feel better about the wiring job ;)

Oh and re: C64's comment, That's exactly what I read around the place too.

[duhvoodooman]

Some more progress last night--mounted the board into the chassis and wired in the mains, fuse, PT connections, rectifier socket, and associated switches. More pics:

http://duhvoodooman.com/miscimages/musical/18W/18W_chassis+board.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_power_wiring.jpg

[cebreez]

WHAT??!!?? I hate getting to the last pic and then .... well ... NOTHING! What I can't believe is that you guys not only do some beautiful work but you take time to photograph it. I keep meaning to but get so focused on the build that I don't stop for pics.

Nice job duhvoodooman! Any mods or is this a straight build?

[duhvoodooman]

Any mods or is this a straight build?
Stock 18W TMB, at least to start.

[bcdon]

That is excellent looking solder work!

[duhvoodooman]

Thanks, Don. Lord knows I’ve had enough practice! :thwap

[Tig]

Looks great.
Remember, "failure is not an option"!

http://content.artofmanliness.com/uploads/2009/07/genekranz.jpg

[Robert]

I only have one word.

Finally

[duhvoodooman]

Remember, "failure is not an option"!Awright, Gene Kranz! :AOK Lemme go find my white vest for tonight's solder-fest!


I only have one word.... And I have TWO words for you.... ;)

[Robert]

Awright, Gene Kranz! :AOK Lemme go find my white vest for tonight's solder-fest!

And I have TWO words for you.... ;)


Funny Owls?

[duhvoodooman]

Funny Owls?Close enough....

Next photo--completed wiring for tube sockets (except shielded cable for inputs), output impedance rotary switch (4/8/16), and speaker jacks:

http://duhvoodooman.com/miscimages/musical/18W/18W_tube+output_wiring.jpg

[Commodore 64]

Man you are cruisin' along. I gotta wait until the weekend to get some work done...

[sunvalleylaw]

It's amazing to me that you guys can build this stuff. I can barely play my guitar let alone build new gear for it. Keep the pics coming!


+1! Love it!

[duhvoodooman]

Man you are cruisin' along. I gotta wait until the weekend to get some work done...Yeah, it’s coming along pretty well. Been putting in an hour or two the past couple of evenings and getting a fair amount done, even at a slow & careful pace. At this point, I just have to wire the control pots and input jacks, and then run the shielded input cables down to make the preamp tube connections. After that, it’s just a thorough check of all the connections and then start plugging in tubes and applying power! I already tested the mains, PT and rectifier function, so it’s just the preamp and output stages that I’ll need to go through.


It's amazing to me that you guys can build this stuff.I assure you, it’s really not as hard as it may look. You need good soldering skills, for sure, but if you get a good quality kit with detailed instructions, it’s just a matter of following them carefully. Many of these amp kit companies have forums or other technical support resources on their web sites. Trinity Amps, where I bought this kit, has a such a forum, with a bunch of good technical info and step-by-step build photos. And if you run into a problem that you can’t find the answer to, you can post and ask for assistance.

[Monkus]

Looking great DVM!

[Commodore 64]

Are all your resistors Carbon Comp?

[ZMAN]

Looks very exciting. I may have missed something but what type of amp will it be? I really only have Fender or Marshall as reference points. Will it be a head or a combo?
I guess this is what they refer to as "point to point" wiring?
After having a couple of situations arise lately where some soldering experince would come in handy I feel I should look into a decent iron kit.

[duhvoodooman]

Are all your resistors Carbon Comp?Most, but not all. There are a couple of metal oxides and ceramic wire-wounds in the high DC voltage portions of the circuit, one metal film across a couple of the pins of V2, and the four 68K input resistors are carbon films. But the rest of the resistors in the signal path are all carbon composite. I assume they were chosen for "historical accuracy" to the original Marshall 18W circuit. Personally, I would have chosen metal film for their tighter tolerance and reduced thermal noise, but then there's a whole crowd who extol the "warmth & mojo" of carbon comps and deride the "sterility & lack of character" of metal films. Personally, I think it's BS, but "opinions vary", as they say....


I may have missed something but what type of amp will it be? Will it be a head or a combo? I guess this is what they refer to as "point to point" wiring?It's a Marshall 18W clone, and will be a head. Two channels, Normal and TMB (treble-mid-bass), with one high and one low input jack on each channel. I bought the kit in December 2009 (yeah, you read that right....) from Trinity Amps in Ontario and finally got around to building it. Yes, this is point-to-point wiring, using a turret board.

[Commodore 64]

Yeah, the most plausible thing I can figure from reading the intarweb is that carbon comps can distort in the 2nd harmonic when there's a high voltage across them (which may be construed by some as "warmth or mojo"). So, in the signal path with high voltage (plate resistors) would be a good spot.

[Tig]

but then there's a whole crowd who extol the "warmth & mojo" of carbon comps and deride the "sterility & lack of character" of metal films. Personally, I think it's BS, but "opinions vary", as they say....

Silly cork sniffers
http://wwwdelivery.superstock.com/WI/223/1773/PreviewComp/SuperStock_1773R-3330.jpg

[Ch0jin]

...... Personally, I would have chosen metal film for their tighter tolerance and reduced thermal noise, but then there's a whole crowd who extol the "warmth & mojo" of carbon comps and deride the "sterility & lack of character" of metal films. Personally, I think it's BS, but "opinions vary", as they say....


Why not meet half way and use Carbon Film ;) Given the propensity for variation in sound between different tubes, I'd not be losing too much sleep over the choice of resistors, and I'm quite sure you aren't either :)

(I ordered Carbon Films for mine. We'll see how they go when they arrive)

Looking good though DVM! What kind of speaker cab are you planning on running it into?

[bcdon]

But the rest of the resistors in the signal path are all carbon composite. I assume they were chosen for "historical accuracy" to the original Marshall 18W circuit. Personally, I would have chosen metal film for their tighter tolerance and reduced thermal noise, but then there's a whole crowd who extol the "warmth & mojo" of carbon comps and deride the "sterility & lack of character" of metal films. Personally, I think it's BS, but "opinions vary", as they say....

This quest for 'historical accuracy' in amps brought to mind a quote from Randall Smith, founder/designer at Mesa Engineering.



http://www.mesaboogie.com/Reviews/guitarist-F-50/Designing_f-50.htm
But as I came up 30 years ago, I wanted to take what I had been repairing for years and try to kick it up to another level and satisfy the wishes I kept hearing from the players I knew. They weren’t all that stoked with what we would now consider vintage treasures. They saw sonic limitations and they wanted more from their amps. That quest led to ...

[duhvoodooman]

DONE!! Finished it up last night. Fired up perfectly first time. Sounds great--LOUD!! More on that later, but here are the latest batch of photos (don't have final lead dress done w/ wire ties, so don't gig me on that!):

http://duhvoodooman.com/miscimages/musical/18W/18W_controls+input_wiring.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_full_gut.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_top_front.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_top_back.jpg

[Tig]

Wow, that looks top notch!
:applause

[Commodore 64]

It really does. Very nice. I'm amazed how fast it went together (once you got started ;) ).

[bcdon]

Well done. That looks so nice. What I find so amazing is that such a simple circuit made from discrete components can do so much and produce such art. Bravo! :dude

[duhvoodooman]

What kind of speaker cab are you planning on running it into?I have a Drive ported 2x12 cabinet (http://www.duhvoodooman.com/miscimages/musical/Drive_cab_front.jpg) that I loaded with an Eminence Red Coat Wizard and a WGS Green Beret (Greenback clone). The cab has a definite British edge to it, so should match up well.

[Katastrophe]

Beautiful, clean work you did there, DVM! Congrats on completing the project!

[Blaze]

Wow !! that's a beauty ..You finaly did it DVM.. Great job as usual ..I m sure you will love it ..

Congrats ..

Obviously an audio Clip is a must !!

[Monkus]

Looks flawless DVM, great job....clips?

[deeaa]

Pro Work dude!

Sent from my HTC HD2 using Tapatalk

[duhvoodooman]

Last couple of photos--mounted in the head cabinet, which I also bought from Trinity. Was in a blond mood that day:

http://duhvoodooman.com/miscimages/musical/18W/18W_cab_front.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_cab_back.jpg

[marnold]

I think the question that is on everyone's mind is: Will it give me screaming solos?

[duhvoodooman]

I think the question that is on everyone's mind is: Will it give me screaming solos?This amph will most definitely give you screaming solos. Particularly on the high input to the TMB channel, with the gain cranked up around 8.

I will try to post a clip. Hopefully, it will take me somewhat less time to do so than it did to get started on this amp....er, amph.

[Nelskie]

Considering the length of the build time, could this now technically qualify as a "vintage" amp . . . ?? :poke

Seriously nice build there, DVM - just as I'd expect. Cheers.

[marnold]

Considering the length of the build time, could this now technically qualify as a "vintage" amp . . . ?? :poke

Seriously nice build there, DVM - just as I'd expect. Cheers.

Well, DVM himself qualifies as "vintage" so . . . *ducks*

Good to hear from you again, Nelskie!

[duhvoodooman]

Considering the length of the build time, could this now technically qualify as a "vintage" amp . . . ??
Well, DVM himself qualifies as "vintage" so . . .

To both comments, I respond with the words of former Vice-President Spiro T. Agnew: "Nolo contendere"

Good to see you here, Jon!

[ZMAN]

Absolutely stunning!

Last couple of photos--mounted in the head cabinet, which I also bought from Trinity. Was in a blond mood that day:

http://duhvoodooman.com/miscimages/musical/18W/18W_cab_front.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_cab_back.jpg

[ZMAN]

If you don't mind me asking what tubes did you use. The recommended " The Tube Store" on the Trinity Web site is just down the road from me. I have bought several tubes from the. I am one of the few people who have used there walk up sales desk.

[duhvoodooman]

If you don't mind me asking what tubes did you use. The recommended " The Tube Store" on the Trinity Web site is just down the road from me. I have bought several tubes from the. I am one of the few people who have used there walk up sales desk.The EZ81 rectifier came from our own Tunghaichuan (tip-o-the-hat....a very generous guy!), but the rest are JJ's from Eurotubes.com. Bob & the gang do a great job over there--super service and excellent pricing. And I've had good luck with JJ tubes.

[otaypanky]

Sweet build DVM :)

[duhvoodooman]

UPDATE 2/29/12:

To tame the output volume while maintaining the nice Marshall crunch, I bought a voltage reduction module (VRM) kit from Trinity Amps and installed it. These units install on the DC rail of the amp and let you drop the DC voltage while the AC filament heater voltage remains unaffected. They have the reputation of doing a great job of reducing the output volume without a significant amount of tone loss, which is a common complaint with external attenuators. For a cathode-biased amp like this 18W, it's a very straightforward installation, and it works exactly as advertised. I can dial down the DC voltage enough to run the preamp gain up all the way and the master volume high enough to get some nice power tube saturation, and still keep the volume to a non-lethal level! Pretty slick little modification!

Couple of photos below. The VRM consists of a MOSFET mounted against the chassis (with an insulator pad in between) to facilitate heat dissipation, a small PCB with a handful of components, and a 1M pot to control the DC voltage output. It's wired in between the standby switch and the first filter cap, and I have the control pot mounted through the back of the chassis, between the mains connector and the output impedance selector switch. The Trinity kit also came with a couple of DC blocking caps for the inputs to the first preamp tube, in case you find that the volume pot(s) on your guitar pick up some scratchiness. This can happen due to a very small amount of low voltage DC current getting back to the guitar controls through the input jacks when the voltage is cranked way down, but I haven't had to install those on mine.

http://duhvoodooman.com/miscimages/musical/18W/18W_gut+VRM.jpg

http://duhvoodooman.com/miscimages/musical/18W/18W_VRM.jpg

[Ch0jin]

Nice one. Am I right in thinking this amp doesn't have a master volume hence the need for the VRM? I considered a similar approach for my JTM45 project, but instead went for a Lar/Mar style MV setup. Hopefully that works!

[duhvoodooman]

Am I right in thinking this amp doesn't have a master volume hence the need for the VRM? Yes and no. The Normal (low gain) channel is non-master volume, but the TMB (high gain) channel has Gain (preamp) and Master Volume controls. The problem is that it's one of those MV controls where it goes from silent to ear-bleeding loud between 0 and 2. So the VRM actually lets me dial the MV control up far enough to get some power tube saturation before it's so loud that my brains start leaking out of the holes in my head....

[Nelskie]

I will try to post a clip

The natives are restless, dude. Fire that 18W blonde up and get down to it! :poke

[sunvalleylaw]

Holy voice from the past Nelsk!!! Great to hear from you!


BTW, I agree with you wholeheartedly. DVM, let's rawk!

[marnold]

The natives are restless, dude. Fire that 18W blonde up and get down to it! :poke

I call shenanigans. I think the amph is still in parts at his house. The pictures are just a very creative use of crayons and Photoshop. :poke

[Nelskie]

. . . tick . . . tock . . . tick . . . tick . . . tock . . . tick . . . tock . . . tick . . . tock . . . tick . . . tock . . .