Tweed Champ (5F1) in Europe?

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Hello, I'd like to buy a 5F1 Tweed Champ style amplifier in Europe.
I'd like to stay below 600 EUROs (roughly $800), shipping and taxes included. I'd like a nice speaker in it (a Jensen P8R maybe), and want it to be wired point-to-point.

My first choice would be a Victoria 518 or 5112, but with shipping to Europe and custom taxes it would be several hundred dollars more expensive than what I can afford at the moment. My second choice would be a Fender 57 Champ reissue, but that's also quite pricy (in Europe it costs about 900 EUROs).

I found this kit at a store in Germany ("Tube Amp Doctor"):

http://www.tubeampdoctor.com/english-store/Amp-Kit-Tweed-Champ-Style-5F1-pid-840.htm

but with shipping and a speaker (not included in the kit) it comes to almost exactly 600 EUROs. The problem is that I've only built pedals so far, I don't own a drill which seems to be required, I'm afraid I might electrocute myself, and while I have some soldering experience, I don't trust my cabinet work skills. And the price doesn't allow me room for paying somebody else to build the kit.

Does anybody know where an already built 5F1 Tweed Champ clone can be bought from, either in Europe, or cheap enough from the US (yes I'm also considering eBay :) )?

Thanks!

[tunghaichuan]

If you're looking for something that looks and sounds like a real 5F1 tweed Champ, then that kit from the Tube Amp Doctor is probably your best bet.

You might take a look at this kit:

http://ceriatone.com/productSubPages/ACChampUltra/ACChampUltra.htm

That kit is a bit more complicated than the TAD kit, but it is more versatile tone wise. It doesn't look like a real 5F1, but it should be able to cop the tone. You'd have to convert the prices your Euros, though. And it does come with a head shell so you'd have to have your own speaker cabinet.

One of the main limitations of the original tweed Champ is the small speaker and cab. If your going for that sort of tone, then the TAD kit would be better.

Mojotone does make a kit, but it is like $500 before shipping. American-made products tend to be very expensive.

Really, the 5F1 amp is as simple as it gets. Any simpler and it isn't a guitar amp. Those amps are not hard to build, but if it doesn't power up the first time it could be hard to debug if you don't have the necessary trouble shooting skills. .

As for a drill, maybe you could borrow one?




Hello, I'd like to buy a 5F1 Tweed Champ style amplifier in Europe.
I'd like to stay below 600 EUROs (roughly $800), shipping and taxes included. I'd like a nice speaker in it (a Jensen P8R maybe), and want it to be wired point-to-point.

My first choice would be a Victoria 518 or 5112, but with shipping to Europe and custom taxes it would be several hundred dollars more expensive than what I can afford at the moment. My second choice would be a Fender 57 Champ reissue, but that's also quite pricy (in Europe it costs about 900 EUROs).

I found this kit at a store in Germany ("Tube Amp Doctor"):

http://www.tubeampdoctor.com/english-store/Amp-Kit-Tweed-Champ-Style-5F1-pid-840.htm

but with shipping and a speaker (not included in the kit) it comes to almost exactly 600 EUROs. The problem is that I've only built pedals so far, I don't own a drill which seems to be required, I'm afraid I might electrocute myself, and while I have some soldering experience, I don't trust my cabinet work skills. And the price doesn't allow me room for paying somebody else to build the kit.

Does anybody know where an already built 5F1 Tweed Champ clone can be bought from, either in Europe, or cheap enough from the US (yes I'm also considering eBay :) )?

Thanks!

[red]

If you're looking for something that looks and sounds like a real 5F1 tweed Champ, then that kit from the Tube Amp Doctor is probably your best bet.
Yep, looks like it. Another thing that worries me about a kit (besides getting electrocuted, etc.) is that it's resale value is very very low compared to the initial cost.

I've actually emailed the TAD guys and asked for a quote if they build the kit themselves and ship the finished product to me, and they came up with 260 EUR for the build alone (that's roughly $350). Would that be a reasonable price for that sort of thing, or just their way of telling me no without saying no?


You might take a look at this kit:

http://ceriatone.com/productSubPages/ACChampUltra/ACChampUltra.htm

[...]

Mojotone does make a kit, but it is like $500 before shipping. American-made products tend to be very expensive.

The Ceriatone is roughly the same ammount before shipping too, if I get a cabinet and everything from them.

As for American-made products and their prices, I'm finding out the hard way that they're actually not that expensive compared to the alternative. The quote for the pre-built TAD kit I've got from them was 823 EUROs for the amp + 22 EUROs for shipping, and a Fender 57 Champ is 900 EUROs in Europe. A Victoria 518 is 990 EUROs. So if I'd really have no choice but to get up in the 800+ EUROs, I'd rather get something that will keep it's resale value rather than some noname kit.


Really, the 5F1 amp is as simple as it gets. Any simpler and it isn't a guitar amp. Those amps are not hard to build, but if it doesn't power up the first time it could be hard to debug if you don't have the necessary trouble shooting skills. .

As for a drill, maybe you could borrow one?
Obviously, the drill is not the main problem, but rather just one in a series of shortcomings I feel I have as a builder.

I guess the only way that financially makes sense (though sense doesn't seem like a word I should continue to use in connection with this thing) is to get the kit, try to get it right the first time, when there are no dangerous voltages in the caps, etc. - and if I screw up get it to a tech to fix it, which would hopefully cost less than the build would.

[tunghaichuan]

Yep, looks like it. Another thing that worries me about a kit (besides getting electrocuted, etc.) is that it's resale value is very very low compared to the initial cost.


If that is a major consideration, then I wouldn't build a kit. Most of the time you're lucky if you can get half of what you put into it. Looking at it from a buyer's point of view, they don't know how skilled the person doing the assembly was. They don't know if there are any hidden problems, or even potential problems.



I've actually emailed the TAD guys and asked for a quote if they build the kit themselves and ship the finished product to me, and they came up with 260 EUR for the build alone (that's roughly $350). Would that be a reasonable price for that sort of thing, or just their way of telling me no without saying no?


That's a fair price. It takes a while to build one of those amps, despite the low level of complexity. Figure it takes at least 10 hours or so. At the minimum, the tech is making $35/hour which isn't bad. Of course the longer it takes, the less the tech makes but I think someone who has build that amp several times before and is used to working on amps should be able to crank that circuit out in 10 hours or less.



The Ceriatone is roughly the same ammount before shipping too, if I get a cabinet and everything from them.


So really, it depends on your needs/desires. Do you want a fairly accurate replica? Do you want a versatile tone machine? Will the small speaker be okay tone wise? Etc.



As for American-made products and their prices, I'm finding out the hard way that they're actually not that expensive compared to the alternative. The quote for the pre-built TAD kit I've got from them was 823 EUROs for the amp + 22 EUROs for shipping, and a Fender 57 Champ is 900 EUROs in Europe. A Victoria 518 is 990 EUROs. So if I'd really have no choice but to get up in the 800+ EUROs, I'd rather get something that will keep it's resale value rather than some noname kit.


If resale is important to you, and it seems like it is, you might look for a used Victoria or Fender amp. Either is going to keep a fairly high resale value, unlike the kit amp, which you will take a big hit. It will never be worth anywhere near what you paid for it. You may be able to find a decent used Fender or Victoria.




Obviously, the drill is not the main problem, but rather just one in a series of shortcomings I feel I have as a builder.

I guess the only way that financially makes sense (though sense doesn't seem like a word I should continue to use in connection with this thing) is to get the kit, try to get it right the first time, when there are no dangerous voltages in the caps, etc. - and if I screw up get it to a tech to fix it, which would hopefully cost less than the build would.

That is a good way to go, but only if you are 100% sure you will build it correctly. The problem is that if you make a seemingly minor mistake, you could cause lots of damage to the amp. I've heard of first-time builders shorting out transformers, and those are the most expensive part of the amp. There may be collateral damage as well, and other parts that would have to be replaced. Kit amps can go from being a real bargain to an endless money pit in a hurry. Not trying to be the voice of gloom and doom, but I do want to give you some realistic, possible scenarios as a first time amp builder.

Having said all that, if it were my money, I would look at first buying a used Fender or Victoria. If you can't then I would save up the extra cash to get a either a new Fender or Victoria.

Building amps is a fun hobby, but it isn't a good way to save money. Nor is it a good investment.

Just my $.02 as a long-time amp building hobbyist.

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That's a fair price. It takes a while to build one of those amps, despite the low level of complexity. Figure it takes at least 10 hours or so. At the minimum, the tech is making $35/hour which isn't bad. Of course the longer it takes, the less the tech makes but I think someone who has build that amp several times before and is used to working on amps should be able to crank that circuit out in 10 hours or less.
You're probably right, however there were two reviews on the TAD website for the kit. One of the reviewers said it took him 6 hours to build, and the other one said it took him 5. Assuming that the TAD builder is at least as good as the second guy, that would be $175 at $35/hour, which is half price. And that doesn't take into account the fact that A) the TAD builder is probably generally faster and more experienced than a random customer, and B) he doesn't need to waste any time reading the instructions since he probably designed the amp and picked the components in the first place. But that's nitpicking on my part, and I'll leave it at that. We'll agree that TAD's was a fair price, just that it took me out of my budget range.


So really, it depends on your needs/desires. Do you want a fairly accurate replica? Do you want a versatile tone machine? Will the small speaker be okay tone wise? Etc.
An accurate replica. I've played a Victoria 518 and basically want an amp just like that. Don't care for versatile tone machines, I love simplicity (one pickup guitars and amps that just nail it with just a volume knob). I have no problem with the low wattage or the speaker, and actually prefer the small size that lets you carry it around. I'm neither confused about what I want, nor unsure if the classic 5F1 amp tone suits me.



If resale is important to you, and it seems like it is, you might look for a used Victoria or Fender amp. Either is going to keep a fairly high resale value, unlike the kit amp, which you will take a big hit. It will never be worth anywhere near what you paid for it. You may be able to find a decent used Fender or Victoria.
Yes, I'm afraid resale is important to me. Unfortunately. It's a shaky economy, and I'm not a rich person (obviously :) ). I wouldn't want to have to sell it, but if I'm forced to, the resale value does count.

So yes, I'll be looking for a used Victoria or Fender, or come brighter times I'll buy a new one. If anyone's got a good deal for me on one of those please let me know ;).

Thank you tunghaichuan, your advice has been extremely useful. I really appreciate your help!

[tunghaichuan]

An accurate replica. I've played a Victoria 518 and basically want an amp just like that. Don't care for versatile tone machines, I love simplicity (one pickup guitars and amps that just nail it with just a volume knob). I have no problem with the low wattage or the speaker, and actually prefer the small size that lets you carry it around. I'm neither confused about what I want, nor unsure if the classic 5F1 amp tone suits me.


Great, knowing what you want in an amp is a useful thing to know. I had the chance to play a buddy's real '58 tweed Champ, it sounded glorious. A newly made one will take a little while to break in. If you luck out and find a nice used one, it may already be broken in.



Yes, I'm afraid resale is important to me. Unfortunately. It's a shaky economy, and I'm not a rich person (obviously :) ). I wouldn't want to have to sell it, but if I'm forced to, the resale value does count.

So yes, I'll be looking for a used Victoria or Fender, or come brighter times I'll buy a new one. If anyone's got a good deal for me on one of those please let me know ;).


Even though the Victoria is about 100 Euros more than the Fender, I would take a Victoria over the Fender any day. The Victoria is built like the original; the Vic is a more accurate copy.



Thank you tunghaichuan, your advice has been extremely useful. I really appreciate your help!

You're very welcome. I was approaching this a hobbyist who has built at least 10-15 different versions of the tweed Champ/Princeton circuit. I've gotten more money invested in this that I'll ever be able to get back.

Let us know what you come up with.

[tunghaichuan]

Update:

Just found this link today:

http://store.marshamps.com/product_info.php?cPath=21&products_id=28&osCsid=r2c99125uhr2kal4jddgp3v906

Complete kit from Marsh amps. You'd have to get the European power transformer upgrade for $20, but at $455 before shipping it might be a good deal. As you know, the Tweed Champ's cabinet is not very big, so shipping might be reasonable. You'd have to check with Marsh to see what it would be to Europe.

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Complete kit from Marsh amps. You'd have to get the European power transformer upgrade for $20, but at $455 before shipping it might be a good deal. As you know, the Tweed Champ's cabinet is not very big, so shipping might be reasonable. You'd have to check with Marsh to see what it would be to Europe.
Thanks! Will check with them, definitely looks like something to consider.
Sorry for the late reply, have been very busy the last couple of days.

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You're very welcome. I was approaching this a hobbyist who has built at least 10-15 different versions of the tweed Champ/Princeton circuit. I've gotten more money invested in this that I'll ever be able to get back.

Let us know what you come up with.
After much talking with various kit vendors in Europe and the US, and with Victoria and Fender distribuitors, I ended up pulling the trigger on the Tube Amp Doctor kit. It looks like it's using solid components, and frankly it's all I can afford right now and it doesn't look like I'll be able to afford a more expensive one in the foreseeable future. Hopefully with attention and proper regard for safety I should end up with a good amp.

Meanwhile I've built myself a capacitor discharge tool out of a pair of insulated alligator-clip-ended wires and a 5W 22kOhm resistor that I've put many layers of insulating tape around. I intend to hook one alligator clip to the chassis (ground) and put the other one on the end of a wooden chopstick when discharging caps, then check the results with a digital multimeter, so hopefully that'll be safe enough.

Also, I've been reading these:

http://angela.com/thetrainwreckpages.aspx
http://www.geofex.com/tubeampfaq/taffram.htm
http://www.aikenamps.com/TechInfo_2.htm
http://www.freewebs.co.uk/valvewizard/index.html
http://www.diyguitarist.com/Misc/J_Darr.htm
http://ax84.com/p1.html
http://www.tubebooks.org/technical_books_online.htm

I still have about a week I think until the package gets delivered, so if there's anything else it would help to read I'd really appreciate the advice.

Thank you to everyone who replied in this thread, thanks for your time and suggestions!

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I've received and started building the amp, and sure enough the first problems appeared. Ironically, the part I was afraid of went smoothly - I've managed to drill just fine through the cabinet, the board and the chassis, and I've attached the input and output transformer to the chassis.

I've also populated the eylet board, and where applicable (i.e. no wires that need to be attached at a later point) I've started soldering the components to the eylets, using a 40W Weller soldering iron with a Philips-screwdriver head that everyone said would be OK to use. I've soldered many things many times before (pickups and pots, BYOC kits, etc.) so I do know how to wipe the tip, wet it with a bit of solder, keep the heat for 1-2 seconds on the joint, etc.

BUT, here's my great idea: measure the resistors before and after soldering.

Case 1: resistor on the schematic is 22kOhm, resistor before soldering is 23kOhm, resistor after soldering only one leg is 45kOhm

Case 2: resistor on the schematic is 68kOhm, resistor before soldering is 70kOhm, resistor after soldering only one leg is 85kOhm.

Obviously I'm both confused and annoyed. I've written TAD and am waiting for their reply. I've scanned the Internet for more details and found that this is supposed to happen only if the resistors have been improperly stored in a humid environment.

Any thoughts on the subject? Did you have similar experiences with carbon comp resistors?

[tunghaichuan]

Case 1: resistor on the schematic is 22kOhm, resistor before soldering is 23kOhm, resistor after soldering only one leg is 45kOhm

Case 2: resistor on the schematic is 68kOhm, resistor before soldering is 70kOhm, resistor after soldering only one leg is 85kOhm.

Obviously I'm both confused and annoyed. I've written TAD and am waiting for their reply. I've scanned the Internet for more details and found that this is supposed to happen only if the resistors have been improperly stored in a humid environment.

Any thoughts on the subject? Did you have similar experiences with carbon comp resistors?

I usually only measure the resistors before I install them and then not worry about it.

As far as carbon comps go, they can be very noisy. And as you've found out there are problems with them absorbing too much moisture in a humid environment. I'm not convinced that they add any mojo to the circuit. If I were you, I'd replace them with carbon film.

I would put 2W metal oxide flame proof resistors in the power supply (decoupling resistors between the three PS caps).

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I usually only measure the resistors before I install them and then not worry about it.

As far as carbon comps go, they can be very noisy. And as you've found out there are problems with them absorbing too much moisture in a humid environment. I'm not convinced that they add any mojo to the circuit. If I were you, I'd replace them with carbon film.

I would put 2W metal oxide flame proof resistors in the power supply (decoupling resistors between the three PS caps).
I'll probably go that way with the resistors, first of all because they're easier to source locally. The metal oxide flame proof I didn't know about. I'll look it up.

[tunghaichuan]

I'll probably go that way with the resistors, first of all because they're easier to source locally. The metal oxide flame proof I didn't know about. I'll look it up.

Another thing that just occurred to me: you may consider putting a 2W metal oxide resistor from about 470 ohms to 1.5k ohms from the second power supply cap to pin 4 on the octal socket. Pin four connects to the 6V6's screen grid. Installing this resistor will allow you to crank the amp by preventing the screen grid from drawing excessive current.

Normally a wire would go here, so you can just leave it off and connect the two points with the resistor. Make sure you insulate the leads.

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Another thing that just occurred to me: you may consider putting a 2W metal oxide resistor from about 470 ohms to 1.5k ohms from the second power supply cap to pin 4 on the octal socket. Pin four connects to the 6V6's screen grid. Installing this resistor will allow you to crank the amp by preventing the screen grid from drawing excessive current.

Normally a wire would go here, so you can just leave it off and connect the two points with the resistor. Make sure you insulate the leads.
Thanks, will take that under careful consideration! Could that possibly impact the amp's tone in any audible (read: undesirable :) ) way?

What do you mean exactly by "cranking the amp"? More headroom? I'm asking because I really want it to start breaking up as early as possible.

[tunghaichuan]

Thanks, will take that under careful consideration! Could that possibly impact the amp's tone in any audible (read: undesirable :) ) way?

What do you mean exactly by "cranking the amp"? More headroom? I'm asking because I really want it to start breaking up as early as possible.

If you're worried about it affecting the tone, use a lower value resistor, i.e., 470 ohms, make sure it is at least 2W rated.

By cranking, I mean turning it all the way up. The tweed circuits tend to start to overdrive at about 3 or 4 on the volume control, turning it up all the way to 12 will push the 6V6 tube very hard. The screen grid resistor protects the screen grid under this condition. It ensures your tube's screen grid doesn't burn out.

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If you're worried about it affecting the tone, use a lower value resistor, i.e., 470 ohms, make sure it is at least 2W rated.

By cranking, I mean turning it all the way up. The tweed circuits tend to start to overdrive at about 3 or 4 on the volume control, turning it up all the way to 12 will push the 6V6 tube very hard. The screen grid resistor protects the screen grid under this condition. It ensures your tube's screen grid doesn't burn out.
Thanks for the advice! Will do.

I guess while I'm waiting for TAD's reply I'll wire the speaker.
IIRC, plus goes to the mono jack tip, minus to ground, right?

[tunghaichuan]

Thanks for the advice! Will do.

I guess while I'm waiting for TAD's reply I'll wire the speaker.
IIRC, plus goes to the mono jack tip, minus to ground, right?

That is correct plus/hot goes to tip, negative/ground goes to ground.

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I would put 2W metal oxide flame proof resistors in the power supply (decoupling resistors between the three PS caps).
Do you mean after the first 3 caps, reading the layout left to right, and in parallel with the 4th cap? The kit comes with a green 5W 470 5% resistor there.

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If you're worried about it affecting the tone, use a lower value resistor, i.e., 470 ohms, make sure it is at least 2W rated.
Just took a peek inside a Victoria 518, and they use what looks like a 1W metal-film 460 resistor there. It looks like a metal-film resistor (it's blue, for one).

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I've started wiring the input transformer to the rectifier tube. Here's a TAD picture of the rectifier tube wiring:

http://www.tubeampdoctor.com/images/KIT/5F1/AmpKit5F1Champ18.jpg

What I'm not clear on is this: the layout says I should wire the two yellow wires to pins 2 and 8, and the two red wires to pins 4 and 6. But they don't say which of the pair goes where. I'm assuming that it doesn't matter? Any of the yellow wires can go to either pin 2 or 8, and any of the red wires to 4 or 6?

[tunghaichuan]

I've started wiring the input transformer to the rectifier tube. Here's a TAD picture of the rectifier tube wiring:

http://www.tubeampdoctor.com/images/KIT/5F1/AmpKit5F1Champ18.jpg

What I'm not clear on is this: the layout says I should wire the two yellow wires to pins 2 and 8, and the two red wires to pins 4 and 6. But they don't say which of the pair goes where. I'm assuming that it doesn't matter? Any of the yellow wires can go to either pin 2 or 8, and any of the red wires to 4 or 6?

The yellow and red wires are not polarized, it doesn't matter which yellow wire goes to pin 2 or pin 8 and it doesn't matter which of the red wires goes to either pin 4 or 6.

Also make sure you twist the yellow leads together and twist the red leads together as shown, this helps in noise reduction as both the yellow and red leads are AC.

[tunghaichuan]

Do you mean after the first 3 caps, reading the layout left to right, and in parallel with the 4th cap? The kit comes with a green 5W 470 5% resistor there.

To clarifiy:looking at the first photo on this page:

http://www.tubeampdoctor.com/newsdesk_info.php?newsPath=18&newsdesk_id=40

To put in a screen grid resistor, go to the eyelet for the second cap from the left, the one where the green and brown resistors are. You would solder in the end of a 470 ohm 2-5W resistor there (in addition to the two already there) and solder the other end to pin 4 on the 6V6 tube socket.

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Also make sure you twist the yellow leads together and twist the red leads together as shown, this helps in noise reduction as both the yellow and red leads are AC.
Of course, AC isn't polarized, and it's the input transformer :thwap. Now I can apply for a special bus pass.

Twisted and connected. Thanks!

[red]

To put in a screen grid resistor, go to the eyelet for the second cap from the left, the one where the green and brown resistors are. You would solder in the end of a 470 ohm 2-5W resistor there (in addition to the two already there) and solder the other end to pin 4 on the 6V6 tube socket.
OK, I did get that - I just thought that by "decoupling resistor" you meant the second green resistor from their picture. BTW, my kit came with one green resistor (the 5W one connected in parallel with the 4th cap). The one connecting the legs of the 1st and 2nd cap is a carbon comp 1W/10k. Hopefully it won't change its resistivity rating when soldering, as I don't have a replacement for it.

I thought about using a clip-on heat sink of some sort (most likely a plain alligator clip) when soldering the next resistors, but I keep wondering if that will solve anything since once I power up the amp the resistors will get current flowing through them with likely similar effects.

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And now they got me a bit confused again. In this picture:

http://www.tubeampdoctor.com/images/KIT/5F1/AmpKit5F1Champ23.jpg

The blue wire coming from the output transformer connects to the power tube socket, and the red to the eyelet board. But in the layout they printed out and sent with the kit, it says that the red goes to the tube socket and the blue to the eyelet board. This is probably a mistake, since A. the pictures are somewhat proof of a working amp, and B. I've looked up several other layouts on the Internet for a 5F1 and they all said that the blue wire goes to the tube socket and the red to the board. I've sent an email to TAD trying to make sure before I melt solder there - they'll likely reply on Monday.

The other wires from the output transformer I've connected thus (as per their layout): black to ground, green to tip (black to ground seems to be a common theme with the speaker wires too).

[tunghaichuan]

And now they got me a bit confused again. In this picture:

http://www.tubeampdoctor.com/images/KIT/5F1/AmpKit5F1Champ23.jpg

The blue wire coming from the output transformer connects to the power tube socket, and the red to the eyelet board. But in the layout they printed out and sent with the kit, it says that the red goes to the tube socket and the blue to the eyelet board. This is probably a mistake, since A. the pictures are somewhat proof of a working amp, and B. I've looked up several other layouts on the Internet for a 5F1 and they all said that the blue wire goes to the tube socket and the red to the board. I've sent an email to TAD trying to make sure before I melt solder there - they'll likely reply on Monday.

The other wires from the output transformer I've connected thus (as per their layout): black to ground, green to tip (black to ground seems to be a common theme with the speaker wires too).

The blue and red wires are the 6v6 plate/anode and B+ connection.

Since you have negative feedback in this amp, it matters which color wire goes where. Technically speaking hooking up the wires one way will put the primary of the output transformer in phase with the secondary. If you hook up the red and blue wires out of phase, you will have *positive* feedback injected into the amp and it will squeal as it is turned up.

So you have two choices if you wire it incorrectly: 1. switch the primary wires (blue & red) or switch the secondary wires (don't know what color you have but the US standard is black and green.) It might be easier to switch the output (secondary wires) since they are on the jack.

This was one of the first things I learned when I built my first 5F1 about 15 years ago. The output transformer was wound so that the blue was B+ and red was the plate connection. I hooked them up in reverse order, normally the standard: red as B+ and blue as plate/anode. Squeal city. At the time it was easier for me to switch the secondary/output wires, so that green was grounded and the black wire when to the hot/tip of the output jack.

If you want to be sure, email TAD and ask them what the correct color coding is.

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So you have two choices if you wire it incorrectly: 1. switch the primary wires (blue & red) or switch the secondary wires (don't know what color you have but the US standard is black and green.) It might be easier to switch the output (secondary wires) since they are on the jack.

Yes, the secondary wires are green and black. I've mentioned them in my previous post (wired: green to speaker jack tip, black to ground), but I've obviously got a lot more to learn (about tube amp terminology and technology) and English is not my first language, so I guess sometimes I'm not as clear as I could be - sorry.



If you want to be sure, email TAD and ask them what the correct color coding is.
I did already email TAD, but they won't answer until Monday probably. But you've made the correspondence between the primary and secondary wires pretty clear, so if I had to get it done quickly it wouldn't be much of a gamble. As it stands, I have to wait anyway for a new batch of resistors I've ordered to replace the ones in the kit that changed resistivity more than what the tolerance band spec'd - so hurying to solder the output transformer wires won't make much of a difference with regard to the power-on day. I'm just trying to ask questions and learn as much as possible.

Thank you, I really appreciate your help! If you ever write a book about tube amps, autograph the first copy for me and let me know where to send the money. :)

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This was one of the first things I learned when I built my first 5F1 about 15 years ago. The output transformer was wound so that the blue was B+ and red was the plate connection. I hooked them up in reverse order, normally the standard: red as B+ and blue as plate/anode. Squeal city.
Looks like that would have been my fate as well, had I decided not to email TAD and be too smart for my own good about it. They've answered my email, and apparently the pictures on their website have been taken a long time ago when they were shipping the kits with a different output transformer. So just in case anyone else trying to build a TAD 5F1 Champ stumbles across this thread: take the layout's word over the pictures on the website. In my case, red goes to the power tube plate and blue to B+.

Went out hunting for a metal oxide 470 Ohm resistor today, the local shops did not carry any 2W ones, but I've managed to find a 3W 470 Ohm metal oxide resistor. I guess that should do fine.

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Another thing, the TAD schematic specifies voltage at various points in the circuit, measured with DVM read to ground. At one point it even goes up to 390V. Now, if I do that measurement I will do my best to stay safe (clip one DVM to the chassis and tape the other lead to the end of a wooden chopstick) - but my digital multimeter is a cheap one, and the probes look like this:

http://www.vellemanusa.com/images/products/1/dvm850blu.jpg

My DMM is a Velleman DVM850BL (click for specs) (http://www.vellemanusa.com/us/enu/product/view/?id=350297#). Supposedly it can handle up to 600VDC, but looking around on the Internet I came across the concept of a "high voltage probe". Do I need a pair of those? Should I go out and buy them or just skip the measurement step altogether if the amp powers up and works?

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I've decided to stick to carbon comp resistors just because Victoria uses them and I love the way the 518 sounds. They're probably overkill to use all over the place, but it makes my life simpler, and if the noise they add won't be more than what the 518 puts out, I'll be happy.

I've sourced some new carbon comps (still waiting for a couple of 100k ones that turned out to be harder to get) and started wiring the board and soldering them in place. This time no surprises with the resistivity rating after soldering.

But - the two 68k grid resistors came at 71-72k and turned 73-74k after soldering. And the 220k power tube grid load resistor came at 250k and went to about 254k after soldering.

I don't think that either drift is spectacular or particularly important for the well-being of the finished amp, but as CCs will do, they will most likely continue to slowly drift upwards. The two "68k"s won't make a noticeable difference, but I'm worried about the "220k" - what if it goes to 300k? I'm assuming it won't affect the tone but will affect the power tube "loudness", and the power tube itself.

Hmm, maybe that's actually a good place for a metal or carbon film. If I understand it's purpose correctly, no signal actually goes through that resistor, except maybe to "go away" to ground.

[tunghaichuan]

Don't worry about the slight increases in resistance. Those old carbon comp resistors are typically +/- 20% so they can be 20% under or over the value and not cause any problems.

I checked the data sheet for the 6V6 and the maximum resistance for the grid load resistor (the 220K) is 500K, so at +/- 20% you're well below the max.

The main problem with carbon comps is that they drift in value over time compared to metal film, metal oxide, or carbon film resistors. Sometimes when they drift just right the amp sounds very good. Other times, it doesn't doesn't work out so well. That's partially why some vintage amps sound great and others don't.

They can be noisy in certain positions, such as the plate load (100K). But some think that there is some magic/mojo if you put carbon comp resistors in those positions. I have not tried it myself, but I think it would be hard to tell the difference in a double blind test.


I've decided to stick to carbon comp resistors just because Victoria uses them and I love the way the 518 sounds. They're probably overkill to use all over the place, but it makes my life simpler, and if the noise they add won't be more than what the 518 puts out, I'll be happy.

I've sourced some new carbon comps (still waiting for a couple of 100k ones that turned out to be harder to get) and started wiring the board and soldering them in place. This time no surprises with the resistivity rating after soldering.

But - the two 68k grid resistors came at 71-72k and turned 73-74k after soldering. And the 220k power tube grid load resistor came at 250k and went to about 254k after soldering.

I don't think that either drift is spectacular or particularly important for the well-being of the finished amp, but as CCs will do, they will most likely continue to slowly drift upwards. The two "68k"s won't make a noticeable difference, but I'm worried about the "220k" - what if it goes to 300k? I'm assuming it won't affect the tone but will affect the power tube "loudness", and the power tube itself.

Hmm, maybe that's actually a good place for a metal or carbon film. If I understand it's purpose correctly, no signal actually goes through that resistor, except maybe to "go away" to ground.

[red]

Don't worry about the slight increases in resistance. Those old carbon comp resistors are typically +/- 20% so they can be 20% under or over the value and not cause any problems.

I checked the data sheet for the 6V6 and the maximum resistance for the grid load resistor (the 220K) is 500K, so at +/- 20% you're well below the max.

The main problem with carbon comps is that they drift in value over time compared to metal film, metal oxide, or carbon film resistors. Sometimes when they drift just right the amp sounds very good. Other times, it doesn't doesn't work out so well. That's partially why some vintage amps sound great and others don't.

They can be noisy in certain positions, such as the plate load (100K). But some think that there is some magic/mojo if you put carbon comp resistors in those positions. I have not tried it myself, but I think it would be hard to tell the difference in a double blind test.
Once again, a quick and very clear answer! If you're ever in Romania, let me know because I owe you some glasses of your favourite beverage :beer:

I'm sorry for my novice questions, I'm learning as fast as I can and it's quite a lot to absorb. I've looked everywhere BUT at the 6V6 data sheet. :thwap Sometimes I get a bit tired with the research and the everyday stuff, that I tend to overlook obvious things...

I've read R.G. Keen's article about carbon comp resistors and he seems to make a case for the mojo factor. If that's one of the main differences between how the Swart Space Tone 6V6LE (which I've only heard online) and a Victoria 518 (which I've played) sound, there's definitely a warmer vibe to the Victoria. Not that there's anything wrong with either approach, just a matter of taste.

Any opinion on whether I should try to check the voltages inside with my cheapo multimeter/probes?

If anyone else stumbles upon this thread and needs more info about the 5F1, here's a very nice explanation of the preamp stage in a 5F1: http://www.classictubeamps.com/preamp.html

Thanks again, tunghaichuan!

[tunghaichuan]

Once again, a quick and very clear answer! If you're ever in Romania, let me know because I owe you some glasses of your favourite beverage :beer:

I'm sorry for my novice questions, I'm learning as fast as I can and it's quite a lot to absorb. I've looked everywhere BUT at the 6V6 data sheet. :thwap Sometimes I get a bit tired with the research and the everyday stuff, that I tend to overlook obvious things...


No problem, glad to help out. Definitely Google the 6V6GT data sheets. FWIW, the 6V6GTA is the same tube but is rated as a 14W tube for maximum dissipation. The 6V6GT is only rated at 12W. The "A" designator means slow warmup for use in tube equipment that runs the filaments of the tubes in series. (Filaments are wired in parallel in the 5F1.) The 'GT is identical to the 'GTA except for the "A." The 14W vs. 12W discrepancy is due to the way the tube industry rated the tube. You'll need this number if you want to check the bias of your 6V6 tube. Be aware that the JJ/Slovak 6V6S is not really a 6V6 tube, it can dissipate up to about 18 watts or so so it is more like a metal 6L6 or 6L6G in terms of power dissipation.

The bottom line is that some 6V6 tubes can be biased up to 14W with no problems, while other will over dissipate ("red plate") and will have to be biased down to 12W.




I've read R.G. Keen's article about carbon comp resistors and he seems to make a case for the mojo factor. If that's one of the main differences between how the Swart Space Tone 6V6LE (which I've only heard online) and a Victoria 518 (which I've played) sound, there's definitely a warmer vibe to the Victoria. Not that there's anything wrong with either approach, just a matter of taste.


RG Keen has forgotten more about electronics and tube circuits than I'll ever know, so I will defer to his judgment on this ;)



Any opinion on whether I should try to check the voltages inside with my cheapo multimeter/probes?


That meter should be fine. When measuring the B+ or any other high voltage DC use the 600V setting set for DC. If you want to measure the raw AC coming out of the PT, use the 600V setting set to AC and measure from one end of the high voltage lead to the center tap. Don't measure across the entire HV winding or you might burn out the meter.

To measure cathode voltages, set the scale to the nearest appropriate voltage level on the DC setting. There is about 1v on the 12AX7 cathodes and about 20V or so on the 6V6's cathode.

You might want to get a set of retractable hooks for the meter. One for the black and one for the red lead. You can hook up the black lead to ground and then measure the voltages with one hand. Put the other hand in your pocket or behind your back as a safety precaution.



If anyone else stumbles upon this thread and needs more info about the 5F1, here's a very nice explanation of the preamp stage in a 5F1: http://www.classictubeamps.com/preamp.html

Thanks again, tunghaichuan!

Thanks for the link, I had not seen that site before.

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RG Keen has forgotten more about electronics and tube circuits than I'll ever know, so I will defer to his judgment on this ;)
Oh I'm sorry, I thought the link to the article had already been posted somewhere in this thread. Here it is:

http://www.geofex.com/article_folders/carbon_comp/carboncomp.htm



You might want to get a set of retractable hooks for the meter. One for the black and one for the red lead. You can hook up the black lead to ground and then measure the voltages with one hand. Put the other hand in your pocket or behind your back as a safety precaution.
Yep, that's the plan. Thanks!

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Another noteworthy piece of information I've come across is that Victoria and the Weber 5F1 kit use a 25uF capacitor in parallel with the 1K5 resistor coming from pin 3 of the 12AX7.

Here's the Weber 5F1 layout:

http://taweber.powweb.com/store/5f1_layout.jpg

And a short film from Victoria humorously illustrating a 5F1 build:

http://www.youtube.com/watch?v=1xj6d9MLCpo

Supposedly this is a bypass cap, added in order not to screw up the 12AX7 bias as far as DC goes, but boosts the mid and low frequencies (or rather cuts some of the high ones?) in the AC current.

In any case, I don't have a quality electrolytic capacitor to add there, and I'm fed up as it is with waiting for parts so I'll just try the 5F1 I have as soon as I can, and if there'll be any problem with the tone I'll make that adjustment then.

[tunghaichuan]

Putting a cathode bypass cap across that 1.5k resistor is a common mod. I believe that some 5F1 Champs came out of the factory with it, stock, although it was not on the schematic.

You can use values from .68uF to 22uF. The practical range is from 2uF-4uF for humbucking pickup guitars and 4uF-10uF for single coil equipped guitars.



Another noteworthy piece of information I've come across is that Victoria and the Weber 5F1 kit use a 25uF capacitor in parallel with the 1K5 resistor coming from pin 3 of the 12AX7.

Here's the Weber 5F1 layout:

http://taweber.powweb.com/store/5f1_layout.jpg

And a short film from Victoria humorously illustrating a 5F1 build:

http://www.youtube.com/watch?v=1xj6d9MLCpo

Supposedly this is a bypass cap, added in order not to screw up the 12AX7 bias as far as DC goes, but boosts the mid and low frequencies (or rather cuts some of the high ones?) in the AC current.

In any case, I don't have a quality electrolytic capacitor to add there, and I'm fed up as it is with waiting for parts so I'll just try the 5F1 I have as soon as I can, and if there'll be any problem with the tone I'll make that adjustment then.

[red]

It works! It sounds good "out of the box" :), but it's getting better fast - the filter caps are probably settling in, maybe some undecided carbon comp resistors still figuring out what value they want to be, and definitely the speaker getting more and more in a vibrating mood.

Thanks for all the help, tunghaichuan!

http://www.thefret.net/imagehosting/thum_18854c168d73b37b4.jpg (http://www.thefret.net/vbimghost.php?do=displayimg&imgid=1623)

[tunghaichuan]

Glad to hear everything worked out for you. It may take a while for the speaker to break in, but it will only get better sounding. Great job, I like the looks of that little amp. :AOK


It works! It sounds good "out of the box" :), but it's getting better fast - the filter caps are probably settling in, maybe some undecided carbon comp resistors still figuring out what value they want to be, and definitely the speaker getting more and more in a vibrating mood.

Thanks for all the help, tunghaichuan!

http://www.thefret.net/imagehosting/thum_18854c168d73b37b4.jpg (http://www.thefret.net/vbimghost.php?do=displayimg&imgid=1623)

[red]

Glad to hear everything worked out for you. It may take a while for the speaker to break in, but it will only get better sounding. Great job, I like the looks of that little amp. :AOK
Thanks! It looks even better in real life :D but there was not enough light and the flash kept going off. I actually took a bunch of pictures but that turned out to be the best of them, hehe.

Future plans for the amp include changing the red pilot light with a blue one, and add that bypass cap across the 1K5 resistor (I do like those low frequencies a lot, and I understand that it will also reduce some of the noise I inevitably get as a single-coil guitars fan).

Other than what I get because of the single coils, the amp is pretty silent. There is a tiny hum when the volume knob is at 12 (maximum), but it's definitely not louder than what I've heard from the 518, so I'd say the carbon comp resistors aren't any inconvenience here.

Now I have to try and find the best books to have on tube amps and start learning about it in more detail. And maybe start thinking about the cheapest way to get quality parts for a 5E3 :).

[tunghaichuan]

Other than what I get because of the single coils, the amp is pretty silent. There is a tiny hum when the volume knob is at 12 (maximum), but it's definitely not louder than what I've heard from the 518, so I'd say the carbon comp resistors aren't any inconvenience here.


With carbon comps, it is usually hiss, not hum so it sounds like you lucked out.



Now I have to try and find the best books to have on tube amps and start learning about it in more detail. And maybe start thinking about the cheapest way to get quality parts for a 5E3 :).

Here is a site to get you started on building amps:

http://www.pmillett.com/tecnical_books_online.htm

There is enough info there to keep anyone interested learning for a long time.

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Here is a site to get you started on building amps:

http://www.pmillett.com/tecnical_books_online.htm

There is enough info there to keep anyone interested learning for a long time.
Thanks!

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With carbon comps, it is usually hiss, not hum so it sounds like you lucked out.

I don't know, maybe I did. With no input and the amp turned all the way up on the Champ clone, there's a very small amount of hiss. That's exactly what I hear out of my Peavey Classic 30 with no input on the clean channel turned up about halfway - and there are no carbon composition resistors in the PC30.

Actually the loudest thing I hear in the situation described is a tube. Probably the power tube. Cooking away.