First amp build, codename “Heavyweight Champ”. In progress.

[jcpst]

This is going to be a 5F1 circuit, but with a 15w output transformer and a 15” speaker.

After some time considering building an amp, I actually decided that I wasn’t going to go DIY for my next amp. I didn’t want it bad enough yet.

But then there was the sad news that BYOC was going out of business, and along with it a very generous discount code. Knowing that there were amp kits, I checked what was left. I saw all the heavy stuff to make an amp almost like one I was considering- a 5f2 15w 15”. There was a chassis left for a 5f1. That was close enough so I went for it.

I don’t want to sound like I’m all excited I got a deal because they had to close shop. BYOC was such a great piece of the web for quite a while.

From BYOC, I got a 5F1 chassis, PT and 15w OT, and a Jensen P15N.

Once I secured those parts, I ordered a RawCab. He already had a 5F1 15” combo as an option in his ebay store.

Then I got the small parts kit, grillcloth, feet and handle from mojotone.



I got a start on it today. Mounted hardware in the chassis, and placed components on the board. There’s a bit of awkwardness from mixing and matching parts of various kits. I reconciled the difference with a quick trip to the hardware store for nuts and bolts.

 

[CanadianDave]

I’m digging that cab.

what’s your plans for finishing it?

 

[jcpst]

I’m digging that cab.

what’s your plans for finishing it?

My plan is to do a stain. With the TV-style cab, I think it would be cool if it looked like a piece of furniture.

If for whatever reason I decide I don’t like it, I could always wrap it in tweed.

 

[CanadianDave]

My plan is to do a stain. With the TV-style cab, I think it would be cool if it looked like a piece of furniture.

If for whatever reason I decide I don’t like it, I could always wrap it in tweed.

Take my advice for what it’s worth, but I would look into French polishing with dewaxed shellac. You’ve got a cool grain on that plywood, and stain can go blotchy very easily.

Shellac is a strange process when it’s your first time, but you mix the shellac flakes with alcohol, then rub it on with a pad (that’s how I got rid of my old socks).

It takes no effort to get a mirror gloss. You can add tinted shellacs and build color, which will sit on top of the wood and act like a tinted lens.

And the only fumes you’ll get is the evaporating alcohol, leaving it dry to the touch in a few seconds.

It will sand and polish beautifully once it cures for a week, and if you decide to add extra clear with lacquer or polyurethane, the shellac should make an excellent sealer.

… can you tell I’m a fan?

I just finished this walnut with hardware store spray shellac. Definitely takes longer to dry than French polishing. It also took a little extra work with 0000 steel wool and some car polish, but I’m happy with it.

 

[jcpst]

Take my advice for what it’s worth, but I would look into French polishing with dewaxed shellac. You’ve got a cool grain on that plywood, and stain can go blotchy very easily.

Shellac is a strange process when it’s your first time, but you mix the shellac flakes with alcohol, then rub it on with a pad (that’s how I got rid of my old socks).

It takes no effort to get a mirror gloss. You can add tinted shellacs and build color, which will sit on top of the wood and act like a tinted lens.

And the only fumes you’ll get is the evaporating alcohol, leaving it dry to the touch in a few seconds.

It will sand and polish beautifully once it cures for a week, and if you decide to add extra clear with lacquer or polyurethane, the shellac should make an excellent sealer.

… can you tell I’m a fan?

I just finished this walnut with hardware store spray shellac. Definitely takes longer to dry than French polishing. It also took a little extra work with 0000 steel wool and some car polish, but I’m happy with it.

Oh I saw your cab in another thread. That’s beautiful!

 

[jcpst]

Oook. Pretty sure I psychologically shot myself in the foot on this one. No more in-progress threads for me!

I had to take a break from this- I was getting tired of reconciling the difference between two sets of docs and two wiring diagrams.

But, I finally came back to this over the weekend. The circuit is mounted in the chassis, and I have about half of it wired up.

Not in a pretty way though. I either have the wrong tool, or the wrong technique, but I’m making a frayed mess with that cloth covered wire every time I try to strip it. So I think I’ll only address the mess if I’m having noise issues or something.

I’m going to hold off on finishing the cab until some more consistently warm weather arrives.

 

[Synchrony Pedalworks]

Oook. Pretty sure I psychologically shot myself in the foot on this one. No more in-progress threads for me!

I had to take a break from this- I was getting tired of reconciling the difference between two sets of docs and two wiring diagrams.

But, I finally came back to this over the weekend. The circuit is mounted in the chassis, and I have about half of it wired up.

Not in a pretty way though. I either have the wrong tool, or the wrong technique, but I’m making a frayed mess with that cloth covered wire every time I try to strip it. So I think I’ll only address the mess if I’m having noise issues or something.

I’m going to hold off on finishing the cab until some more consistency warm weather arrives.

View attachment 89851

I think it is looking great. Amps are really satisfying to build. For the cloth wire, I push the cloth back and do not strip the insulation. It will still be a little frayed, but it can work well.

 

[ThatDude]

I had to take a break from this- I was getting tired of reconciling the difference between two sets of docs and two wiring diagrams.

I know the feeling. Sometimes you get too close to it and starts to look like non-sense. That's when I usually start making silly mistakes. I wasted a perfectly good Hammond Chassis a few weeks ago because I flipped the layout in my mind for the controls, but not for the internals. It was all mixed up. I took two weeks off from it while the replacement chassis was on its way, and we're back on track. Keep on doing it. It'll be worth it when you get to play through it.

 

[Feral Feline]

It can be very good to take a break, come back and see things from a different angle/head-space.

I, too, know the feeling.

My first amp-build was a 5F2A (Champ with a tone control), a CheapAF kit that someone abandoned.
My amp-sifu assigned me to build the kit, but...
The CHASSIS was mirrored to what it should be so I had to flip the layout to pull it together and going back and forth over the way it should be and the way it was... Burned off more than a few brain-cells trying to get The Little Princeton to work. Transformer was dead, and a ... host of other issues.

In the end, I was quite glad the amp wasn't my own 'cause it was so screwed up. Learned a ton.

After turning that debacle around and forcing it to work, the owner never did come and pick it up. That was 2021 — I think that it's still sitting in my Amp Sifu's shop (it was a year ago when I visited).

I then built a 5E3 for myself.

 

[RetiredUnit1]

Take my advice for what it’s worth, but I would look into French polishing with dewaxed shellac. You’ve got a cool grain on that plywood, and stain can go blotchy very easily.

Shellac is a strange process when it’s your first time, but you mix the shellac flakes with alcohol, then rub it on with a pad (that’s how I got rid of my old socks).

It takes no effort to get a mirror gloss. You can add tinted shellacs and build color, which will sit on top of the wood and act like a tinted lens.

And the only fumes you’ll get is the evaporating alcohol, leaving it dry to the touch in a few seconds.

It will sand and polish beautifully once it cures for a week, and if you decide to add extra clear with lacquer or polyurethane, the shellac should make an excellent sealer.

… can you tell I’m a fan?

I just finished this walnut with hardware store spray shellac. Definitely takes longer to dry than French polishing. It also took a little extra work with 0000 steel wool and some car polish, but I’m happy with it.

Finishing walnut and pine are very different. Pine needs to be sealed before finishing or it will be blotchy!

I used Varathane seal first, then their 'gunstock' color stain on this. Then rattle can Minwax satin poly. I used the oil based product for all three of these.

Then knocked down the dust bumps with 400 wet/dry, then polished with superfine steel wool wet with soapy water, then waxed 3 coats with pure carnuba and a orbital polisher. Feels like a freshly waxed show car! Throw a rag on top and it just keeps sliding to the other side and falls off, lol...

I wanted a mostly non-reflective varnish, satin worked great!

 

[CanadianDave]

Oook. Pretty sure I psychologically shot myself in the foot on this one. No more in-progress threads for me!

I had to take a break from this- I was getting tired of reconciling the difference between two sets of docs and two wiring diagrams.

But, I finally came back to this over the weekend. The circuit is mounted in the chassis, and I have about half of it wired up.

Not in a pretty way though. I either have the wrong tool, or the wrong technique, but I’m making a frayed mess with that cloth covered wire every time I try to strip it. So I think I’ll only address the mess if I’m having noise issues or something.

I’m going to hold off on finishing the cab until some more consistently warm weather arrives.

View attachment 89851

At first I was touching my frayed cloth wire ends with a flame, but that only traded frayed ends for soot on the cloth.

I was always opposed to wire strippers and was convinced a sharp box cutter was more efficient until I treated myself to a pair of Tsunoda MWS-125 wire strippers. I’m sure other brands with a similar design would work well, but I’m sold on Tsunoda hand tools.

You also might find that if you can pre-measure and get a good clean cut with your cutters, the cloth wire has enough give/ compression if you pull it back for one side of the wire. However, the bigger issue to keep an eye out for is that solid core wire breaking if you move those wires around too much. Nothing caused more cursing at my work bench than those ends breaking, and I found that where they tended to break was where I stripped the wire.

And I feel you on the psyche out. You’re probably saving yourself work by not working on something when your head isn’t in the right space. My solution to combat this is to print out a copy of your diagram, use your multimeter to check your continuity between connections, resistor values, and visually check the values and polarity of your caps. As you check everything, black it out with a sharpie on your diagram. The 5f1 is a simple enough circuit that it doesn’t take long, and gives you a lot of piece of mind. It also saved my ass from a stupid mistake when I recently swapped some filter caps.

Good luck with the build. It will be worth it when you’re done and learn how to tame it. I just saw an interview with Jeff Tweedy where he said the Champ is still his best amp. And when you play the right guitar through that thing, you’ll probably say to yourself “ohhhh, now I get it.”

 

[jcpst]

Thanks for the advice and encouraging words @CanadianDave. I do indeed know that feeling when the ends break off the wire!

I like your idea for validating continuity.