Costs of DIY Amps

Just thought I'd contribute two points:

1. My DIY Marshall actually did save me money. I'm a horrible woodworker, but the amp is in a temporary cabinet for now, and it cost me somewhere in the neighborhood of $800, where a new 2203 will run about $2000. No contest.

2. I'll provide a thumbs up review of the Hammond iron. Both the PT and OT of my amp are Hammond, and they survived my building troubleshooting process - which involved discovering that I had a shorted speaker cable (great time for that to happen). The iron itself is massive too. I hear that some of the Hammond PTs have highish voltages, but mine measured out near perfect, with exactly 6.3v on the filaments (which was my main concern).

It's the little things that add up though. I think I paid $3 apiece for those stupid Marshall knobs...

 

I haven't had any problems with the Weber iron, and I dig the high/low voltage secondaries on a lot of the PT's. I understand it's so that Weber doesn't have to stock as many different transformers, but I like having the extra flexibility.

And I've got nothing but good to say about Hammond iron, either. Well-built stuff that you can pass on to your grandkids. BTW, the reason that they tend to put out higher-than-expected voltages is because lots of them were spec'd out in the 1940's/1950's (when line voltages were lower), and they haven't changed since!

- Scott

 

Why? I've built and repaired several tube amps and never had a need for an oscilloscope. A good mulitmeter, yes...

 

At some point you'll get a problem that you just can't track down with a voltmeter.


steven

 

Could a good chassis be made of aluminum? How thick?

All chassis I see to buy are predrilled for pots and with printed lettering, plus are expensive.
I'd like to find one from old eqpm but another option would be to be made locally in alu

 

I work in both. There's nothing hypothetical about this, I've done the work and I know what's involved.

Aluminum: Sure it's easy to work especially if it's a thin spotwelded chassis. It's also not as durable as steel. Whack the amp or take it on the road, the chassis will deform. I've seen them bent so far out of shape that the welds pulled out.

Steel: That's more like it. Still, try drilling holes as neatly as a CNC guided laser.

I recently restored a Super Reverb. The chassis was all bent out of shape, no one accused Fender of making a wimpy chassis. Bent around the transformer, pushed at the middle of the control panel and the spotwelds were torn out of the transformer side.

I suggest that you keep more accurate track of your time. Try starting with a blank JTM45 chassis and ending up with everything clean and in the correct location.

Depending on your quality requirements.

Kinko's can't do a faceplate as nice or as durable as a laser teched or silkscreened faceplate. The trick is to get a one-off faceplate that looks "manufactured" or as good as a pre-production prototype. I've made the round of my local sign shops, trophy shops, etc.. Some of the trophy shops are especially proud of their work, I've gotten estimates in the range where I can buy the entire chassis, faceplates and circuit boards for the same money.

Yeah. It's a matter of taking inventory of what you do well and trading to fill the gaps. There's a lot I can do except that some things take me forever... If someone else can do something as well as I can for less money they're the guys I'll be talking to.

Been there, done that. Back in '84. As a combo. "Tight fit" doesn't begin to explain it...

 

Strategically-placed 1/2" angle iron is great for stiffening up aluminum chasses around the transformer area. :idea:

- Scott