starting amp build advice/suggestions

[Richard]

I have a Super 60 head carcass that I want to build. I plan to make a AA964 Princeton except SS rectification, LTPI, and 6L6. I would like to then experiment with added features (tone stack, MV, PPIMV, extra gain stage, 6V6s, cathode bias, etc.) I have done a fair bit of work on my Princeton (with help from the forum, thank you) and am adequately skilled. I will make a schematic and layout drawing before I start.

What advice would you give someone starting their first build, mistakes to avoid, things you wish you knew when you started?

What are some simple mods I may want to try?

Any layout suggestions to leave room for expansion? I'm thinking I should skip a few turrets in between the different sections of the amp.

Thanks

[ric]

Hey, Richard, My thoughts for a build you may want to change would be to "breadboard" it first and do your changing then. There are a couple threads in theory & design with several different techniques discussed. One needs to be careful with exposed high voltage, of course. Best of luck with the project, have fun & work safe. -ric

[Zozobra]

Plan your layout as meticulously as possible. Think about where your wires will be routed and how all the hardware will fit together. Make sure you can actually get in to places to assemble the hardware as this can be challenging in a small chassis.
With a pre-drilled chassis things should be easier. It can by unfortunately easy to make a bit of a school boy error when drilling your own chassis, as I often do...

[Mick Bailey]

If you're planning on the amp being a platform for experiment it may be worthwhile taking a modular approach and reduce (or remove) any dependency on layout. Taking this approach, you'd build a power supply with all of the nodes physically located on the same board, then a separate preamp board and a separate power amp. I'd also break out the tone stack onto its own little board. So the amp actually looks like its block diagram. Make everything an identifiable unit, with clear inputs and outputs.

[Zozobra]

The modular idea is well worth following. I build like that now with a separate board for the power supply, PI and preamp. This way if I get board with a preamp I don't have to hack a huge board up.

I'd avoid underboard wiring if you can. If one works loose is makes debugging and repairing much more arduous.

[Mick Bailey]

I'd avoid underboard wiring if you can. If one works loose is makes debugging and repairing much more arduous.

+1 on that! especially a few years down the line and you've forgotten what was wired under the board. Worked for Leo, but he made thousands of the same amp and produced exquisite drawings.

[Tooboob]

If you'd like to hand-wire an amp, built from scratch, go for it.

On the other hand (and it sounds like you did this with your current amp), if you buy a used amp with a known schematic, you get an enclosure, covering, chassis, corners, rubber feet, covering, grill, power entry module, knobs, pots, jacks, power transformer, output transformer, handle, a set of tubes, etc.

Used amps can be had for $200. You might save $400-$600 using one as a starting point. I got a clean Carvin XV-112 yesterday for $200. It has 4 6L6 sockets, 100W transformers (with taps for bias and +/- 15V supply), LTPI, diode rectification, tank reverb, channel switching, and a 5-band GEQ.

You can replace the main board with your handwiring if you wish, but many amp designs are a simple mod of the PC Board/component values. It's real easy to take apart, most of the goodies are on one board, and everything is accessible. That's why I probably have the world's largest collection of 'em. They're old, but nobody considers them vintage, they're built like tanks, and I think they're the ultimate modder fodder. They get pretty Deluxe running 6V6s (bias cool, use JJ's, and set the speaker impedance switch one position lower impedance - maybe boost the screen resistors to 1K too).

Somewhere in the middle, you could cannibalize a used amp for lots of what you need.

It's funny how you can buy a simple amp kit for three times the price of a new Fender Super Champ x2.

[eschertron]

It's funny how you can buy a simple amp kit for three times the price of a new Fender Super Champ x2.

Funny like that certain smell?

The good thing about getting an amp that is not sought after is, as you said, keep what you want, throw away (design-wise) what you don't. And salvage the rest. Richard doesn't say if the amp was burnt, soaked, or otherwise damaged. If not, there's opportunity to build on and mod what's there.

What I think is 'funny', is that for the price of a decent kit amp, there are folks offering CBS-era Champs on Ebay. What's that smell?

[Enzo]

Apples and oranges. Buying a new amp doesn't give the satisfaction and experience of building. I just bought a 24 ounce can of beer at the store down the road for $1.39. (Same beer cost $8 at a detroit Tiger ball game a few seasons ago) If I walk into an area bar and order that same can of beer, I won't get much change from a $5 bill, if any. But at the bar, I got to watch "the game" with my friends, shoot some pool, flirt with the waitress, or whatever I get from the experience. Or I could sit alone at home.

[J M Fahey]

flirt with the waitress

Specially if you get this kind of waitress to bring your beer

[Enzo]

Oh yes, that has the certain mojo I like. Yes, for you Fraulein, I will not smoke. And six of those in one hand, why I imagine she has quite a good grip...

My wife likes to say someone has a certain "je ne sais quoi" when she finds them appealing. I am of the other school, our waitress has a certain je sais quoi.

[tedmich]

12L carry takes skill and good grip strength


flatter chest may help too...

[Enzo]

yeah, check the arms on that girl. She has lifted a few.

[The Dude]

I hadn't noticed that she had arms.

[Leo_Gnardo]

12L carry takes skill and good grip strength

Oh my, now I'm reminded of a visit my college GF & I made to the Munich Hofbräuhaus January '74. No glass there, thick crockery mugs instead, in liter and half-liter denominations. For. Serious. Drinking. Only. Warned ahead of time, tip your waitress well, and don't ever start a fight, they'll flatten you in a trice. Too bad one of 'em didn't whack Adolf when he shot a pistol into the ceiling in 1923. Would have saved the world a LOT of trouble.