Advice for salvaging old amps?

[Boxnix]

I saw a couple guys talking about finding old radios and phono's and getting the iron, tubes and sockets out of them. I would love to try this for my first 5e3 build. I know a kit is recommended but I'm more interested in learning than having a working amp next week.

Are there certain amps you guys look for that are known to have the right sized transformers and tubes for a 5e3 or do you just have to design around what you find? It's gotta be hard to figure out the specs on an old dusty xfmr on the spot right?

[olddawg]

Just about anything with a couple of 6V6 output and a couple of preamp tubes will work. Old organ amps and PAs have more usable chassis if you go that route. I would look around yard sales and thrift stores. The damn things are more than they are worth on eBay nowadays, especially with shipping charges, and half the time you get a bad power transformer. I usually just use the iron and vintage tubes and start with a new clean chassis. It's inexpensive to make a new tag/turret board with new reliable components and jacks, switches, and modern ceramic tube sockets with shields aren't a major investment either. Sometimes I will reuse some parts like pots, switches and jacks if they are pristine.. You want to avoid old component headaches. If you can, measure the voltages on the PT and label the leads. Also label the primary and the taps on the OT before you gut an amp if it will power up. Do it with a speaker load. Mono PP amps make easier conversions than stereo single ended amps, but you can convert a stereo single ended amp to a mono PP if you don't mind sourcing a different output transformer.

[tedmich]

greasy old iron can be useful but also pretty trashy; between Antek (PTs) and Edcor(OTs) there is some very reasonably priced new iron to be had! And they tell you what all the wires are....

[petemoore]

You want something with a PT, to isolate the AC input.
Make sure you IEC, Earth first, grounded plug.
An amp that kinda works a little bit [even sputters means the PT and OT are 'probably good, I've seen a smoke stained OT that were not exactly good tho.
Basic get it going work:
Filter Caps and tubes that work usually get it going to good working status [clean replace pots, etc.
Tweeking it:
The circuit for organ or tape or Hifi may have more bass than you need [want], and may be nice and conservative [I like conservatively rated systems...trimming the bass means smaller staging caps will do it, there may be other ways.
Rebuilding it:
Leaving the heater wires, perhaps the gridbias or other resistors in place, getting rid of everything else...new tube sockets to go with newly assembled circuits certainly helps produce a clean and reliable unit. Use a wire toothbrush/steel pad [I like coarse] on the chassis, to my likings, it is well worth cleaning the old, fitted, laid out, drilled chassis and transformers.
Then just pick a circuit that puts the same load on the heaters [uses original tube compliment or if removing tube say for something you don't need, loading the heaters to be within +/- ~10% of the filament voltage requirement.
If changing a jack, be sure you're not introducing a chassis ground connection.