• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

LA-2a for first project?

Teletronix LA-2A


I've done several opto comps, but not the LA-2A. While smashing sounding there's no really need for a tubed sidechain circuit. Also the PSU could do with an update.

I don't use the T4B gain reduction opto cell. It's too expensive and unreliable. I prefer discrete LDRs or Vactrols.

Beware there's several version os of the LA-2A, using UTC or Triad transformers for in/out. I'm not sure these can be found today. Perhaps you can get them as spare parts from Universal Audio (the company that currently builds it) or UREI (the company that used to build it).

You can also get the T4B cell from those companies. Very expensive and so are the trannies probably. I think Sowter (UK) have a direct drop-in output trannie..

All the tubes are availiable today at a reasonable price.

It's not too difficult to build, there's some VERY good schematics/articles on the net. Do you have those? I've also seen complete plans on how to to it yourself.

I'll dig the stuff up if needed.

Since a new UA LA-2A will run you about 3500US$ (same price as a good vintage, no coincedense, I guess) I do think it's worth to make one your own.

Lemme' know if you need nay help!