yeah, anytime i have a panel fabbed i include those key holes, but i dont have the means to DIY something like that. also didnt have any non-keyholed washers available, so here we are haha.lookin' good-- please get the toggle switch washers right; the littlr hook is to prevent the switch from turning, and needs to fit into a divot on the panel (preferably the rear side).
but really nice and clean so far
sure! they came out of an old MCI console, 10k:10k for the input, 600:600 for the output. havent ever been able to find a spec sheet for them or anything, so i cant tell you too much more than that other than i liked them a lot in other projects.
If you're looking for new production, AMI makes some but only for the A-10, A-24, and A-26. There's a slew of UTC A-21s on eBay currently, but not exactly for cheap. Other than that, Thordason made direct replacements for most, if not all, of the UTC A line. Wishing I hadn't sold off all my UTCs at the beginning of the pandemic—sure seems like they've tripled in value in the last two years.
There was a seller on eBay from Poland that had several, but as of now they appear sold out. I bought ∼25 before I found a strong matched quartet, just as a warning. If you're okay with less than 3% tolerance for a stereo pair, I can sell you what I have. Just let me know.Where are you guys finding 2n3820? Is there a known equivalent?
Thanks for the heads up. I *might* have found a supplier that has about 750 NOS 2n3820 in stock. I sent a quote request out so I'll know soon. I will keep you in mind if nothing else works out. Planning on picking up about 40 so I can match enough to make two units. Sweet spot seems to be 1/5 for most people.There was a seller on eBay from Poland that had several, but as of now they appear sold out. I bought ∼25 before I found a strong matched quartet, just as a warning. If you're okay with less than 3% tolerance for a stereo pair, I can sell you what I have. Just let me know.
If they are being used 1:1 there are countless options. It depends on your definition of "good". If you mean similar to UTC, then yes, the Thordarson are a great choice. If you mean vintage, there are Triad A67 for about the same price. Hammond (old or new) are excellent, as well as the usual suspects like Jensen, Cinemag, etc.
the MCI's i put in mine sound great, and are available for good prices. I think someone actually has some for sale in the black market right now, but honestly I imagine any suitable 1:1 from the usual suspects would do just fine in this circuit. I have some cinemag opt transformers that would work that i might throw in just to compare but im not sure how worth while that would be