The Amp Garage

First of all, this looks awesome!

But also, you are located in Bellingham? How have we not crossed paths??

Oof. This one was a rough read since i can just imagine the same thing happening so easily. But seems like you handled it well and that the resolution was nearly as good as getting full payment for parts and labor. I luckily haven't had to deal with any customers stiffing me on the bill at this poin...

I have seen a surprising amount of Fender RI amps from the late 90's/early 2000's era that have leaky coupling caps before the power tubes and have caused bias drift that is higher than I will tolerate.

I have started routinely changing those caps as well as part of my service on these amps.

Since you posted this I have told a buddy i could help build him a 300W amp so I will be following this thread very closely! I did read up a bit more on the Meatsmoke circuit in the last few days and saw a lot of references claiming it is a "tweaked SVT preamp with a Mesa 400+ power amp" or somethin...

Heads up that Ben Verellen is a super nice guy and may even just send you the schematic if you email him. This is the email that i used to get in touch with him last: verellenamplifiers@live.com I started tracing a Loucks that I had on the bench, and those things are put together tighter than a drum...

Finally got this resolved and had to close the loop on it in case anyone else comes across this and has the same frustrations that I did in solving this. The short version: THESE AMPS NEED SOMETHING PLUGGED INTO THE INPUT JACK TO PULL FULL IDLE CURRENT ON THE POWER TUBES The longer, more frustrating...

sluckey wrote: ↑Fri May 01, 2026 11:15 pm

Bobwith2Bs wrote: ↑Fri May 01, 2026 3:56 pm Took forever to track down a schematic for this one (will post it on the thread in a bit).

Where's the schematic?

Just got home from work. Attached the schematic to the initial post.

Stevem wrote: ↑Fri May 01, 2026 10:38 pm To me -40 sounds cold for a EL84.

This amp has EL34s.

Yeah, the compu-bias i typically use has a similar setup but wires come out the side of the tube socket adapter...

With the Blackstar amps the tube sockets are recessed low enough below the chassis that there is no room to get them in there.

Thanks everyone! I guess i should have mentioned that the transformer winding measurement was my backup plan, but was hoping someone knew the bias test point voltage that is expected on these. I will dive back in and report back with where that voltage lands in case anyone else needs the info in the...

Anyone have info on these amps? I have a Blackstar HT Studio 20 on the bench. Just needs some power tubes swapped but the tube sockets are recessed so far below the chassis that it is impossible to get my bias probe in there. Took forever to track down a schematic for this one (will post it on the t...

Do you remember what switch you ordered for the impedance selector replacement? I need a couple for some V4 rebuilds i have going on. I think i just ordered some Switchcraft DP3T slider guys like this but haven't installed them yet: https://www.cedist.com/products/slide-switch-switchcraft-dptt-3-pos...

Have any of you that have placed an order recently from PCBWay or JLCPCB to the USA had to pay a tariff for the minimum order?

I haven't ordered any pcbs since all of that started and am curious what what to expect in tariffs for a set of 5 boards.

I'm not sure if it is still around or active but there used to be a "SloClone" forum.

Okay, thanks for the confirmation!

Sounds like rolling with what is available and adjusting the circuit as needed is the best move going forward. Thanks again!