The Amp Garage

The first amp shown has a different screen circuit than the first one. The first one has that 2.2K attached to pin 5 and then pin 4 gets a 470 to ground. The second one is a traditional Fender screen supply with pin for bridging to pin 6 - but no values so will assume 470 ohm. What's the deal here? ...

bepone, thanks for the direction to Modulus Amp. You are right, they have a lot of nice things there.

I just installed this in a Ceriatone factory built JTM100 amp (quad of Gold Lion KT66s). A little history, the amp has a few extras installed in it: a half power switch, a PPIMV, a 3-way NFB switch (different than the Robinette 2-way although it occupied the same type switch), and a non-powered EFX ...

Thanks for the comments. I'm turning it 90 degrees, there's room and I know this has always worked for me. As to the headphone deal, yes, I appreciate there are a few ppl who abide in this method but I'm not that anal about the task. Besides, it always looks wonky and, too, I've never seen any white...

Weird thing here? The chassis you show has the PT and the OT oriented the way I would build an amp - however - when Marshall made these amps the orientation was diff. In the Marshall product the coils were turning the same direction (in a line) and not with the OT 90 degrees to the PT. This post cau...

Red? As in Communist China no doubt. You guys need to get out more.... :lol: "Red Series On paper, the RED Series products are nearly identical to our renowned Vintage Replica line. The only difference is that they are assembled in our international manufacturing facilities and will be offered at a ...

MV could fit next to the pilot light? Especially if it's a micro size like the stock pots. $1900 just amazes my senses.

The YT video demo was a surprise and also an ear opener. I've never really paid much attention to the Fluence humbucking pickups, only the Greg Koch videos with the P90 versions. Thanks for the post.

I was wondering why I was seeing so many NOS Mallory tubular yellow metal film caps lately. I won't comment on how they might sound different, but I can point out that there is an easy way to determine the old from the new. The old yellow 150M Mallorys are stamped with a four digit date code. In the...

Thanks for the input, LOUDthud. Your explanation makes perfect sense. I will add that some of my confusion exists because the use of a continuous NFB pot doesn't seem to have a problem? My thinking was a 'make then break' switch would behave in a similar manner. Oh well.

Follow me down this rabbit hole for a minute. Let's talk about this type of switch in a NFB loop. If the switch was truly 'make then break', it seems to me that switching between two different resistive values connected to the PI tail could be accomplished without turning the amp 'OFF'. Say for exam...

I've sorted the reverb problems I was having with AAE PC board build. Yep, it had some serious reverb grounding noise that stalled the sound sample process, very strange vs. what I've experienced with a trad built PR. Even what seemed like voltage on the chassis via the reverb return. Basically, bec...

Update. I will keep the 1K resistors on the tube sockets but after running through a few resistor options (in series with the choke) it turns out that with this particular ClassicTone OT (if I was set on using a choke) I should have initially started with the a vintage AC30 choke (the Hammond 194E c...

Update on the playtest. Changed the screen resistors to 1K and still find the screens hotter than the plates, around 3-4 volts hotter. Looking at the Marshall 18W circuit and looking at the Marshall OT (that this OT is a copy of), I see that the screen (choke) resistor is 8.2K. This was something I ...

I'm all wired up at this point, ready to start connecting the many leads. I confess, the multi-colored wire that Andrea presents in his build diagram might make this last part a bit easier. However, yellow wire was on hand... A couple of things I'm doing diff from the stock AA1164 is to add a Band-M...