The Amp Garage

I'd consider V2, grids or cathodes

820R resistors may read as high as ca 1k. if you really crank an amp 15nf may differ noticably from 22nf, mostly from a quicker response with less blocking distortion To be honest, I do like the 820R mode—it adds a pleasant warmth compared to the 2.7K mode—but I’ve been a bit conflicted because, wh...

Regarding the 18n, Valvestorm has been selling 18n NOS Mustards for a long time. Also 27n and 39n but sometimes they aren't available. Then they come back sometimes. 22n NOS Mustards have gotten quite expensive, these oddball values are relatively cheap. Also, the little red 47pF dogbones sound rea...

With the exception of #5, I’ve installed switches and tested for all the other points. 01.jpg 02.jpg Although some of these serve overlapping functions, each offers a slightly different nuance, which makes me want to keep them all. I could satisfy this desire by installing a few push-pull pots, but...

Marshall's are my wheelhouse. In my experience, the optimal combination varies from amp to amp. Some amps sound great with an 820R on the split cathode Bright channel while other get too loose/boomy in the lows. It also of course depends on your target tone. Is it at the dirty end of the spectrum l...

Here's a couple of layouts. …due to the 9k1 tail as opposed to the 24k tail in the regular OTS above. Also interesting is that they both attempt to eek out a bit more gain than the typical 82k/100k you see in most Fenders and Marshalls. Thanks! I will search the schematics of those layouts. I see t...

some new speakers worth trying w. trainwrecks: - blackback g12m 55hz: darker than the greenback RI, flatter response - v-type ceramic and neo: smoother, darker (the neo is a bit crisper and more articulate than the ceramic model) - g12m creamback 65w: less treble than greenback RI - g10 greenback: g...

anyway, there are no magic values. it is about finding the right mix overall - for a particular player.

I like my amps brighter and more unforgiving than many other do (and my hearing is still good)

I went down this rabbit hole too, not long ago. The article from Roe is excellent, also see the massive amount of historical data here: https://marstran.com/Historic%20Data%20Base.htm I am not sure why, but the database only contains 50W models. Still, it should give you a pretty good idea of typic...

- V1 cathode configuration (split vs. shared) - Bright channel coupling capacitor value - Bright channel bright capacitor value - Presence of V2 cathode bypass - NFB (Negative Feedback) value split 820r/330uf - 820r/.68uf 2n2 5n ? 47k a 1967 by contrast would have shared 820r/330uf 22n 100pf or 5n ...

as consequentialists, we may be required to maximize the value of amps by cloning and building maximally? Right on! Why get hung up on deontology? Let’s blow this thing wide open!! So let’s say the goal for DPS is to produce a small number of clones at a very high price and prevent others from clon...

as consequentialists, we may be required to maximize the value of amps by cloning and building maximally?

Got it Roe, thanks again. Upon re-reading my post; I think I misunderstood the switching. What I typed is still hot switching, isn’t it? Re: 1 - understood, RGKs “one true ground”. Re: 6 - understood, so 2 amp mains/.5 HT then? Re: 8 - also understood, so leave the DC routing from rectifier into th...

Thanks for the advice Roe! I was just reading up on the switching on these amps and came across a method to eliminate the “hot switching” that Marshall built into these. Let’s see if I can type it out correctly… 1. Connect the PT Center Tap directly to main chassis ground point. 2. Attach HT Leg 1 ...

schematic