Tube Amp Archive

Hey fellas, After repairing a Princeton Reverb clone (Headstrong Lil' King to be exact) I got a bit hooked, and I really want to build a Blackface Fender from a kit. I love the simplicity of the Princeton, I don't really care for the dual channel setup of its big brothers but it's really difficult t...

Hi guys, I've got an old JCM800 with the SE Lead mod, which I totally love apart from the low end being a little loose. Not a big surprise with 4 gain stages, all 22nF couplers and 100k/4ohm NFB, though it has a 100/100uF filter cap between the B+ resistors that tighten things up a bit. I'm not sure...

That’s interesting, I’ve noticed several errors as well. The last amp I built was a legit 2204 JCM 800 and it sounds great. I found myself setting it very differently for high and low gain tones, so I decided on a Jubilee based build. I’m building it now, slowed down a bit by the panels. I’ve been ...

Hey guys, I might have posted about this some time ago, but not in this forum I think. For a really long time I have been chasing the ultimate compact rig, considering everything from tube preamps with power amp simulation/IRs to Kemper and other digital solutions. Kemper is great, but the Powerhead...

Funny thing about the Silver Jubilee circuit is that even the official schematic isn't necessarily accurate - what I mean by that is that my amp could be an earlier revision, but I compared the official schem to my original '87 2550 (left the factory in September or October) and there are quite a fe...

If you're using the later Presence control with the 25k pot, then yeah, that thing does nothing up until 7/8. Works ok with little NFB (100K on 4ohm), but with anymore then I find it horrible to use. So much change in such a small range! With regards to the treble pot, you could change it to a 250K...

The official clip sounds good, although slightly too hairy. Tweaked sounds best, more control in the sound I think. Did you have the Treble and Presence on 0 in the tweaked clip? Cheers man, I sent it over to Jay and according to him that's how it's supposed to sound. The owner thought it sounded g...

I'm aware that they did do a fair amount of testing out different companies including Mercury, and ended up going with TDS. As far as all the design specs go, I only know that with their 15w models they ran the OT's at 4k, a lower primary impedance than the usual 6k -8k most amp manufacturers seem ...

the 2203 is brighter than #34 due to: - the 150k resistor on 34 - the 220p snubber - the 2n2 peaker - more gain and compression gives a thicker, tone with more harmonic content But #34 is brighter because of - the partially bypassed cathodes, although this boost low mids and high bass, not just hig...

he recorded with G12Ms and the #34 on UYI. a stock 2203 sounds as bright as the #34 imho The #34 is more about the high mids I guess, but the 0.1uF cathode bypass in particular adds a LOT of high end content as well. As does the 0.47uF cathode bypass and 2200pF treble peaker, a single 220pF plate b...

Only seen this on the Friedman Dirty Shirley, in conjunction with a 470k resistor between the PI grid and the 10k. I'm assuming the two are counteracting each other to a degree. I did try that circuit in my old JMP, but of course a lot of other things were different from a stock 800 so hard to say e...

Thanks a lot for posting, is this done by Dave himself? A few interesting things there that deviate from the standard BE circuit, like no cathode bypass on the pre-CF stage and no plate bypass. Also looks like that yellow coupling cap is 22nF?

Dave Friedman worked on the #34 amp and he himself said it was a ridiculously bright amp. What speakers are you testing it through? https://www.youtube.com/watch?v=y4_3CSZkVHU&t=1s Here is that amp through a Marshall 1960B cab, which I think has G12T-75 speakers. Pretty sure Slash uses V30s almost ...

Hey guys, I recently started accepting other people's amps for modding, after working on my own for a few years. My first job was a '77 JMP with a Friedman style mod not too long ago, and I also did a Vintage Modern for the same guy quite recently. Yesterday I got a 2203x in for a #34 mod, which is ...

Hola amigos, I've recently found myself outside of the familiar and comfortable modded Marshall camp, as I recently acquired a few hand built amps for a steal. One of them is an AC30 clone, I love the top boost channel but the normal channel is not my cup of tea and I've always heard such great thin...