for those of you that changed the preamp in your express

[wsaraceni]

what did you go with. i'm A.) not skilled enough to build a real good wreck clone and B.)not the biggest fan of the amp. i've seen a few people change to jtm 45 preamps. a few komet 60 preamps, and a few other things i cant remember. what did you guys go with? what part did you splice them together? power amp? phase inverter? gut shots? schematics? pictures?

anything you have would help give me some ideas. i was thinking of going to a komet style with 6v6s. maybe the concorde into a straight up express power amp and power supply. then i could run 6v6s or el34s. thoughts on how that would sound? work? would i be best to leave the 220k in the PI or remove it?

[dave g]

To start, just try removing the cathode bypass cap on the second stage. It's a very simple change but I think it might give you what you're looking for.

[wsaraceni]

oh. i dont have anything on the preamp board built. i was just looking at what others have done for some ideas as to what works and doesn't.

[overtone]

I was on the fence a long time over the express too. I really only heard one clip that really pressed by button.

2012 I went with Ian's Junkbox trainwreck (Gingertube), mainly because I also had a junk Australian PA too.

I slightly changed the circuit to my taste. Both our schematics are under the Junkbox thread in the technical section.
It turned out good, very musical. Not aggressive, until I want it to be.
http://ampgarage.com/forum/viewtopic.php?t=17851

No board, just good old rats nest ptp with old junk I had lying around on the floor.
Last weekend I switched from SS to tube rectifier and am still evaluating that.

As for the back end, cathode biased 6V6 right now, but have used 5881, KT66, 6L6 and just got some 7851a to try.
EL34 / KT77 are too much filament curent draw for the old PT.

tony

[HobbswheresCalvin]

http://ampgarage.com/forum/viewtopic.ph ... c&start=30

[wsaraceni]

chassis is in. ordering a faceplate set now. my last amp i ordered the faceplates last and had to desolder a bunch of stuff (fuse holders, IEC, pilot light, etc) and figured this time i'll just put them on there right away. i learned a lot from the last build so i hope this build goes a lot smoother.

[Smokebreak]

I learned a lot from building it up stock first, then going back in and dialing it back in various places/modding it. On one of mine I like no cap on 1st stage, 56k +50k trimmer between 2 and 3stage(should have put it on faceplate)Cap over one of the plate resistors. 6V6. Sure desoldering faceplate stuff can be a tiny bit annoying but it's better than scratching your faceplate while you build, if you mount it first.