Started New Express build

[cesout]

I like seeing somebody else building an Express that isn't laying the thing out millimeter by millimeter identical to the real ones. Come on folks, it doesn't matter that much as long as you aren't doing something blatantly ignorant.

I recently built one and did it close to the original, but I used a different grounding scheme (star/buss) which only ties signal ground at one point to the chassis. Very quiet and it favorably affects the sonics when the ground return currents are handled correctly.

I was tracking down a weird 'ghost' note (E-flat high E string, 11th fret) and fiddled with hot gluing the wires down, etc, nothing worked. Tried different tubes, etc. Eventually I re-soldered all connections, which I thought were OK but turns out something was cold. Problem disappeared.

I'm building another with different turret boards, each one right at the tube with it's cap. Waiting on three resistors to finish, so I don't know if I've got the goods or I'm back to the drawing board.

[Reeltarded]

Come on folks, it doesn't matter that much as long as you aren't doing something blatantly ignorant.

Now you have me paranoid. I must remember to turn off my webcam before I work from now on.

Cool amp there. On the notta-marshall stuff I do I spend half my time trying to get magic things to happen around the cf/slope/treb cap area of the board that I ignorantly bumped into while being ignorant.. err.. careless.

[cesout]

Of course there are those moments of blatant ignorance, like posting a whole new topic instead of a reply... yeah.

[Reeltarded]

I see that.

Tom the kindly wonderdood will come along and wipe all evidence away as soon as you beg him and send $29.95 to:

Fix Me
(Thread Title Here)
paypal pobox511@ampgarage.com

[cesout]

Hot dang, I'll go ahead and send in double cuz I know I'm gonna do it again.

[M Fowler]

Looking good Mark, nice to see another build using this layout! I went back to the old-school presence on my Express because the presonance whistled at some extreme settings. I liked the tones, though. It will work either way, and it's easy to switch over, as described at the end of the thread on that amp. https://tubeamparchive.com/viewtopic.ph ... 761#209761 I could not be without the PPIMV and cut.

I got my last G-10 board from McMaster, a 12"x24" piece... that's how the eyelet board in the amp got to be 12" long ;^)

Unless I dial the presonance past 2pm or so it feed backs when turning up the master volume. Not sure what that is from, will press on because I like the tone of this amp. Nice to be able dial in some great low end

I did have to get out my trusty dental mirror and move a ground wire under the board that was apparently some how grounding out one cathode of V1. Moved the wire and presto

Also, had to make a new shielded wire for 820R grid to volume wiper because it was grounding out. All fixed now.

Mark

[martin manning]

Mark, recall I was able to kill the squeal with the cut control. I believe what is going on is the resonance end of the presonance creates a phase shift in the FB signal that brings it too close to 360 degrees. I gave up, but others are using it successfully on Expresses as well as Liverpool's.

[Colossal]

I do have stability in the Presonance circuit, but I do have a cut control as well. My upcoming Express and Liverpool builds will be stock however.

[M Fowler]

Thanks guys I did copy and keep Martin's instructions for converting back to presence and Dave's notes.

Got to get another JCM800 combo built and then back to the Express.

Mark

[cbass]

My presonance in my concorde like build is stable.I just made the layout up as I went a long on a board meant for a marshall so who knows why it works.I'm gonna build a real one one day but that takes money and these dang kids want to eat like everyday.

[cbass]

That is a different layout, nice to see.
Is the cab in the picture the one you call the "100 dollar cherry" cab from Ebay.?
Thanks

Here is the $100 ebay Cherry cab unfinished, hope to start on that soon but not sure what color tone I'm going with in the stain.

Trying to keep the build cost way down on this one.

Mark

Spray with lacquer and set in a sunny window for aout a year no need to stain.

Cool amp by the way

[LeftyStrat]

Spray with lacquer and set in a sunny window for aout a year no need to stain.

Yeah, one of the things I love about cherry is that it will darken with age. It will develop a deep color no stain could match.

[Bob S]

Not sure why my Liverpool Presonance works.
It gets a little squirelly at the extremes of pot sweep, but otherwise it is very versatile.
Maybe just good luck.
I also power scaled the whole amp without any additional caps.
Hmm.
My luck is usually the other kind.

[Reeltarded]

The Martinizer worked in one of my amps, but not in two others without sending the output into an electron storm when the control is fully res end.

Love that control! 2 in the place of one is always great.

[C Moore]

That is a different layout, nice to see.
Is the cab in the picture the one you call the "100 dollar cherry" cab from Ebay.?
Thanks

Here is the $100 ebay Cherry cab unfinished, hope to start on that soon but not sure what color tone I'm going with in the stain.

Trying to keep the build cost way down on this one.

Mark

Spray with lacquer and set in a sunny window for aout a year no need to stain.

Cool amp by the way

Always had to be CAREFUL with un-finished doors.
If any sunlight got to them, it could be trouble. If you had one door leaning on another, but part of the door underneath was exposed to sun, you would get demarcation. Sunburn so to speak. Right through the window of a building. Even just a few hours of uneven exposure could be disaster.
best