1st EXPRESS gig

[Buschman]

I played it last night without a cabinet. It looked cool sitting there with the tubes a glowing like little Christman trees.I have a couple observations

Volume? I don't know what all the fuss is about. I played on about 1 oclock & it was fine. It was a pretty big room but the amp is not as loup as a 50 watt JMP mark2 I used to play. I would say it is right in there with a 4x10 Bassman.

I have to play with the preamp tubes some more. I could only occassionally get a note bloom & the sounded more like od order harmonics-like a vox would do.

The amp is brighter on stage than it seemed at home. I am playing through a 15" Blue dog. It wasn't harsh but I would like 2 Greenbacks better. Hum & buzz did not seem to be an issue with the lights in a live situation.

I played my D'Lite on 2nd set, turned way up. The D'Lite is a bit sweeter. Not as aggressive. Probably a bit better blues amp unless you like Gary Moore type blues. Volume wise they were not far off but I did have some dial left on the EXPRESS. The Express is definatelly punchier. I put 6l6s in the D'Lite this AM so we might have to revisit this.

I had intended to play my 60 Bassman for the third set but it wouldn't fire up. Wound up being a bad v1. I sure wanted a complete comparison but maybe next time.

It was a fun night with some of my toys. Thanks for reading my ramble! If I can get the Express to talk back a bit more I will be a real happy camper.

[BBQLS1]

Cool, I think Greenbacks would be just right for the TW.

[drhulsey]

I played it last night without a cabinet. It looked cool sitting there with the tubes a glowing like little Christmas trees.

I used mine without a cab for a few gigs, but now have it in a custom drawer I have had plenty of volume to compete with a loud drummer and a horn section, and I'm still getting used to controlling things from the guitar
I am trying out SED Winged C EL34's. I have some Schuguang EL34's to audition, as well. I would like to find a current production power tube I could live with. The Winged C's sounded good Friday night. I'm still trying different NOS 12AX7's.
I didn't notice the brightness as much live as at home. I thought it helped "cut through the mix" better than any amp I have used.
I had a great time building this amp, but a lot more fun gigging with it

[Bob-I]

Volume? I don't know what all the fuss is about. I played on about 1 oclock & it was fine. It was a pretty big room but the amp is not as loup as a 50 watt JMP mark2 I used to play. I would say it is right in there with a 4x10 Bassman.

Really? My only experience with a TWreck was listening to a few that friends have built, and they blow my 6L6 Dumbles away, like I wasn't even playing.

Great report. It'll be awhile before I get mine done. 3 projects ahead of it

[Lonely Raven]

I played it last night without a cabinet. It looked cool sitting there with the tubes a glowing like little Christmas trees.

I used mine without a cab for a few gigs, but now have it in a custom drawer I have had plenty of volume to compete with a loud drummer and a horn section, and I'm still getting used to controlling things from the guitar
I am trying out SED Winged C EL34's. I have some Schuguang EL34's to audition, as well. I would like to find a current production power tube I could live with. The Winged C's sounded good Friday night. I'm still trying different NOS 12AX7's.
I didn't notice the brightness as much live as at home. I thought it helped "cut through the mix" better than any amp I have used.
I had a great time building this amp, but a lot more fun gigging with it

I'm running a tired set of Winged C I picked up for $15 just to see if I liked them....and YES, I do like them! So I now have a fresh quad on the way so I have a spare set.

If you do find current production you like better, let me know!

[geetarpicker]

Try some of the new Groove Tubes EL34M tubes. I'm not kidding, they are some of the best tubes I've ever run in my original Express.

ALL of my video clips have been with those tubes, along with my old early 60s Sylvania 12AX7s.

GK

[Lonely Raven]

Try some of the new Groove Tubes EL34M tubes. I'm not kidding, they are some of the best tubes I've ever run in my original Express.

ALL of my video clips have been with those tubes, along with my old early 60s Sylvania 12AX7s.

GK

Interesting! That just turned me on my ear! (pun intended)

I never would have thought Groove Tubes!

Adding to list of *to try*.

[Fischerman]

You might try reversing the polarity on your speaker cable. I haven't tested this with my homebrew Express but I did with my homebrew ODS with built-in D'lator and it definitely made the amp feedback/sing better. There are different hypotheses as to why this is but in the case of the ODS...an odd number of phase-inverting stages before the PI sounds better with a 'reversed' speaker cable. An ODS with built-in D'lator has an odd number of phase-inverting stages before the PI where an ODS without the D'lator has an even number of stages (and an ODS without the D'lator sustains/feedsback/sings better with a regular speaker cable).

An Express has an odd number of phase-inverting stages before the PI so it's possible that a reversed polarity speaker cable might make it sing better. In any case, it's worth a try just to set your mind at ease that your speaker cable is the 'best' polarity for your amp. And it does make significant, noticeable difference in my ODS.

You ever tried this Glen?

[paulster]

An Express has an odd number of phase-inverting stages before the PI so it's possible that a reversed polarity speaker cable might make it sing better. In any case, it's worth a try just to set your mind at ease that your speaker cable is the 'best' polarity for your amp. And it does make significant, noticeable difference in my ODS.

I gave a similar thing a quick try on my Express the other day when I finished building a transformer-coupled amp splitter which I'd put phase reverse switches on (like a Lehle P-Split).

The Express and Liverpool both invert phase between input and output and switching the phase made a noticeable difference to how the feedback bloomed.

I need to do some proper experimentation with it because I was running it at home, unattenuated, and couldn't get away with it for long enough to form an overall opinion, but there's definitely something to be said for trying this.

Over to you, Glen!

[Buschman]

I will try reversing the speaker polarity. Who woul have thought!. I am currently running older Sventlana el34s. I have also tried a set of the older Teslas(pre JJ)They sound similar to me.

Who is manufacturing the Groove Tube el34m?

[dartanion]

Anyone have a technical explanation of why this phenomenon is true?

My 30watt Liverpool type build sings nicely, however my 18watt version doesn't so much. I've got to have the volume up quite a ways before this happens. Same guitar, same cable, same cab.

[ampgeek]

Stepping WAY out onto a limb here....but I *ass*ume that the singing phenom is the result of an acoustic coupling between the pressure waves exiting the speaker(s) and the vibration of the guitar string(s). In phase is generally additive and out-of-phase is generally subtractive.

When counting gain stages to evaluate this effect is it safe to assume that cathode followers don't "count" because that signal is in phase with that at it's associated grid?

Dave O.

[Fischerman]

dart,
There is a thread at TGP about it...it is regarding a Fuchs amp. I'll admit that I have hypotheses why but I don't know so I'll just say that with one polarity the sound coming out of the speakers drives the string and the other polarity damps the string.

[Lonely Raven]

dart,
There is a thread at TGP about it...it is regarding a Fuchs amp. I'll admit that I have hypotheses why but I don't know so I'll just say that with one polarity the sound coming out of the speakers drives the string and the other polarity dampens the string.

That's what people have said...but wouldn't room acoustics and/or distance from the amp change that?

Or is it the electrical coupling of the guitar to the amp, *and* the amplified acoustical coupling the key?

[klingo]

Hi!

Grounded cathode gain stage (not the non inverting CF) invert signal but not a real 180°. RC coupling , tonestack, transformer shift the phase (swirl?).
that's why it's picky to introduce negative feedback more than 3 stages before, imagine a 60° phase shift (common) at the same frequency on the three stages...3x60=180°...you have positive feedback

for the fun i would like to see the phase shift curve of a screaming guitar amp

Anyway, i remember a phase inverter switch between OT and speakers on a DC30 hand drawn schematic....i thought it was to match phase with the others musicians