We're On a Roll... Yet Another Express

[jeff12]

Howdy

I know we have some really talented cabinet builders on TAG. I'm not one of them, so I try to spread my business around. This will be the third cabinet that Jeff Jones has made for me, and if you don't already know, he does really beautiful work. Not sure whether he prefers to build entire amps or is OK with supplying just cabinets, or what his usual turnaround time would be, but you might give him a try.

Cheers,

Greg

Thanks for letting folks know about my cabinets. I would be happy to make some cabinets for folks here, as time allows.
Looks like you have been hard at work on building some cool amps.
I need more hours in a day to keep up.

[dcribbs1412]

Thanks, Darin,

No, those are electrolytic, molded into plastic housings. They only do it for the smaller size caps.

http://www.mouser.com/ds/2/427/138aml-239889.pdf

I used to use smaller tantalum caps for pedals and inboard guitar circuits - how would they perform as amp bypass caps?

Cheers,

Greg

Thanks Greg
I have not tried tantalum caps in tube amps
except for presence and FET circuits in D style amps

Darin

[gktamps]

Slowly breaking in this amp, doing a little tube rolling while Jeff completes my gorgeous cabinet, and started another Rocket in the meantime.

So far, it sounds great. No bad habits yet, very stable, small amount of hum, attributable to the Les Paul I've been using, which needs some attention to the pickup shielded wire connection. No hum with my Ibanez RG3120. No obnoxious hiss, snap crackle or pop, just excellent clean to mean as hoped and expected.

I ask forgiveness from the purists, as I know how deviating from the KF components is strongly felt to make a big difference. As you can see, my grounding scheme deviates from the bus, but this system has worked well for me for several amps now. I used Merlin's scheme for the heater wiring for the power tubes, rather than looping below the sockets.

Also, I used an oddball mix of capacitors. Not sure how to give an objective evaluation of the caps in each position, but the tone seems really well balanced, if a tiny bit bass heavy on the neck pickup, but the quality of the dirt and distortion is really musical, with lots of harmonics and pick sensitivity. And that's with barely an hour of time on it so far. My rationale was as non-empirical as it comes. I used the Solens at the PI, just speculating they could be a better choice where the preamp voltages are higher; used 716p caps because they are the only ones I had in that value for that position; and the STKs because they looked interesting, and I thought they might perform well in the tone stack. Completely nonsensical, but so far, definitely musical!

Next installment after faceplate is installed and chassis is in the cabinet.

Cheers,

Greg

[gktamps]

Hi Dave,

Now that the amp has about 15 hours on it, it is breaking in nicely. The STK caps seem to be excellent. The amp has a really well-balanced tone, really nice cleans with the guitar turned down, great grit and distortion when turned up, and it thickens up nicely. The mid and bass tone control response is excellent, with no flab or mud until the bass is turned way up, then just a little boomy. Seems to me the STK caps are pretty nice.

Actually, the amp sounds so good, I don't intend at this time to make any changes to the mixed selection of caps. The Solens and the 716p also seem to be really nice in this amp.

I still haven't A/B'd the flyback diodes (vs. none), but it's next on my list before this goes into the cabinet Jeff made for me that arrives in the brown truck today (!)

Nearing completion is another Rocket, this one with Allyn's Pacific transformers in his chassis, along with my now pretty standard modifications (filter caps, gain options, capacitor choices). I decided to go with NOS Russian PIO caps for C6-C11, then standard Mica, and PVC Cut Cap. Should be able to fire that up tomorrow.

Cheers,

Greg

Looks good Greg. I built a few hybrid platforms. How do you like those STK caps? Do you have any opinions about using flyback diodes vs. not?

[Colossal]

Nice report Greg! I did install the flyback diodes, more for completeness but function as well. I didn't really notice a change in tone so they will stay. I have used 716P in an Express test amp and I liked them. I did not find them sterile.

[gktamps]

Thanks, Dave. I have not found any aspect of this build to sound sterile or stiff. In fact, as it has broken in, it is producing very controllable feedback and sustain while retaining good articulation (more than I can produce these days with my aging hands).

I'm not getting that with my more traditionally built Express - the new one has much better tonal balance and more pleasing, musical distortion than that amp, which has a paralleled V2 and 715p caps. The tone is too thick and forward for me, with lots of fatiguing gain and harsh distortion, which prompted me to use a 5751 in V1. This new build has inspired me to return to single triode V2 and re-voice it in the near future.

Cheers,

Greg

[gktamps]

She's now in her beautiful cabinet, made by Jeff Jones.

[jeff12]

Looking great,nice build.

[cbass]

Looks chewy