Tech21 Trademark 10 (small combo amp w/SansAmp GT preamp)

[Steve A.]

I've had one of these for a year and a half now and I'm looking for a schematic for the ss power amp section. I use the amp strictly in the clean mode, with the output quite a bit less than the Marshall and Mesa Boogie modes. To play gigs in small bars I will insert a BBE Boosta Grande into the FX, which works great. But I would like to look at the schematic to see if there is some way I can increase the signal going into the power amp. (The amp has a really nice Fender simulation, along with reverb with real springs- my favorite practice amp!)

Thanks!

Steve Ahola

BTW I checked out the Trademark 30 last summer, figuring that it was exactly what I was looking for but it did not get any louder than my Trademark 10. With the 10" speaker it did get a really nice sound which was fuller than the 8" in the Trademark 10. But I did not consider it to be enough of an improvement to justify the price ($275 w tax) especially since I got the TM10 for $129.99.

[Nyqusit5]

This is one great little combo. Also very good for recording thanks to the XLR output and the Sansamp circuit. I do all my demos with it.

I don't have the schematic and although I am sure that the signal going to the PA can be increased, the circuit is pretty much all SMD and therefore not modder-friendly. However, there are several alternatives that can help you reach your goal:
_ you can use the FX loop output to drive an additional guitar amp (through its PA in or FX loop return). I did this once for a gig in a 1000 seater and it worked great.
_ you can plug into the PA using the XLR out of the TM10 (with the speaker simulation NOT off). It sounds very, very good, if you engage the low cut filter of the mixer's channel,
_ you could also use an alternate enclosure with high efficiency speakers (Vintage 30s, centurys or others). I use mine like that.

You will have to more or less modify your tone settings in all cases but it should work well. Hope this helps!

[Steve A.]

I need to take another look at the pcb- I understand how much of the circuit is SMD but there are the pots and heatsink'd output devices.

Running the boost pedal in the FX loop seems to do the job but I was thinking of a more elegant solution- even tapping a 12vdc power supply from the amp would be cool since I could leave my Boosta Grande plugged in- maybe even mounted to the sidewall with velcro.

I tried several other speakers last summer, seeing if I could make it sound more like the TM30 but the stock speaker in mine is very flat and very efficient.

Thanks!

Steve Ahola

[J M Fahey]

As an option, you might make an extension cabinet, with an efficient speaker plus an LM3886 or TDA7294 50/70W chipamp embedded.
You may even use a small yet efficient 10" Eminence, to keep size at a minimum.
Not even a control panel, just bolt it to the cabinet floor and add a small aluminum plate with an input jack and an IEC power connector (well, maybe a LED too).
At rehearsals or small gigs, use yours as is; in somewhat larger ones, bring the "extension cabinet" and use it as a stand for the little combo.
Best of both worlds with minimum fuss.
jm2c

PS: it works well in the real world: I sold tons of similar amps to guys who bought small, excellent sounding 2xEL84 or single ended tube amps and got drowned on stage in a bad way.