An even smaller special

[telentubes]

Progress on another 50 Watt Small Special, This time squashed into a 2.5 X 8 X 15 inch chassis.

[Synchu]

Looks excellent!

You really seem to like this amp, don't you?

One of my favorites so far as well. I've got quite a few requests locally for building some more, but with a day job, two small kids - it will take forever.

Niki

[telentubes]

These things are great. Might be fun to build one with reverb at some point, and the original 100 Watt version as well. Thanks again for your work on this.

[Synchu]

Thanks. I would think that a 100 watter should sound even better and there are a number of good sounding one tube reverb designs out there that will complement it just fine.

[xtian]

I read a handful of threads on "small special" but couldn't find a schemo or layout. What are you using?

[Synchu]

The layout is posted here:
http://ampgarage.com/forum/viewtopic.ph ... c&start=15
A schematic can be found here (there are some values changed in the layout though):
http://ampgarage.com/forum/viewtopic.ph ... 6&start=15

[sunny]

This looks great!

I'm collecting the final parts to build something like this 50w version as wel, incl. reverb and some extra tonal options.

You guys motivate me!!

Paul

[telentubes]

Progress pics. Put some components in place and stuck the chassis in the cab to see what it will look like fini.

[Aaron]

That little combo looks great. Nice little jam amp.

Aaron

[telentubes]

Finished and burning in. So far, nice sounds. I changed the first dropping resistor from 2K2 to 4K7, and added a second bright cap (100pf and 180pf) on an ON/OFF/ON mini toggle. I don't use either, nor do I on the first amp. Best to my ears without.
Voltages later.
I like the caps and resistors in parallel with the diodes on the rectifier. Smoother, or just an illusion?

[Dr d]

That looks fantastic! Really nice build quality. I love the simplicity of this circuit....and what a sound!

[telentubes]

Hey Dr D, Amazed at how much you fit into that chassis on your project! Puts my claims of "squashed into a 2.5 X 8 X 15 inch chassis" into perspective.
"Small Specials" are the new "Rocket". Everyone should have one!

[Deric]

Nice!!!

[Synchu]

Looks great (and should sound the same, right? )!

I have a bunch of inquiries to build this amp from friends. Wish I had the time ...

[telentubes]

Well I did have to do a little tweaking to get the voltages closer to spec after all.

In amp # 1 and amp # 2, I changed the bias-pot resistors from 27K to 33K.

In amp # 1 the dropping resistors were changed from 2.2K and 10K, to 12K and 9.1K

In amp # 2 they are 10K and 10K

Amp # 1 with JJ 6L6s.
V1, 237V, 237V
V2, 293V, 295V
V3 and V4 plate, 441V
Bias is, 38mV and 39mV, at -47
B+, 441, 441, 376, 354

Amp # 2 with Winged C 6L6s
V1, 238, 239
V2, 269, 269
V3 and V4 plate, 447
Bias is 33mV, and 35mV, at -46
B+, 448, 447, 379, 355

Amp # 2 is in a combo cab with an Emenence "Swamp Thang".
Amp # 1 doesn't have a home yet, but it will also be a combo.