A212 Question

[Sunn-y-boy]

Hi all, I just got an A212 combo amp that somebody repainted and covered all the lettering that tells what the knobs and inputs and switches do. I've figured out what some of the knobs do, but not all. I read on this wonderful site that this amp has distortion, but all I get is clean sounds, even with the channel volume up all the way. How do I get the driven sounds? Can anybody tell me what the knobs and switches should be labeled?? A picture would be worth a thousand words if there is anybody out there with the same amp.
Also what can you tell me about the 128g transducer speakers that this amp has.
Any information would be greatly appreciated.
thanks,
Sunn-y-boy
P.S. I live in Portland, OR and i think that Sunn used to manufacture right down the road from me in Tualatin but, I still can't seem to find anybody that knows about these amps in town!

[Isaac]

Yes, Sunn used to be in Tualatin. I visited the factory twice, I think. It was in Amburn Industrial Park, IIRC. Before that, it was in Portland, but that's before my time.

[Don T.]

Hello:
 If you are talking about the Alpha 112 / 212 series amps, they use the same cmos distorstion that the Beta's have. There should be a drive and a master volume level.

I believe the 81-0128 speakers were 16ohm versions of the 81-0126. Should be a round 30 oz magnet, 1.5" VC, with a mesh dust cover. Great sounding yet cleaner and punchier than Celestion. Although, retrofiting with the latter was a common occurance. Earlier versions had the speakers with the metal dust cover with a vent hole in the center.

[Isaac]

No, the A212 is a tube combo amp that came out in the early 70's. It was available then, anyway, and was in my 1974 catalog, back when I had one.

[Sunn-y-boy]

Yes Isaac, this is the tube model, made in 1974. My brother found it at a second hand store for $25!!! It works and sounds great. There is a master volume on the far right, but, I still can't get any overdrive, even with the channel volume maxed. I tried different preamp 12ax7 tubes and they made it sound more clean.(and damn, it's LOUD).
Any info on labeling the switches would be great. (I think the red ones are a bright switch)

[Sunn-y-boy]

Is there anybody out there?
Nobody knows the treble I've seen.

[Isaac]

I'm here, but I don't see what I can do without getting my hands on it. So, unless you're in Oregon, or maybe Vancouver WA, I can't help. On the other hand, if it's just not suiting your needs, I'd be willing to take it off your hands...

[Guest]

Sunn-y-boy.
Check ebay for Sunn amps.There is a current listing for a Sunn A212 amp.
Item number 3741052754.The product description might have the info that
you are searching for.You might get in touch with seller and ask if he can help you in anyway.(?)

[Isaac]

Yes, I read that ad. One of the switches is a Low-Normal-Distortion switch. If you think it's a bright switch, and keep it off, that could easily prevent getting any distortion.

[Sunn-y-boy]

Thats got it!!! Now it works and sounds great.
Thanks to you all for your help.
Now here's a question, The footswitch only controls reverb. Is there a way to hook my guitar up to both channels at once and a/b select between the two?

[Anonymous]

Not built in to the amp, I don't think. Shouldn't be difficult to make an A-B box, switching between the channels, though. One input, one DPDT (double pole, double throw) switch. Wire the poles (the center two connectors on the switch) to two outputs, one to each channel. Wire the input from the guitar to opposite corners, then the remaining two to ground. That should do it.

[Sunn-y-boy]

An a/b switch is a good idea for going direct to the amp from the guitar. I have a stereo guitar preamp effects unit and I was wondering if I could hook the left output to one channel and the right output to the other. Then I could use my footpedel to MIDI pan between the two channels and have a clean/drive blend. Do you think this would hurt the amp? It would be connecting the grounds from both channel inputs through the effects box. Bad news?

[TubeMan]

Hey Sunn-y

im so glad to see more and more people enjoying these amps. i was starting to think i had the only one in existance.  

anyway.. you are right that they are mind numbingly loud.. but there is very little distortion. i believe the main reason for this is the fact that the preamp is wired in a split-rail configuration like a solid state amp. this in turn uses negative voltage to operate a an additive mid boost.
the split rail ends up with a gain of unity and the mid boost serves to up the apparent volume considerably.

i recently experimented with mine and removed the split-rail circuit. i rewired the amp as if it was a 2 tube model t. the wattage was the same, but the apparent volume decreased by what sounds like half. it is also much easier to break up into a nice crunchy but singing overdrive.

i have plans to add a preamp tube and put the mid-boost circuit back in, while still maintaining the added gain of a standard wiring configuration.

stay tuned on that.

Also, JoeArthur has loads of information regarding this type of amp.
We have been in limited correspodance in the past and i surmised that his second gen Model T is very similarly (if not identically) wired to my A212... at least in the preamp section.

[pafballou]

I finally got one of these rascals and all i can say is "Oh My God"

First is it the loudest amp I have ever played through. Way way way louder than you would expect from a 212 combo.

Second, it is clean and warm and just completely blows my rocktronic twin out of the water for sheer spirit

Finally, the distortion is perfect. Just plain authentic..organic. Better than any kind of peddle or overdrive set-up.

I love this amp