Moog Music Forum

I recently bought a Sonic Six, but there were some undisclosed problems. The scale pot is not working and Oscillator B is not recieving Keyboard CV.

Are there any Sonic Six owners out there who have experienced these or similar problems with their synths?

Im a Sonic Six owner and have had all sorts of problems with the synth.
The biggest problem being the 2 large curcuit boards which are connected by a rather large soldered 'spine'.

I have the synth working but there are always the tuning problems and intermittent things that just happen to pop up.

I wish you luck in finding service.

Larry B
Sonic Music

eric coleridge wrote:I recently bought a Sonic Six, but there were some undisclosed problems. The scale pot is not working and Oscillator B is not recieving Keyboard CV.

Are there any Sonic Six owners out there who have experienced these or similar problems with their synths?

i owned a sonic six until recently. when i got it, it also had issues with that scale pot. i couldnt get the thing to scale an octave across 12 keys. it was off by a half-step or so. i had my tech look at it. i believe he said it had something to do with the power supply. one side of the voltage is more or less than the other +/-. Something like that.

Anyhow, he's based in Boston if you want a contact. goo dluck. I will say that once functioning, the 6 is soooo bad-ass.

Thanks, I live in NY and I do have a really good synth tech; His name is Armen and he has a synth repair shop.

I was able to find all of the problems in the "trouble-shooting" section of the service manual, and for all it suggests replacing particular components.

However, within a few hours of writing the original post above, the entire synth went dead and won't turn on. So now I'm definitely going to have to take it in.


I was able to play it for a while though and definitely got the impression that this is a very strange and unique synth. Mine has the Moog filter I think, it sounds like it. But it still doesn't sound like any Moogs I've played. The Ring Modulator was particularly interesting. I was running a microphone through it and modulating by the LFOs. Very cool processing.

eric coleridge wrote:Thanks, I live in NY and I do have a really good synth tech; His name is Armen and he has a synth repair shop.

I was able to find all of the problems in the "trouble-shooting" section of the service manual, and for all it suggests replacing particular components.

However, within a few hours of writing the original post above, the entire synth went dead and won't turn on. So now I'm definitely going to have to take it in.

Ahh...yes...the wonder of it all!
Back in the 70's the Sonic was my only and main synth. A guy up in Boston(I live in CT about an hour out of NYC) was the only one who could fix it. I'd drive up in the morning, and back at night for the gig.....I'd turn it on....and....nothing!!!!
Like I said, that 'solder spine' was almost always the culprit.

Good luck and please keep us posted of your story!

Oh...BTW, my 'band' Sonic Music is named after the Sonic 6!!!

Regards,
Larry Benigno
Sonic Music

Oh...one more thing.
I hope all works out, because there is NOTHING that sounds like the Sonic.

I always thought it sounded like a cross between a minimoog and an Arp Quadra....especially since you can have one oscillator glide while the other didn't.

Larry B

Yes, I had similar problems with my Sonic Six. Oscillator B, after awhile, would hold the same note in the bottom octave... and work in the rest of the octaves for awhile... and then every note would scale down to the note that was held in the lowest octave. It was very odd... but that connector was to blame. I paid a lot of money for my tech to discover what that was and fix it. It was sad.
But I agree... the Sonic Six is a VERY cool synthesizer... I would buy one back, if I had the money, in an instant. It has a fantastic sound... very unique. It sounds really "discrete," despite the fact that it has ICs. The only thing it lacks is a decent envelope... but all else is great!

yeah, it did sound pretty good. Although, it is drastically under-developed in the envelope department.
It's amazing how much an envelope can contribute to a synths sound.

I'd like to get an external envelope module to use with this synth, but the S6
doesn't have a gate out to trigger an external ENV.

I've heard that people modify their Sonic Sixs for CV and Gate outputs. Does anyone know how this could be accomplished?
I have a schematic, and I have an idea of where to extract a gate, but if someone has already successfully done it, I'd love to hear.

eric coleridge wrote:yeah, it did sound pretty good. Although, it is drastically under-developed in the envelope department.
It's amazing how much an envelope can contribute to a synths sound.

While I agree that it is does not have the depth of the mini, there are different things you could do with it's envelope via the contour generator.

My old band used to be very disapointed when I would have to 'rent' a mini when the old Sonic would crap out

Larry Benigno

Fwiw, I stopped working on S6's a while back.
Too many that I encountered needed so many parts and time, they just cost too much for the client.
I was replacing so many caps, trimmers and carbon resistors, it was like rebuilding the whole thing.
It's a really strange oscillator design and the parts have to be very precise for good tracking, especially when played as a two voice.
Later ones are better in terms of reliability.

With all that said, nothing does modulation like an S6.
They're really amazing.

My Sonic Six is either 1277 or 11277, can't quite read it. This places it just above the cut-off for "later" S6s, plus it has all the artifacts of a later version, I think.

It has the darker plastic, the "Sonic Six Synthesizer" scroll and later S6 layout, the Moog sticker instead of the embossed Moog on the outside case, and the seperate switches for monitor and speaker, etc and so on.

But there are two little signed Moog inspection tags inside that date it to mid '73. Which seems awfully early to me, as I understand they began production in '73.

So, I guess that all of the "early" S6s must have been made in the beginning of '73 and all the "later" S6s are mid-73 to when ever they stopped making them ('78?).

Also, everything seemed to be working quite well, aside from the problems I listed. And after inspecting the inside, the synth boards looked immaculate and like they had never been opened for any kind of service before.

The guy I bought it from just attached a new cord where the two-prong input once was. The person he bought it from put an attached lead on it, but it was fraying or something, so my seller replaced it prior to selling it to me.

So I'm guessing it went dead as a result of this new power cable shorting something out. Maybe it wasn't grounded well.

Earlier ones are considered s/n 1300 and before.

Btw, one thing that can really throw off a tech with S6's is that the pcb holes are not plated through. You actually have to solder both sides.
At least that's how the last one was. It was an early one too.