Odyssey Inspired Build

[Aaron]

A friend gave me an old amp a while back, so on the weekend I thought I would do some circuit testing with it.

I wanted to try the Odyssey Circuit and was also inspired by the Odyssey Bass that was on ebay not too long ago. But a guitar version.

No bells and whistles at the moment, just a basic tonestack (with no switches) with a 12AU7 P.I and 12BH7 Driver, into 50W Power Amp.

Wired everything up, turned on, and it screeched like a banshee
Spent hours looking at the Williamson circuits and mods, and thought, maybe I'll try swapping the output transformer wires round first, and PRESTO works perfect

Here is a schematic and gut shot.

I haven't had a proper play yet, but first impression is very clean sound.
I'll try and record a quick demo tomorrow.

Thanks,

Aaron

[Colossal]

Hey Aaron, very cool build and thanks for sharing your schematic and gut shots! Any impressions as to what the amp sounds like?? You said very clean and it looks it just by inspection of the schematic. A good pedal platform perhaps?

[Max]

A good pedal platform perhaps?

If it's close to an original Odyssey Concert in its overall character, then IMO it might be a good clean platform to try how you like the different Dumble tone stacks. I would recommend starting with the 2nd generation ODS "pre-classic" tone stack and then to replace this by the transition generation ODS "classic" tone stack for a "comparison" (not in an A/B sense of course).

Many years ago I tried two Odyssey Concert amps together with a 2nd generation "pre-classic" ODS 50W combo in this setup: ODS preamp out > stereo Dumbleator > H3000 / TC2290 > stereo Dumbleator > two Odyssey power amps > two Dumble (oversized) 1x12" PI cabinets in a wet/dry/wet "Kevin Dukes stereo setup".

And on this occasion I tried just the clean preamp (dummy load) of this 2nd generation "pre-classic" ODS in combination with an Odyssey Concert power amp, too, and l liked this combination a lot.

Cheers,

Max

[Colossal]

Max, thanks for the reply and recommendations regarding the tone stack choices; very helpful. I am unfamiliar with the tone of the Odyssey Concert but interested in its potential as a clean amp. I like the PI and driver configuration which is what caught my interest. I realize it probably has its own distinct tone, but wondering if you might be able to generalize what it might sound similar to (e.g. Twin, Vibroverb, etc).

Your stereo w/d/w rig must have been smokin'

EDIT: Ok, I'm a little more up to speed (http://ampgarage.com/forum/viewtopic.ph ... ey+concert)

[Colossal]

Aaron,

What's going on with those two pull-pots in the left hand corner? Just mains on/off and standby in the absence of toggle switches?

[Aaron]

Max
Posted: Mon Sep 24, 2012 4:01 pm Post subject:
Colossal wrote:
A good pedal platform perhaps?
If it's close to an original Odyssey Concert in its overall character, then IMO it might be a good clean platform to try how you like the different Dumble tone stacks. I would recommend starting with the 2nd generation ODS "pre-classic" tone stack and then to replace this by the transition generation ODS "classic" tone stack for a "comparison" (not in an A/B sense of course).

Hi Max,

You read my mind. I might drill another hole and try the Silver Alligator tonestack.

Colossal
Posted: Mon Sep 24, 2012 8:45 pm Post subject:
Aaron,

What's going on with those two pull-pots in the left hand corner? Just mains on/off and standby in the absence of toggle switches?

Hi Colossal,

You are correct, rotary on/off and standby switches.
The preamp doesn't break up at all. Even on 10 it stays clean, my 124 build breaks up with the preamp up, but not this. Maybe the 150k slope resistor playing a part here.
I haven't had the master past 4 yet. But there is no flabby bottom end.
AFAIK the Concert doesn't have a tonestack, only volume and accent.
Thanks,
Aaron

[Max]

I realize it probably has its own distinct tone, but wondering if you might be able to generalize what it might sound similar to

I'll think about how to explain this with words and without being able to post a clip. Perhaps you can listen to some Eric Johnson or Kevin Dukes tracks recorded with an Odyssey Concert in the signal chain? AFAIR these two (and others) often used Odyssey Concert power amps.

Cheers,

Max

[Aaron]

Hi Max,

I watched the David Lindley link you posted. IMO, it looks like he uses his 2 ODS on the left for slide. On the right is his SSS and Odyssey, and Dumble modded head??
Do you think the SSS and Odyssey are used as a stereo set up?

Thanks,
Aaron

[ER]

Hey Max-

Birds of a feather AGAIN.

I have my 2nd gen-ish 100w twin combo done and just ordered some speakers to put together 2 more 2-12 cabinets for a wet dry wet set-up (pine slightly oversize oval back cabinets with 5/8 floating baffle and alnico heppner organ-donor smooth and ribbed speakers). Working on a layout for an all-in-one stereo loop and power amp combo in the 35-40 watt per channel range using old Sansui hi-fi iron. Hoping to pick up a strymon flint for the L/R wet signal.

My question is how did you split the signal out of the pre-amp, as well as bring it back to the dry power amp? Were there any impedance issues splitting the signal to three different sources? Do you think it could be useful to have a third "dry" buffer channel?

Cool video, I also like the Rockplast a year or so later where Mr. Dave plays with Rory Gallagher.

Thanks, Erik

[Max]

My question is how did you split the signal out of the pre-amp, as well as bring it back to the dry power amp?

Most of the original 2nd generation ODS amps have originally been built without a loop but with only a "preamp out" (see the attached 2nd generation layout). So the power amp of the 2nd generation ODS combo only sees the dry signal anyway. So this combo is and stays the "dry only amp" in any kind of multi channel setup anyway.

For a "wet/dry/wet" three channel setup you connect the "preamp out" of the original 2nd generation circuit with the "input" of a Dumbleator II. AFAIU this tech stuff the Dumbleator then helps to "isolate" what happens after the "preamp out" outside the 2nd generation combo from what happens inside the 2nd generation combo.

Then you connect the "send" output of the Dumblelator II with the input of some stereo fx device set up for internal "mono in / stereo out" processing.

Then you connect the two L/R stereo outputs of the stereo fx device with the two "A" and "B" "return" inputs of the Dumbleator II.

Then you connect the two "A" and "B" "recover" outputs of the Dumbleator II with two separate power amps (Odyssey Concert e.g.) connected to two separate speaker cabinets.

So you have the 2nd generation ODS combo "dry channel" and two additional wet channels - one for the R and one for the L stereo fx signal. And you have (at least) three indipendent volume controls: One for the "dry channel" (ODS master volume), one for the wet R fx channel ("recover A"), and one for the wet L fx channel ("recover B").

Does this "low level tech" kind of explanation make some sense in regard to your questions?

@Aaron: I'll look and listen again to this video to find an answer to your questions.

picture source: http://personalpages.manchester.ac.uk/s ... ator%20II/

Cheers,

Max

[ER]

Thanks Max,

That makes sense, unfortunately my amplifier has dual masters before the pre-out/in. I think I will add a third dry recovery to have the flexibility if I need to turn the clean and OD masters way up to hit the front end of the dumbleator hard enough.

[boldaslove6789]

My question is how did you split the signal out of the pre-amp, as well as bring it back to the dry power amp? Thanks, Erik

Some 2nd gen amps had a Single Jack for the FX Loop interupt, it was a Stereo jack that you had to use a TRS Stereo Y cable. The Tip was the Send, the Ring was the Return, and the Sleeve was Ground.

Although like Max stated some of these amps only had a Preamp Output and no access to the Pwr amp to Return the FX Into.

[Max]

Some 2nd gen amps had a Single Jack for the FX Loop interupt, it was a Stereo jack

Greg, do you know the serial number of a 2nd generation ODS that has originally been built with such a single stereo jack loop? Or could you perhaps post a picture or a link to some picture of such a 2nd generation ODS?

I ask because the only ODS that comes to my mind right now originally built with such a single stereo jack loop is the transition generation "classic" ODS 100W #0075 (see the attached picture).

AFAIK most of the 2nd generation ODS amps have originally been built with only a "preamp out" (see the attached picture of ODS #0027).
AFAIK some 2nd generation ODS amps have originally been built with a loop (see the attached picture of ODS #0055).
AFAIK some 2nd generation ODS amps have later been updated with a loop (see the attached picture of ODS #0049).

pictures:
http://www.audities.org/audities/collec ... ve_a3.html
http://personalpages.manchester.ac.uk/s ... ey/dumble/

Cheers,

Max

[LeftyStrat]

Hate to bring up an old thread, but Aaron, what are your overall impressions of the amp now you've had it a while?

[Smitty]

Those grid and cathode voltages on the LTPI seem weird to my eyes. Are they all referenced to ground? 49 seems low for the 22K tail and 128 seems high for the 820R shared cathode resistor.

The 49 seems weird.

If those voltages are correct, that gives you a grid bias of almost -80 volts which is very high for that circuit.

I've gone as low as 4K7 and 270R with a 12AU7. Not as much constant current so I stagger the Rps.

These tubes draw way more current and so you get larger voltage drops.