ODS #020 for sale on Reverb

[martin manning]

For what its worth, I asked the seller to clarify the loop situation. This was their response:

"Based on the info we have from previous owners, there was a dumbleator installed. I was skeptical of this, and tested the preamp out, and sure enough its a buffered effects loop. There are a few articles out there that mention this amp having it as well. Albeit a bit vague and veiled in mystery as per the usual Dumble Mojo."

I don't think they actually know.

And it sounds like the seller has never looked inside!

[dbharris]

For what its worth, I asked the seller to clarify the loop situation. This was their response:

"Based on the info we have from previous owners, there was a dumbleator installed. I was skeptical of this, and tested the preamp out, and sure enough its a buffered effects loop. There are a few articles out there that mention this amp having it as well. Albeit a bit vague and veiled in mystery as per the usual Dumble Mojo."

I don't think they actually know.

Thanks for asking and reporting back. I am sure they are basing this on the (mis) understanding of a prior owner. All of the sources seem to parrot the same info.

PXL_20231128_152244903.jpg

PXL_20231128_152332918.jpg

[yeahyeah]

Haven't posted here in a while, but I just got to play this thing. Never thought I'd ever get so close to a real one. I was a bit nervous considering the monetary value, but I took all the knobs for a spin and gave it a good listen. Didn't get a look inside.

It really does sound nice and the aluminum trim is all polished to a mirror shine, a really nice aesthetic touch. I don't think it has a buffered loop, perhaps the FX loop was added as a mod and that was misunderstood as a "dumbleator" IDK. The "mid cut" does function a lot like a presence control... was curious about that one.

[bepone]

Haven't posted here in a while, but I just got to play this thing.
It really does sound nice ....

what is with the OD? the OD doesnt sound good.. like a bad transistor amp, fuzzy, fizzy...

[yeahyeah]

Its low end was a bit more loose than expected for a 100W amp but I wouldn't call it fizzy. The preamp switches work left to right and it took some listening get acquainted and to realize that the "jazz and rock" label was reverse of the function. With it left toward "jazz" it was actually louder and in "rock position" as I've come to understand it, w more gain and mids overall. Perhaps the demo's you listened to were done in the thinner/weaker sounding jazz position.

Sounded great to me. Did the clean harmonic doubling sustain thing really really well. The cleans would ring into overtones really nicely.

[beasleybodyshop]

Thanks for sharing your experience with it. When you say the Mid Cut sounded more like a presence control, could you clarify?


Btw for what its worth, I asked a follow up question to the seller about the Dumbleator and they ignored me. No interest in understanding the truth I guess.

[beasleybodyshop]

Bad news for the seller if the buyer gets wise to their ad description inaccuracy:

https://reverb.com/page/reverb-protection

So if anyone wants to wire me a few hundred grand, I'll throw down on it, make some detailed measurements, and cash in that buyer protection clause

[oldmacman]

Here is some more information that I got from a forum member almost 20 years ago. Since then, the amp has been sold a couple of times, and a gut shot and most of the values ( https://ampgarage.com/forum/viewtopic.php?f=4&t=33286 ) have been posted here already, so I’m going to go ahead and share what I have. This has been the circuit in my primary amp since then.

V1a (clean) plate/cathode: 180K/1K, 130K/2K2
V2b (OD) plate/cathode: 220K/2K2, 100K/1K8

Measured voltage on V1a plate: 138V

25 uF bypass caps on V1a/V1b, 5 uF bypass caps on V2a/V2b

OD entrance is 220K into a 100K trim pot

V1b coupling cap is .05u

OD coupling caps are .01u / .005u

Tonestack is Skyliner, but with a .02 uF mid cap and a 270 pF treble cap

Presence cap is .68 uF

My understanding is that the amp was originally a 2nd-gen ODS, but it went back to HAD in the ‘80s to be updated. After that, it looks like the Vintone folks replaced the front and back panels and did some messing around with the front panel controls. It looks like there is now a mid switch installed — if I had to guess, maybe they used a 330p and 1500p in series to get 270p, and shorting the 330p gives a mid boost. And I have no information about what’s up with the mid cut control — whether it’s original or something they added.

As mentioned before, the alternate hot/cold biased preamp stages are similar to ODSR #60, and the white plate resistors in the gut shot look to be the same as for ODSR #60. I used modern Dale RN65s in my amp and it sounds just fine. I would be interested in learning if there are any other amps that HAD did this way. From a circuit design perspective, it’s pretty interesting, as it puts the tubes in a less linear region of operation, and sets up the non-linear / first-clipped portion of the transfer function to always operate on the same side of the waveform.

How does it sound? Well, if a regular ‘80s ODS sounds like Michael Brecker, this one sounds like Joe Henderson, and I quite like that. The demo video from Dream Guitars is not at all an indication of how the circuit sounds. I have no idea what they did in that video — as another commenter said, maybe they had the rock/jazz switch backwards.

Here are a couple of clips of my copy of #20:

Clip with 1978 Yamaha SA-1200S, bridge pickup, ribbon mic: https://voca.ro/1hbcK4nNHgeX

Clip with Carvin Holdsworth Fatboy, bridge pickup, ribbon mic: https://vocaroo.com/1bSQLtEtXGiu

[dbharris]

Thanks for sharing!

-Dan

[beasleybodyshop]

I wonder if it sold? The listing on Reverb ended....

[yeahyeah]

Thanks for the info oldmacman!

Very interesting to hear whats going on under the hood here. I'm like 99% sure the rock/jazz switch got installed upside down, just based on how it sounded. It took a while to figure out what was going on because I was trying to dial it in while in "rock" mode and it just didn't sound right, then when I flipped it on "jazz" there were all the familiar rock mode sounds.

The compressed cleans were nice.

[yeahyeah]

When you say the Mid Cut sounded more like a presence control, could you clarify?

It functioned exactly like a presence control would, maybe it just got re-named something else. Pretty dead until the last 10% of rotation, then it boosted highs just like a presence control...and the amp did not have another knob for presence.