Check this out......

[rogb]

This is the bad boy.....more pics later

Is it this one ?

[redshark]

Yes, it is.

[ayan]

Yes that is the one.

It looks like a straight build of his standard board onto a PCB.

For what it's worth, that amp supposedly was not particularly a good sounding one -- according to the photographer.

G.

[glasman]

Yes that is the one.

It looks like a straight build of his standard board onto a PCB.

For what it's worth, that amp supposedly was not particularly a good sounding one -- according to the photographer.

G.

Must have been the white goop that sucked the tone out.

[UltraHookedOnPhonix]

These are the values I see (along with some educated guesses):

[IMG486]http://i205.photobucket.com/albums/bb176/jdavidsson/ODS%20Values.jpg[/img]

Externally, the chassis looks just like Steve Kimock's 50W ODS #86, so if I where to venture a guess, this amp would land in the late 80s-early 90s, serial number wise. We don't see to many of these gold-on-black chassis, maybe #86 has a PCB pre too? Here's what Kimock had to say (http://www.online-discussion.com/SteveK ... .php?t=402):

If my memory serves me correctly, number 86 has 3 internal trimmers. Looking from the front of the chassis, there's one trim-pot to adjust the gain of the FET input. There's a trimmer to the right side of the pre-amp board that allows you to adjust the gain to the overdrive channel. Somewhere off to the right, in a smokey haze of monkeys staring into the back of a TV, is a trim-pot that adjusts the amount of presence when you engage the "accent" switch. That's it.

[IMG:701:271]http://i205.photobucket.com/albums/bb176/jdavidsson/86.jpg[/img]

The amp redshark posted (thanks for the pics BTW!) also looks like it has a presence adjust trimmer (500R). Like Kimock mentioned, this preset control sets the amount of presence when the accent switch is engaged.

Another observation: the feedback resistor looks to be series connected 3K3+270R, for a total resistance of 3.57K.

Also, I'm guessing but the treble cap is probably 500pF and the snubbers in the 270pF range.

Really neat to see an ODS with a PCB pre. Whatever the reason for Dumble's foray into using PCBs for the preamp, one thing appears certain, he never looked back to this mode of assembly.

Thanks Glasman for posting pics of the blue suede head too!

[ic-racer]

Less number of PC boards in that than in later amps.

Black/Gold = 6PC boards
Typical HRM (200+) = 7 PC boards

[Max]

... so if I where to venture a guess, this amp would land in the late 80s-early 90s, serial number wise. We don't see to many of these gold-on-black chassis ...

The (yellowed) white on black chassis of the amp redshark posted is IMO a completely typical "transition generation" chassis, black version, RATIO control on front, ACCENT switch on front, serial number in the range between #0070 and #0100.

BTW: AFAIR an internal ACCENT trim pot is a rather usual feature you'll find inside such a black version of a "transition generation" chassis with an ACCENT switch on front. ODS #0093 as an example (see the attached picture).

Whatever the reason for Dumble's foray into using PCBs for the preamp, one thing appears certain, he never looked back to this mode of assembly.

He did look back: ODS 150W #0121 as an example.

Cheers,

Max

[Aaron]

He did look back: ODS 150W #0121 as an example.

Cheers,

Max

Interesting........

[UltraHookedOnPhonix]

Max,

Out of the hundreds of ODS amps Dumble completed after this one, how many did he use PCB pre's on? With separate PCBs for V1-3?

Let's put it this way, out of the one's we've seen come by us on the ampgarage over the years (10 for me yikes!), how many? There is a overbearing trend to use eyelet board for the pre. If there are more exceptions to the rule than the 150W you named, I'd love to see them! You're the one sitting on the library of "Alexandria" right?

BTW, I'm not convinced that this is "yellowed white". Zoom in on the first pic redshark posted. Why didn't 93 "yellow" with age?

Oh, now you've gone and done it Max, you've got me...
[IMG:480:480]http://i205.photobucket.com/albums/bb176/jdavidsson/Splitting%20Hares.jpg[/img]

[Max]

Let's put it this way, out of the one's we've seen come by us on the ampgarage over the years (10 for me yikes!), how many?

AFAIR this is the only ODS posted here up to now with separate PCBs for V1 – V3 and the only ODS posted here up to now with V1 -V3 in two different rows.

There is a overbearing trend to use eyelet board for the pre.

IMO 1 out of 10 might be an indication of some kind of trend in regard to the (around) 240 ODS amps not posted here up to now. But who knows.

You're the one sitting on the library of "Alexandria" right?

My library didn’t burn up to now.

Why didn't 93 "yellow" with age?

IMO: different environmental conditions (smoke, beer, dust, illumination, etc.)

Cheers,

Max

[redshark]

Max, being the first to post pics like this on the Dumble side of the forum makes me feel special!! even more being a trainwreck guy.
I have never tried to build a Dumble inspired amp but if I decide I want to do it I would do a tweedle deluxe first and then probably try an overdrive special but probably highplate classis, no hrm. This guy is lowplate classic with no HRM.
I hope some of you guys can help me.
Before I do that I need to build a trainwreck Liverpool. I have built 2 expresses before and 1 rocket!!

Thanks!!

[talbany]

So this is interesting! and thought I would mention it?
I actually experimented with the relay to add more NFB when in OD..It actually works pretty well to tame some high end and helps tighten the low end a bit when you go to OD..I recommend it looking into it..Works great!!

T

[Structo]

Good tip Tony.

Does it give the OD a more refined distortion?

I have a switched pot on my presence to turn off the NFB which really increases gain.

But to have varying levels of that without affecting the presence would be a dream.

[Structo]

I have never tried to build a Dumble inspired amp but if I decide I want to do it I would do a tweedle deluxe first and then probably try an overdrive special but probably highplate classis, no hrm. This guy is lowplate classic with no HRM.
I hope some of you guys can help me.
Before I do that I need to build a trainwreck Liverpool. I have built 2 expresses before and 1 rocket!!

Thanks!!

The Tweedle Dee is nice but in no way represents a Dumble ODs type amp.

I pretty much ended up with your specs with on my ODS.
Except I like the Skyline tonestack better.

It's a 100w, (4x 6L6) High plate, Skyliner with a few tweaks.

If you are used to an Express you should build the 100w version.
Bigger, better tone that with a good master volume can be played just about any volume.

[redshark]

I like the rocket better than the express actually!!
But I still appreciate the express gain and sustain.

I though about the tweedle dee because of portability more than tone, but I still appreciate the tone of a good tweed dlx. If this is better I'll be happy.

This amp has Fender transformers. The power tranny is big.

Did he use twin or dual showman transformers?

Those are the high power fenders, or is it the same transformer on both?

This amp also seems to have 2 chokes. I wish i was more knowledgeable to figure this amp out.