Dumbleland update (was SSS) :D

[thyx]

I gots ta know...does anybody have the answer?

Is the SSS Ultra-Linear as an SVT, or is it a standard OT configuration?

[Funkalicousgroove]

Depends on the SSS Some have twin Iron, some have Ampeg Iron, Some have Sunn/Dynaco Iron.

[thyx]

Depends on the SSS Some have twin Iron, some have Ampeg Iron, Some have Sunn/Dynaco Iron.

OK...some of those may be Ultra-linear and some may not. So again...Ultra-linear (with screens running through seperate taps on the OT) or not (screens on the other side of a resistor or choke from B+)? Aside from power-handling issues and primary impedence, this is the single biggest thing that will effect your sound.

PS - Not trying to be a smarty-pants...there is a difference, especially in distortion character. And before anybody says it, I intend to run a tubescreamer in front of it to get it to distort...

[thyx]

Bumping for charity...

[Funkalicousgroove]

Fwiw, I haven't seen one that actually uses the UL taps, I did hear of one that used Music Man Iron, so the plates were like 688v, and screens at 344v, but not via extra OT taps.

[thyx]

Fwiw, I haven't seen one that actually uses the UL taps, I did hear of one that used Music Man Iron, so the plates were like 688v, and screens at 344v, but not via extra OT taps.

Well...that depends on how the voltage distribution after the PT was set up. It could also have been 688v at the plates and around 684v (or so) at the screens...but I kinda doubt it. Very, very few tubes could stand that much screen voltage. But if the screen voltage was half the plate voltage (which isn't hard to do regardless of the PT used), it's certain that no OT U/L taps were used. Have you or anyone you know ever measured the voltage at the screens and plates?

[Funkalicousgroove]

The ones I have seen are around 500 on the plates, high 490's on the screens.

[thyx]

Thanks FG...that helps a lot!

[dr. who]

So do the filters control the amount of NFB locally or globally in the circuit or is there one filter for GNFB, and one Locally placed? Where would the NFB have the most impact on sound, v1 or the pi or something else?

[dr. who]

so nobody knows if the hi/lo filters are doing anything to v1 or pi? no descent guesses? Can anyone look at the TR sterling shots and idenify where these caps and resistors would have the most effect for these two frequency ranges. Lets crack this sss mystery.

[stratcat62]

A friend of mine told me about an electronics shop in VA that does custom amplifier voicing. I checked them out and they claim to have experience with Dumble amps, as well as many other brands. One of the amp techs and I started emailing back and forth when I asked him about what Dumbles he was familiar with. He tells me that he can build a SSS from a Twin donor. Here is some info from the emails:
"I know Dumbles as I have worked on a few. The Dumble SSS uses 4x6l6, plus the transformers need to be bigger than that in a twin. We need to fit the cabinet with a D-130, change the transformers, add the Dumble circuitry and then voice to taste."
He'd be building it in the Twin cabinet instead of putting it into a head cabinet. This seems like a pretty exciting endeavor. What do you guys think?

[Funkalicousgroove]

the first 4 SSS's used 6l6's, and plain jane fender twin Iron, and I seriously doubt this guy in VA has beein inside any of them #1 and 4 belong to henry kaiser, #2 is the one with red switches that john mayer has(used to live in Japan), #3 was the snakeskin one lindley used to own. all the ones after that are 150W and use 6550's.

The guy is most likeley going to charge you a bunch to change the OT, and convert it to a dumble Style EQ.

The Hi-Lo filters are like tone controls after the EQ Recovery stage.

[dr. who]

in the pics it looks like there is a set of two wires(blue and green) that connect from the speaker jack to the high filter switch. Would it be possible to make a circuit to use the high and low filters together to effect the same place in the feedback loop like the way in which a tonestack works? I do not see any other wires except one that goes from the power tube closest to the pre tubes, but it doesn't head straight to the low filter that I can see.
Thanks

[dr. who]

double post

[tomrasdf]

I think those go to the footswitch Jack. The speaker jacks are farther left. I spent a fari amount of time squinting at the sterling shots. It looks very similar to #17 ODR w/o the od section. The hi-lo filters, best as I can tell, are independent of the reverb signal, after v1b. Looks to me like the internal trimmer next to the inductor is a send control for the filters. There's a run of coax running from the filters to the left side of the ax7 just to the right of the PI. Consistent with #17, the other side that ax7 is fed by a coax run from the reverb return pot. As far as the filters themselves, your guess is as good as mine. There are plenty of places to look for inspiration, though. This might be an interesting option, though it's more of a mid-cut as is:

http://www.has-sound.com/control_images/Varitone_OD.JPG