SSS Reverb Board location and Blasphemy.

[ViperDoc]

Looking quite a bit at the SSS #002 documents, how necessary is it to have the reverb board so far away from its circuit connections to necessitate such long leads? What if it were relocated to eliminate such long wires? I was imagining the reverb driver and reverb tank jacks could be located in the chassis bottom panel and secured to the reverb tank on the head cabinet. Is there so much risk in noise bringing it away from the lower right corner? I know. Blasphemy! Just curious. I've been working on a unique layout, even putting the effects loop on the front panel to eliminate those leads as well.

[erwin_ve]

There are 11 tubes in the Sss002, where do you think there is room?
I've never encountered issues regarding its current location. And then there is coax for "long" runs.
Why fix something that ain't broken?

[ViperDoc]

You raise a good question, Erwin. I admit, redesigning a Dumble is likely a fool's errand. The last few amp's I've built have taken an approach to reducing the amount of wire used and also relocating power supply caps next to their circuit ground points. Some of them are pure P2P designs with no boards. The high end content is much richer. I built a P2P Express that is just awesome. It can swing both ways, but I thought I'd see if I could run everything together in a way that could eliminate some "spaghetti". It's tough with so many components! The Express only has 12, if I recall. HAHAH! I'll keep drawing until I either get excited or offended. The first version went preamp-->CF mixer-->reverb-->PI..., but the reverb sat right next to the PI. SO, the second one went preamp-->reverb-->CF mixer-->PI..., all obeying the schematic. If I share it now, I'll get kicked off the forum. Better to keep it civil around here, like normal.

[erwin_ve]

You can try, no one is holding you back

What I like about the Dumble design is that each function in a guitar amplifier has its own compartment.
Easy to do measurements and troubleshooting.
In a complex amp like the Sss002 doing p2p you sacrifice this clarity for unknown tonal aspects and difficult troubleshooting.

[jabguit]

Why fix something that ain't broken?

I'm sure HAD got that alot back in the day.............

cheers,

[beasleybodyshop]

I went through a similar phase - tried to "optimize" layout and wire length , shorten wires and distances to things in previous builds and they never sounded great. Not bad, just didn't have the same harmonic content and liveliness. Layout seems to be a factor, albeit somewhat intangible. Some things just need to crosstalk in the circuit to work right. "Monkey see monkey do"

[ViperDoc]

I went through a similar phase - tried to "optimize" layout and wire length , shorten wires and distances to things in previous builds and they never sounded great. Not bad, just didn't have the same harmonic content and liveliness. Layout seems to be a factor, albeit somewhat intangible. Some things just need to crosstalk in the circuit to work right. "Monkey see monkey do"

"Some things" would be...?

I've read in previous posts, if I recall correctly, that plate and cathode wires in the preamp are intentionally run parallel at points to encourage interaction. Anything else?

The other question I have about the SSS is the power supply. Look at the SSS 002 schematic in the files section. Why is there a series pair of 50 uF (25 uF effectively) prior to the standby switch and a series 100 uF (50 uF) afterwards? 4 caps to make a 75 uF plate supply? It seems the other layouts do not have this configuration. It appears up to the builder.

[erwin_ve]

I went through a similar phase - tried to "optimize" layout and wire length , shorten wires and distances to things in previous builds and they never sounded great. Not bad, just didn't have the same harmonic content and liveliness. Layout seems to be a factor, albeit somewhat intangible. Some things just need to crosstalk in the circuit to work right. "Monkey see monkey do"

The other question I have about the SSS is the power supply. Look at the SSS 002 schematic in the files section. Why is there a series pair of 50 uF (25 uF effectively) prior to the standby switch and a series 100 uF (50 uF) afterwards? 4 caps to make a 75 uF plate supply? It seems the other layouts do not have this configuration. It appears up to the builder.

I dont know, seems odd to have only 25uF on the plate and 50uF on the screens, but it works fabulous in SSS002. Check member builds here; lots of headroom, massive bass...

[ViperDoc]

I dont know, seems odd to have only 25uF on the plate and 50uF on the screens, but it works fabulous in SSS002. Check member builds here; lots of headroom, massive bass...

On the SSS 002 schematic, the 50s and 100s are both on the same node going into the plate supply and choke, so they combine when the standby switch is thrown.

[erwin_ve]

I dont know, seems odd to have only 25uF on the plate and 50uF on the screens, but it works fabulous in SSS002. Check member builds here; lots of headroom, massive bass...

On the SSS 002 schematic, the 50s and 100s are both on the same node going into the plate supply and choke, so they combine when the standby switch is thrown.

Yes correct, 25uF and 50 uF together, fwiw I use 47uF at the screens, so after the choke instead of 33uF .
Leads to 25uF-standby-50uF-choke -33uF(or47uF) screens.
My guess for the position of the standby switch it is to prevent a big inrush current.

[beasleybodyshop]

It's anecdotal but it seems like the amount of coax you use in the build, as well as lead dress with plate/cathode wires, and the spacing of preamp components, especially the clean/OD stages just seem to be a factor. I'm not trying to be intentionally vague here. Just seems like those things are critical to getting it to sustain right and not sound congested. That and having the right amount of negative feedback.

I built a version of ODR#60 and rebuilt it 3 times because the OD tone was just too congested. On the third and final attempt, I copied the layout on the preamp board as close as I possibly could to the photos, and experimented with a few different amounts of global negative feedback and the amp just came alive. Wish I had a more scientific method and reasoning but it does appear that layout is such a factor. I've seen dumble mention this in interviews (albeit in his silly cryptic way) and once I stopped trying to "improve" the layout and be a bit more exacting to photos it seemed to solve the problem.

[beasleybodyshop]

Seems like the split mains filter + standby switch arrangement is done to function as a bit of a softer inrush on the caps downstream. Partially charged, the circuit doesnt have to charge up as much. JM2C.

[ViperDoc]

Seems like the split mains filter + standby switch arrangement is done to function as a bit of a softer inrush on the caps downstream. Partially charged, the circuit doesnt have to charge up as much. JM2C.

It's anecdotal but it seems like the amount of coax you use in the build, as well as lead dress with plate/cathode wires, and the spacing of preamp components, especially the clean/OD stages just seem to be a factor. I'm not trying to be intentionally vague here. Just seems like those things are critical to getting it to sustain right and not sound congested. That and having the right amount of negative feedback.

I built a version of ODR#60 and rebuilt it 3 times because the OD tone was just too congested. On the third and final attempt, I copied the layout on the preamp board as close as I possibly could to the photos, and experimented with a few different amounts of global negative feedback and the amp just came alive. Wish I had a more scientific method and reasoning but it does appear that layout is such a factor. I've seen dumble mention this in interviews (albeit in his silly cryptic way) and once I stopped trying to "improve" the layout and be a bit more exacting to photos it seemed to solve the problem.

All very much appreciated. I can't build at the moment, so I've been drawing all kinds of stuff--no real chance it would be better than the original. Unless I build it and find out otherwise. Good to know about the established layouts. I looked for some files on an Overdrive Reverb amp and came up empty [EDIT: I found it.
https://ampgarage.com/forum/viewtopic.php?f=4&t=17935]. Sounds interesting. I love the custom versions (of course, they were all custom). The Amplified Nation "Ampliphonix & Gain" looks like a winner.

[beasleybodyshop]

I've got a layout I did ages ago somewhere on my PC.

ODR#60 is probably my favorite ODS variant, hands down.

After I got it built proper it was magic. Sustain, clarity, harmonics, bloom that took off at reasonable volumes....all the stupid buzz words. Have to give credit where credit is due there - Jelle was a big help in making that final push happen

But yes, trying to adhere to layouts based on photos just seems like a known good recipe. There are ways to deviate from the classic parts and layout that work though. Look at Fuchs amps for example. Andy uses modern off the shelf parts to make a damn good D style amp. I have no good answers just observations

[ViperDoc]

I've got a layout I did ages ago somewhere on my PC.

ODR#60 is probably my favorite ODS variant, hands down.

After I got it built proper it was magic. Sustain, clarity, harmonics, bloom that took off at reasonable volumes....all the stupid buzz words. Have to give credit where credit is due there - Jelle was a big help in making that final push happen

But yes, trying to adhere to layouts based on photos just seems like a known good recipe. There are ways to deviate from the classic parts and layout that work though. Look at Fuchs amps for example. Andy uses modern off the shelf parts to make a damn good D style amp. I have no good answers just observations

I can't argue with that.

Another thing I've noticed is on the #102, the choke on the layout looks like it's almost in contact with one side of the output tubes, then the SSS has it in the middle, or not specified. Is this rather intentional? I know the OT placement on the TW Express puts it close to one side on purpose, but was wondering about the Dumbles.