SSS002 build log

[erwin_ve]

Tim,
Those Koa speer look at lot like metal oxide indeed.
The first time I saw a Dale RN65d resistor I had the thought it must be a cap. Lol
All the resistors I sent you are nos carbon film Beyschlag.

[timrobertson100]

Those Koa speer look at lot like metal oxide indeed.

You prompted me to look closer. Interestingly Mouser list them as Carbon Film Resistors but on the actual KoaSpeer doc they show as Special power film, Metal Film for power applications.

I discovered too that the Yageo ones (pink on the board) are also Metal Oxide but listed as Carbon Film on Mouser and their packaging... urffff.

Thanks for the prompt!

[timrobertson100]

Low filter day

[timrobertson100]

Here's how I ran my heaters. The same wire type as Erwin, routed more similar to Ryan.
The rest will fly over the top.

[Richard1001]

Whats the benefit of this wiring as apposed to the way Dumble wired the heaters?

[timrobertson100]

What's the benefit of this wiring as opposed to the way Dumble wired the heaters?

Hey Richard. I actually don't know how dumble ran his heaters (I feel somewhat stupid for not exploring)... I'm just following the pics that Ryan and Erwin put up as a guide and using the wire I have to hand (solid core, cloth) which is probably less malleable than stranded.
I've always run heaters flying over the top Fender-style, so this is approach is new to me. If you have reason to suspect this will cause problems please can you say?

Edited to add: Perhaps the question is how I join the signal tube heaters at the driver board? I just copied Erwin's (give or take) but I routed around the tubes rather than through them. He was happy with the noise floor of his build:
https://ampgarage.com/forum/download/fi ... &mode=view

[Richard1001]

The wiring is drawn on the japanese schematic. Both 'strings' of preamptubes (1,2,3 and 4,5,6,7) are wired to the closest powertube socket in parallel.
The powertube socket has 2 soldering holes in one pin. Dumble puts both wires from the preamp tubes in the bottom holes and the wires from the previous powertube socket in the top holes. It makes cleaner wiring and you don't not have a bundle of wires under the driver board.

You can see the wiring this way implemented on the original sss-001: (the wires comming from V1,2 and 3 are under the blue and yellow wires)

[timrobertson100]

Thanks, Richard. I changed the routing

[erwin_ve]

Hi Richard,

You did some thorough research!
I chose to do my heater parallel from preamp tube 7 and not the powertube.
The wires from the driver board to the grids of the powertube also has to cross that section and I didnt want that bundle of heaters at the powertube for that reason.
My standoffs are probably higher in comparison with the original, using short standoffs might give trouble with the way I wired it.
What do you think, valid approach?

Erwin

[Colossal]

Hello Tim,

Nice work on your build. For what it's worth, my personal preference is to overhead wire heaters in the D-#102/Fender style, or, to minimize the potential for AC hum loops by running the leads across the socket and keeping them close, as shown below. Now, many will argue that heater hum and induction is a non-issue, but I would rather leave nothing to chance. Rework is something I try to avoid and especially with a complicated circuit like the SSS. There are, of course, many examples where builders "get away with it" such as the Lazy Loop style of Trainwreck heater wiring (I have done this myself with no issues), the classic Marshall heater method (which yours closely matches), and even the Parallel leads method used by Soldano.

heaters.jpg

[Richard1001]

Hi Richard,

You did some thorough research!
I chose to do my heater parallel from preamp tube 7 and not the powertube.
The wires from the driver board to the grids of the powertube also has to cross that section and I didnt want that bundle of heaters at the powertube for that reason.
My standoffs are probably higher in comparison with the original, using short standoffs might give trouble with the way I wired it.
What do you think, valid approach?

Erwin

Sure, but you have to put 3 wires in one hole on the small socket. It seems easier to use the powertube socket. I did it like this (purple wires on opposite sides of the power tube socket) :

[timrobertson100]

..or, to minimize the potential for AC hum loops by running the leads across the socket and keeping them close, as shown below

Thanks for taking the time to read and annotate the image Colossal.
Since the signal wires come up vertically and don't run through these hum zones, and since I have high standoffs I'm tending towards leaving it like this. I hope I don't regret this decision.

I'd naively assume going across the socket would make the most sense when signal-carrying wire is on the same plane and running nearby.

[Colossal]

..or, to minimize the potential for AC hum loops by running the leads across the socket and keeping them close, as shown below

Thanks for taking the time to read and annotate the image Colossal.
Since the signal wires come up vertically and don't run through these hum zones, and since I have high standoffs I'm tending towards leaving it like this. I hope I don't regret this decision.

I'd naively assume going across the socket would make the most sense when signal-carrying wire is on the same plane and running nearby.

No worries. It may turn out to be a non-issue, but just thought I would mention it as a "best practices" comment. Carry on!

[timrobertson100]

Thanks, Colossal

Nothing of specific interest here but a few photos of the progress. This is a 35W 2x6L6 build with vibrolux iron, so the PT is spun 90 degrees on the same plane to avoid a bracket.

[timrobertson100]

Getting close to putting in the boards.