Another SSS #002 build thread (Ryan/Erwin)

[timrobertson100]

Finally got round to starting a build using the bag of bits I bought from a member here. I feel extremely lucky to have another of these chassis which aren't available now.
SSS #2 is of course documented thoroughly but maybe others, like me, enjoy watching build threads

Day 1: hardware and pre. heaters, following Erwin's approach.
I was dreading the 3 way on the 9 pin, but it wasn't quite as fiddly as I expected, although I'm glad it wasn't PVC wire.
Isolating washers on the reverb jacks, also paying attention to clearance on the standoffs which bit me last time.

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[Matt J]

Very cool! I'm looking forward to seeing how this comes out!
I'm about to start a 2nd Gen ODS build with one of Erwin's chassis myself.
Matt J.

[GAStan]

Looking good so far!

One thing to check before you get too far along is clearance between the corner of the Reverb board and the XLR jack for the foot pedal. I remember it giving me a bit of a problem, but it may have been due to the height of the standoffs I used.

[timrobertson100]

Thanks Matt, Glenn!

I'm about to start a 2nd Gen ODS build with one of Erwin's chassis myself.

Nice! I'd like to see that build too. I see Erwin only has one of those chassis left. Mmmm...

One thing to check before you get too far along is clearance between the corner of the Reverb board and the XLR jack for the foot pedal. I remember it giving me a bit of a problem, but it may have been due to the height of the standoffs I used.

Good point, thank you. It just clears with 15mm standoffs, which still give a nice distance to the heaters.

Got the high filter wired using the typical Japanese #002 / Ryan schematic values and not Martin's - just what values I had in this bundle of bits and I've found my existing SSS filters to be usable.

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[timrobertson100]

Found some time to build and have some questions I'd appreciate any thoughts on (thank you in advance)

Switches assembled first on a cardboard strip, to make it easier

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Boards mounted with the bits I have to hand; some sourced from a bag of donor parts so I don't know the origin.

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I'm not so hot on identifying resistor types and wattage visually. Please can you let me know if anything looks suspicious to you?
The 100K 5W resistors appear to be Panasonic(?) metal oxide to me. Ryan's layout calls for wirewound. These should be OK though, right?

I also had a mix of 6PS and 715P and used what I had so far, and went for the 0.022uF on cx1 and cx2.
Would anyone advise me strongly not to use a few of the 715P I have for this build please? (I understand 6PS is the preferred option for ODS, and ?maybe SSS too)

I have a couple 33uF 500V F&T. At 50% over they seem a bit too high to sub in for the 22uF's. Or would you say that this would not really matter, please?

Note that the Ryan layout and PCB labelling have the signal board V2 and V3 cathode bypass caps swapped (1uF and 5uF).
I think this based on an belief the Japanese schematic is likely wrong, as suggested in this thread so I went with what Erwin has in his.
(Edited: I see this is well discussed in the original Ryan/Erwin thread here)

[rccolgan]

Incredible work! I love the precision in your bends

[ThePanda]

Switches assembled first on a cardboard strip, to make it easier

IMG_8857 (1).jpeg
...

I am stealing this. Looks great!

[rccolgan]

My reply didn't save so hopefully this time it will..

Those big 5w resistors are fine! They get warm for sure and this should be ok.

I personally have not swapped around capacitor types so I don't have much to comment there outside of what might be "theoretical".

I would suggest finding 22uf on those spots that call for it instead of 33uf. They are relatively cheap compared to the overall cost of your build. The higher capacitance may cause overloading of the PT since it's already stressed with the additional tube to heat.

I would do the swap as suggested in the thread (and I now corrected the layout) Thanks for pointing this out to me!

[timrobertson100]

Thanks Ryan. I’ll get the next batch of stuff ordered.

[dorrisant]

That start looks very nice. Looking forward to more.

[martin manning]

Got the high filter wired using the typical Japanese #002 / Ryan schematic values and not Martin's - just what values I had in this bundle of bits and I've found my existing SSS filters to be usable.

You can always make up a new filter assembly and swap it out with little trouble. I'll bet you a slab that you'll find the revised filters more usable ;^)

[timrobertson100]

Ok Martin - I’ll come back to that and we can see about your slab later.

I see on Erwin’s PCB labelling, 10nF 630V for the rectifier diode suppression caps. The ones I bought from TubeTown are 305V. Will they do please?
I don’t know enough about voltage spikes they may see.

[martin manning]

What is your power transformers secondary voltage, and how many diodes in series? For a two-phase rectifier you need rectifiers rated at least two times the B+. With two diodes on each leg of the PT secondary you would need caps rated at least equal to B+. If you use UF4007 rectifiers you can omit the parallel caps.

[timrobertson100]

Thanks

As it happens I did use UF diodes, out of coincidence. These have 2 diodes is series, and the PT is a Hammond 290FEX with 640VCT @518mA so I guess(?) 440V B+. I’ll leave these off then.

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[martin manning]

Sounds good. I believe adding the caps to UF4007 actually does more harm than good wrt reducing switching noise.