Fancy Parts

[Guest]

Does anyone know if these caps will fit on the st-35 pcb board? I was thinking of replacing the coupling caps.

Or, are there any other "musical" caps one might suggest (that physically fit )?

thanks,
JG

[EWBrown]

If you are referring to the big Russian teflon caps, they will definitely not fit on the PCB, they are nearly as large a(and heavy) s D size batteries.

One semi-"fancy" cap I've tried and it does fit nicely , is the Solen "Fast" capacitor, 0.1 uF 630V (the 0.22 should also fit) these are about the same cost , perhaps a small amount more, as the orange drops. I've tried them on one unit, and they sound just fine. I know, that's not very technical or analytical, just one person's opinion, and my ears aren't the best, either.
I haven't yet tried out any scientific measurements using my dirsotrion or harmonic analyzer (both restored and re-calibrated Heathkit units of mid 60s vintage). The "Auricaps" in 0.1 400VDC will also fit, these are more costly, in the region of $10 each, they are smaller than the Hovlands, and about equal in performance.

Don't overlook the two input coupling caps if you are going the "fancy" route. The alloted space for these is somewhat smaller than that the four EL84 grid coupling caps.

The Russian caps could be used, but they would have to be connected to the board with long leads, and be clamp-mounted to the chassis. The added lead length will be susceptible to unwanted noise pickup, so any advantage gained might be lost.

I plan to try out two in another upcoming SE amp project, which will be all point-to-point wiring, with a single ground point, etc.

/ed brown

[Shannon Parks]

Don't overlook the two input coupling caps if you are going the "fancy" route. The alloted space for these is somewhat smaller than that the four EL84 grid coupling caps.

You can put a real low voltage rating in there, too, as it's just a DC blocker for the input signal. The ultimate fancy replacement would be a wire jumper, if you have a clean source.

Shannon

[Guest]

would those be C26 & C27?

thanks,
jg

[Shannon Parks]

would those be C26 & C27?

thanks,
jg

Sorry I didn't specify these. No, the input DC blockers are C18 and C19.

C26 and C27 are part of a positive feedback circuit (!). Once I get back to the ST35, I'm going to look into why they (err, Hafler) didn't just bypass the voltage gain cathode with a capacitor instead of this method.

Shannon