JTM 45 capacitor question

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mikepukmel
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JTM 45 capacitor question

Post by mikepukmel » Sun Apr 01, 2018 9:15 pm

Hi,
I am working on the V.S. JTM45 kit. The parts list page on the valvestorm store, lists a TAD 32uf 500v cap

"TAD 32uf Can 500v
Used with Metro builds "

The cap is listed as an alternate/optional phase inverter cap. The standard build instructions use half the dual 16uf can cap mounted over the power transformer for the phase inverter.

I purchased this cap, and intended to use it as described.

My question is: does anyone use half the 16uf can cap to feed the preamp tubes, rather than mounting a 16uf cap on the board? I planned to drill a hole for the dual 16uf cap, and mount it on top of the chassis, under the board, next to the choke, where the wiring to the + and - turrets for this cap would be as short as possible.

Can anyone see any problem with that? This would give me room to mount the 32uf TAD cap where the dual 16uf cap can is mounted in the standard build instructions.

Thanks!
Mike

Roe
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Re: JTM 45 capacitor question

Post by Roe » Thu Apr 05, 2018 8:27 am

it will compromise the grounding if you share a cap like that
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neikeel
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Re: JTM 45 capacitor question

Post by neikeel » Thu Apr 05, 2018 2:26 pm

The TAD 32uF 500v can is typically the can that goes topside between V5 and V6 (GZ34) an is just for mains filtering.

The can that goes inside the chassis above the PT should ideally be a 32/16 can for PI and screens respectively, like an original (with the single 16uF on the middle of the board for pre-amp). The other option would be a dual 32uF inside with 32 screens and PI (which would be my choice as I think a 16/16 in that spot would be too low).

Importantly what other cans have you got with your kit?

Like Roe I would not share cans and implement Larry grounding - they are totally hum free when you build with that scheme and decent wire dress (tight heater wiring and usual rules re wires crossing).
Neil

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