Help!! Silent WAD 300B PSE

[Dik Dolan]

Cheers Guy.

I'm looking forward to finding out... but I'm the laziest, slowest most nervous person on earth, so it might take me a while longer to actually start.

I love my glasshouse, it's definitely my amp for life, I'm slowly but surely fitting the best bits I can afford in her- it's just a shame that things like v-caps and AN silvers are so damn pricey, and I'm so poor=)

Not sure if it will ever truly be "finished", but the journey is a blast. Rewiring it all with 0.5mm silver in ptfe tubing is also on the cards for "one day".

[Richard]

Originally Posted by Dik Dolan

Apologies for bumping an old thread, but I spotted these on ebay and wondered if anyone has any thoughts on them as coupling caps. Like Richard's amp, mine I think (also Glasshouse 300b) currently has the old paper in oil audionotes 0.015uf's- I cant see that the 0.005uf drop would make much difference, but what about the voltage rating? I've not measured it, but surely there isn't that much across a coupling cap?

http://www.ebay.co.uk/itm/3601976162...84.m1423.l2649
Not my sale, just looking for thoughts on suitability. At £3 each, can't really go wrong...can it=)
I just bought a couple, "just in case" so I guess I'll be able to answer my own questions, when I get around to trying 'em... but has anyone else tried them, or similar types?

Hi Dik,

Those caps are 350V rating. They would be ac signal coupling caps but also dc blocking caps. They couple the ac music signal from the anode of the first valve to the grid of the second, but, they block the dc on the anode of the first valve from the grid of the second.

At switch-on the voltage at that point may be the full Point B 400V if the EF86 is cold and not conducting (the anode resistors wouldn't be dropping voltage). It may be higher still if the rectifier conducts before the EF86 and other amp valves as the supply will be unloaded - quite likely as the rect is directly heated.

IIRC my AN Coppers are 630V and that's what I'd replace with or possibly 500V silver mica

[Dik Dolan]

Hi Richard,
Many thanks, you saved my amp from me murdering her=)

[Dik Dolan]

I've decided to stop messing and ordered a pair of the AN silvers. The fact that the HFC newsletter included a jubilee offer of 10% off helped ease the pain, and here was me thinking that nothing good would come from all this jubilee nonsense=)