[PT914]

Hello,

Much have been discussed on the SS section of the GK-1 with good results.  I especially like Ginger's mod of switching C4 with L1 and changing R14 and R13.  Beautiful top end.

Nothing has been said about the high voltage tube section.  Since I've been playing with the "felicia" project, I have a few 20 uF polypropylene caps just sittting around so.....I removed C18 and C17, soldered a 18g flexable wire to the high voltage feed to the tube and to ground.  Connected .25 inch spades to the wire ends.  Now I can evaluated different caps in this section without soldering and unsoldering the caps.  Caution high voltage up to 250v before filament comes on.

My base line is a BG 33 uF 160v (too low a voltage) with stock MKT plastic film cap solder to small board with wire female spades.(Will have to put the stock Rubycon 33 uF 250v back on the baseline board)

ASC oil filled polypropylene 20 uF 440vac with Reliable RT .22 uF 400v...did not sound right.  Sounded like both sides were out of phase.  Did not have much burn in time and did not play with polarity leads.

Solen 20 uF 250v with Auricap .47 uF 400v... beautiful.  This complimented Ginger's mod with clearer midrange.  Leading edge of music is clearer but maybe that is what the tube section should be doing.  Will have to listen longer... but this is fun

Happy listening,
Philip

PS I think BG 150 uF 350v VK will fit at C24 and C23 if you split the board in half and move center junction of R20 and R21 to tube pin 5

[AKSA]

Philip,

Thank you for your contribution;  this issue of caps on the power supply of a tube is VERY important, even on a cathode follower.

Of course, the Solen/Auricap combo is very large.  This is always and inevitably the trade-off, but for those with a hankering for the very best sound, this is a great area to tackle.

The Rubycon 33uF cap used for C18 is a very good cap, and an excellent compromise.  I like all the Rubycons, almost as good as BGs but no burning in time.

Again, and to Ginger also, thank you for the tip - appreciated.

Cheers,

Hugh