Being a DIY'er at heart I've gone ahead and made some changes which have been highly successful.
1> for the line stage section, I have replaced the white CJ design bypass capacitors with like value Multicaps. I choose these because their physics makes sense, prior success with an Adcom DAC and relatively low cost (~$15 per capacitor). This immediately resolved the high frequency rolloff and some of the compression I was hearing.
2> I replaced the power cord in (typical lampwire)with a Furutech IEC socket. When i cut this cord it was heavily oxidized. This stage require care not to damage the transformer, make sure you place a solid obstacle buffer between the transformer and the work area where the metal must be cut to insert the IEC socket. total cost about $15 for socket. Significant improvement in base and dynamics if you use a quality power cord.
3> I replaced the 5 legacy tube sockets (bakelite?) with hybrid teflon, gold plated sockets, each ~$6 or total of $30. easy soldering replacement if you have a desoldering tool. This helped soldify, tame "wooliness" in the base and eliminated edginess in the highs.
Solder used throughout, Cardas.
ecstatic to have my preamp sounding great again.
Still waiting on delivery of the Multicaps for phono stage but I have no doubts they will wipe out the slowmess which still remains in phono transients. Only annoyance here is that 0.15uf 400 VDC wasn't available, per other upgraders advice i've ordered 0.22 uf values.
Total cost to bring a PV10-A back to 1993 newness for line stage around $75 + soldering tools. Will post outcome later this week for phono stage.
1> for the line stage section, I have replaced the white CJ design bypass capacitors with like value Multicaps. I choose these because their physics makes sense, prior success with an Adcom DAC and relatively low cost (~$15 per capacitor). This immediately resolved the high frequency rolloff and some of the compression I was hearing.
2> I replaced the power cord in (typical lampwire)with a Furutech IEC socket. When i cut this cord it was heavily oxidized. This stage require care not to damage the transformer, make sure you place a solid obstacle buffer between the transformer and the work area where the metal must be cut to insert the IEC socket. total cost about $15 for socket. Significant improvement in base and dynamics if you use a quality power cord.
3> I replaced the 5 legacy tube sockets (bakelite?) with hybrid teflon, gold plated sockets, each ~$6 or total of $30. easy soldering replacement if you have a desoldering tool. This helped soldify, tame "wooliness" in the base and eliminated edginess in the highs.
Solder used throughout, Cardas.
ecstatic to have my preamp sounding great again.
Still waiting on delivery of the Multicaps for phono stage but I have no doubts they will wipe out the slowmess which still remains in phono transients. Only annoyance here is that 0.15uf 400 VDC wasn't available, per other upgraders advice i've ordered 0.22 uf values.
Total cost to bring a PV10-A back to 1993 newness for line stage around $75 + soldering tools. Will post outcome later this week for phono stage.