Jolida jd-502p

Hi Wilson667

I can't find that other thread where you were mentioning getting a quad of KT-120 tubes custom matched by TC Tubes. I'm thinking about this as well but then I found for the same money one could get a cryoed quad of KT-120s. I then also found factory matched tubes for about $25 less. Ugh. The decisions. I'm wondering which would be better.

Also if you try to get in touch with Jolida to find the plate voltage info etc for the TC tubes matching it is better to call them. I e-mailed them some questions and it took a couple of days for them to get back to me. They must be really be busy.

Just an FYI

I contacted some tube sellers regarding 12AX7 alternatives for the Jolida JD-502P. Here is what they told me. I'm just sharing info.

suggestions from Brent Jesee:

12AX7 Mullard UK made OEM labels, 1960s

12DF7 industrial low noise 12AX7, Westinghouse 1960s

12AX7 RCA made for Tung Sol long greyplate, 1950s

"Again, these 12AX7 tubes will deliver the sound you want. The 12DF7 is probably the best bargain here."

Suggestions from Jon @ thetubestore.

Preferred Series 7025

Northern Electric 12AX7

These tubes are out of my price range right now. For my 502P I'm trying matched and balanced Tung Sol re-issues now. Later I'm going to try JJ preamp tubes and then Penta low-gain 12Ax7 tubes from Doug's tubes. If I can get quality NOS tubes that are a bit easier on the wallet then I may give those a try.

I'm poking around for Jolida input/driver tube options also...Just to throw some other opinions in there, Michael Allen at Jolida likes the (expensive-ish) Phillips Mini Watts, and Jolida Jerred likes GEs. I have reservations about buying older NOS or "used but tested" tubes only because of inconsistency issues (although likely not an issue) and the fact that those little socket wires often look shopworn and corroded. Maybe an easy fix but still...it bugs me. I'm looking at new versions of various things that are both high gain and quiet but maybe sound different than the stock Tung Sol/EH that came with the 502P. Gold Lions maybe...or those Psvane versions. Again, so many opinions that I get dizzy, but I'll try something eventually.

Gentlemen,
I strongly urge you to do some reading on 12AX7 tube spec regarding Max heater to Cathode Voltage.
The spec says 100V.
SRPP based configuration calls for a raised filment to avoid this stress.
Jolida does not have raised filament, just an AC supply with a grounded (vs raised) center tap.
Your prized vintage tubes will have one triode in each tube aging real rapidly.
The $$$ wasted on premium vintage tubes can buy you properly designed amps.

First, I'm no gentleman. Second, instead of wasting my $$$ on vintage tubes I'm merely enjoying my inexpensive, although perhaps not properly designed, Jolida. Apparently the rapidly aging triodes sound great. Who knew? WU KNEW!