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I am not certain which "he" you are referring to, but don't think this was Dave Ellis.Quotewhen I came to meet pemo for buying a pair of Ellis 1801b, I could notice that he was using Jolida/EH 12AX7 and 12AT7 valves on his amplifier Jolida JD-302B.
when I came to meet pemo for buying a pair of Ellis 1801b, I could notice that he was using Jolida/EH 12AX7 and 12AT7 valves on his amplifier Jolida JD-302B.
I used Amperex Bugle Boy tubes (orange logo?) for the 12AT7 and 12AX7. I also had some Mullard tubes for comparison, but I don't recall which these replaced.
Since I have ordered some sonicap capacitors, I guess they are rated for 600V. Could it be a problem for my 220V amplifier?
Could you clarify that, and add your opinion as to wether the platinum's are worth the premium and where they would do the most good?
I haven't 'read' resistor values yet but I do have a band reference color chart. These are the resistors that come of the tube socket bases, correct ? RA I take your word seriously as you mod these things for a living.
I have notice you also did this on your personal amp a while back. These resistors are the grid stop resistors and should be 1k ohm (up to 2.2k ohm at most) rather than 10k ohm. Using such a high value in this position would have an adverse effect on the frequency extensions and also not necessary to do it's intended job.
I haven't tweaked a Jolida 502, but believe the layout is very similar to the 302.
1) Sound on the warmer side - AuriCap or SoniCap Gen II (they pretty much sound the same)2) More precise but without the same level of warmth - SoniCap Gen I or Theta AudioCap3) Seductive presentation - Jensen or Audio Note PIO4) The best in refinement and overall most musical presentation - SoniCap Platinum or V-Cap.
Hello Dave, I hope you don't mind but I have to point out a correction in your mods as listed on the pdf list you provided. You mention: "GREEN - Replace 4 OEM 10k ohm resistors with Mills MRA5 10k ohm resistors" I have notice you also did this on your personal amp a while back. These resistors are the grid stop resistors and should be 1k ohm (up to 2.2k ohm at most) rather than 10k ohm. Using such a high value in this position would have an adverse effect on the frequency extensions and also not necessary to do it's intended job.
I didn't change any typology or values when swapping compoents in my 302. I simply upgraded resistors from the sand-cast OEM units. I think it's very possible that factory amplifiers were shipped with a few different configurations. Also... I don't think the value of these resistors was listed on my schematic. I thought they were the emitter cushion resistors, but I could be incorrect.
I also think that Bill knows these amplifiers, and his comments are safe.
These resistors are to stabalize the circuit to control oscilation. Using a higher value will not hurt anything but they should be no higher than 2.2K for performance.
Ahhhh, okay. This makes good sense. The factory installed 10k ohms when only 2.2k ohms is necessary