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  1. J M Fahey

    Orange drops in a Princeton Reverb ?

    Only way different capacitors could influence sound if they are terrible and capacitance is all over the place. Or varies with voltage, which only happens in low quality ceramics when over-volted anyway. Typical tests showing how ceramics distort, show cheap 50V ceramics with 60V applied,or...
  2. J M Fahey

    Orange drops in a Princeton Reverb ?

    Repeat with me: "Caps-have-no-sound" Capacitance is what changes sound. * Same value, same sound. * Different capacitance value: different sound. * Different brand or colour, same capacitance: same sound. "But ... but ... I read in a Forum that ......." Forget that, read it in a book...
  3. J M Fahey

    Question about a boost pedal into an already maxed amp

    WEIRD. With a cranked 100 watt superlead YOU are the elephant in the room, who smashes the band mix and is hated by everybody. Would LOVE to know where you play and what the rest of the band uses to drown you.
  4. J M Fahey

    Suhr PT100 Blowing Fuses - Replaced Powered Tubes Still Doing it

    You should. Peoplen clicks on thread, finds it a 3 year old one and turns off. Same: you are asking to an OP who 90% of the time solved his problem (or not) and left, . Open your own fresh thread. Fine. But there are tons of problems which do not involve bad tubes. Turn amp on again *without*...
  5. J M Fahey

    Roland JC-77 - Replacement Parts?

    Agree with Jeff´s suggestion, would add : post a couple pictures, both of jack and pot. We might ask for a couple measurements afterwards (case diameter, shaft length, etc.) but in due time.
  6. J M Fahey

    What to do with unused international taps on a PT?

    Fine, just make *certain* exposed ends are covered and insulated, and insulation can´t slip off easily.
  7. J M Fahey

    Any 12" speakers particularly suitable for small cabinets?

    Way too small cabinets tend to sound honky/nasal/middy. A scooped sounding speaker may help tame that.
  8. J M Fahey

    Partial, Intermittent Failure of Output Transformer

    I find that very unlikely. See no mechanism for a Zener type breakdown, where below a certain voltage nothing happens and with precision and repeatability, above a trigger voltage it shorts, time and time again. Yes, there is insulation breakdown any day of the week, but then it never "self...
  9. J M Fahey

    Jensen Speaker Numbers

    Thanks. Any clickable link?
  10. J M Fahey

    Modify Baffle in Orange PPC112 (to 2x10)

    Tight job but if it fits, it fits :) Congratulations. The minuscule cone edge blocking by mounting cleats is irrelevant.
  11. J M Fahey

    Partial, Intermittent Failure of Output Transformer

    You bet. WAY worse than clipping and even crossover distortion, which is saying something. And yes, those "stabilization" caps must have been a desperate measure, they are certainly cheesy and not more than a bandaid. They must have been stuck with a few thousand OTs, which they wouldn´t junk.
  12. J M Fahey

    Jensen Speaker Numbers

    :worthless Specially pics showing a ruler against magnets themselves (not any cosmetic covers) showing exact ferrite ring/donut diameter and height/thickness. That can be compared to confirmed C10N measurements. If at all possible, try to use mm to measure, sick of medieval measurement...
  13. J M Fahey

    Roland JC120 replacement speakers

    Fane is a killer speaker, way above any Celestion. Not "famous" because "Jimi/Jimmy/Ritchie didn´t use them", point being that Jim found them *expensive* . Same happened with Partridge transformers, famously he only used two ... which he got as free samples for testing. Fane speakers and...
  14. J M Fahey

    Vintage Peavey wiring question

    Yes. Since this is a **safety** ground, we do not want to mess with it at all. Electrically grounding bto existing "G1" tab or to a new one 1 inch away from it is thye same, difference is "mechanical". Dedicated grounding tab screw+nut will be tightened, if available a star washer will make...
  15. J M Fahey

    Adding an AC fan to cool a tube amp? Any constraints or considerations?

    The 6.3VAC > diode bridge > 4700uF x 16V capacitor supply gives you around 8VDC as mentioned above and works fine, I have installed lots of them. No need to point exactly at tubes, you are not cooling *them* , at least not the hot plates themselves, which are inside a very well insulated glass...
  16. J M Fahey

    Partial, Intermittent Failure of Output Transformer

    Interesting. So this poorly designed/wound transformer causes bad enough phase shift to make amp unstable. Weird they didn´t catch the issue at Factory. Or maybe it was just one bad batch. EDIT: Speakers are quite inductive and show it more at higher frequencies, as you say a Zobel should...
  17. J M Fahey

    Vintage Peavey wiring question

    1) remove both caps. technically you could leave the one across Mains and just remove the one with one leg grouned at G1 but in any case it will not meet modern standards anyway, so ... 2) replace Black and White wires with those from new 3 wire cable. 3) ground green wire to G1 soldering tab...
  18. J M Fahey

    Roland JC120 replacement speakers

    I think loud clean is what´s needed, guess Jensen G12K, which are heavy magnet and large voice coil are closest to originals, which I guess were custom made by Pioneer for them.
  19. J M Fahey

    New Electro Harmonix EL34 without logo. Is it normal?

    Believe it or not, these are **2008** Russian tube factory pictures:
  20. J M Fahey

    Speaker identification (cone codes)

    The old pictures show Alnico ring magnets, they have the proper geometry. Large alnico rings, similar to what Jensen P12N or early Celstion had, we´d need exact dimensions to decide. The newer pictures show HUGE CTS square magnets, what would be used in the most powerful amps, so , say, not a...
  21. J M Fahey

    Question on Jensen P12Q v P12N

    How would you ...or anybody else know? Lacking a HG Wells or De Lorean time machine, of course :) As of Weber sound, with due respect, I think he´s (commercially) riding the wave of RI Jensen hate and *on purpose* building undermagged speakers, to meet what Users expect. Easy to do. A friend...
  22. J M Fahey

    Modify Baffle in Orange PPC112 (to 2x10)

    Not sure they will fit, you should upload pictures where speakers are *actually* visible, preferrably from the back, with the back panel removed. A full one and a closeup showing available space between speaker frame and side/top panels. Also showing whether front panel is screwed to all around...
  23. J M Fahey

    Dead treble cap? Top Boost treble control does nothing? AC30CC2X

    No, not shorted, that would turn treble control into a Volume control. Maybe pot itself is broken, wiper lost contact, etc. Really hard to explain by remote control since circuit is SO simple that it MUST work, or else. So there must be something staring at you but you don´t notice it. Is it...
  24. J M Fahey

    Outboard reverb unit with two pans

    No problem, just check RCA jack grounding, some are floating and that may complicate things a bit.