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  1. J M Fahey

    Anyone make a solid state power tube replacement?

    IF there is a market, they may certainly be done. One problem would be that of dissipation, a power tube dissipates some 25W from a thumb sized plate structure which means it works very hot, way too much for any semiconductor, they also dissipate using pure radiation, which makes them work even...
  2. J M Fahey

    Fender Speaker Identification Help

    Frames look like Rola/Jensen Chicago made speakers. The Mutter Company owned two factories:Jensen proper and Rola ,both in Chicago. Jensen proper closed , and production/machinery was transferred to the other plant, where they supplied "Fender" speakers for years ... very much like yours...
  3. J M Fahey

    "Blistered" filter caps

  4. J M Fahey

    Gigging a mic'd 5 watter?

    I am surprised at the answers above, my experience is a drummer will BURY you. Unless you either prop it on a stand at ear level a couple feet away or have really really good monitoring (and a very good Sound Guy) No, don´t tell me you´ll plug it into a 4x12", I guess the idea was to *reduce*...
  5. J M Fahey

    Preamp tubes... do they wear?

    Do the test above, but in any case: yes, preamp tubes also wear, but at a much slower pace, they have a very light job. Even the cheesiest preamp tube should give you, 6-8 years life; good one easily 15 years. And they sloooooowlyyyy wear, you will not find any difference day to day. They may...
  6. J M Fahey

    I need a loud efficient 4 ohm 12 inch speaker, is there such a thing?

    In the datasheet, but as I mentioned in other posts, "the number" by itself tells very little, if at all, since it varies wildly at different frequencies. The real deal lies in the curves. See that the red curve (4 ohm) is 1 to 4 dB BELOW the blue (8 ohm) and green (16 ohm) above 1 kHz. Below...
  7. J M Fahey

    I need a loud efficient 4 ohm 12 inch speaker, is there such a thing?

    Sadly 4 ohm speakers are darker and less efficient than same one in 8 or 16 ohm. See it for yourself, here Jensen C12N in all impedances. Other Manufacturers hardly post such data, notice all match at low and low mid frequencies but at higher ones red curve is visibly below 8 and 16 ohm ones...
  8. J M Fahey

    To hot for attenuater.

    A conservative design (whatever Leo or Jim designed back in the day) should have no problems. Specially because an established Company does NOT want extra Warranty problems, a mess, so they are extra cautious. I don´t blame them,of course, makes perfect commercial sense. Now some Boutique...
  9. J M Fahey

    Putting effects loop on vox hand wired?

    In a Power Amp distortion amp, Loop will always be before clipping stage. Loops make sense if preamp or some pedal distorts and then you can work with post-distortion signal. * Power amp clipping: you´re done * PPIMV: almost the same, signal there is some 90V RMS , pedals require some 100-200...
  10. J M Fahey

    Boutique Amps Distribution on fire/burnt down :(

    Just as a side comment, people moving through borders is controlled/blocked but goods trade has no restrictions. Containers come and go with no problem at all. Shipping has no restrictions and Air cargo was a life saver for Companies which lost 95% of their passengers or worse.
  11. J M Fahey

    Boutique Amps Distribution on fire/burnt down :(

    HAPPY you saved stock and machinery, (and no human damage, of course) even if you had to abandon the original building and move which is a mess even if not done under pressure. Hope you are on your tracks in a couple Months :)
  12. J M Fahey

    Is my Blackstar HT100 head a hybrid amp?

    Basic signal path is Tubes but you have lots of extrs: switchable channels, loop, boost, reverb .... all that is done with SS of course, or you´d need 8-10 12AX7
  13. J M Fahey

    Does cabinet size have an effect on a closely mic'd speaker

    Thanks for your test. Through junk PC speakers, not a *drastic* difference, but I hear the first half "more open" and the second one "boxier" or slightly muffled by comparison.
  14. J M Fahey

    Does cabinet size have an effect on a closely mic'd speaker

    As mentioned above,cabinet size will influence speaker *resonance* peak, both in frequency and intensity. Say exact same speaker has a 120Hz 6dB peak at resonance in a small closed cabinet (fighting trapped air elasticity rises frequency and Q), 105 or 110Hz 4dB in an open back combo and 100Hz...
  15. J M Fahey

    Modern vs. NOS 12ax7s tubes. Are NOS worth the cost?

    Problem is that the question is TOO wide. Many modern manufacturers and dozens of old ones, you can not lump all together by any means. NOS by itself means NOTHING, unless you also add something like "special edition Telefunken made in the 50´s for Radio an Recording Studios" or "made in the...
  16. J M Fahey

    Peavey rage 158 speaker upgrade

    Loved the sound and performance. That said, RMS power is just *one* part of the equation; 15W into a 98/99 dB speaker is way louder than into a 94/95dB one. But if that´s enough for you, fine. Pity you turned off YT comments.
  17. J M Fahey

    Output impedance question

    Basically that. :) In greater detail: Power tube working is defined by "load lines" of which a seat of the pants definition could be "impedance". There´s more to it but the above is close enough. So proper way to do it would be reverse engineer amp: * draw schematic, including voltages. *...
  18. J M Fahey

    Can I use a (deep) bass cab for guitar?

    Thanks. Did seller mention Brand-Model? Getting proper datasheet would help a lot.
  19. J M Fahey

    Eminence "Made in USA" 10" ?

    You posted exact same question twice :)
  20. J M Fahey

    Can I use a (deep) bass cab for guitar?

    That label as-is means NOTHING. 1) you have not seen the speaker Frequency Response Graph/Curve 2) typical Guitar speakers have a HUGE 10B peak between 2500 and 4000 Hz which gives them bite - attack - presence ; these will definitely not. Guitar speaker curve: Bass speaker curve: Compare the...
  21. J M Fahey

    Is it reasonable to assume this guy blew up my amp?

    Important data is being held and questions are not being answered.
  22. J M Fahey

    Speaker ID help?

    Cones don´t say much if at all, what´s unique to manufacturers is the stamped frame/bell , because the die set (cutting a large disk > stamping a basic cone > stamping sub-levels and edge lip >punching a circle in the bottom > punching frame holes in various patterns > punching mounting screw...
  23. J M Fahey

    Tube amps and the lack of new unique circuits?

    OP is right, no real *design* in decades. Only endless variations of the same ingredients (how many Mc D variants can you make with the same 5 or 6 ingredients?) Double burger? Double cheese? meat - cheese - meat instead of meat - meat - cheese? Or cheese - meat - cheese? Typical Booteek...
  24. J M Fahey

    Is it reasonable to assume this guy blew up my amp?

    Sorry but it is VERY hard to understand your message here: 1) that won´t happen, they couldn´t care less and don´t need to: they are an auction/sales operation, not a Tech site. No need to be a Tech to state that an amp "blows fuses", that´s well within a "normal" user area of knowledge...
  25. J M Fahey

    Preamp and power amp pedal with "regular" cab?

    You mean Preamp > Pwer Amp > 212 Cabinet? Yes of course, they are designed to do that. You must split the signal coming out of your Preamp. Maybe it has 2 outputs (some do), if not get a Y cable (1 plug at one end, 2 cables leave it and go to 2 separate plugs) Mono to two mono plugs. Beware...
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