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  1. PRR

    SPU Cartridges and Transformers Thread

    If it does not store energy, it can't be an inductance, an audio transformer. Someone is just making this stuff up. I'd even say "some ignorant person" is making this stuff up.
  2. PRR

    So I bought a peak hold voltmeter, now what?

    Yes; or even simpler. A 1N400x diode and a 0.1uFd cap, plus maybe a 10r 1W resistor, to any cheap DMM, will "determine if an AVR is clipping." The 0.6V error is insignificant on typical 30V peaks; or can be fudged-in. Unless you only listen to male announcers, raw, peak is as good as peak-peak...
  3. PRR

    So I bought a peak hold voltmeter, now what?

    "the manual is incomplete and poorly translated (annoyingly so)." "Good DMM. Terrible user's manual. The user's manual was obviously written by someone for whom English is a second language. So bad could not figure out how to do simple measurements like resistance. Web site which is...
  4. PRR

    The food thread

    There's lots of "Acadians". Some on the bayou, some still near Quebec, some out to Nova Scotia, a festival in the crown of Maine, and some in my area, north-east Maine. (hidden shame: catholics of all backgrounds were persecuted here, it was the KKK's other target.) Aside from growing and eating...
  5. PRR

    Faital Pro 12FH500 Driver Measurements in DATS versus Specifications

    I apparently derived a similar idea (without publication or extended thought) before Dickason. (Many insights are "in the air" a while before someone nails them down.) I used Qts for no very good reason, Qes may be more what we want; but I was working with very high BL drivers so Qes ~~= Qts and...
    • PRR
    • Post #12
    • Forum: Parts
  6. PRR

    diode bridge 30A

    That's very small resistance in wiring or inside the capacitor.
    • PRR
    • Post #2
    • Forum: Parts
  7. PRR

    RCA JAN832A ...OTL Headphone preamp..?

    The cathode (your output) impedance is 1/Gm or 1/3500uMho or 286 Ohms per section, 143r for both in one bottle. Driving 38 Ohm load the gain can't be as high as 0.21. You will need near 7Vrms (10V peak) at the grid. THD will be quite high. This tube really wants to be push-pull transformer...
  8. PRR

    Fisher KX-200 Bias circuit problem

    http://www.fisherconsoles.com/non%20console%20manuals/fisher%20kx-200%20sm.PDF I have not seen one of these in 50 years. In its day, these ran HOT but did not smoke. Whatever you did, something is wrong. Is it possible that the CAPACITOR is 'smoking' (boiling), not the resistor? Where did...
  9. PRR

    Discussion: Unwanted clipping in solid-state e-guitar preamps

    A large paper cone has dozens or hundreds of resonances. Which vary in F with drive level. If we actually understood that, a supercomputer might simulate it. But it is still early days in level-varying response theory. A 1930s-style paper cone is still cheaper and smaller than the emulation.
  10. PRR

    Faital Pro 12FH500 Driver Measurements in DATS versus Specifications

    You are gonna do two things: break it in, and put it in a box. Break-in reduces the stiffness. Box increases stiffness. The mass is not going to change, and the BL can hardly change. Changing the stiffness changes Fs but not mass or BL, so is not real important, except that we like to work with...
    • PRR
    • Post #6
    • Forum: Parts
  11. PRR

    What do members of diyAudio use as music players?

    It is absurd to say that edbarx posted a marketing survey. I do believe he wants ideas for his own system. Agree on "useless". We'd get better answers from CatFart (ChatGPT). We may have already.
  12. PRR

    Deeply odd phase splitter/driver problem - Ampeg SVT 300

    I forgot the 47k parts. Yes, the grid current (if any) is normally into the grid (electrons come out). A straight cathode-follower driving the grid can see large cathode current, OTOO a 1k resistor (+10V makes 10mA). But the 47ks swamp that. 48k/3 = 16k is not a dangerous load for 12AU7 (showing...
  13. PRR

    The Weather

    "Maine is known for its cold weather, but a popular pond hockey tournament was postponed, some ski resorts curtailed operations and organizers even put the kibosh on Saturday’s events at the National Toboggan Championships." "If people have to go outside, then they should dress like their lives...
  14. PRR

    Deeply odd phase splitter/driver problem - Ampeg SVT 300

    They drive grids of 12AU7 which has very low leakage and is rated 1Meg grid path resistance. Also this is actually one of the most reliable high-power amps ever made. The series resistors ARE high because otherwise when the power stage touches AB2 (rare but it does happen in this amp) the poor...
  15. PRR

    Edit time in Conversation

    30 minutes: Oops! We ran into some problems. The time limit to edit this message (30 minutes) has expired. It used to be even shorter. I sometimes compose off-line in WordPad or other plain-text editor, so I can look it over many times or even overnight. Has also saved my butttext when a...
  16. PRR

    NAD 1000 preamp cap questions (signal path vs power filtering)

    I don't see a problem with any of your red/blue marks. Power supply IS "in the signal path", and significantly for most discrete circuits. So while C205 is more a filter thing, I see no harm in using a sweet-sounding cap. Does it cost more? Enough to agonize over?
  17. PRR

    Edit time in Conversation

    I thought it was out to 30 minutes now? Is my sundial slow? Does the forum know I am old and slow and cut my finger last night? Timer: 8:46p 8:51p 9:05p 9:09p 9:15p
  18. PRR

    phonograph

  19. PRR

    13.8V Power Supply

    That would power car-sound chips. 2 Watts in 8 Ohms, 4W in 4 Ohms, maybe 18 Watts two channels bridged on 4 Ohms. LM3886 might not even turn-on? (It has a low-voltage mute.) You want 40V to 80V total, preferably as two 20V-40V rails. You can have a LOT of fun with the 12V car-sound chips...
  20. PRR

    Copland CTA 301 missing Resistors

    You mean, what to replace it with? Even though there are millions of type-numbers, LEDs are not complicated. Go by shape size and color.
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