Recent content by nerdorama

  1. nerdorama

    Revisting the ADS 1290/2's (with better electronics...and tubes)

    Well, the calculator you link doesn't include the driver impedance so isn't very useful. Also remember that the woofer impedance in the 1290's is two in parallel and at 500 Hz they might already be into the inductive rise section of the impedance curve. Just isn't enough info without actual...
  2. nerdorama

    Gillespie triode Williamson build

    I'm thinking of installing a pair of nice speaker binding posts next to the location of the original speaker terminals with a wire from the positive post coming out near the terminal block with a fork lug so changing impedance would only require moving the wire with the fork to the appropriate...
  3. nerdorama

    Half Century Old Miracle: My Fischer 400

    The OP was last here 5 years ago so probably isn't watching any more. I like my 400. It has all of Dave Gillespie's improvements.
  4. nerdorama

    My first integrated tube amp suggestions

    You might consider a restored older Eico or Heathkit amp(s). Where they are well restored they are really nice sounding. As you are a subscriber, well done, you could post a want to buy ad in Barter Town. You might be surprised at the things you would get offered. I think you can do better...
  5. nerdorama

    Sansui 1000A find

    Nice. And a 4 pot bias too.
  6. nerdorama

    SEUL feedback

    You might also try plate to plate local feedback. Put a 100k resistor from the 6L6 plate to the 6SN7 plate. It might, probably will, change the SN7 biasing a bit but it's easy to try and won't require the same amount of tuning that global feedback often needs. Just another option. I had to...
  7. nerdorama

    Bogen AP-60 found in the dust

    I have an owner's manual for the RP-40. These several pages look like they might also apply to the AP-60 speaker connections. Hope this helps.
  8. nerdorama

    Williamson tube amp. Noise at turn off.

    Those are small adjustable capacitors. You shouldn't have touched them. Probably in either the feedback loop or maybe a shelf network to tune HF response. If you have an oscilloscope, or maybe someone you know has one, you could check the high frequency square wave response and then tune the...
  9. nerdorama

    Bogen AP-60 found in the dust

    I always buy over $100 from Mouser, sometimes $200, to amortize the shipping.
  10. nerdorama

    Tube Display, Storage

    Just be prepared for your tubes to smell like mildew. I’ve had a few tube caddies..
  11. nerdorama

    Dave's G's well spoken info.

    I don’t think this one is in the list. I’m doing a pair of W4’s based on this thread. https://audiokarma.org/forums/index.php?threads/gillespie-triode-williamson-build.795322/
  12. nerdorama

    New Toroid Output Transformer Marketed?

    Maybe they could be driven by a cathode follower.
  13. nerdorama

    Cold solder joint on a dynaco fm3

    Haven’t used mine in quite a while but thought it sounded really good. I did most of the upgrades based on articles from Audio Amateur magazine.
  14. nerdorama

    Sansui 1000A Where to start?

    If you can clean up the chassis rust a bit, wire brush or sandpaper, to smooth it out then you can daub on some Ospho and it will convert it to a stable black-ish color that isn't so obvious. It is very liquid and you can daub it with a small brush. I got my quart at Ace hardware. It takes so...
  15. nerdorama

    Multi-cap cans - always replace??

    I think only the CE cans rated at 450V and below are 85C. Above that they are either 65C or 55C as you go up in voltage rating.
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