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  1. mdye

    The official Fairchild 412 registry thread!

    Thanks, Andy. I'll give this .01 X/Y a shot.
  2. mdye

    The official Fairchild 412 registry thread!

    Andy -- sorry I missed your question earlier. Yes, I can confirm that both platters are filled. I'm actually looking to replace the arc suppressor capacitor across the power switch. Looks like the original bumble bee cap that's in there is a .056uf 600V. I do have some .01uf X1/Y2 safety...
  3. mdye

    The official Fairchild 412 registry thread!

    Alright, some quick pics to share of my two 412s. On the right, the Model 412 Basic Chassis with connector for the 412-ED speed control regulator, and what appears to be a pulley for 45 rpm records. This pulley appears a bit crude compared to the rest of the engineering, so I'm not 100% sure...
  4. mdye

    The official Fairchild 412 registry thread!

    Thanks for the tip, Andy. I have just messaged Sam--fingers crossed.
  5. mdye

    The official Fairchild 412 registry thread!

    I'm the owner of two Fairchild 412 turntables. One is an older "basic chassis" with 45 adapter, original plinth and Papst motor. The other appears to be a later model with the Fairchild labelled motor. No plinth for that one. I will post serial numbers and pics as soon as I can. I'm...
  6. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    Haven't had a chance to listen to them yet with the exception of a 30Hz test tone, as I am apparently supposed to let the glue cure for 24 hours. Not sure about the black dust cap, but it sure looks original to me. It is odd that I can't find any other pics of a black cap LE8 though. Before I...
  7. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    The finished product. I installed the new surround that I purchased from Rick Cobb. It doesn't look like a perfect speaker driver, but it sure does look a hell of a lot better than it did before.
  8. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    I've been very slowly scraping away more of the silicone. It's looking a bit better, but it's starting to take a toll on the cone lip. I understand that the proper way to replace the surround on these is to glue the surround to the back of the cone as in the original design. I've also seen...
  9. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    So I tried to gently pick, scrape and pull the silicone off of the cone, but it just wants to take a top layer of paper with it. Since removing the surround and glue from the bottom of the cone already took a layer of paper underneath, this is leaving the cone lip dangerously thin. I tried...
  10. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    After removing the the gasket and original surround, I'm left with what you can see in the attached pictures. I did accidentally tear a little chunk out of the edge of the cone, visible in the top right of some of the pics, but overall I'm happy with how it went, especially considering that...
  11. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    Being a helpless tinkerer, 'try to clean them up' is exactly what I ended up doing. Very slowly and carefully pulling away the silicone with some tweezers reveals the original Lansalloy surround underneath.
  12. mdye

    JBL LE8 Early Version - Disaster or Salvageable?

    Greetings, I've just come into possession of an early JBL LE8 driver with whizzer cone that came as part of a very cool Ampex SA-10 field monitor. I understand that there have been a number of variations of the LE8 over the years, but I can't seem to find another one quite like it on the...
  13. mdye

    Regency HF-350A Monoblock

    That's a nice, clean example right there! Beautiful. Can you elaborate on how it stopped working?
  14. mdye

    Regency HF-350A Monoblock

    Hey Collins300G, and welcome to the forum. I still have my HF350A, but still haven't gotten around to working on it. I've been holding off for another to make a pair and was then going to refurb both at the same time with identical parts, etc. I've had mine for about 3 years, but still...
  15. mdye

    Loud Buzz When Preamp Is Turned Off

    I also don't believe that there is anything out of the ordinary with the preamp and the interconnects. They've been used in countless configurations without any issues whatsoever. How about my shielded cable wiring though? I'm using single conductor with a shield, and the shield (I'm now...
  16. mdye

    Loud Buzz When Preamp Is Turned Off

    I used single conductor with shield; shield side grounded at RCA jack ground tab only. RCA jacks are insulated from chassis, but run to a star ground.
  17. mdye

    Loud Buzz When Preamp Is Turned Off

    Yeah, I've frequently seen the resistors right at the input jacks as well. I've done it this way a few times before without issues, but I've also been told that this can sometimes cause problems. No idea how good the info I've been given is. Unplugging the preamp hasn't helped either. I...
  18. mdye

    Loud Buzz When Preamp Is Turned Off

    I'm using some RCA cables made from shielded Belden 8402. I've tried a few other generic cables I had laying around, but no change. I won't be able to have a closer look until the weekend, but I'm wondering if I made a simple mistake in my input wiring. Due to space constraints, I soldered...
  19. mdye

    Loud Buzz When Preamp Is Turned Off

    The preamp is a Dynaco Pas-like unit, with new boards (slightly different circuit) from a company that isn't around anymore. Input impedance on the amp is 100K.
  20. mdye

    Loud Buzz When Preamp Is Turned Off

    Yeah, I guess this is just noise being picked up at the input jack and amplified. I've built a number of amps over the past few years, but I've never seen one pick up noise in this way. Certainly I can just follow the standard amp on last/off first formula, but just for the sake of knowledge...
  21. mdye

    Loud Buzz When Preamp Is Turned Off

    I've tried rotating the tubes around and trying completely different tube, but no change. The sockets are also brand new and the pins are tight. I did find my rca grounding dummy plugs, and after inserting those in the inputs I get no noise. The amp is dead silent. So...I'm making progress...
  22. mdye

    Loud Buzz When Preamp Is Turned Off

    RWood: I'll need to look around for some rca dummy plugs. I used to have some around here, just need to locate them... I'm only just noticing the issue now, but I can't say for sure if it was present immediately after I completed the build or if it just developed within the past few days.
  23. mdye

    Loud Buzz When Preamp Is Turned Off

    Edited the title. I'm now realizing that the buzz is coming from both speakers when the preamp is turned off. It's just louder in the left channel than the right.
  24. mdye

    Loud Buzz When Preamp Is Turned Off

    Greetings All, I recently completed a single ended 45 amp build which, up until today, I thought had come together with zero issues. I've been enjoying it immensely the past few weeks, however I just discovered a strange issue with buzzy noise coming out of the left channel. It only happens...
  25. mdye

    Hum Pot for DHTs

    Thank you all for the very helpful info! Perhaps my search has been too specific, as I was looking for "hum balance" pots. Are hum balance pots nothing special, and just standard, linear pots like the ones found here...
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