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  1. mlucitt

    Cable capacitance. How low can YOU go?

    Twisted pair geometry is ideal to reduce typical magnetic interference from 60 Hz AC motors and fluorescent lighting, etc. through CMRR. However, my HAM radio operating at 500 Watts at 12.350 KHz RF will punch right through any cable that is not 100% shielded. And yes, I have some Cat 6A twisted...
  2. mlucitt

    New Member: Planning my PL400 rebuild

    Additionally, you will need the experience of the folks who chimed in above. No one gets it right the first time, ask questions and be ready to show us high resolution pictures. We have collectively made every mistake possible, so you don't have to. You still get the satisfaction of doing the...
  3. mlucitt

    Cable capacitance. How low can YOU go?

    I believe the low pF/m reading for the diamond-braid cable is because there is no shielding. I would not want to run an interconnect without shielding.
  4. mlucitt

    Not So Sure

    Personally, I would not trust those curves for Chinese audio components.
  5. mlucitt

    BIG METERS, What to do with them.

    I would make the left one "Left Skating Force" and "Right Skating Force". The one on the right is not symmetrical, so maybe "Tonearm Up" and "Tonearm Down". You will have to design the sensors to actuate the meters.
  6. mlucitt

    Phase Linear 4000 Resurrection

    You can upgrade it with 86 new electrolytic capacitors (those in the audio path should be bipolar types) and replace the RC4136 and RC4739 audio OPAMPs with OPA2134 devices on Brown Dog adapters. Then reflow all the solder connections on the daughter boards and the motherboard. If it works, put...
  7. mlucitt

    Cleaning alu

    Most of these audio equipments use anodizing on the aluminum parts. Any type of abrasive cleaner/polish will remove the anodizing and leave you with raw aluminum. You can polish the aluminum with Flitz or Semichrome or any of the products mentioned above until they look like a mirror, but unless...
  8. mlucitt

    Cross Slide Vise Brand?

    Grizzly makes cross slide vises from $640.00 to $95.00. I like the G5757 at $220.00 (free shipping) It is robust and accurate. https://www.grizzly.com/products/grizzly-compound-slide-table/g5757
  9. mlucitt

    Phase Linear 4000 Resurrection

    28VDC is Power Supply voltage. I suspect it will be more than a cold solder joint... Is this the preamplifier with the joystick in the center of the face plate? If so, it is not worth repairing. Good design on paper, but the assembly was a hot mess.
  10. mlucitt

    Friggin hats.

    I cannot believe no one mentioned the Tillley hat. Made in Canada and guaranteed for life! It is machine washable, has folding sides and almost indestructible. I got mine at West Marine and it was not cheap, but hey guaranteed for life, who does that anymore?
  11. mlucitt

    phase linear 400

    My 2005 Chevy Silverado truck had an in-line fuel filter in the frame rail and I would replace it every 20K miles. Imagine my disappointment when I went to the local auto parts store to buy a fuel filter for my 2019 Suburban... The fuel filter is inside the fuel tank! I imagine there is a lot of...
  12. mlucitt

    Crown Macro Reference Monster amp rework.

    I have two Crown COM-TECH 200 rack amplifiers that were advertised as needing some help. I think I have the schematic somewhere. I wonder how worthwhile it would be to bring them back to working condition?
  13. mlucitt

    Isolated Variable Transformers? Or Separate Iso and Variac? Plus a Newbie Tech Question

    My understanding is that an isolation transformer magnetically couples the AC voltage to an "isolated" output jack. The ground is connected to the chassis on the input and the output to shield the transformer and still provide a path to Ground in the event of a device failure. Typically, there...
  14. mlucitt

    Funny pictures...

    What did you leave us?
  15. mlucitt

    We need your help. OC16 button is gone

    Likely the repair is more than the cost of a suitable replacement microphone. The prices of good sounding microphones have come down due to the increased number of podcast "artists".
  16. mlucitt

    WOPL 700B Rebuild Left Channel Buzz

    Referencing Post #7, no Grounding jumpers are allowed here. Every Ground wire originates at the STAR Ground (between the main capacitors). That includes the Gray and White Ground wires stuffed into the Phoenix Terminal Block, one wire per position please.
  17. mlucitt

    PL700II Cylon -> VU ?

    Like these:
  18. mlucitt

    New guy from Alaska

    You have a transitional PL700 Series II. The change from the PL700B to the PL700 II happened in 1977/1978. Note that your RCA Driver Transistors have a 1977 date code on them. Phase Linear continued to use the transformer stickers they had in stock (likely already glued to the transformers) on...
  19. mlucitt

    700II resistors/diodes

    Phase Linear chose to reduce the control board voltage from 100V to 15V with large power resistors and Zener diodes. This is not optimal as shown by the "browning" of the circuit board. The White Oak Audio Rev G1 Control Board uses two +15V and -15V precision power supplies (dedicated power...
  20. mlucitt

    700II On/Off Switch ?

    These PL400 and PL700 Series II latching power switches are known as TV-5 (5A steady rated, 78A peak) or TV-8 (8A steady rated, 117A peak). These switches were designed for tube televisions that had high inrush current demands, and were approved and rated by Underwriter's Laboratory (UL). You...
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