Recent content by BlueCrab

  1. BlueCrab

    Scope

    So for about the same cost you could have a Pico scope (I'm assuming you have a desktop or laptop that could be used with it.). The Pico scope is a no-brainer with regards to setup with the computer and includes a built-in signal generator - which is great for learning how to use it. And it...
  2. BlueCrab

    Scope

    I have one (2205A) in addition to a bunch of Tektronix scopes. For audio work the PicoScope is all you need, even the cheapest lowest bandwidth one. HP made some nice scopes, but I always preferred the Tek scopes. BTW, I used that 1741 back in the day (probably mid-80's). Storage scope is a...
  3. BlueCrab

    Scope

    Go for it, if it is working (all functions) and at a good price, otherwise I'd go for a PicoScope. See here: https://www.picotech.com/oscilloscope/2000/picoscope-2000-specifications
  4. BlueCrab

    Phase Linear 2000 Pre-Amp Rebuild

    And I agree that caps with a 25 wvdc rating are inadequate. 35 volts would be ok, 50 volt caps would be better.
  5. BlueCrab

    Phase Linear 2000 Pre-Amp Rebuild

    Without a load the filter caps will charge to the peak voltage of the transformer output minus the voltage drop across the diode, which in your case should be about (17.8vac x 1.4) - 0.7 = 24.2 vdc. Pretty close to what you are measuring. Looks good to me. There will be next to no ripple...
  6. BlueCrab

    Cathy Has Returned

    As you increase the power supply capacitance, the on-time of the diodes in the bridge rectifier gets shorter and shorter, which increases the peak current that the diodes must conduct. I have no idea what the peak current demands are with the present power supply capacitance or even if it is...
  7. BlueCrab

    Phase Linear 2000 Pre-Amp Rebuild

    This may shed some light: https://www.analog.com/en/technical-articles/output-voltage-noise-measurements-for-linear-regulators.html#
  8. BlueCrab

    Phase Linear 2000 Pre-Amp Rebuild

    Very ambitious. My recommendation is to start simply, make one set of changes, such as power supply electrolytics, and then retest that it still works, but I'm sure you're doing that. With regard to resistor wattage, it's impossible to make a blanket statement that 1/4 watt are sufficient - it...
  9. BlueCrab

    Technics M85 - worth restoring?

    For mine, the FF and Rewind were inconsistent, I could see it was slipping. I've ordered a new idler tire and pinch roller for it.
  10. BlueCrab

    Technics M85 - worth restoring?

    That is a seriously nice deck. It's nice to see something done well, it looks great, works well, and was well made.
  11. BlueCrab

    what are you listening to?

    Streaming KJAZZ from Long Beach, CA, which I feed into my Ramsey FM transmitter so I can listen anywhere in the house where I have an FM radio or in my detached garage where I have my workshop. And any neighbor within 1/4 mile as long as they tune to 95.1 MHz.
  12. BlueCrab

    Technics M85 - worth restoring?

    Thanks. I'll give them a try.
  13. BlueCrab

    Technics M85 - worth restoring?

    Does anyone have a speed calibration cassette they'd be willing to sell? Making one myself would be like using your own voltmeter to calibrate itself. I'd be willing to buy a reference tone tape that someone made themselves from a good machine that is known to be true. I'm not looking to have...
  14. BlueCrab

    Technics M85 - worth restoring?

    Finally pulled RS-M85 off the shelf and gave it a go. I'm sure it hasn't been turned on since the 90's. Initially, nothing worked - couldn't get a tape to play, occasionally it would go into FF, but then I couldn't stop it - it seemed as if none of the switches worked. As Elite-ist predicted...
  15. BlueCrab

    Adjust DCP timing?

    Just to finish up on what actions I took. Initially I bought one of the Delay-On Relays I mentioned in an earlier post. Cost about $30, which I thought was reasonable. And it does the job. It was easy to mount inside the PL4000, timing is easy to set, you can use either AC or DC for control...
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