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Gene, You have a Left Channel issue, no? Bad Left Channel Bias voltage could point to the Bias Transistor supply circuitry (2N5088 are the good ones). Can you change the Left Channel Bias Voltage by operating R2L Bias Potentiometer? Next I would ring out D1L-D4L, part of the Bias Feedback...

Failing MJ21195 and MJ21196 transistors is sorta rare. The specs on these devices are pretty impressive. It will be interesting to see what you discover. I am with Lee, if your Bias Transistor in that channel is original it could be a cause as well as a casualty. I seem to remember if the Bias...

This is a typical well-used Phase Linear Control Board. Those large 1 Watt Resisters and Zener Diodes were used by Phase Linear to reduce the B+ Rail Voltage (+80VDC for the PL400 and +100VDC for the PL700) down to +20VDC for circuit board control voltages. The result was heat and a lot of it...

The first CD imported to the United States was Born In The U.S.A. by Bruce Springsteen, released in September 1984.

PM sent.

If your four-fin unit came with the two Transistor Covers, I would be interested in them for my four-fin PL400. Mark

Thoughts on the Staco?

They are 190 miles south of me. Sorry, Mark

The four fin PL400 is the earlier model. Most have the capacitors attached to the side of the chassis with clamps, while the later amps use an aluminum cradle above the transformer. There were other improvements in the later models such as the lighting arrangement for the meters. Most of the...

Or, originate...

I believe in this case the manual is correct. My (2) PL2000 preamplifiers came with 10uF caps at C42 and C43. Are you sure C42 and C43 are not 47uF? This is what I did to my PL2000 Series I: Upgrade (C42, C43) from 10uF to 100uF/35V, Mouser P/N 647-UFW1H101MDD1TA. Upgrade C21, C22 from .22uF to...

Just wait a few years for your hearing to become "adjusted" and then all of your set ups and room modifications will sound just about the same.

Be careful when using current feedback op-amps like the LM 4562 and be extremely careful if you have caps across feedback resistors when using CFB op-amps. The LM4562 was introduced by National Semiconductor in 2007, this was 17 years ago and it was a competitor to the 1997 Texas Instruments...

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...

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...

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.

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

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.

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...

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...