I've a Quad preamp with impulse noise. At first I suspected the single 6111W dual triode, and replaced that, however, the noise the left channel continues.
This transistor seems to be in the left channel signal path. I thought it was only the tape out buffer, but not sure--lack a good schematic.
I've replaced the 7805 regulator already, but the noise continues. It's mostly left channel domimant with some cross talk of lower frequency to the other channel.
The part number seems to be an internal part number. VN10LP is a diode part number, but the schematic I have shows transistors a this location. Any idea what transistor Quad used here? Or a good cross reference?
This transistor seems to be in the left channel signal path. I thought it was only the tape out buffer, but not sure--lack a good schematic.
I've replaced the 7805 regulator already, but the noise continues. It's mostly left channel domimant with some cross talk of lower frequency to the other channel.
The part number seems to be an internal part number. VN10LP is a diode part number, but the schematic I have shows transistors a this location. Any idea what transistor Quad used here? Or a good cross reference?
Wow, that's wild... Quad used the wrong schematic symbol:
It's odd that my Google search turned up a part with the same number as a diode.. Gotta check to see if this part is available in the US.
It's odd that my Google search turned up a part with the same number as a diode.. Gotta check to see if this part is available in the US.
I've replaced the tube, and now, the regulators and the two FETs and the pre-amplifier STILL makes a huge amount of fast risetime impulse noise in the left channel. The power supply rails are quiet. I've monitored at the diode banks, all three of them. There's not much else in there that I can replace. Probably going to go for the plate resistors next. Too bad I'm out of freeze spray--that used to be helpful in zeroing in on the component that was temperature sensitive.