Posted by Walt N

March 28, 2022 - 02:48 pm

OK. BTW, I did not replace the C103 caps that you said should probably be replaced. Do you think that is worth doing?

Posted by Steve L.

March 28, 2022 - 02:24 pm

Hi Walt, Yes, I think those Q102 collector voltages will be okay. By the way, I notice that the schematic shows 9.4V at that point, so that's a bit closer to what you are reading.

Posted by Walt N

March 28, 2022 - 02:12 pm

I ran the "no load" voltage checks as per the Cortina manual on the phono preamp. All of the transistors read high, but within tolerance (15%) EXCEPT for the Q102 Collector. That one is supposed to be 10.4V. I got 7.1 (DMM) and 7.6(VTVM) on the bottom one and 6.6(DMM) and 7.0(VTVM) on the top. This is about 30% off. I'm not sure whether to suspect the transistor or some other component, or is this OK?

Posted by Steve L.

March 25, 2022 - 03:20 pm

Hi Walt, I would call the 2N5089 an upgrade. In the Cortina, it should not increase the output.

Posted by Walt N

March 25, 2022 - 03:11 pm

Is the 2N5089 a more or less exact replacement, or is there a chance that using it would increase the output?

Posted by Steve L.

March 24, 2022 - 08:37 am

Hi Walt, Yes, the reason that Q102 is less critical noise-wise is that Q101 has already amplified the low-level cartridge signal. So Q102 has far less effect on signal-to-noise ratio. The signal level at Q102 is much higher than at Q101. Thank you for bringing this to light.