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41-608 distortion issue - Printable Version

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41-608 distortion issue - philco4me - 12-11-2024

Hello all
Got a 41-608 that I recapped about a year ago. Lately the highs have been distorted on the phono. I replaced the cart and needle but made no difference. Could a tube be an issue or a cap went bad ?

Thank you

RE: 41-608 distortion issue - jrblasde - 12-11-2024

Good evening! Could you elaborate a bit more on the distortion? Is it perhaps static-y sounding, for instance, or is it higher or lower in tone than it should be? Also, was it a rapid onset or has it been more progressive?

RE: 41-608 distortion issue - philco4me - 12-11-2024

Good evening
For example s sounds are distorted you cringe when you hear it. It seems to have come on suddenly. Highs are the issue lows are fine

Thanks for the reply

RE: 41-608 distortion issue - jrblasde - 12-11-2024

I was formerly an audio-video system engineer. The “s” sound is a great test to the frequency reproduction of a system. I think I understand exactly what you’re hearing now. Probably sounds like a radio that’s not quite tuned to a particular station, doesn’t it?

Sounds like a change in capacitance if you ask me. But given that you say it was a sudden onset, I’m almost inclined to say it’s a tube issue. Certain failures within tubes can cause changes in capacitance from pin to pin.

Just as a sanity check, have you tried playing different records? Does the radio mode sound normal?

RE: 41-608 distortion issue - philco4me - 12-11-2024

I have Tried several different records with same result. I even played the same records on my 46-1209 and they play fine. The radio seems to play fine.

RE: 41-608 distortion issue - jrblasde - 12-11-2024

To me it definitely sounds like an issue with the 7C7 preamp tube. You’ve pretty well narrowed it down. You might just verify that there aren’t any damaged capacitors in that section of the circuit, though I doubt it if you recapped the system last year.

Let’s see if any of the experts here have an opinion! I’m pretty new to tube circuitry, myself.

philco4me - philco4me - 12-11-2024

Thank you so much for the fast reply. I will Test that 7c7 and let you know

Thanks again

RE: 41-608 distortion issue - jrblasde - 12-11-2024

You’re welcome! I’m following with a curiosity. I have a 49-906 which had a tube go out on the FM RF circuit, and it caused a similar issue with audio reproduction. Just the same, I was able to narrow it down to just the one function, and found it to be the tube. That’s really the only reason I’m feeling confident in my assumption.

RE: 41-608 distortion issue - philco4me - 12-11-2024

This set has 7c6 tubes. I will Test both.
Thank you. I’ll post the result

RE: 41-608 distortion issue - jrblasde - 12-11-2024

Ah, so you have a code 122 model of the 41-608. I had to do some digging!