Grundig V35. Hum in left channel

[Pacorl]

I was given an old Grundig V35. I was thinking in using it as a source of parts for a project like Destroyer´s "Blame Es" or similar.

When connected to a decent pair of speakers , it sounds VERY well except for a small amount of hum in the left channel. The intensity of the hum is constant regardless of the volume.I think it´s worth trying to fix it prior to start dismantling...

I have ruled out the PS as source of the hum.

Sound quality seems the same in both channels in spite of the hum. Can be ruled out a failure in drivers?

I was thinking to start checking coupling caps in the signal path as a next stage.

Any other clue?

Thanks in advance.

 

[smartx21]

At first glance, it is not worth dismantling this amp to build the Blame ES. I can't see you reusing many parts, especially for those outputs being Darlingtons.
By the other side, I've had some headache with grounding techniques. It was all right before I decided to connect my Blame ST to real ground. Noise appears when the laptop PSU is connected to the same ground point; when the electronic shower is powered on; and some other situations.
So, if not a failing electrolytic, look for grounding problems (a bad solder, lose contacts, etc.).
Regards,
Max.

 

[Pacorl]

Carlos,

thank you for your feedback.

You´re right, no part from amplifier section can be reused for Dx Blame. However PSU, speaker protection section, volume control and heatsink are in excellent shape.

enclosure is not to big. The main issue would be to fit DX PCB´s inside.

I´ll take into account your input in the following days.

regards,

Paco

 

[smartx21]

Oh, I see... "Paco de Murcia"! Do you also play the guitar? 😀

 

[Pacorl]

I used to play guitar many years ago, but very poorly 🙁.