How to mod ASL MG OTL 32 DT?

[RAART]

I own for for at least 5 years ASL MG OTL 32DT and was always satisfied with the sound however since purchase I had slightly hum at 2 o'clock but as long as pass this point it disappeared. Dead silent before or after.

I heard that some people resolved this problem but I was unable to find anywhere DIY for this.

Does someone here did this mod?

Mine looks like this exactly... ANTIQUE SOUNDLAB

P.S. I use it with Sony's MDR 7506 and Beyerdynamic's DT931 and plan to add Grado's SR325is and AKG K701... one after one!

[Alastair E]

Simple answer, Dont play it at 2pm!

Wait till later in the day!

[RAART]

Originally Posted by Alastair E

Simple answer, Dont play it at 2pm!

Wait till later in the day!

It does not depend on time of the day...

What I wanted to say is that volume knob position is at 2 o'clock...

[M Gregg]

Originally Posted by RAART

I own for for at least 5 years ASL MG OTL 32DT and was always satisfied with the sound however since purchase I had slightly hum at 2 o'clock but as long as pass this point it disappeared. Dead silent before or after.

I heard that some people resolved this problem but I was unable to find anywhere DIY for this.

Does someone here did this mod?

Mine looks like this exactly... ANTIQUE SOUNDLAB

P.S. I use it with Sony's MDR 7506 and Beyerdynamic's DT931 and plan to add Grado's SR325is and AKG K701... one after one!

I had this problem,

This may not be linked, however this is my tail it might or might not help..

My OTL had a hum problem at 10 o'clock before and after was quiet.

It is /was linked to heater leakage in the preamp section. It did not matter if I lifted the heaters (HT divider) or grounded through 2 x 220 ohm psudo CT. The hum was still there..

The answer was to float the heaters with a 0.1 uF polypropylene cap between the heaters and Gnd. The cap charges due to any leakage and equalises the cathode to heater voltage.

Regards
M. Gregg

[RAART]

Originally Posted by M Gregg

I had this problem,

This may not be linked, however this is my tail it might or might not help..

My OTL had a hum problem at 10 o'clock before and after was quiet.

It is /was linked to heater leakage in the preamp section. It did not matter if I lifted the heaters (HT divider) or grounded through 2 x 220 ohm psudo CT. The hum was still there..

The answer was to float the heaters with a 0.1 uF polypropylene cap between the heaters and Gnd. The cap charges due to any leakage and equalises the cathode to heater voltage.

Regards
M. Gregg

Sorry for so late reply, but I moved to new place and still have everything packed. But while I plan to fix everything soon (next few months) and therefore I like to fix that light hum on the ASL.

While I am not very well versed in tube stuff or electronic, can you please explain in further details what I need to do... With good explanation I will be able to do it...

Regards.