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previous: Randall Aiken Glad to be of help!... -- 1/8/2000 4:33 PM

Re:Thanks RG and Randall!

1/9/2000 4:30 PM
lion	Re:Thanks RG and Randall! Randall ! Thank you for the suggestions. I tried sometime ago disconnecting the ground on the return jack – it didn’t seem to have any effect on the hum. Maybe I should have a look at it again. Another thing is that I just discovered that the hum level change when I move the connection cables around – so maybe it’s something picked up by the cables. The loop send is placed after the TS – wich is driven by a cathode follower. From the return jack the signal goes direct to a tube recovery stage followed by a 100K (return level) pot and then to the PI. The send is taken from the wiper af the treble control and then to a 100K (level send) pot.- and so is a low impedance signal (less sensitive to noise), right? I originally wired up this circuit in a few minutes as an experiment - but it worked so good that I haven’t bottered with it since. Looking at it again it just hits me that maybe I missed a few components in the hurry. I have no coupling cap at the send nor the return – and no resistor to ground at the grid of the recovery tube. Thanks again for your interest. Regards Lion PS: Any clues on where to find schematics of a transformer-coupled loop?

1/9/2000 4:30 PM

lion

Re:Thanks RG and Randall!

Randall !
Thank you for the suggestions.

I tried sometime ago disconnecting the ground on the return jack – it didn’t seem to have any effect on the hum. Maybe I should have a look at it again.

Another thing is that I just discovered that the hum level change when I move the connection cables around – so maybe it’s something picked up by the cables.
The loop send is placed after the TS – wich is driven by a cathode follower. From the return jack the signal goes direct to a tube recovery stage followed by a 100K (return level) pot and then to the PI. The send is taken from the wiper af the treble control and then to a 100K (level send) pot.- and so is a low impedance signal (less sensitive to noise), right?

I originally wired up this circuit in a few minutes as an experiment - but it worked so good that I haven’t bottered with it since. Looking at it again it just hits me that maybe I missed a few components in the hurry. I have no coupling cap at the send nor the return – and no resistor to ground at the grid of the recovery tube.

Thanks again for your interest.
Regards
Lion

PS: Any clues on where to find schematics of a transformer-coupled loop?

Replies:

Joe L q{Any clues on where to find schema... -- 1/9/2000 7:42 PM