Adding Wet-Only Output to old obscure Tape Echo

[templemark]

I have an old obscure Sochor tape delay made in Poland ~late 70's / early 80's. No schematics or info available online I could find.

With some tinkering I managed to add a wet-only output.... and it sounds really cool for warbly tape processing. I tapped the delay signal from the delay-volume pot and it sounds good, however there is an issue. Some of the dry signal is bleeding through and coming out also. Its very low, probably only 2% of the total signal, but can be noticeable especially with drums/etc.

Somewhat of a vague/generalized question here, but any advice to try and stop this signal bleed when tapping off the wet-only in a typical echo transistor circuit?

Buffer the output? Add some resistance? Any ideas I could try?
Ill post some pics.

Thanks,

 

[abbey road d enfer]

This happens generally because the delayed output is mixed passivly with the input for regeneration. The best way is to buffer the delayed output.

 

[templemark]

Is something like this practical for audio circuit? (just a single transistor and single resistor)
http://www.learningaboutelectronics.com/Articles/Transistor-buffer-circuit.php
I'd like to keep the unit to its time period (avoiding any ICs).

 

[abbey road d enfer]

You need something more like the second schemo, but you need more realistic values.

 

[Tubetec]

Have a look at the schematics of the Watkins copicat , the later transistorised version had an output buffer , just one transistor . The trick with the copicat is to tap the delay only signal from the foot switch by attaching a jack socket at the end , it can still serve as a foot switch if you want , or you can tap the effect signal with a DI box ie Hi-z input .

As far as the break through is concerned remember these devices are probably expecting instrument input , not studio line level , if your driving it from a mixer send or computer interface make sure the output are levels reduced especially on something like drums where it can get really loud on the peaks .

Maybe show us a few photos of the unit if you can ,