Balancer and De-Balancer on a TRS Jack to upgrade unsymmetrical gear

[Janus Audio]

Hi everybody,

I made SMD boards to balance inputs and outputs of some of my outboard gear, because I often hat hum problems with some devices. The boards are just some line receiver and line driver circuits based on LM4562s and can be fed from internal power supplies of the modded unit (as long it is a true bi-polar power supply). I tested them with up to 20dBu (which is all my DAC can do) and got THD less then 0.0012%

So far I upgraded my Quadraverb, Lexicon, LPX-1 and dbx 163A

Let me know, what you think!

Cheers, Sebastian

 

[TwentyTrees]

Great stuff, that's a very neat and compact solution to the problem. Nicely done.

 

[thomasdf]

Very clever design and neat build ! Bravo !

 

[Janus Audio]

Thank you!
I will test them with syngthesizers next. I sometimes get hum with some synths when they are connected via USB-MIDI

 

[Janus Audio]

Modding the Alesis Microverb II with symmetrical inputs and outputs

Checking the PSU where we can tap into the power rails:


Removing the old TS jacks:


Connect the sub-boards to the PSU V+ and V- taps and to the tip and sleeve solder pads of each TS jack:


Put the cover back in place: