Variations on the Shunt Pot Mod

[david]

Hi Richard, All,
Killing a bit of time in a Greek Port while our friends run a mercy mission in their car to recover my passport which the apartment manager held onto by mistake........

Firstly, the shunt pot wiring I used was the tweaks version. I tried the other way round and it seemed to improve things, but I didn't do any measurements.

All the action in my TKD pot happens between 7 (0) and 9 o'clock. So probably on Monday I will measure the resistance at these points in two modes:

-as if the pot were connected conventionally
-with the pot connected in shunt mode as per tweaks

My theory is the former will be a normal log progression, the latter may still be log but will be a strange shape.......

I can't explain Bearded Fiddlers measurements as you say with two separate tracks, but it suggests an earthing problem where the earths are commoned. My guess is his earth connection here is faulty, which may exacerbate hos on /off sensation.

I need a motorpot and have previously been very happy with Panasonics as an upgrade from Alps, but Panas are now hugely expensive in log form and the conventional earth connection is commoned, ruling out the Tweaks version of shunt wiring.

The TKD is great, but this short usable volume range is annoying. I am about to try a Tocos, which I will motorise myself.

The motorpot no is CP2500.

My DAC outputs a bit over 2v rms. With 100k shunt into 20k pot this gives max 400mv out which works fine into the Alps wired exactly the same way.
Sensitivity of the 300b push pull clone is 300mv and my speakers are 89db sensitive.

The Alps volume range is still limited but the channel balance goes right to the end of the track whereas the TKD exhibits this measurement of 600ohms /300ohms right to left at the point where I am listening to quiet music.

David