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Some quick comments

Hi,

As I had a little itty bitty hand in this, one or two comments.

First, all the signal and ground wiring is silver (soft annaeled) in PTFE Sleeving, 0.2mm for the signal, 1mm for the Ground. The RCA connectors are also silver plated!

The input capacitors are mandatory. In this circuit the DHT operates in fixed bias mode, so cathode straight to ground (okay, via a 12 Ohm bias sense resistor).

In this case the input capacitor (0.047uF PTFE & Tinfoil - only sensible upgrade would be AN Copper or Silver) is essential, without it the volume control would short out the bias and/or send the bias voltage to the source.

The benefit of using fixed bias is that we can dispense with the cathode Resistor and capacitor usually needed. And trust me, a 0.047uF PTFE & Tinfoil Capacitor in front of the grid sounds much less intrusive than a 100uF electrolytic capacitor (or a Nicad Battery) on the cathode... :-)

As it stands the signal goes:

Input ->

Volume Control ->

0.047uF PTFE & Tinfoil ->

DHT Stage ->

10uF Obbigato Copper in parallel with 2.2uF Polypropylene & Tinfoil ->

Output

It is hard to better this without bring in worse problems through the back-door.

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?


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