Schottky Diodes and Remote Volume

[m@tty]

Not sure what’s happened to the Gallery?
Was wondering if this would be a complete drop in replacement for the Diodes in the power supply
The Full Wave Bridge Module

http://avondaleaudio.com/audiophile-linear-power-supplies/

Also have never really got on with the Valab Attenuator and thinking about a Motorised TKD pot and remote Module from Hifi Collective

https://hfc-fs.s3-eu-west-1.amazonaws.com/s3fs-public/gh_remote_instuctions_0.pdf

Should be able to power it off the 6.3v heater supply

[Paul Birkeland]

Not sure what’s happened to the Gallery?

There were some issues with externally linked images with broken links causing performance issues with the forum, so the gallery was temporarily disabled.

The Full Wave Bridge Module

http://avondaleaudio.com/audiophile-linear-power-supplies/
Not sure what’s happened to the Gallery?

I would expect the diodes to fail very quickly due to the difference in voltage between a Naim power amplifier and a Crack.

Also have never really got on with the Valab Attenuator and thinking about a Motorised TKD pot and remote Module from Hifi Collective

https://hfc-fs.s3-eu-west-1.amazonaws.com/s3fs-public/gh_remote_instuctions_0.pdf

Should be able to power it off the 6.3v heater supply

A remote is very unusual for a headphone amplifier, as you are tethered to the headphone amp by the headphone cable.  The actual motors used to drive volume pots don't use a particularly large amount of power, but that PC board has a rectified DC supply, a regulator, a relay, etc.  The 6.3V winding on the Crack power transformer doesn't have a ton of additional available current, so it's tough to know how taxing such a module might be.  I have also read some discussions about noise with motorized pots powered from heater windings, but YMMV. 

Stepped attenuators will exhibit very good low level channel balance, which is one of the more popular reasons to use them.  A motorized Alps or TKD pot is more similar to the stock part, and may still have a bit of channel imbalance.

[m@tty]

The Valab attenuator I used seems to have been made with a very poor switch and appears to be microphonic at certain steps.  I have found TKD potentiometers to have exceptional channel balance so might give the remote a go as the Crack is now on a high shelf out of reach of my two year old daughter hence why I wouldn’t mind a remote!

[Paul Birkeland]

Yeah, I have some Valab attenuators that I bought some years ago which are installed in a crossover I built.  They have oxidized pretty badly and look like they've lived their whole lives in salt water, but they've been on a shelf in a heated, dry room for their whole lives.

It's not impossible to move the volume pot to the front of the wood base if that would be helpful. 

-PB

[m@tty]

To be honest the bug to build something else has bitten so I might try a SEX or Crackatwoa but would still like to implement a remote volume control and could make the amp a bit more child friendly at the same time!
I already have the HifiCollective board installed in a Pass B1 preamp I made so I could whip it out and could give it a go and see what happens noise wise!

[Paul Birkeland]

Yeah, you can also put your meter in line with one of the wires going to the PC board, set it to AC current, then see how much current it draws while the motor is turning.

[m@tty]

It appears to draw 1.40m A at all times this is powered from a lm317 regulator set to 9vdc.

[Paul Birkeland]

1.4mA isn't correct, the motor will draw at least 100mA.

[m@tty]

0.16 amps at idle 0.2 amps with volume adjustment

[Paul Birkeland]

That's not too bad and shouldn't bother the power transformer.