Passive Volume Control for DACs/Sources

@T.Rainman I tend to agree with your sentiment. While I have not tested TVCs in my system, we all know how hard it is to find good magnetics that can be truly called "transparent" (if we can even define that term in the first place). The only application I would consider using a TVC was if I wanted to utilize the advantage of a transformer coupled input anyway (either for balanced/unbalanced conversion or phase splitter or CMRR) or if I wanted to get a bit more gain into the first stage.

I would add that all "normal" pots are not created equally. Different resistive elements can definitely add measurable amount of distortion, with the precision metal film (as used in the GoldPoint steppers) resistors being the most linear and lowest noise available. All traditional (taper) pots will either use conductive plastic or a carbon track element, which will not quite be on the same of performance. Whether that distortion is below the threshold of ours senses or playback chain (or even measurement thresholds) is a different question. I guess smartphone's volume nub buttons sound ok......

 

Has anyone tried the Bottlehead Submissive?
http://bottlehead.com/?product=submissive-volumesource-control-kit

 

http://www.khozmo.com/shipping.html
Looks interesting; Those Poles!

 

khozmo guy also has a line of high end fancy looking passives
http://hattor.com/

 

Thanks! The khozmo looks pretty nice and it's comparably priced (and looks better). But what are its min/max input and output impedances? According to the 6moons review the input impedance varies between 10k and 100k but that article is written like poetry so I can't follow it. The bottlehead has 20k-40k ohm input and 140ohm-10k ohm output impedance so it works well between the Yggdrasil and a tube amp.

 

Did some testing at @shaizada 's house with my Bent Audio NOH with silver trannies. It was amazing. I'm done with preamps.

 

I find you the shiniest toys don't I?

 

Oh.....you are NOT done!

 

These are pricey. I thought about making my own with an joshua tree attenuator (relay based) i had lying around.

 

Shh shh, give the poor guy a couple weeks to let his wallet recover before showing him more toys...

 

This current passive he has, can be kept for a long long time. From what I heard with his passive preamp (which I have kept for a week here to tweak some things I felt can be improved upon), he can can actually "grow" his speaker system with before any limits are realized.

He heard and RECOGNIZED what an "End of Life" preamp sounds like! It usually ends up with a tubed and active gain stage done by a master artisan that has 70+ years of life/design experience, most (90%) of that in the professional space AND built most of the analog electronics that the studios in which the recordings you and I hear are made.

 

Hopefully in a not so long time, a lot of audio purchases can be bought on a whim for me.

 

I'm known to sweat a lot about volume controls, but then I see Nagra preamps using a Blue Velvet... My perfect combo would be using a simple 24 step passive attenuator and a good digital control for finer adjustments.

 

Congrats! Impedance matching is a critical part of passsive preamps. Bent uses Slage transformer, I've done some reaserch months ago, some UK transformer is the best (accodring to many many reviews I've read) but too expensive.

 

I got some info about the Khozmo. The 10k version has input impedance 10k-110k and output impedance 0-100k. There's also the 50k version which has an output impedance of 0-500k. With the source being a Yggdrasil and the amp a two stage tube amp (pentode follows by 300B), what would be the better option: the 10k or the 50k version?
Thanks!

 

if you have a source with a 1k output impedance, then you should
probably pick between 10k and 50k pot. If you have a source impedance
of 47k, then you should pick between 50k and 100k.

 

The Yggdrasil will be the source. It's output impedance is 75ohm unless I'm mistaken.

 

Golpoint does a huge range of different variations on in, volume control, out. Something for everyone.

Was tempted, but bought a 2nd-hand pre-amp.

 

If your source output impedance is 47k, something is very wrong and/or you're gonna want to slap a very specific active buffer in between.

 

Bent typically uses Slagle Autoformers, but that's not what Oggh has. He does indeed have the UK S&B transformers in them, and the super speshul ultra mega rare silver variety.