Passive Volume Control for DACs/Sources

My therapist said something similar.

 

valhalla use ALPS blue pots. having two alps blue pot will be less transparent.
one alps blue is already coloring the sound.

 

could you please compare mjolnir2 pre amp into lsr305 vs bypass the mjonir and go direct from DAC to lsr 305 and use digital volume control from your music player like jriver, foobar, ect?
I really wonder how better or worse units like mjolnir 2 or valhalla2 is compared to digital attenuation

 

very interesting
I have pass b1 buffer and ifi itube. I think I still prefer the digital attenuation of jriver compared to my pre amps. I was eyeing LDR's attenuator but after reading your comment, I think ill pass.
thanks

 

I recently had to go straight Gungnir Multibit to LSR305's for a couple weeks while Mjolnir 2 was in the shop, using Windows (or Foobar) digital volume to control the volume. I don't really do critical listening with the LSR305's, but with that said I didn't notice any apparent differences in sound

 

^

Did you have foobar sending out a 32 bit signal to the Gungnir Multibit? Using digital attenuation with a 32bit signal shouldn't have any detrimental affects.

 

24 bit, but the same principle should apply with 16-bit source. As I said I wasn't doing a ton of critical listening, and they are "just" LSR305's, but didn't notice any difference in SQ with or without the Mjo 2 as a preamp middle man

 

with 24bit there is still chance of truncation using digital volume control. for 32bit you would have to be using USB

 

Necro post -

Starting to build a real 2 channel desktop system and need something passive. Been thinking about using a Vali 2 until I either build or buy a passive.

I want a preamp that is essentially colorless which is why I'm considering passive. Don't need a fancy one, remote isn't necessary, neither is multiple outs and ins.

LDR Preamps seems to be all the buzz nowadays, but there are some that say there is some major distortion inherent to the LDR type pot which makes the sound artificially warm making it pleasing to the ear. Others say that this is the best way to make a preamp if the goal is to achieve a colorless sound. Who's lying?

I'm considering all possibilities, Some preamps that I have my eye on are: Goldpoint SA preamps, Tortuga preamps, and vintage Mod Squad stuff. On the DIY end of things the AMB Delta 1, Pass B1, and a LDR kit.

Any help would be greatly appreciated!

 

1 vote for GP passive pres. Or any passive pre.

 

It's all about keeping a clean signal path right? So instead of a pot, I'm gonna use some unstable resistors whose values change depending on the amount of light they receive. Those light sources are unstable and their output varies depending on the signal fed to them. That signal is likely controlled by a pot...

... and if there were concerns about electrical noise and other wibbly wobbly things, that noise is going to affect your light sources anyways. Yay!

 

TVC or AVC gets my vote. That's how you'll get colorless sound.


On another note, I got a Bent Audio NOH TVC using S&B TX-102 Silver trannies coming in next week. Has remote too! Very excited!

 

If balanced, then TVC definitely gets my vote as it keeps it purely isolated from ground.

 

What do you guys think about this one -
http://www.promitheusaudio.com/tvc.htm

From the research that I've done, there doesn't seem to be a whole lot out there. Bent Audio preamps seem to be discontinued, even the DIY parts. Only chance is to snag one used. Not many other current options out there. If I don't get the Prometheus, I'll probably wait to see if I can get something used.

Thanks for all the suggestions thus far.

 

There are quite a few out there. Slagle, Sowter, Tribute, Glasshouse. That Prometheus is actually quite cheap though.

 

Had the Tortuga LDR for a trial. It definitely belonged to the clean and invisible kind. There was no warmth to be found there.
No "light distortion" either...

 

No other TVC options as cheap as the Promitheus as far as I'm aware, except for one Chinese ebay option. You can order Sowter transformers yourself but total cost to build a preamp is likely more expensive than the Promitheus (depending which level you get).

Next up on the price scale is the Glasshouse kits, then Django. After that, you're looking at Music First (who occasionally have units on sale, but they go super fast). If you go crazy there's Bespoke but you're starting at 5 figures and up from there.

 

Yes, but they are AVC not TVC.

 

All TVC are bandwidth limited (to both sides of the audible spectrum) and add measurable amounts of distortion.
The fact that this is not heard as such (limited) and sometimes a limited bandwidth could even be a blessing is another matter.
Plus side... a TVC can actually amplify the input voltage level where the other options can only attenuate.

LDR volume controls are not bandwidth limited but are non linear (in a distortion kind of way) and add measurable amounts of distortion.
This is because an LDR isn't a 'normal' resistor but its a semiconductor that changes its properties depending on the amount of light on it AND the voltage across it.
The music signal across the LDR is a varying voltage and thus distortion is added.
Having 2 LDR's instead of 1 in one channel alleviates some of the non linearities when set at 50% volume drop.
The fact that this is not heard as distortion, or sometimes even preferred over other volume controls is another matter.

AVC's are NOT bandwidth limited (I never found one that deviated between 0Hz and 1MHz) and are linear components, thus can not add distortion /coloration even if they wanted to.
This is true for both stepped as 'normal' potmeters and is only valid (the distortion thing) if contacts inside are operating normally.

Still, some prefer TVC, LDR, or steppers over 'normal' potmeters...
Me ... I don't care one bit... but do prefer not to use TVC or LDR's myself because of their technical limitations.