Understanding volume control directstream bhk pre

I know this topic has been discussed in a great detail, so pls hear me out before saying “Not Again” :slight_smile:
The context of volume levels is when one has both a DS dac and a BHK pre in their system.
I have heard @Paul talk about volume control on the bhk pre in context of the taking your foot of the brakes. So i took away from that - let the volume on bhk go to the most acceptable level, in my case thats a wondrous 66-70.
But that means everything @tedsmith talks about the SNR ratio and no bits being dropped in the DS and good results at DS (running Windom) volume being between 90-100 - dont work. For me that translates to the DS sitting at around 33.
I know at the end of the day its each ear and each song to its own.

I wanted to understand why the BHK vol should be set at a higher or lower level when being used alongside a DS dac or why the DS Dac should be kept ast between 90-100, given thats the recommendation another very trusted @jamesh has recommended.

I was wanting to understand the why - a simple primer of a signal going from the source to the power amp and what high vs low in the dac vs pre mean in terms of sound quality given the strength /weakness of the DS- senior and BHK pre.

The DS’s volume is very good considering it’s a multiply. HOWEVER the noise floor on the DS is constant no matter what the volume setting. The BHK’s volume is pretty good too, but it’s analog and therefor not perfect (nothing is.) But the BHK noise floor goes down with the volume. If you have both volumes in a sweet spot configuration then the DS’s volume is probably more transparent for small changes.
So, if you are hearing all the detail you want and no noise, then your DS volume setting is fine. You aren’t alone listening at very low DS settings, but most here wouldn’t make that choice.

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So Ted this is where I get lost:
If the noise floor on the DS is constant and the noise floor on the BHK decreases as volume increases - doesn’t that mean u get the lowest noise floor when the BHK pre volume is high ?

Exactly the opposite. Turning the BHK’s volume down lowers both the signal and the (BHK generated) noise together. It doesn’t change the signal to noise ratio (to a first approximation.) Lowering the DS’s volume lowers the signal and leaves the (DS generated) noise alone which lowers the signal to noise ratio.
So changing the BHK volume doesn’t change the SNR much, but changing the DS’s volume changes the SNR directly.

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Thanks much. The great thing about this hobby is u can trust your ears and enjoy the art but continue to understand the science. Without folks like u and forums like this - it would be a scary Windom to climb.
One last q - what if any impact does the type of tunes have on the snr in the BHK Pre.
Once again Ted - thank you.

I don’t have a BHK pre, so I can’t answer from personal experience. But I doubt it matters much. The BHK (and DS) aren’t the kinds of equipment that favor one kind of music over another.

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Now that i reread the post - if the noise increases on the bhk pre as volume increases, then why do i have the bhk ?
At the same time i know with the bhk in the system it sounds great.
I was hoping to reconcile this with logic - but i keep going into a tizzy :slight_smile:

With the BHK, in principle, if the noise is acceptable at any volume it will be acceptable at any other volume. The signal to noise ratio is constant. This is the expected behavior for most preamps.

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It sounds like to best config is 100 on the DSD and low on the BHK.

BHK/ DS owner here

Looked into this a fair bit and tried different volume settings on both,
Directstream seem transparent at whatever volume, BHK “sounds better” at its 3rd relay click (53 on volume) and above.
Directstreams normally around 50ish.

At night, I put the BHK to 25 and bump up the Dac volume.

Its all a function of your systems gain/ speaker efficiency, so different for different folks.

System/ears dependent of course, as Ted has said before try and see what settings you like.
Its nice to have the option.

Do y’all notice me NOT reacting… :rofl:

Paul has already commented on this. He sets his DS DAC in the mid 80s and his BHK preamp in the 50s to 70s depending on the level of the music being played.

For me, the best sound has been 90 for the DSS and then adjusting the voluming on the BHK to whatever I need/want/allowed at the moment. Typically that’s been 30-35 for normal listening, 20-25 at night (when the wife is sleeping, although that is 3 stories away) and if she’s not home and I feel like pushing the volume, it ends up around 45 (much more than that and I need to leave the room!)

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Ted, Is this not worse?

Yes a low signal to noise ratio isn’t ideal :slight_smile: Since the nose is fairly white it’s not too intrusive. It’s also quieter than tape noise or vinyl noise so it’s not a problem if your system (with the DS) lets you use the DS comfortably near the top of it’s range. Still multiple people like using the DS with the volume down around 20 to 40 so the lower SNR obviously isn’t a problem for them.

This is one of the reasons I balk when people talk about the DS having a preamp - it doesn’t, it has a volume control which is only a part of a preamp.

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Ted’s done a great job explaining it. For what it’s worth, I keep my DSJ at 100 and adjust the volume with the BHK pre from there. DSJ never changes unless I accidentally hit its volume button.

Not the perfect analogy, but I think may help. Say you’re at a graduation and someone goes up on stage to speak. They’re a little nervous and don’t really know how to speak into the mic and bring their face close enough to it. Inevitably the person doing sound will need to turn up the gain a bit on the mic. There’s inherent ambient noise in the auditorium, and if the gain on the mic is high enough, you’ll be able to hear that noise through the PA system. If the speaker is a loud mouth like me and is speaking at a good volume, the sound guy won’t need to turn up the mic that loud. That ambient noise that is being picked up will be obsolete compared to the speaker.

In this not-perfect analogy, the speaker is the music’s signal from the DAC and the ambient noise is the DAC’s static inherent noise floor.

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FWIW, I also set my DS DAC at 100% (fixed) and adjust the BHK Pre according to desired volume. This makes a lot of sense to me as well (I think of it as bypassing the DS volume altogether). If I set my DAC to something lower than 100% I would run out of “steam” when really cranking the tunes via vinyl (have SPP set to medium gain with 0.35mV cart). The BHK is set at around 90 for really letting loose on those LPs with lower signal levels.

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Jamesh in your analogy ( a great one - i now get the concept of gain and noise) what will the bhk pre be ?

Thanks. The BHK pre would be the sound guy playing with the mic’s gain.

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But the mic guy while adjusting the gain is also introducing noise (and gain) - no ?