Music bleeding at zero volume


Trying to understand why music continues to play when I have the DAC/pre turned all the way down...

When it’s dead quite in the house - I don’t even need to turn up the volume from zero. It plays loud enough to hear comfortably. Using XLR interconnects. 

Sim Audio W5 power amp
Mertrum Acoustic Jade pre/DAC
bluesound node 2i
Von Schweikerts VR4 floor standing speakers
128x128ghulamr
@ ghulamr
You have to reduce the gain on the Jade!  

To appreciate Jade’s digital preamp functionality in the proper light, it’s instructive to remember basics. Regardless of type, typical volume controls throw away gain unless we listen above unity gain. Unity what? Source output voltage. Unless that’s unusually low; your amp’s input sensitivity is; or you listen very loud... you’ll be reducing source signal strength, not adding to it. Hence wiring up source to amp would be far too loud to require a gain cut. Voilà, the argument for passive preamps. Why generate gain only to throw it out again? But even passives do. After all, you’d not run one if you needed more. So unless you crank their volume to the max, you’ll still dump gain. You just won’t add to what you’re throwing away as you would with an active. Not so a circuit with true variable gain. It only generates what you actually listen to; no more. In that sense, the clever Jade is more passive than even a passive. Shouldn’t that predict sonic behaviour?


Part Deux of your due diligence today should be a return to the last page: in-house dipoles and Forte amp. By activating a room’s ambient field where direct radiators do not, dipoles behave closer to real instruments, hence make better fuller tone. Next, the Forte was deliberately designed to mimic a tube hybrid. "It’s an idea from when I had such amps for pleasure listening and critical evaluations. What I did not like was the fact that triodes suffer aging. In simulation software, I started to imitate triodes with Fets. The good thing with triodes is their low gain and high bandwidth without needing feedback. That was my goal. It took me a few weeks of simulations but I hit upon the desired result. It falls somewhere between a 12AU7 and 12AT7 on gain but with a bit more bandwidth. The disadvantage is that it runs on the same high 350V rails as real tubes would. From there we drive a class A/B output section (10 watts in class A, 50w/8Ω, 100w/4Ω, 170w/2Ω). Damping factor is 200. Compared to my old hybrids, there’s no sonic difference but less noise. Now we’ve turned this into a commercial product with a lot of added protection because during startup, we must charge up 176’000µF. And that, in a nutshell, is the Forte platform." As my review explained, its sonics play to the Pass Labs XA30.8 class A aesthetic - dark, earthy, heavy, dense.

OSX recognized the Jade as hiFaceTWO UAC 2 Output with a 384kHz limit. The shown 9:00 volume equaled standard levels balanced out into LinnenberG Allegro monos driving Audio Physic Codex.

Armed with this background, you’ll likely conclude that our Dutchies wouldn’t think of additive editorializing in a preamp as desirable. They neither need nor want it. The obvious question is, do you? If you’re eyeing our Nagra Jazz, you do. If you’re lusting after the just reviewed £9’000 The Bespoke Audio Company transformer passive, you don’t. Now you’re a perfect candidate to get jaded. Go green. It’s nice for the environment, too.


"I forgot to inform you about the following. As mentioned, the jumpers at the edge of the board will set the mother board for fixed or variable gain. As a matter of fact, that is just a part of the story. I told you that in case of the fixed position, the outputs conform to Redbook specs and are set by the upper jumper. If the upper jumper is set to the right, max output voltage is 3Vrms for the RCA output, 6Vrms for the XLR. But if you set this jumper to the left, this becomes 2/4V respectively. In case of sensitive power amps, that can be more convenient and as a result, the output level will decrease by 3.5dB." Very useful.



@yogiboy 
thanks!!! Do you know where those jumpers are at the ‘edge of the board’? 
Holy crap! Turning down the DAC/pre is another word for attenuating the signal is another word for lowering the volume is another word for reducing the signal. Reduce, lower, down, these are not the same as cut, off, eliminate. The volume turned down is lower. The volume turned down is not zero. 

There. See how easy that was?
Holy crap!

There. See how easy that was?

MC - Your answer is correct but why do you have to be so mean in your style of providing it?  You do this every time....so condescending. Sheesh.
Post removed 
Thank you @tvad @yogiboy 

I will try to see how to adjust the internal jumper to reduce the XLR gains by 3db. That’s the best option unless I switch to RCA. But I just bought new Belden 8402 XLR IC’s. 
Post removed 
@ three_easy_payments,
It is evidently difficult for the self proclaimed geniuses.  The love of thy own voice coupled with all-knowing cranial prowess leaves a lot to be desired by the masses when it is consistently displayed in the form of condescension.  Sad when one does not realize their writing manner, sadder yet when one intends to write in this form.   Something Almarg and other great minds here never displayed.  
@yogiboy I think the jumper setting is only relevant to when the lower jumper is set to fixed. 
... I told you that in case of the fixed position, the outputs conform to Redbook specs and are set by the upper jumper. If the upper jumper is set to the right, max output voltage is 3Vrms for the RCA output, 6Vrms for the XLR. But if you set this jumper to the left, this becomes 2/4V respectively...

I tried moving the upper jumper left keeping the lower jumper on variable (as I want to continue to use the jade as preamp) and it made no difference. Any thoughts? 
@ghulanr
Sorry but that’s about it with my thought on why you are having that problem. All the best!

@three_easy_payments 

“so condescending. Sheesh”

Agreed - what’s with the (perceived) axe to grind attitude?
Actually Three-Easy, I don't think that Miller is any more correct here  than he usually is.

Turning the volume "down" does not preclude zero. I would never design or build a component which did not have a zero. Especially volume. The OP's concern is valid. Miller's response, for all his scorn, is not.

IMO.
There was a Partridge Family episode where Chris could hear AM radio through a loose filling in his tooth and it kept throwing off his rhythm and he couldn't drum until they got him to a dentist.  
Volume controls do wear. I have an older Krell KBL that has the same problem. This is not a definite answer but a possibility.
I reached out to the Metrum Acoustic engineering team, and they are super good at getting back and being helpful. This is taken directly from our email exchange. ........

 It is perfectly normal that you still have a small amount of signal with the volume control completely counter clockwise, as this is inherent to the principle Metrum regulates volume with. We implemented it this way because it sounds better than using a regular potentiometer circuit.

If a gain mismatch between amp and DAC is present, the easiest way to temper the output signal of the Jade is by using a t-pad resistor network in the connectors of the interlink cables. Doing it this way introduces the least distortion. This modification implies that your cables become 'directional' in the sense that one end needs to go into the DAC, and the other end needs to go to the amp (and not the other way around). Please let me know if you are interested in this modification. It requires 4 resistors per channel when using XLR or 2 resistors per channel when using the RCA output. These resistors need to be soldered to the cable.



Unfortunately I am not super handy with tools and think will do more harm then good trying to add resistors to the XLR cables. But I do believe and agree the design on the volume control is superior to your run of the mill components. This is taken from one article I read about the Jade DAC. Again this is for folks that are interested in knowing. Thanks 

........”The Transient Two modules connect directly to the outputs without an extra analogue stage, so volume control in the Jade is achieved by raising and lowering the reference voltage over the R2R circuit. Not by stealing bits from the stream, nor by putting a chip or a potentiometer in the analogue domain. It’s a very clever idea that I have only seen once a long, long time ago”