[quartet]

I tried an interesting experiment with my VDA-2 this weekend, and I'd appreciate any help interpreting the results.

Here's my system:
-- stock Squeezebox SB3 using digital output
-- Harmonic Technology Digital Copper I/C
-- VDA-2 (updated) with VAC-1
-- Conrad Johnson PV10AL line stage
-- Speltz anti-I/Cs
-- Simaudio W4070 power amp
-- Thiel CS .5s

I've long been curious about whether I really need a line stage, especially with the output characteristics of the VDA-2 and it being part of a product family that includes a passive pre, so I tried taking the line stage out of the circuit and using digital volume control in the SB3.

I was expecting one or more of the following outcomes:
1) I'd probably be using the SB3 volume control right at the bottom of its range, and have little fine control
2) Since I was using a digital volume control, the sound would probably be really awful, with perhaps clearly audible and really strange artifacts
3) I'd miss the "tube magic" of the CJ, and the sound would be rather sterile and flat

The results are interesting. My first expectation was right on the money. Of the 40 levels I've been rangeing between 2 and 6, and often I just can't get the listening level I want.

If the digital volume control is doing something obviously nasty I must be deaf. When I used the line stage and volume control together, I found that if I moved the SB3 volume control off max (bypass) the treble seemed just a little pronounced. I think I'm observing this now, but it isn't any worse than when I was near the top of the volume range. The digital volume control just doesn't seem to be that big a deal.

Now for the really surprising part. I hear improved clarity at both the frequency extremes, and it isn't subtle. The timbres may be just a little leaner in balance, but instruments seem to have much more individual tonal character, and certainly don't sound bleached. I even feel like I hear improved dynamics, especially at higher frequencies, and more space between instruments.     

Artifacts or not, the digital volume control just isn't practical: I need finer control. But I LOVE the sound I'm getting now. Sometimes instruments and voices sound so real it's almost creepy. I think I can get used to that  . At this point, a man who sells passive pres might suggest that I replace the CJ with one. Is that the answer? Is that what I've demonstrated that I need? And that it will work for me? I could turn the SB3 volume to max or disable it, presumably get some improvement from that. But presumably even the high quality components that Dusty uses will lose me at least a tiny bit of the clarity, but how much?

I think you all get the idea. Any thoughts? Thanks in advance ...
( Oh, my listening is small and large classical, small group acoustic jazz, and some blues and blues/rock )
 

[chadh]

First, isn't there a squeezebox (or slimserver) feature that allows you to turn down the overall gain of the unit?  That might let you use the SB volume control over a wider range.

The other thing to note is that the 40-step volume control is associated with pretty old versions of the software.  As far as I understand, later versions of the software have improved the linearity of the volume control.  So that might give you more usable range as well.  (Plus, the new versions give you 100 steps to the volume control).

Chad

[Jon L]

What you need is either EVS ultimate nude attentuators or Endler attenuators. 

I would not go with a "passive in a box" preamp.  IME, that additional wiring inside, chassis, extra connectors, and the need for one more run of interconnects make ALL the difference in the world against above, for the worse. 

[gitarretyp]

I'll second what Chad mentioned. I use FW 15 with the latest stable server software, which allows adjustment from 0-100. For most music, i listen with the digital volume around 30.

[quartet]

I'll second what Chad mentioned. I use FW 15 with the latest stable server software, which allows adjustment from 0-100. For most music, i listen with the digital volume around 30.

Indeed, many thanks to both of you. I run an old slimserver because I was running an old version of Os X on what I'm turning onto a music server, and didn't see a reason to upgrade. Now I do ... I tried connecting to the newer version of slimserver on my laptop and the volume control is very reasonable.

There does remain the question of whether using the digital volume control is a good thing sonically, but it sounds fine to my ears.
 

[JLM]

I'm a KISS guy with a system that consisted of an older modded SB3, VMB-1 monoblocks, and 89 dB/w/m, 8 ohm single driver speakers.  Being modded the rated output was down to about 1.1 volts, OTOH the VMB-1 input sensitivity is only 0.6 volts, so plenty of drive.  Had no problem with the size of the 40 digital volume steps or the overall range, it was quite usable.  In fact I have more problem now with VPC-3 and 2.0 volt CDPs (having to keep it typically between 8:00 and 9:00).  Your issue appears to be poor sensitivity matching of components, which could also lead to hearing any background noise, shielding related issues, etc.

I was early to try the SB without a pre-amp, but like others here since at AC, had no problem with sound quality.  In fact, in line with your observations, most preferred the SB sans additional interconnects or gain stages. 

[Double Ugly]

Now for the really surprising part. I hear improved clarity at both the frequency extremes, and it isn't subtle. The timbres may be just a little leaner in balance, but instruments seem to have much more individual tonal character, and certainly don't sound bleached. I even feel like I hear improved dynamics, especially at higher frequencies, and more space between instruments.     

Your observations mirror my own from a couple of years ago, minus the "leaner" part, but I didn't move from a tubed linestage.  Interestingly enough, the removal of a Placette Audio RVC (passive Remote Volume Control) and a battery-powered ack dAck! from the chain precipitated my direct-connect awakening.

I was early to try the SB without a pre-amp, but like others here since at AC, had no problem with sound quality.  In fact, in line with your observations, most preferred the SB sans additional interconnects or gain stages. 

I definitely fall into the "most" camp.  There is nothing wrong with the digital volume control that I can detect.

I began with a Bolder Squeezebox 2 and now use a modified Transporter, and I'm very happy with the sound produced when my source is connected directly to my amps.  Save for the Burson Buffer, I've yet to place a component in the chain that didn't detract from the openness and clarity.

-Jim

[JLM]

A loss of bass or leaner sound can also be the result of impedance mismatch.

Dusty, what is the output impedance of the VDA-2?

[CIAudio]

A loss of bass or leaner sound can also be the result of impedance mismatch.

Dusty, what is the output impedance of the VDA-2?

680 ohms, and should have no trouble driving a passive preamp.

[JLM]

Dusty, you've anticipated my next question: 

Would you share your opinion regarding the need for impedance matching of low voltage components?  (Seems like there has been much interest in buffers lately.)

Thanks

[Badwater]

Any thoughts on using the CIA VPC-3 Passive controller in lieu of the digital on the SB3?

Bill

[JLM]

Welcome Bad,

I had a SB3 and used it's volume control (no problem) and now own the VPC-3.  The VPC-3 is light, so heavy/stiff cables don't let the it stay put.  And thanks to the 2 volt output of my sources combined with the low input sensivity of my amps I use only about 1/3 travel of the volume control.  And at this time I have no need for source switching.  But the VPC-3 works fine.