A world class volume control for pennies on the dollar


In my role as a reviewer I have had five different DACs in-house for the auditioning process in the last six months. Two of them have analog volume controls ( Bricasti Design M3 / Rockna Wavelight) that negate the need for a preamplifier because their performance using their internal volume devices is excellent. However, the other DACs have no internal volume control and have to be used with some type of preamplifier. In what I refer to as my big system, my go to preamplifier is the terrific Coda Technologies 07x. In my smaller system I had sold off the line-stage I used to a friend who really wanted it for his system. So, the search was on for a high quality truly balanced preamplifier for a very reasonable amount of money.

In my search I came across a rave review on Six Moons from 2010 about the SPL (Sound Performance Lab) Volume 2 active totally balanced in/out XLR based volume control from Germany. SPL mainly designs and builds very high quality devices for the professional recording industry. The only piece aimed at the audiophile market is the Volume 2. This is a "hair shirt" design, one XLR input-one XLR output, no remote volume control, a mute button, large volume knob, and a on/off switch on the back (recommended that you leave it on for ever). It either comes in sliver or black, and retails for $450.

The DAC that was going into this system, the Mhdt Balanced Pagoda, really only shines if it is driven balanced and uses its XLR analog outputs into a balanced preamplifier. In the past I have had some of the finest transformer and resistor based passives, two different Shitt Audio preamps, LED based buffered designs and excellent tube based line-stages. Well, I saw that on US Audio Market, someone was selling a pristine condition SPL Volume 2 for $200. Hell, when I used to go out for dinner to a new joint, before the damn virus, I would often spend about that amount on dinner/drinks. Often, the food was not that good, but you don’t know unless you try. I could afford the loss, if the Volume 2 turned out to be a bust or just OK.

The SPL Volume 2 turned out to be a "killer" linestage/volume control. It adds "nothing" to the signal that’s feed to it. It is a pure conduit at passing on the upstream gear’s tonality/colors, dynamics, and spatial qualities. It has a vanishing noise floor, that allows micro-details to pop out to be easily heard. The volume control is not stepped, so you can easily deal-in the "sweet" spot for each musical selection. I got all this for $200 bucks! With the beautiful, musical Mhdt Balanced Pagoda into the Volume 2 controlling the dB levels, the system had the timbres/tonality of the NOS Western Electric 396 tubes and an over all liquidity/ease that this DAC produces was passed on intact by the SPL piece.

The SPL Volume 2 is my new "reference" for someone looking for a truly balanced design for less then a thousand dollars. So, if you run a balanced DAC without an internal volume control, want to spend a very small amount of money, $450, and not be bothered about not having a remote volume control, this well designed, German built piece might be a wonderful addition to your system.


teajay

Showing 3 responses by mitch2

This product seems to be an active buffer with an Alps potentiometer for volume adjustment.  I suspect there are op amps that provide unity gain but I cannot find any pictures of the internals.  IME, a well-implemented buffer typically sounds better than an unbuffered volume control, particularly in maintaining tone and dynamics.  If you want a remote volume control they offer the Elector analog preamp for about $2K more.  However, it would seem feasible to utilize the same powered potentiometer that is used in the Elector to offer remote volume control in the smaller Volume 2 unit.  I like that it is balanced and I would be interested in knowing more about the active components.
@dgarretson That is sort of like my Metrum Adagio where the pot controls the reference voltage.
@teajay I did go to the site and must have missed the 6moons review but I see it now.  They always have the best pictures.  I really like how they will not review something unless they can post pictures from under the hood.  I will have to take the time to read the review - I didn't realize this has been out there for 10 years!  Seems like maybe a good alternative to basic resistor volume controls like the Goldpoint and Endler attenuators I own.  I wonder if there are better op amps that could be used now.
Hello @teajay 
In your review of the SPL Elector and two SPL amplifiers you were impressed with their
"overall silky-smooth presentation...grainlessness,,,balance where all frequencies are woven together in a natural, seamless manner...and great overall macro-dynamics"
I am curious whether the comments above also describe the Elector preamp on its own, or only when used with the amplifiers, and whether the Elector preamp offers the same musical capabilities you described in your OP above for the smaller Volume2: 
"It is a pure conduit at passing on the upstream gear’s tonality/colors, dynamics, and spatial qualities. It has a vanishing noise floor, that allows micro-details to pop out to be easily heard."
I am also curious about specific design differences that may affect any sonics between the Elector and the Volume 2.  I am having trouble deciphering the specifications as to the amount of gain provided by each of the SPL preamps.  The specs for the Volume 2 report gain as:  "∞ bis -4dB."   The specs for the Elector discuss the output level (max. output level 32,5 dBu) but do not specifically provide a value for gain.  From the literature, I also cannot determine whether the Volume 2 uses their high voltage VOLTAiR 120V technology that is used in the Elector.

Any insight you can provide about the gain and sonic differences between the Volume2 and Elector would be appreciated. 
BTW, let the folks at ST know that some of us appreciate photographs of the gear internals (as provided by one of the other pubs).