SPL Volume8 Review

[amirm]

This is a review and detailed measurements of the SPL Volume8 8-channel, balance volume control. It was kindly sent to me by a member and costs US $799.

SPL nails the look and feel of this active unit. It is a substantial box but not too big. 8-gang volume control is custom made and muting is performed using a relay. Input/output is provided through DB-25 connectors so you need to buy those "pigtail" cables to go to and from XLR (or RCA):

SPL Volume8 Measurements
I set the unit to max volume and tested channels 1 and 2:

Distortion is quite low at -120 dB but I was disappointed to see power supply noise and harmonics bleeding into the unit. That sets the SINAD, i.e. dwarfs distortion as we can see in SNR measurements:

Frequency response is flat and extended which is nice:

Not so nice is modest channel separation:

Distortion rises with frequency:

The higher noise floor shows up as a constant as we sweep the input level:

I was surprised to see channel match lost even at higher volumes:

As usual, your sample may vary.

Conclusions
As I noted in the introduction, I really like the look and feel of the Volume8. Ability to handle 8 channels is also handy in multichannel setups. At this price though, I expect to see perfection and we miss that in a number of places. I worry about noise degradation through the unit and loss of channel balance.

Swayed by the nice large volume control , I am going to recommend SPL Volume8.

-----------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[respice finem]

I like the design, except the overly bold logos, and it's useful for those in need of this special application.
Expensive, as most "niche" devices are.

 

[5th element]

By the looks of things this isn't a fully balanced design. It takes the differential inputs, converts them to single ended, does the volume control stuff, then sends the signal back through a single ended to differential line driver. What a disaster. No wonder the channel separation is terrible. If it was fully balanced inside this would be far better.

They'd get better performance using two CS3318 volume control chips. Buffer the inputs, feed the CS3318s, buffer the outputs. Fully differential input to output. Then you'd get perfect channel matching, no degradation over time and no requirement for an 8 gang pot. You can control the volume using a cheap single channel pot and simple micro controller. Multichannel balanced volume controls are not meant to be done via potentiometers.

 

[Rja4000]

Very similar results than its small brother Volume2 (2 channels, half the price) that I measured here, back in 2019.

This design becomes dated, I think (we see "2005" on the board of the Volume2).

But that's a nice looking device, without real fault (except the mains leakage, but I can't hear it) and pleasant to use due to this big smooth knob.

I've performed some Measurements on SPL Volume2 (Model 2602) volume control

Hi I own a SPL Volume 2 and wanted to check how it measures. So I tried. SPL (Sound Performance Lab) is a German company, specialised in Pro audio electronics. They are not new comers in that market (they say they're in the business for 30 years). They offer analog preamps, channel strips...

www.audiosciencereview.com

 

[Rednaxela]

Edit: never mind. Wrong thinking.

 

[wisechoice]

Thanks for this review, Amir! Looking forward to trying this (used) unit in my 4-DAC balanced setup for 5.1.2 home theatre and surround listening.

For those who are interested, @pos measured the balance of all 8 channels across the volume range many years ago. He posted the results here:

I've performed some Measurements on SPL Volume2 (Model 2602) volume control

Hi I own a SPL Volume 2 and wanted to check how it measures. So I tried. SPL (Sound Performance Lab) is a German company, specialised in Pro audio electronics. They are not new comers in that market (they say they're in the business for 30 years). They offer analog preamps, channel strips...

www.audiosciencereview.com

Tl;dr is that channel balance appears to be best at 50% volume and higher.

 

[Ralf Stocker]

Some companies can't even make a decent potentiometer. This $10 device will then charge $800.

 

[Billy Budapest]

I expected much better performance from an engineering-focused company like spL.

 

[Geert]

SPL has the looks and the price, but somehow never manages to convince me. Decades ago a colleague of mine had their expensive channel strips..., naaah...

 

[Rja4000]

SPL has the looks and the price, but somehow never manages to convince me. Decades ago a colleague of mine had their expensive channel strips..., naaah...

What made them un-avoidable in Pro sound at some point was this device:

https://spl.audio/classics/transient-designer-4/?lang=en

 

[Geert]

What made them un-avoidable in Pro sound at some point was this device:

Man, that's long ago.

 

[Count De Money]

Gee, going off the SPL website you’d think these guys are at the cutting edge of engineering.

im becoming increasingly sceptical of all manufacturers claims

 

[Rja4000]

Gee, going off the SPL website you’d think these guys are at the cutting edge of engineering.

im becoming increasingly sceptical of all manufacturers claims

Well,
Their main target is the Pro market, which is quite conservative.
The products like the Volume2 or Volume8 are using old designs and components one could find in consoles in the early 80's.
They do the job.

Their products may not be at the cutting edge of performance, but they developed some interesting and innovative devices, like the Transient Designer, that were great value for Pro.

OK, that was quite some time ago.
Now the Pro market is pretty much about software... or legends.
So you can understand they are more building on this legend... look at diversifying target with more "Audiophile" products (they try to monetize the legend), and don't invest a lot of money on R&D. (But I may be wrong)

 

[mdsimon2]

Gee, going off the SPL website you’d think these guys are at the cutting edge of engineering.

im becoming increasingly sceptical of all manufacturers claims

Unfortunately it is pretty much dead on the SPL specs. They quote A weighted noise at -102 dBu (presumably 20-20 kHz), knocking this down 3 dB to roughly get unweighted gives you -99 dBu. In terms of residual noise this is 10^(-99/20)*0.775 = 8.7 uV. Calculating SNR at 2.4 V gives us 20 x log (2.4 x10^6/8.7) = ~109 dB so very close to the ASR measurement. Even if you don't knock it down 3 dB for A weighting you are still looking at no better than 111 dB SNR at 2.4 V.

Michael

 

[Rja4000]

Unfortunately it is pretty much dead on the SPL specs. They quote A weighted noise at -102 dBu (presumably 20-20 kHz), knocking this down 3 dB to roughly get unweighted gives you -99 dBu. In terms of residual noise this is 10^(-99/20)*0.775 = 8.7 uV. Calculating SNR at 2.4 V gives us 20 x log (2.4 x10^6/8.7) = ~109 dB so very close to the ASR measurement. Even if you don't knock it down 3 dB for A weighting you are still looking at no better than 111 dB SNR at 2.4 V.

Michael

Which is, most probably, enough for the task.

 

[mdsimon2]

Which is, most probably, enough for the task.

I guess? I bet a lot of people use this device to avoid digital volume control but it isn't hard to beat this level of noise with a DAC like the MOTU Ultralite Mk5 so you are actually hurting performance by using this. Now you do get a nice big knob and I personally find mains related noise less audible than wide band noise so in practice I bet it is fine, just seems like a lot of money for how it performs.

Michael

 

[ExUnoPlura]

As a total aside, I’m quite suprised this works in English. Most interesting. Learn something every day.

"Gang together" switches/controls is common English parlance. Etymology likely from gang as a group of people working together. Here's from Oxford's LD:

Old English, from Old Norse gangr, ganga ‘gait, course, going’, of Germanic origin; related to Scottish gang ‘go’. The original meaning was ‘going, a journey’, later in Middle English ‘a way’, also ‘set of things or people which go together’.

Not surprising that it would work in German, Dutch, etc. in a similar way. Sorry, linguist in me couldn't resist tracking it down!

 

[Rednaxela]

Thanks @ExUnoPlura, much appreciated!

Thing is gang must be one of the best known English false friends to Dutch speakers.

From your explanation I understand they have more in common than I always thought.

 

[sarumbear]

What made them un-avoidable in Pro sound at some point was this device:

https://spl.audio/classics/transient-designer-4/?lang=en

View attachment 212327

And this!

https://spl.audio/en/spl-produkt/stereo-vitalizer-mk2/

 

[sarumbear]

Gee, going off the SPL website you’d think these guys are at the cutting edge of engineering.

im becoming increasingly sceptical of all manufacturers claims

Their specs and what is measured here are exactly the same. Why the “gee” and skepticism?