December 2023 Newsletter

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Spatial Audio

December 2023 Newsletter
« on: 18 Dec 2023, 05:07 am »
Greetings to our Audiophile Community!

It’s the end of 2023 and we are so grateful for the opportunities that we have had this year. This is a great community and we are excited about the future of Spatial Audio Lab because of all the positive feedback we have received from our customers and because of the new products we are bringing to market.

What did we do in 2023?

  • We worked with Clayton to reboot an iconic brand

    We delivered on a backlog of X4 orders (some people waited over a year!)

    We developed a high performance version of the X4 crossover (X4 Ultra)

    We exhibited at Pacific Audio Fest in June (where we got to meet some of you!)

    We continue to develop new speakers (like winter, they are coming. Q6… hmmm?)

    We worked with Don Sachs and Lynn Olson to bring to market a 300B amplifier combo that will definitely make a splash next year (read on below…)
What is coming in 2024? Delivering the Revelation Amplifiers! Definitely some new speakers 🙂 And, we are bringing on another employee to help manage operations as well as to provide more engagement on social media. More on that in January.

Recent Developments:
X4 Update
The X4 Premium is gone and we have a new variant of the X4 Ultra… the “X4 Ultra-2024”. This is in addition to the original Ultra and we intend to continue offering both versions. Both versions are $9,800 and are orderable by calling us at 801-357-1664

What happened to the Premium? It just wasn’t very popular. Everyone who ordered an X4 in 2023 opted for the Ultra version.

Why two versions of the Ultra?? The original Ultra is the version of the X4 that we think offers the best blend of musical characteristics in terms of soundstage, imaging, instrument separation and detail. Paired with high performance audio components and source (phono, streamer, DAC, amplifier, etc), we think the Ultra is the way to go. But, there is a downside in that the Ultra can also reveal aspects of certain recordings that may not be to your liking and the 2.5-way design does give up some bass presence in favor of midrange dynamics and clarity. The Ultra-2024 is a 2-way design that can be more forgiving across a wider range of components and recordings.

If you would like to learn more about the X4 Ultra-2024, you can call us. Or, Ron at New Record Day (YouTube) is working on an in-depth review in the very near future.

Revelation Series Monoblock Amplifier and Preamp
Earlier this year we announced our collaboration with Don Sachs and Lynn Olson to introduce the “Revelation Series” 300B monoblock amplifiers and preamp. Now that we have a full set built, we will be sending them out for third-party testing to confirm our calculations. I expect those will be completed in February (hopefully sooner). There will be some cosmetic improvements. But, the engineering is finished and they sound amazing. We are accepting deposits on these. If you are interested, please call us at 801-367-1664.

Power requirements are 112-130 VAC at 60Hz with export models available in the future or on special order.

300B Monoblocks ($9,995 ea)
Update / correction: 25 watts Class A triode with true steady-state power; 18 Hz - 30kHz frequency response @ 2 W (+/- 0.5 dB). 25 Hz - 30 KHz at full power

“All of the critical functions are done passively ... noise isolation, distortion cancellation, and output matching. Balanced pairs of the most linear vacuum tubes do the amplifying, with a signal path of nothing but transformers and vacuum tubes, powered by silent 200-watt linear power supplies with 130 dB of isolation from outside noise. What you hear is what ISN'T there ... no phase inverters, no coupling caps, no load resistors, no dynamic loads, no DC servo circuits, and no feedback. Just triodes, as you've never heard them before.” - Lynn Olson





Balanced throughout (NOT a Mullard circuit with SE front end).
Two inputs - RCA and XLR. RCA goes through a Cinemag 1:1+1 input transformer for the phase splitting for the balanced 6SN7. The XLR goes directly to the 6SN7 grids with the input transformer out of the signal path thanks to a bypass switch.
The balanced 6SN7 drives a custom Cinemag transformer designed specifically for the amplifier. That drives the balanced KT88 drivers which drive another, different, high-current Cinemag interstage transformer. This drives the 300Bs which have a Monolith PP output transformer with 4 and 8-ohm taps. That’s the entire signal path. No RC coupling is used anywhere. All circuits are in Class A including the output section.
The power supplies for the input + driver and output section are completely independent. So, if the output clips, the input and driver are unaffected.
The balanced signal is re-summed through each transformer. So, audio frequency (dynamic) imbalances do not accumulate from stage to stage unlike other PP amplifiers. (Each pair of grids is fed an accurately balanced signal with no added phase-splitter distortion.)

Input Tube: Two 6SN7 (octal)
Driver Tube: Four KT88 (KT66 or 6L6 are alternates)(octal)
Output Tube: Four 300B (four-pin)
VR Tube: Four VR105 (octal)

Revelation Preamplifier ($4,995)
The preamp is balanced throughout, neither SRPP, nor single-ended, unlike most tube preamps. It is balanced from input to output, regardless of RCA or XLR input format.

All inputs go through a Cinemag 1:1+1 input transformer which does the phase splitting for the balanced 6SN7. The output of this transformer goes through a custom Khozmo volume control, using an array of high-precision resistors in a matched-balanced configuration.

The Khozmo volume control includes not just a remote control, but a remote with a left/right balance control, in 1 dB steps. Is the center image not quite where it should be? You can adjust it without getting up, or wrestling with uneven L/R tracking from a conventional volume control pot. And the L/R balance stays where you set it, as volume is ramped up and down.

The balanced 6SN7 tube then drives a custom Cinemag output transformer, specially designed for this project. This output transformer not only maintains circuit balance, but it multiplies current 4.5 times, delivering far more current than most vacuum-tube preamps. Taking a cue from the Western Electric line drivers of the past, this preamp can drive long lines without running out of current ... it's not just a preamp, but a tiny power amplifier, optimized for cable driving.






The regulated power supply for this circuit has a remarkable 130 dB of isolation from line noise ... greater than the dynamic range of any signal source, digital or analog. We then go a little bit further, with VR-tube shunt regulators, so the current draw on the voltage regulator is absolutely constant, regardless of the audio signal.

Since this is a zero-feedback circuit, the load from the cable, or the power amplifier, has no effect on circuit stability. Internal balance is likewise not affected by external loads, and the 6SN7 remains in Class A operation regardless of cable type.

  • Inputs – 4 sources

    2 x XLR

    2 x RCA
  • Outputs:

    1 x XLR

    1 x RCA

    2 x 12v output trigger

Upcoming Events:
We are planning to be at Southwest Audio Fest in Dallas, TX from March 15-17, 2024. If you are in the area, please come by to say hello and listen to some of the best speakers and audio components in the industry.

Spatial Audio in the Wild:
Thank you to Steven Z for sending us this beautiful photo of his X4s!




X4 ULTRA in full Ultralam (front/back) in a nicely treated listening room

Thank you for your ongoing support and we hope you have a wonderful holiday season with your friends and family!
~ David Whitt, General Manager
« Last Edit: 18 Dec 2023, 06:05 pm by Spatial Audio »

dls123

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Re: December 2023 Newsletter
« Reply #1 on: 30 Dec 2023, 01:26 am »
Hi all
A bit of an update on the Raven preamp.  The approximate specifications of the Blackbird mono amps are shown above in David's post.  I also ran a frequency sweep on the Raven preamp and it is dead flat from 18 Hz (the bottom of my signal generator range) to well over 40 KHz.  A set of the amps and preamp will go to my good friend Troy Joseph Crowe in Ontario for complete analysis, including distortion measurements.  Troy has some very high tech measuring equipment.  This should happen in late January or early February, and we will post the measurements when we have them.  The whole system is very low in distortion, you can hear that, or rather not hear it.  The sound is really about what you don't hear, that you hear in most any other amps, which sound a bit gray by comparison.

cheers,
Don

Early B.

Re: December 2023 Newsletter
« Reply #2 on: 30 Dec 2023, 04:22 am »
This is all great news, Spatial!!

Don -- what is the gain on the preamp?

dls123

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Re: December 2023 Newsletter
« Reply #3 on: 30 Dec 2023, 04:07 pm »
Hi
The theoretical gain of the circuit plus the custom Cinemag output transformer is 4.44X, which translates to 12.94 dB.  I will have to measure it next time on the bench, but that is about right.  Some real world experience...  My speakers are 95 dB and I am using the Lampi Pacific DAC XLR out to the Raven preamp, which drives the Blackbird 300b amps via XLR.   I get low listening levels at maybe 10-12 on the 64 step Khozmo attenuator.  Moderately loud levels are 20-25, and very loud is 35 - 40 depending on how hot things are recorded on the original file from Tidal or Qobuz.  I also know when we ran them at Spatial in Utah with less efficient speakers (maybe 90 dB) we still had screamingly loud levels at 40-50 on the volume display.  So the gain setup is very good for most people's systems.

Presb4

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Re: December 2023 Newsletter
« Reply #4 on: 31 Dec 2023, 05:55 am »
This Pre-Amp is sounding flipping awesome, just what I have been looking for.
All analog, tube, discrete, remote with balanced connections. = love

bellicon

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Re: December 2023 Newsletter
« Reply #5 on: 15 Feb 2024, 10:36 pm »
Hi all
A bit of an update on the Raven preamp ......I also ran a frequency sweep on the Raven preamp and it is dead flat from 18 Hz (the bottom of my signal generator range) to well over 40 KHz.  A set of the amps and preamp will go to my good friend Troy Joseph Crowe in Ontario for complete analysis, including distortion measurements.  Troy has some very high tech measuring equipment.  This should happen in late January or early February, and we will post the measurements when we have them.  The whole system is very low in distortion, you can hear that, or rather not hear it.  The sound is really about what you don't hear, that you hear in most any other amps, which sound a bit gray by comparison.

cheers,
Don

Hi Don,

Are the Raven and the Revelation one and the same preamp? I see the latter but not the former here. https://www.spatialaudiolab.com/revelation-preamp
Were they both co-designed by you and Lynn Olson?

As one of these (?) are among those on my preamp short list, it is extremely fortuitous that Troy Crowe is reviewing them. I have the utmost confidence in his measuring methodologies, subjective listening evaluations and professional integrity for delivering a very thorough and impartial review. I will certainly be looking forward to Troy's report. 

dls123

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Re: December 2023 Newsletter
« Reply #6 on: 16 Feb 2024, 01:29 am »
Hi Don,

Are the Raven and the Revelation one and the same preamp? I see the latter but not the former here. https://www.spatialaudiolab.com/revelation-preamp
Were they both co-designed by you and Lynn Olson?

As one of these (?) are among those on my preamp short list, it is extremely fortuitous that Troy Crowe is reviewing them. I have the utmost confidence in his measuring methodologies, subjective listening evaluations and professional integrity for delivering a very thorough and impartial review. I will certainly be looking forward to Troy's report.

Hi. Yes absolutely.  Lynn and I were calling the preamp the Raven and the amps the Blackbirds.  Spatial has named them the Revelation series.  They are one in the same.  Lynn and I designed and prototyped them.  I am just finishing one that will go to Troy within a couple of weeks.  He will listen and measure.   It is in my prototype case, but the circuit is identical to the production version.  The Spatial production version looks nicer, and we moved to a lovely Monolith Magnetics power transformer and choke to match the amplifiers.  The prototype used internal Toroidy transformer and choke.  Same circuit so specs will be identical.   I have lived with this preamp and  the amps for 6-8 months and they are rock solid reliable and sound amazing.   

I got another question today about turn on thumps with the preamp powering a solid state amp.  Cannot happen.  The preamp is transformer coupled on input and output.  It has dual tube damper diodes for rectification.  It comes up slowly over 15-20 seconds to operating point, and the output transformer completely isolates the output jacks from any possibility of a turn on thump.  They are on the other side of the transformer from the tube circuit, so it cannot happen.