[RonN5]

Solid idea, and something we talk about here a lot -- integration.  The Stereo Maraschino was a winner due to a just a bit of integration.  Thanks for your kind post (:

In the end, it comes down to commercial viability...so the DAC/Amp might work...but only if the volume control had a remote....and along those lines, I suspect that offering the DACDAC models with a remote....if doing that didn't hurt the sound....and with voltage sufficient to fully power all of the amplifier options would be even more marketable

[Jonathon Janusz]

...so the DAC/Amp might work...but only if the volume control had a remote....

Pivoting in this direction (and leaving business motivation speculation alone, because that is a topic I could get sidetracked on all day long! ), this is something I thought an odd exclusion when I saw Tommy's DAC DAC with volume control considering it needs literally only volume control as a user adjustable function (no input switching, etc.).  Couldn't something like the Alps remote volume system packaged from Bent Audio (http://www.bentaudio.com/index2.html) for example be put in place of the manual pot driving the digital volume control already in the DAC DAC with VC as an easy turn-key solution to adding remote volume to it with no change in either the signal path or volume control implementation other than sorting out how to feed the 3-5-ish VDC to the remote control board?  I've seen similar even less expensive setups in quick searches of ebay, aliexpress, etc.

Sure, this doesn't satisfy the folks looking for a more feature-rich remote controlled solution to an all-in-one "everything integrated", but if the target is just getting volume up and down without having to get up from the chair, this seems like a pretty quick and easy fix with no down side?

[AmpDesigner333]

Have you thought about trying to add a RF/EMI Schaffner filter? FN-9244B

My designs have the necessary filtering already, AC line and otherwise.

Are you an engineer?  Can you point an amp design or two that you have done as an example of your work in this area?

If you had 100mVpp of power supply noise, and the amp has 60dB PSRR with 22dB gain, what is the lowest output noise floor you can attain (at that frequency)?

The whole idea for running from batteries is to lower power supply noise.  How much that means depends on what the power supply is driving.  In the case of Cherry MEGA and Maraschino amplifiers, low power supply noise and PSRR work together to allow a super low noise floor.  What would be the difference between an isolated bench supply running the amp and batteries?

[maty]

Yes. Not EE.

I already know that the hard have filtering, but they tend to be insufficient for the current reality.

On battery power I can not pronounce myself.

[AmpDesigner333]

Some time ago I solved the problems with the terrible electrical grid that arrives at my house. I only have one left: when the voltage exceeds 238 Vac, the sound gets worse. When it is close to 230 Vac my second audio system sounds amazing.

If the AC line staying within spec voltage, and changing by less than 4% affects your sound, there's a problem!

253VAC is "high line" for 230VAC nominal, 242VAC is "high line" for 220VAC nominal, so 238VAC should be fine.

Of course, there's also line distortion to consider, but the amp's power supply should handle that too, with simple filtering on the DC side.

The other thing is that "sounds amazing" is pretty nebulous.

[maty]

The problem, my friend, is that in the mid-nineties the EU set the 230 Vac as mandatory. Countries like Spain went from 220 Vac to 230 Vac. Many of the hard kept their designs for the 220 Vac. So yes the 238 Vac are too many!

A few days ago the tension reached 239 Vac. I managed to mitigate the problem by changing Kernel Streaming by ASIO4ALL, with custom values.

https://www.audiosciencereview.com/forum/index.php?threads/kernel-streaming-asio-wasapi-and-music-players-foobar-jriver.7412/post-187920

https://www.audiosciencereview.com/forum/index.php?threads/kernel-streaming-asio-wasapi-and-music-players-foobar-jriver.7412/post-187923

Since a few days ago we suffered a wave of Saharan heat. The air conditioners have been connected in a massive way and the tension has dropped -> sound this afternoon was spectacular.

https://www.diyaudio.com/forums/music/6958-playing-listening-post5838138.html

Fabrizio De André - La Buona Novella (1970), Vinyl, RCA remaster 2017, Italy

[AmpDesigner333]

In the end, it comes down to commercial viability...so the DAC/Amp might work...but only if the volume control had a remote....and along those lines, I suspect that offering the DACDAC models with a remote....if doing that didn't hurt the sound....and with voltage sufficient to fully power all of the amplifier options would be even more marketable

Yes, indeed!  The Cherry DPA (digital preamp, in development) will have a remote for volume.

[AmpDesigner333]

Pivoting in this direction (and leaving business motivation speculation alone, because that is a topic I could get sidetracked on all day long! ), this is something I thought an odd exclusion when I saw Tommy's DAC DAC with volume control considering it needs literally only volume control as a user adjustable function (no input switching, etc.).  Couldn't something like the Alps remote volume system packaged from Bent Audio (http://www.bentaudio.com/index2.html) for example be put in place of the manual pot driving the digital volume control already in the DAC DAC with VC as an easy turn-key solution to adding remote volume to it with no change in either the signal path or volume control implementation other than sorting out how to feed the 3-5-ish VDC to the remote control board?  I've seen similar even less expensive setups in quick searches of ebay, aliexpress, etc.

Sure, this doesn't satisfy the folks looking for a more feature-rich remote controlled solution to an all-in-one "everything integrated", but if the target is just getting volume up and down without having to get up from the chair, this seems like a pretty quick and easy fix with no down side?

We looked at using a motorized pot board, but it was too large.

For those who don't know, the Cherry DAC DAC 2 HSV adds volume control to the DAC DAC 2 HS with digital attenuation.  This means the analog signal path isn't any longer than without the volume control.  An analog pot is "measured", and the setting of the digital attenuation is controlled with this measurement.  The analog pot also provides a "nice analog feel".  The end result is that performance is not affected by adding the volume control this way.  24-bit post-attenuation data assures plenty of dynamic range even at mouse fart volumes.

[maty]

Just one more curiosity. Many of the cheap Chinese tube amplifiers are prepared for 220 Vac!

In Spain the population still believes that they are 220 Vac. Until the late sixties it was 125 Vac.

Tarragona was one of the first areas where it was migrated to 230 Vac. I suppose it was because of so much petrochemical industry and the four nuclear power plants (only two active now, other two closed by seniority).

[AmpDesigner333]

Regarding volume control, most systems these days are driven from a music server of some sort.  Using your phone (or other WiFi device) to control track/volume is now inexpensive and reliable.  Check out my other thread about hi-res audio.  It started to sway toward the topic of streaming services (like Qobuz):
https://www.audiocircle.com/index.php?topic=163396.0

[AmpDesigner333]

Fancy power cords????

In case you haven't seen my comments here (written before this thread was started):
https://audiophilereview.com/audiophile-news/can-power-cords-have-an-effect-on-an-audio-systems-sound.html

[AmpDesigner333]

What manufacturer shows PSRR in their specifications?  I’m not selling amp chips, but there are chips sold with my technology in them (:

Don’t know exact PSRR off the top of my head, but likely 60-80dB mid-band.  The Maraschino also runs from a regulated supply. The ripple is way out of band.  It’s ultra quiet even at 20kHz.  For the MEGA, the ripple is where PSRR is maxed out, so THD at high power is good (low) on both sides of the spectrum.

Somewhere, I have a photo of the MEGA MK2’s noise floor FFT.  It’s amazing!!  Pretty level at -140dB with -60dB stim.  SNR is the ultimate “proof in the pudding” at about 120dB, so you know the power supply noise isn’t getting through!  It’s a solid design.  This also doesn’t involve the usual chokingly high feedback levels and low phase margins of other Class-D amps.

I’ll be pretty busy over the next few weeks with the Cherry Summer Sale.   Some real bargains on the list.  Email Support@DigitalAmp.com to get it.  We also had a surprisingly huge response to our newsletter announcing the sale!  Looks like being honest and hard working is starting to pay off. Thanks.

[maty]

I think a new push is coming to the sales of amplifiers with the new class D technologies. 2020, if commercial wars do not make it more difficult to buy some electronic components.

Their consumers are usually very interested in numbers, specifications and, above all, in measurements. Many believe, I do not, that fantastic measurements necessarily imply a fantastic sound too.

I recommend that you modify the pages of your products and add the numbers, graphs and... in a very visible way.

[RonN5]

AN OPPOSITE OPINION

We would probably all agree that many people like numbers and it would be nice to see more information from Tommy, especially if it would help us to better understand the compatibility with the rest of our system...BUT....

I'd say that the publication of numbers/graphs at this point in time by various manufacturers is very much hit and miss....if you look at what is being offered by some of the well regarded companies....what they decide to publish is all over the map....from nothing to quite a bit.  Take a look at the pages for two of the most well regarded and publicized amps out there....the Pass XA25 and the McIntosh MC2152

https://www.passlabs.com/sites/default/files/XA25_manual_1.pdf

https://www.mcintoshlabs.com/products/amplifiers/MC2152AN

Yes, they say a little more than Tommy...but they don't give away their "in house knowledge" and it is the same with Audio Research, PS Audio and many others.

Granted....some companies do choose to publish a lot of information... and others publish even less than Tommy.

At the end of the day, information is generally a competitive advantage and if revealing it gives people insight into what you are doing and allows them to easily copy it (think China here).....and if Tommy can sell all of the amplifiers, etc. that he wants/needs to sell based on reviews and word of mouth about how great they sound...then I would STRONGLY advise him to hold information closely and not publish too much.