USB Regen from Uptone Audio

[Ken Moreland]

Maybe I should try it one more time... maybe with one of the well run-in units :) I have heard all the improvements mentioned but also it was bringing brightness and harshness at the top end in my case but at the same time my system is fully SS so I guess more prone to highlighting those issues.

I don't think that is the cause of the brightness you describe. My amps are solid state and the sound is sweeter. The bass is tighter and deeper which gives a fuller,more rounded sound. Could the Regen be showing up some other problem in the system.

A bit of guess work
I Dont have a regen but seb likely has a USB card which will provide a decent enough USB signal it is powered by the teradak linear supply putting a regen on this could be just like washing your jumper twice at it just not get much cleaner
I think Mick is using the usb3 port on the back if the PC so his potential for improvement is much larger

I see two potential areas for Sq loss in the regen at our standard of audio PC mainly power supply but also the additional cabling
Using a cheap smps power supply is kinda like washing your jumper in dirty water
I believe the guys tested a battery powered one at a meet and it was a clear favourite

There are differences in usb cable and the differences are far from small and generally speaking more of it leads to worsining sq

IMO the regen us built for a target market of Mac and desktop and laptop users that will undoubtedly get a large improvement
I'd imagine to get the best out if it it will need some light modding and clean power

My take on the Regen would be very similar to Mick's and I think our power amps are the same. I'm using USB3 PPA Studio V2 card which is battery powered, through Audioquest Jitterbug ,PPA USB cable then a couple of adapters (to bring USB cable's micro B connector up to regular B size). I'm still using the original Regen power supply , with a view to replacement. The bass in particular is deeper and the detail too is improved. I'd certainly recommend it.

[mick]

Nigel could be right. The power supplies are critical for the sound quality.
I am still using the usb3 port at the rear of the PC. I have used the direct connection into the JKDAC 32. I use an Elijha Audio usb cable from PC to Regen. I am also using the supplied smps wall wart.
Listening again today the bass is probably the most obvious improvement followed by detail retrievel. This gives a more solid overall sound.
Given the improvement in sound quality for a very modest outlay it was well worthwhile for me.
Having said that if you cannot hear any difference there is no point in having it. I would persevere with differing connections,etc just to be sure,before giving up on it.

[DaveF]

John,
Just out of interest, do you carefully level match when doing these comparisons or are the differences that great that a few dBs of difference in levels wont lead to false impressions? It's pretty important to start with a level playing field to begin with I think.
When I've done A/B comparisons of equipment in the past I'll admit I was guilty of not doing so but lately I've been putting more of an effort in.

[jkeny]

John,
Just out of interest, do you carefully level match when doing these comparisons or are the differences that great that a few dBs of difference in levels wont lead to false impressions? It's pretty important to start with a level playing field to begin with I think.
When I've done A/B comparisons of equipment in the past I'll admit I was guilty of not doing so but lately I've been putting more of an effort in.

Dave, if the volume changed by just inserting the Regen in the USB signal, then we have a different issue i.e the regenerated USB signal coming out of the Regen is no longer a replica (in the digital domain) of the input USB signal going into it.

[DaveF]

John,
Just out of interest, do you carefully level match when doing these comparisons or are the differences that great that a few dBs of difference in levels wont lead to false impressions? It's pretty important to start with a level playing field to begin with I think.
When I've done A/B comparisons of equipment in the past I'll admit I was guilty of not doing so but lately I've been putting more of an effort in.

Dave, if the volume changed by just inserting the Regen in the USB signal, then we have a different issue i.e the regenerated USB signal coming out of the Regen is no longer a replica (in the digital domain) of the input USB signal going into it.

I'm talking about the comparisons in sound quality from the system as a whole, i.e with the Regen inserted and then without, while level matching at the listening position each time. So is this done? I guess this question also applies to other contentious areas such as software players - MQN, Lekt etc also.

[jkeny]

John,
Just out of interest, do you carefully level match when doing these comparisons or are the differences that great that a few dBs of difference in levels wont lead to false impressions? It's pretty important to start with a level playing field to begin with I think.
When I've done A/B comparisons of equipment in the past I'll admit I was guilty of not doing so but lately I've been putting more of an effort in.

Dave, if the volume changed by just inserting the Regen in the USB signal, then we have a different issue i.e the regenerated USB signal coming out of the Regen is no longer a replica (in the digital domain) of the input USB signal going into it.

I'm talking about the comparisons in sound quality from the system as a whole, i.e with the Regen inserted and then without, while level matching at the listening position each time. So is this done? I guess this question also applies to other contentious areas such as software players - MQN, Lekt etc also.

But Dave, the only change when listening is to insert the Regen into the USB line - no changes to volume or anywhere else to the playback system (perhaps in Tony's we changed volume sometimes but I did tests without changing volume). My point was that the Regen is regenerating the digital USB signal so there is no way that it can affect the volume unless it's changing the digital info!

What I believe you are suggesting is that the Regen & software players are changing the bits? Easily checked & I don't believe that there is any question that it (or software players) are doing this - the Regen has been used between USB HDD & PC with no issues.

[jkeny]

Nigel could be right. The power supplies are critical for the sound quality.
I am still using the usb3 port at the rear of the PC. I have used the direct connection into the JKDAC 32. I use an Elijha Audio usb cable from PC to Regen. I am also using the supplied smps wall wart.
Listening again today the bass is probably the most obvious improvement followed by detail retrievel. This gives a more solid overall sound.
Given the improvement in sound quality for a very modest outlay it was well worthwhile for me.
Having said that if you cannot hear any difference there is no point in having it. I would persevere with differing connections,etc just to be sure,before giving up on it.

Yes, the power supplies are critical for digital audio when it reaches the crucial stage of digital to analogue conversion.

I'm having a back channel conversation with Nige about the importance of the STABILITY of the voltage reference in the Soekris DAC.
We also previously discovered that this is crucial for a PCM1794 DAC. Making these references LOW NOISE & STABLE makes a big difference to the sound.

Essentially a DAC operates by creating the correct voltage output for each bit input. It does this by using the voltage reference as it's reference & generating the correct voltage out. If the voltage reference fluctuates then the voltage output for two bits of the same value will be different i.e it is the equivalent of two different bit values. As the voltage output for the least significant bit in a 16bit signal is of the order of tens of micro volts (millionths of a volt), you can see how important the stability of the voltage reference is.

I believe the important issues here are the LOW NOISE & the STABILITY of a power supply which has to power fast switching digital circuitry as well as analogue circuitry in a DAC.

BTW, the low level linearity of DACs is often NOT better than 1 LSB (least significant bit) - the best being about 0.5 LSB so you might consider the above a moot point but it isn't, for various reasons

[DaveF]

But Dave, the only change when listening is to insert the Regen into the USB line - no changes to volume or anywhere else to the playback system (perhaps in Tony's we changed volume sometimes but I did tests without changing volume). My point was that the Regen is regenerating the digital USB signal so there is no way that it can affect the volume unless it's changing the digital info!

What I believe you are suggesting is that the Regen & software players are changing the bits? Easily checked & I don't believe that there is any question that it (or software players) are doing this - the Regen has been used between USB HDD & PC with no issues.

No, I don't believe bits are being changed at all either in the Regen or SW players.
What I meant was that I thought that as components are swapped in or out, the volume dial on the amp might be lowered to avoid potential nasty pops or clicks through the speaker. Just something I do out of habit when plugging in or out stuff at the source end. But as you say above no changes occurred in volume setting in your tests.

[DaveF]

Yes, the power supplies are critical for digital audio when it reaches the crucial stage of digital to analogue conversion.

While I'd agree with this completely, dont forget the PCB layout and stackup also. It's just as crucial.

[nige2000]

But Dave, the only change when listening is to insert the Regen into the USB line - no changes to volume or anywhere else to the playback system (perhaps in Tony's we changed volume sometimes but I did tests without changing volume). My point was that the Regen is regenerating the digital USB signal so there is no way that it can affect the volume unless it's changing the digital info!

What I believe you are suggesting is that the Regen & software players are changing the bits? Easily checked & I don't believe that there is any question that it (or software players) are doing this - the Regen has been used between USB HDD & PC with no issues.

No, I don't believe bits are being changed at all either in the Regen or SW players.
What I meant was that I thought that as components are swapped in or out, the volume dial on the amp might be lowered to avoid potential nasty pops or clicks through the speaker. Just something I do out of habit when plugging in or out stuff at the source end. But as you say above no changes occurred in volume setting in your tests.

us CA guys are far more careless than that :)
we plug stuff in and out willy nilly
once the analogue side of the dac is connected and or gnded there never seems to be any need to turn down or off amps

you should get a regen out of curiosity dave :)