Tír Na HiFi

DaveF wrote:

jkeny wrote: 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.

Sure, but even in the listening tests in Tony's we tend to just change the input selector when doing the swap in/out of Regen - mostly the volume pot isn't changed between in/out configurations

DaveF wrote:

jkeny wrote: 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.

Can you expand on this, Dave? I believe you are talking about keeping noise off the device's ground plane once the device has a "good" power supply?

Yes, but in the two DACs that I mentioned above that I have been talking to Nige about - a PCM1794 (Sigma Delta DAC) & the Soekris (A R2R DAC using discrete smd resistors & shift registers for D to A conversion), there is a crucial step where the "quality" of the Voltage Reference becomes paramount. In the case of the PCM1794, it is at the point where the reference current is being used to scale up to the correct current value (based on the bit being processed) for outputting. It really doesn't matter what has happened to it before then, the stability & noise on the current reference at this point is the crucial issue. So if a clean, independent current can be supplied directly to this point, the pcb & stacking doesn't matter as long as this current output is not disturbed.

Same applies to the Soekris DAC, although this is a voltage out DAC - the reference voltage at the point where the logic shifters use it is a crucial stage in the processing of Digital to Analogue. Again this Vref can be provided as an independent, high quality supply which seems to greatly improve the DAC's sound quality

nige2000 wrote: 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 :)

Well, with my customers I always suggest that my devices should be plugged into their receiving devices before all devices are turned on. It's really a just in case precaution although I have had a couple of occurrences where my device was killed by plugging into a "live" device but this was almost certainly to there being a ground differential between devices (a design fault on the "live" device)

jkeny wrote:

nige2000 wrote: 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 :)

Well, with my customers I always suggest that my devices should be plugged into their receiving devices before all devices are turned on. It's really a just in case precaution although I have had a couple of occurrences where my device was killed by plugging into a "live" device but this was almost certainly to there being a ground differential between devices (a design fault on the "live" device)

amps not gnded

even gets more fun when your gnd gets pulled into the wall sockets from the various devices in the chain
gnd earthed once at either end works for me

I have recently had a customer who ordered both the Ciunas converter & DAC.
He reported back that he couldn't discern any difference between the Oppo HA-1 (DAC & headphone amp) & the Ciunas DAC or the Oppo with/without the Ciunas converter.

After a lot of head scratching & eliminating the various possibilities, some emails later - I suggested that it was symptomatic of a grounding issue.

He wrote back saying that he thought about what I said & he had no ground in his house electrical wiring in Italy & could "electric grounding compromise the final quality?".

I suggested he get an electrician to rectify this immediately & forget about audio, for the moment!!

Dave we tend to turn the selector as John suggests to an unused output and then back. Always make an effort to leave the volume the same. We have been often caught out but people by and large seem to cop that straight away. Also use the cheapo db readers on mobile phones to check things are very close. Especially when using a few different outputs. But regardless of the efforts undertaken they would not pass the requirements of any scientific/measurable etc criteria required to pass as acceptable for a pro test.

tony wrote:Dave we tend to turn the selector as John suggests to an unused output and then back. Always make an effort to leave the volume the same. We have been often caught out but people by and large seem to cop that straight away. Also use the cheapo db readers on mobile phones to check things are very close. Especially when using a few different outputs. But regardless of the efforts undertaken they would not pass the requirements of any scientific/measurable etc criteria required to pass as acceptable for a pro test.

i got a db reader a while back suppose we should use it

sebna wrote: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.

Hi Seb, did you ever try the Corning Optical cable with the Regen, seems several guys on CA had good success with this pairing?

Hi Seb, did you ever try the Corning Optical cable with the Regen, seems several guys on CA had good success with this pairing?[/quote]

I think that was before the "resistor mod" - it was found that the CORNING cable has an intrinsic resistance and that was why it sounded really good with the REGEN. This lead to the inclusion of a resistor that improved the performance of the REGEN (Amber version).

I am almost confident that the cable has no advantages at this point.

In my opinion that cable is to be avoided for our purposes.

Like most others I found an improvement with the use of the Uptone Regen,
notably a slightly more stable sound stage with a more musical presentation
particularly noticeable with piano and all natural percussion instruments
(synthesised drums etc were even more disappointing knowing what the natural
alternative could deliver). I mainly used the Regen with 3 meters of Supra USB
cable (for convenience, but there is a deleterious effect with this length – see
below) and the Uptone short USB cable. I did not do any A/ B comparisons, but
played through my Redbook collection, of note is the size of the soundstage
which varied considerably from track to track particularly the height which varied
from carpet height to ceiling height. Rips are held on a Seagate HDD and the laptop started with a Hitachi HDD which died and was replaced by an Intel Cheryville SSD. Below is my comparison which is longer than expected because I wanted to include comments on the SSD and Supra cable without the Regen.
1. Hitachi HDD + generic USB cable into Young DAC, very enjoyable musical
presentation. Not quite as detailed as I expected, Steeleye Span’s Gaudete
(The Best of Steeleye Span) gave a sense of a procession of singers walking
towards the listener and then walking away. However, I could not following
the words of the female soloist singing in latin.
2. Intel Cheryville SSD + generic USB cable – unlistenable after 50 hours of
burn-in. Instruments completely overpowered vocals.
3. Intel Cheryville SSD + Supra USB cable – immediate return to the usual
soundstage and very enjoyable except for a slice of the upper treble missing
leaving the sound dullish. The change in the upper registers was accompanied
by a much more powerful bass. Interesting 1 of my favourite CDs, City to City
by Gerry Rafferty was now more listenable – it had a high fatigue factor before
which I attributed to ultrasonic breakthrough. With the Supra cable I could
hear an odd artefact (sound not due to musical instrument) on Baker Street and
the synthesised sound of a train on City to City sounded very odd and probably
had an ultra sonic signature now ameliorated by the cable. Steeleye Span’s
Gaudete had a little more detail, but I could still not follow the female
vocalist plus the procession of singers sounded quiet then louder and then
quieter gain without the sense that they were walking towards and then away from the listener.
4. Young DAC with Uptone cable to Uptone Regen plus Supra to laptop– the
sound was slightly brighter, but without losing anything in the bass (still
missing a slice of treble which I attribute to the length of the Supra cable).
There was an improvement in detail I could now follow the female soloist singing
in latin (but still no sense of a procession), the music was more enjoyable with
a sense of the edge of the notes of percussion instruments in particular having a
beginning and an end (envelope) leaving the sense that the music without the Regen was slightly fuzzy.
5. As 4, but adapter replacing Uptone cable – a little more detail, but noted
on 1 album, The Very Best of Sheryl Crow, the sound was a little strident.
6. Laptop> generic cable> adapter> DAC, after approx. 130 hrs burn-in, back to
enjoyable musical experience without the advantages of the Uptone as above.
Unlike others I attribute only 20-25% of the sound improvement to the Regen and
the rest to the Supra cable (a shorter cable would be better) – still worth the
purchase price IMHO.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Power Inspired UPS AG (500 VA); Seagate External HDD> Advent laptop - SSD (Vista)> Supra USB cable (3m)> Uptone Regen> Uptone short USB casble> M2Tech Young DAC (2011)> Meridian 2 box 207 CDP/ pre-amp (1989)>
50W NAD 2150 power-amp (1989)> KEF 103/3 Ref -with KEF Kube base enhancer (1989)

heres my 2nd attempt at it
nice improvement in clarity