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MDAC First Listen (Part 00101001)

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BE718 said:
I haven't had time today to perform the additional listening, but so far I find the difference with the regen in circuit is so small that I don't know if I am imagining it.

If there is a difference I think I heard on certain tracks what came across as a tiny reduction in sibilance, but that's about it. Nothing significant. To put it into context, the Mdac filters make much bigger differences.

I need to do some more listening, blind too to see if I am imagining it.
Click to expand...

Before you put your Regen on eBay or whatever, I have a couple of comments/suggestions.

1) So far you and I are more or less in agreement. The difference of Regen + SMPS "nothing significant" (you) or "slight improvement" (me) could easily be system dependent, and I only dared post my "small improvement" because I could get it confirmed by somebody else.

2) I get a spectacular improvement when powering my two cascaded Regens from a Paul Hynes 12v supply. These supplies are not cheap, and last time I heard they didn't arrive quickly, so I would not push anyone to go this particular way without finding a way to try things first, so

3) Over at CA people have started trying battery supplies and are reporting good results. Just as a cheap and nasty, I rigged up a 9v PP3 to power mine. Last night when I replaced the PH with the battery I thought "Oh dear", or something similar. No, a cheapo 9v with clip contacts, no capacitor and low quality wire does not sound anything like as good as the PH.

However, I had forgotten what the SMPS sounds like- we get very quickly used to improvements. This morning I found it and put it back in. There are a lot of possible experiments, but I tried the simplest, leaving the first Green Regen powered with 12v and SMPS to the Amber which plugs into the MDAC.

It wasn't a bad sound, "warm glow" perhaps sums it up, instruments there but ever so slightly out of focus, and top subdued. I guess that's what I used to think was OK- now it might be good for dozing in an armchair, when, on some recordings at least, I am now used to an 'edge of the chair' feel.

Now put in the battery on the Amber, and the "glow" disappears and the focus is returning; we might be as much as half way back to the PH linear supply. One new PP3 should give a few hours running- I deliberately used a partly run-down one, and yes the voltage drifts down, but the Regen carries on working over a pretty wide range.

I would recommend this cheap trick to anybody who is initially disappointed by the Regen, not of course as a permanent solution unless you fancy recharging, but as a way to get an idea of what might be possible, not to say a hint of what Detoxing might do.
 
JohnW said:
:( not only do you face the issue level matching (Volume control) between the units but you also need to consider time alignment (Phase) between DAC's one of the purposes of the Master/Slave interface is to insure all channels are synchronised in the time domain.

If you wanted to try, then you would not need a DAC / Unit with DSP as Master FDAC would perform the DSP function and could output via SPDIF - but I'm uneasy for the reasons mentioned....
Click to expand...

Hmm, sounds problematic. Can I just explain what I'm trying to achieve and you can tell me if I have misunderstood my hardware requirements.

I'm looking at a 3 way active arrangement (6 channels in total) using 3 stereo amplifiers for the bass, mid and treble respectively. (The VFETs would be driving the all important mids). So am I right in thinking I will need one master FDAC plus 2 slaves?
 
jamjar784 said:
Bob

Your experience (and I believe some reviewers agree) seems to be at odds with Uptone http://uptoneaudio.com/pages/usb-regen-questions-and-answers While it is true that our own JS-2 LPS makes a slight improvement for the REGEN, it is not a large difference and the REGEN sounds GREAT with just the selected stock supply.

Maybe whenever JW can do some measurements he can clarify what's happening. :confused:
Click to expand...

Well its certainly something I can try. I need to speak to John about sending him mine for measurement.
 
Bob L said:
Before you put your Regen on eBay or whatever, I have a couple of comments/suggestions.

1) So far you and I are more or less in agreement. The difference of Regen + SMPS "nothing significant" (you) or "slight improvement" (me) could easily be system dependent, and I only dared post my "small improvement" because I could get it confirmed by somebody else.

2) I get a spectacular improvement when powering my two cascaded Regens from a Paul Hynes 12v supply. These supplies are not cheap, and last time I heard they didn't arrive quickly, so I would not push anyone to go this particular way without finding a way to try things first, so

3) Over at CA people have started trying battery supplies and are reporting good results. Just as a cheap and nasty, I rigged up a 9v PP3 to power mine. Last night when I replaced the PH with the battery I thought "Oh dear", or something similar. No, a cheapo 9v with clip contacts, no capacitor and low quality wire does not sound anything like as good as the PH.

However, I had forgotten what the SMPS sounds like- we get very quickly used to improvements. This morning I found it and put it back in. There are a lot of possible experiments, but I tried the simplest, leaving the first Green Regen powered with 12v and SMPS to the Amber which plugs into the MDAC.

It wasn't a bad sound, "warm glow" perhaps sums it up, instruments there but ever so slightly out of focus, and top subdued. I guess that's what I used to think was OK- now it might be good for dozing in an armchair, when, on some recordings at least, I am now used to an 'edge of the chair' feel.

Now put in the battery on the Amber, and the "glow" disappears and the focus is returning; we might be as much as half way back to the PH linear supply. One new PP3 should give a few hours running- I deliberately used a partly run-down one, and yes the voltage drifts down, but the Regen carries on working over a pretty wide range.

I would recommend this cheap trick to anybody who is initially disappointed by the Regen, not of course as a permanent solution unless you fancy recharging, but as a way to get an idea of what might be possible, not to say a hint of what Detoxing might do.
Click to expand...
This is interesting but it opens a whole new can of worms, because it doesn't make much sense as far as the claims of the makers of the Regen go as to why it works. I seem to remember that they felt that the psu it uses was the best available at the price. Of course they are happy to sell an expensive psu too, but the idea that the psu they use is so bad that it almost completely masks the effect of the Regen would (if one assumed that the allegedly beneficial effect of the Regen was based on any real effect) be very surprising.

Of course we can all think up some scenario involving rf this and rf that, but it's puzzling. JohnSwenson has IIRC said that linear psus are not necessarily better than switchmode ones and it does seem strange that he doesn't realise that this design is crippled by the psu.
 
JohnW said:
rtrt,

MiniDSP expertises is in the DSP software - the Full scale output level is determined by the Analogue hardware - the FDAC hardware is very different to the mniDSP designs our FS output level is 3V SE & 6V balanced to allow for digital Pre-amplifier "Gain" headroom.
Click to expand...

Right understood John thanks. That sounds positive, though I think it implies that to use multiple subwoofers a splitter cable of some sort will be needed and all subs will be equalised the same, in terms of any delay/freq characteristics?

Will it be possible to split main speakers and subwoofers with different delay (and freq) characteristics?

I suppose the above is dependant on multiple outputs both physically on the back of the unit (like MDAC) and functionally within the FDAC (unlike MDAC).
 
adamdea said:
This is interesting but it opens a whole new can of worms, because it doesn't make much sense as far as the claims of the makers of the Regen go as to why it works. I seem to remember that they felt that the psu it uses was the best available at the price. Of course they are happy to sell an expensive psu too, but the idea that the psu they use is so bad that it almost completely masks the effect of the Regen would (if one assumed that the allegedly beneficial effect of the Regen was based on any real effect) be very surprising.

Of course we can all think up some scenario involving rf this and rf that, but it's puzzling. JohnSwenson has IIRC said that linear psus are not necessarily better than switchmode ones and it does seem strange that he doesn't realise that this design is crippled by the psu.
Click to expand...
Ovar at CA in the Regen thread it has been hinted that JohnSwenson has a new power device for the regen in the works. Which also suggest that you need a LPS for the regen. So the Regen is not so cheap after all.
 
Rune said:
Ovar at CA in the Regen thread it has been hinted that JohnSwenson has a new power device for the regen in the works. Which also suggest that you need a LPS for the regen. So the Regen is not so cheap after all.
Click to expand...
As I said, they are perfectly happy to sell an expensive linear psu too. There is a small market of errrr super-sensitive connoisseurs and the market is about selling as much stuff to them as possible. see mana
 
jamjar784 said:
Bob

Your experience (and I believe some reviewers agree) seems to be at odds with Uptone http://uptoneaudio.com/pages/usb-regen-questions-and-answers While it is true that our own JS-2 LPS makes a slight improvement for the REGEN, it is not a large difference and the REGEN sounds GREAT with just the selected stock supply.

Maybe whenever JW can do some measurements he can clarify what's happening. :confused:
Click to expand...

I'll post results as soon as I have a unit to test :)
 
rtrt said:
Right understood John thanks. That sounds positive, though I think it implies that to use multiple subwoofers a splitter cable of some sort will be needed and all subs will be equalised the same, in terms of any delay/freq characteristics?

Will it be possible to split main speakers and subwoofers with different delay (and freq) characteristics?

I suppose the above is dependant on multiple outputs both physically on the back of the unit (like MDAC) and functionally within the FDAC (unlike MDAC).
Click to expand...

With the DSP option (Once we progress to phase 2 software build which enables the DSP software functions) you can perform the EQ and short delay then output both to internal DAC section and a separately EQ'ed signal via SPDIF to drive the subwoofer (with digital input or via a second DAC) - but note about my reservations to Ian's earlier question on a similar subject.
 
adamdea said:
This is interesting but it opens a whole new can of worms, because it doesn't make much sense as far as the claims of the makers of the Regen go as to why it works. I seem to remember that they felt that the psu it uses was the best available at the price. Of course they are happy to sell an expensive psu too, but the idea that the psu they use is so bad that it almost completely masks the effect of the Regen would (if one assumed that the allegedly beneficial effect of the Regen was based on any real effect) be very surprising.

Of course we can all think up some scenario involving rf this and rf that, but it's puzzling. JohnSwenson has IIRC said that linear psus are not necessarily better than switchmode ones and it does seem strange that he doesn't realise that this design is crippled by the psu.
Click to expand...

I think it was a crazy idea to go through the whole effort to "ReGen" the USB Data and then to power via a switching PSU which would inject extra RF leakage currents into the system!

To me it just suggests that the designers missed the point of the whole exercise...

I look forward to measuring a unit - I'll test with both a SMPS and Linear supply.
 
jamjar784 said:
Bob

Your experience (and I believe some reviewers agree) seems to be at odds with Uptone http://uptoneaudio.com/pages/usb-regen-questions-and-answers While it is true that our own JS-2 LPS makes a slight improvement for the REGEN, it is not a large difference and the REGEN sounds GREAT with just the selected stock supply.

Maybe whenever JW can do some measurements he can clarify what's happening. :confused:
Click to expand...

Well, Yes.... As for confused, join the club!

The only common thread I can find is that all the enthusiasts for SMPS+Regen do NOT have an M-DAC, and the two M-DAC + Regen users (or perhaps more, anybody else out there?) find the SMPS to be close to useless.

In between there are several users on the CA threads who say they get quite substantial improvements with the JS-2 or HDPlex supplies, or even with "El Cheapo", a $60 Chinese LPS, so the Uptone quote is some sort of 'average over customer reports'.
 
iansr said:
Hmm, sounds problematic. Can I just explain what I'm trying to achieve and you can tell me if I have misunderstood my hardware requirements.

I'm looking at a 3 way active arrangement (6 channels in total) using 3 stereo amplifiers for the bass, mid and treble respectively. (The VFETs would be driving the all important mids). So am I right in thinking I will need one master FDAC plus 2 slaves?
Click to expand...

Ian,

I understand your proposed system - but cost is an issue :)

Ideally you should have one master FDAC plus 2 slaves, and really 3 pairs of VFETS - but that's just not financially viable!!! - so I suggest just stay with your current FDAC Master + single slave and we will work with your existing MDAC for LF output (via the Master DSP / SPDIF connection).
 
JohnW said:
I think it was a crazy idea to go through the whole effort to "ReGen" the USB Data and then to power via a switching PSU which would inject extra RF leakage currents into the system!

To me it just suggests that the designers missed the point of the whole exercise...

I look forward to measuring a unit - I'll test with both a SMPS and Linear supply.
Click to expand...

Hi John,

Sent you a PM about sending my Regen to you.
 
BE718 said:
Hi John,

Sent you a PM about sending my Regen to you.
Click to expand...

Alan,

Thank you for the offer - but a fellow PFM member has beat you to it :) and apparently (I'm actually quite exited) it should be with me on Friday - but knowing how it works here in Czech, I'm guessing next week is more realistic.
 
Be interesting to test/measure a few of these devices.. I have an Olimex isolator if thats of any interest.
 
JohnW said:
Have you sold your Kidneys?

If you where anyway serious then I'd have to look into sourcing some more VFETs....
Click to expand...

I've used my dark side drawing skills to make this picture:

DSC_0359_vfet.JPG


Your amps might be a bit overpowered just to drive an AMT Tweeter or two small midrange chassis. But on the other hand.... :D
 
Perhaps Mr John could make half-VFETs for the tweeter and mids regarding the above that are 100Wpc? Like half of the VFET devices populating these amps in same chassis, so stretching the limited supply devices which may work out a bit cheaper too? ...only an idea and intended with respect :)
 
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