AUDIO over IP - REDNET 3 & 16 Review. AES67 Sets A New Standard for Computer Audio

[johnjen]

Isn't the 51V used for mic phantom power?

Yes.
It is then further filtered and regulated down to 48vdc with very carefully controlled current delivery.
 
And we figured that this SMPS is a one size fits all solution for all of the RedNet boxes, some of which do contain mic preamps and the related phantom power supply.
 
 
JJ

 

[johnjen]

  Rednet 3 / D16 power supply specs:
 
Brand: FEREX
Model: FP07M063
Applicable Products: DVB digital TV set - top box
Input voltage range: 100V-240V
The output voltage: + 5, + 15V, -15V, + 51V
Output Power: 10W

Input characteristics
      Input voltage range: 100V-240V AC
      Input voltage frequency: 47Hz-63Hz
 Output characteristics
     Output combinations: + 5V, 2A; + 15V, 0.7A; -15V, 0.7A; +51 V, 80mA
      Ripple: 50mV
      Efficiency: 70% Min. (220V AC / Max Output Current)
 Dielectric strength: AC 3000V, 10mA, 60Sec
 Insulation resistance: 30M Min DC 500V
 Mean time between failures: working time 50000H

Protective function:
 Output Overvoltage Protection (OVP)
 Output Short Circuit Protection (SCP)
 Output Overcurrent Protection (OCP)

EXCELLENT!
 
Thanks for that, it answers a whole mess of questions, and all in the positive at that!
 
Those current numbers match really well, and the rated ripple is 25 times greater than the PSU I have on order.
 
And that +51V was probably originally meant to drive the display on the set top box.
 
JJ

 

[Golfnutz]

  EXCELLENT!
 
Thanks for that, it answers a whole mess of questions, and all in the positive at that!
 
Those current numbers match really well, and the rated ripple is 25 times greater than the PSU I have on order.
 
And that +51V was probably originally meant to drive the display on the set top box.
 
JJ

I was curious about the current myself to see if there was anything suitable for the D16. Doesn't really look like it, at least I couldn't find anything (internal replacement of the FP07M063). Not sure I'm keen to do something externally (have to wait and see how your make out).
 
Might not hurt for someone to reach out to Focusrite and ask them what the voltages are used for. Someone on some other website posted their FP07M63 from a 6 year old piece of Focusrite equipment had recently failed. He emailed Focusrite (UK) and they're sending him a replacement for 24 British Pounds. I would imagine if the guy asked them what each of the voltages were for, they would have told him.
 
Spec's for your PowerVolt are showing as 10.25" (depth), while the Rednet 3 is only 9.75 (depth)".  You may have a hard time doing something internal, unless you're planning on removing all/part of the casing?

 

[wushuliu]

More adventurous, but even cleaner power: Get one of these and one of these (or equivalent, lots of choices). Add two small antek transformers with appropriate voltage and should be good to go, with plenty of space left over.

 

[mhamel]

http://www.ebay.com/itm/Assembled-Special-Linear-Power-supply-board-for-update-OPPO-103-103D-PSU-/322268439445
 
Found these on eBay - they have the +/- 15v and +5v output... might be worth checking out and it looks like it might fit in the case.

 

[wushuliu]

Huh an oppo linear power supply. Well how about that...

 

[wushuliu]

As an additional FYI regarding the Oppomod PSU above, here is a post from Coris at diyaudio who designed the Oppo PS I have now:
 

We have the original Oppo SMPS used in all their models, which exhibit (measured under the same approach(conditions) a very large HF spectre of noise, which it goes up to 200mVpp levels. This SMPS do not dissipate heat.
Alternative to this SMPS (as a serial approach) was/is the Oppomod PSU. This one exhibit a much reduced frequency spectre of noise, and the levels it goes up to few teens mVpp. Huge improvement over the original SMPS.
My LPM it exhibit noise only on the very low frequency spectre (25, 50, 100, 200, and 430Hz) of a level in µV range.

 
Note that Coris' LPS has about ~2uV (not mV) or a little higher  of noise. However his costs several times more than the Oppomod (upon which that specific Ebay LPS is based I believe)...

 

[Golfnutz]

  http://www.ebay.com/itm/Assembled-Special-Linear-Power-supply-board-for-update-OPPO-103-103D-PSU-/322268439445
 
Found these on eBay - they have the +/- 15v and +5v output... might be worth checking out and it looks like it might fit in the case.

Looks to big for the space. You have about 160mm x 75mm x 35mm (guessing it's higher for rednet 3 - maybe around 60 - 70 mm) in the space where the power supply is now. Doesn't look like enough current for the +15/-15 voltage either (needs 7.A). It's showing .4A for each side in the picture.
 
 In the D16 there's a fairly large empty space at the front, but it has a thin strip of PCB across the width. No idea if it could be cut out or not. It might be there for a reason (not going to take the bottom cover off to have a look). If the space is available (by cutting out that strip), it might be possible to have 2 of the ultra low noise/ripple smps (ie. Diatron or Sanken) power supplies (1 dual output, and 1 single output). The issue there is it would be very tight, and the current is only .5A on the -15 side for the Diatron (HFD30).
 
Probably best to wait for JohnJen to see how he makes out. I can see him having issues with depth and width, using the PowerVolt. I really hope not, but I think it's going to be very tight if he does manage it.
 
I just can't see something happening internally that would make it worth it (D16). The only way would be to do something custom like Wushuliu suggested, but that's way above my grade point. And even at that, I'm not sure any benefits to improving the sound would be worth the effort. I think an external solution would be the only way to make is worthwhile. 

 

[wushuliu]

With all the DIY I have done over the years, a linear power supply always improves upon an smps. Always. Especially digital circuits. It will be absolutely worth it, even if you have to pay someone. When it comes to digital circuits the first areas I look to are power supplies and clocks when it comes to improvements. If I'd have known the RedNet supply could be modded this easily I might have kept mine.

 

[Golfnutz]

  With all the DIY I have done over the years, a linear power supply always improves upon an smps. Always. Especially digital circuits. It will be absolutely worth it, even if you have to pay someone. When it comes to digital circuits the first areas I look to are power supplies and clocks when it comes to improvements. If I'd have known the RedNet supply could be modded this easily I might have kept mine.

Fair enough, but there are other factors as well. Mainly the space available, especially for the D16.
 
Would a custom internal modification (somewhat limited) be as good as an external solution could provide (unlimited)?
 
Would a somewhat limited internal LPS be better than a well designed low noise/ripple smps (internal)?
 
Like I said previously, "I think an external solution would be the only way to make is worthwhile". Of course this would be using LPS.

 

[wushuliu]

Sure external. Whatever works.

 

[Clemmaster]

Do we even need the +-15 and +51 in the Rednet 3? Would it work with just the +5V?

 

[johnjen]

  I was curious about the current myself to see if there was anything suitable for the D16. Doesn't really look like it, at least I couldn't find anything (internal replacement of the FP07M063). Not sure I'm keen to do something externally (have to wait and see how your make out).
 
This PowerVolt model was the ONLY PSU I could find that really even came close to meeting the specs needed.
And I too am not looking forward to having to externalize it.  That would be an additional PIA I'd like to avoid, if at all possible.
 
snip
 
Spec's for your PowerVolt are showing as 10.25" (depth), while the Rednet 3 is only 9.75 (depth)".  You may have a hard time doing something internal, unless you're planning on removing all/part of the casing?

I was kinda figur'n on turning the PSU sideways across the 'front' if it'll fit, but equally as worrying is that 4" dimension, because if it has to be mounted that way, well I'm not sure it'll fit that way either…
 
And the task of finding a suitable external enclosure is equally as daunting, especially if I want to keep it fairly small.
 
And the thing is the smaller PowerVolt triple output PSU seems like it would be small enough but it only has ≈ 1/2 the current output, which may (or not may not) be enough to actually run the RN3.
 
But sadly even that PSU might be to big to fit the D16 since it's a 1U height and it has that same 4" dimension.
 
JJ

 

[johnjen]

Do we even need the +-15 and +51 in the Rednet 3? Would it work with just the +5V?

The ±15vdc is needed for the balanced circuits and I'm figur'n that the +51 is not needed.
 
JJ

 

[Golfnutz]

  The ±15vdc is needed for the balanced circuits and I'm figur'n that the +51 is not needed.
 
JJ

Confirmed via email from tech support ("does not make use of the +51v power rail on the supply").