The VR MINI Ultracapacitor Power Supply Thread

[Vinnie Rossi]

All,

 

Welcome the to VR MINI general discussion thread!

 

Last month we began shipping the VR MINI. Here is a link to the MINI page: Vinnie Rossi MINI PURE DC-4-EVR Power Supply

 

 

http://www.vinnierossi.com/mini/

 

Please let me know if you have any questions.

 

Thank you,

 

Vinnie

[mozes]

Hi Vinnie

I am currently enjoying my MINI with my Brooklyn DAC, it never sounded better. My question is why don't you make a variable voltage so the customer can select the voltage depending on the device to be powered by the MINI? Is it cost or performance related?

Thanks

Moussa

 

Sent from my X98 Plus II (C2D6) using Computer Audiophile mobile app

[Vinnie Rossi]

moussaobeid said:

Hi Vinnie

I am currently enjoying my MINI with my Brooklyn DAC, it never sounded better.

Hi Moussa,

 

AWESOME - thank you for posting your impressions of the MINI feeding your Brooklyn dac!

 

 

Quote

My question is why don't you make a variable voltage so the customer can select the voltage depending on the device to be powered by the MINI? Is it cost or performance related?

 

Excellent question! There are mainly two reasons why I did not make the voltage on the MINIuser adjustable:

 

Brian Lowe at Belleson ran various tests and determined at the noise performance of the SPVR-X was not as good with an adjustable implementation. This was because adding switches (or a potentiometer) increased the trace lengths and degraded the quality of his patented super regulator design. Nothing performed better than a high quality, fixed resistor directly on the SPVR-X regulator board - where the circuit path of the regulator is just a few mm long instead of a few cm long. It makes a big difference when you are dealing with this level of low noise.

 

Best regards,

 

Vinnie

[mozes]

 

Thanks Vinnie for your detailed and informative answer as usual! So let it be fixed voltage then

 

 

Sent from my iPhone using Computer Audiophile

[Duke40]

Just placed an order for a 19V MINI for my Auralic Gemini 2000 DAC/Headamp.

(Higher voltage MINI's in the 15 to 24 Vdc range are now available to be ordered).

 

Already have a 12V MINI from Vinnie Rossi, for my Auralic Aries and I am pleased with the performance improvement, so really look forward to the 19V MINI arriving.

My headphone rig will then be totally "off-grid", isolated from the AC mains.

[jtwrace]

Just placed an order for a 19V MINI for my Auralic Gemini 2000 DAC/Headamp.

(Higher voltage MINI's in the 15 to 24 Vdc range are now available to be ordered).

 

Already have a 12V MINI from Vinnie Rossi, for my Auralic Aries and I am pleased with the performance improvement, so really look forward to the 19V MINI arriving.

My headphone rig will then be totally "off-grid", isolated from the AC mains.

 

That should be stellar! I have my Gemini 2000 sitting in the closet somewhere. Thanks for the reminder. lol

[Vinnie Rossi]

Duke40 said:

Just placed an order for a 19V MINI for my Auralic Gemini 2000 DAC/Headamp.

(Higher voltage MINI's in the 15 to 24 Vdc range are now available to be ordered).

Already have a 12V MINI from Vinnie Rossi, for my Auralic Aries and I am pleased with the performance improvement, so really look forward to the 19V MINI arriving.

My headphone rig will then be totally "off-grid", isolated from the AC mains.

 

Hi Duke,

 

Thank you for your post!

 

 

Vinnie

[Vinnie Rossi]

Quote

Special pre-order price of $1095 until the end of this month. Then the regular price will be $1295.

 

All,

 

Just a reminder that the pre-order pricing for the 15 - 24Vdc VR MINI power supply ends this Friday, March 31st.
We've been building away and have all parts in stock.  Current lead time is within 2 weeks.

http://www.vinnierossi.com/mini/

Best regards,

Vinnie

[Duke40]

Hi Vinnie,

 

The 19V VR MINI arrived (very well packed for shipping) and I'm very pleased with the performance improvement.

I now have my headphone rig completely isolated from AC without needing any fancy audiophile power cords or power conditioning like isolation transformers/balanced power supplies.

I am now able to lower the volume a bit further when I listen to music (the details still come thru).

More clarity. Oh, Micro-dynamics improved as well.

Rather than dissect & analyse the music too much using audiophile terminology, one of the best tests I use with new gear/tweaks is ... how long do I actually listen to music. That is, if listening time increase, then it is more fatigue free. My listening sessions have increased in length, so it is a winner.  

 

On the back of my 19V VR MINI power supply, between the heatsink and the IEC ac input, is a silver thread and nut.   Is this some sort of grounding post, or does it fulfil another purpose ?

 

On my 12V VR MINI, it is absent.  Just curious of its purpose.  Thanks.

 

John

[Vinnie Rossi]

Hi John,

 

Many thanks for your post! 

 

This thread on the Vinnie Rossi forum (Audiocircle) was also posted about the 24V MINI:

http://www.audiocircle.com/index.php?topic=148925.0

 

Quote

On the back of my 19V VR MINI power supply, between the heatsink and the IEC ac input, is a silver thread and nut.   Is this some sort of grounding post, or does it fulfil another purpose ?

 

 

Yes, it connects to earth ground (3rd prong of the power cord) - just in case someone is using it with a phonostage or equipment that is connected to other non-isolated equipment that is picking up hum. 

 

Enjoy it!

 

Vinnie

 

 

[flkin]

Hi Vinnie,

 

Any chance you can add a variable DC voltage that is user switchable to the Mini? For overseas users it's simply too difficult to ship back to you for voltage adjustments from time to time not the mention the costs of doing so.

 

Thanks, Kin, Thailand

[Vinnie Rossi]

Hi Kin,

 

Brian from Belleson has tested the custom Belleson  super-regulator that we use for the output of the VR MINI,

and confirmed that when a switch (or variable resistor) is used to allow for voltage adjustment, the is always a

noise penalty associated with it. 

 

I decided that added noise penalty would take away from the VR MINI's competitive advantage over all other power supplies in its voltage/power range, so I will not be offering it.

 

Thank you for your understanding,

 

Vinnie

[sgr]

Hi Vinie,

 

Do you think the Mini could power the Legacy Audio WaVelet?

It is a preamp, DAC, crossover, and DSP and it controls my Legacy V speakers. 

 

Here re are the specs:

 

 

    115V AC input Detachable cord

        Compatible 115-220V inpuT

        12.83V minimum,13.68V (Bill: please confirm this still works for Wavelet)

        5-Amp minimum

        60 Watt minimum

        Black case

 

Thanks,

steven

[Vinnie Rossi]

1 minute ago, sgr said:

Hi Vinie,

 

Do you think the Mini could power the Legacy Audio WaVelet?

It is a preamp, DAC, crossover, and DSP and it controls my Legacy V speakers. 

 

Here re are the specs:

 

 

    115V AC input Detachable cord

        Compatible 115-220V inpuT

        12.83V minimum,13.68V (Bill: please confirm this still works for Wavelet)

        5-Amp minimum

        60 Watt minimum

        Black case

 

Thanks,

steven

Hi Steven,

The VR MINI has a max continous output current rating of 2.5A.  It looks ike your product requires at least 5A, so it will not do the trick.

 

Best regards,

 

Vinnie

[agladstone]

On 1/4/2017 at 0:20 AM, mozes said:

Hi Vinnie

I am currently enjoying my MINI with my Brooklyn DAC, it never sounded better. My question is why don't you make a variable voltage so the customer can select the voltage depending on the device to be powered by the MINI? Is it cost or performance related?

Thanks

Moussa

 

Sent from my X98 Plus II (C2D6) using Computer Audiophile mobile app

@mozes how is the mini performing with the Brooklyn? I see that you're using it tonpower the Brooklyn. On paper, it seems that the 2.5A output is lower than what Mytek recommends? 

What other power supplies have you tried and how does the Mini compare to them in regards to sound quality? 

[mozes]

1 hour ago, agladstone said:

@mozes how is the mini performing with the Brooklyn? I see that you're using it tonpower the Brooklyn. On paper, it seems that the 2.5A output is lower than what Mytek recommends? 

What other power supplies have you tried and how does the Mini compare to them in regards to sound quality? 

The VR mini is the best PSU I tried on my Brooklyn. It is better than the JS-2 that I had before. The Brooklyn doesn't need a lot of juice as the VR is never even warm. I don't use the headphone amp btw.

[agladstone]

@mozes Thank You!! 

Ive actually been considering upgrading from my current HDPlex 100w to the JS-2! 

I just stumbled upon your post here about using the Mini (I had thought the Mini did not have enough amperage to drive the Brooklyn, so I did not even realize it was an option)! 

It seems within the same general price range as the JS-2 and I'm enjoying the LPS-1 so

much with the ISO Regen, so it makes sense that the Mini (which has similar technology as LPS-1) would be the best choice for the Brooklyn! 

 

[agladstone]

@mozes Another question, what are you using as a DC power cable between the Mini and The Brooklyn? I have a star quad Canare 4S6 w/ oyiade connectors that was custom made between the Brooklyn and the HDPlex 100 now, could I just remove one end and either use bare wires into the mini banana / spade connectors or even use screw on speaker banana or spade terminals on the mini end, or should I have another custom Canare D.C. Cable made with spades on one end ? 

[sefischer1]

Hi Vinnie,

 

I obtained a 12V unit from you for use with a Nagra VPS phono stage. I've tried the Nagra supply, paralleled 12V 6000mAH Li-Ion battery packs, and now your supply.  Unexpectedly, the Li-Ion battery pack results in a much less detailed, comparatively warm sound quality.  Your supply results in a complete lack of low-frequency noise compared to the Nagra supply. I suspect that the output impedance of your supply is much lower than the Li-Ion battery pak and this may cause some interaction with the Nagra's internal voltage stepup circuitry.  Any thoughts?

 

I'm curious, with a 12V .6A load, how often will the VR Mini need to transition between the internal banks and is the AC line isolation mechanical or electrical? 

 

 

[esldude]

https://www.audiosciencereview.com/forum/index.php?threads/vinnie-rossi-ultracapacitor-power-supply-review-and-comparison-to-uptone-lps-1.1853/

 

Some good independent information on the Vini supply.  

[Vinnie Rossi]

Hi sefischer1,
I'm not sure if the 12V, 6000mAH Li-ion pack you were using has an output regulator or not? 

If it was just a battery pack w/o output regulator, be careful because the starting voltage will probably be > 12V and the shut off voltage will probably be < 12V.  I'm not sure if the Nagra VPS is ok with this.

 

If the battery pack has an output regulator that follows it, is it a switching regulator or linear regulator?

Your VR MINI uses a 12V, linear, Belleson Super-Regulator.  See:
https://www.belleson.com/store/SPZ-High-Current

It not only might be cleaner, but it could have a lower output impedance over a wider frequency range compared

to what you were using.

As far as timing between bank switching, I would need to time it with a 0.6A load.  I would think it would be

>10 seconds between switching banks, but would need to verify.


Regarding the link that esldude points to:

 

Yes, the AC live goes through the transformer (but the transformer is just in series, just like an inductor), before going to the SMPS charging supply, which then feeds a linear current regulator on the board above it that provides constant current charging to the two ultrcacap banks on that board, which then feed the linear Belleson super-regulator on the output side, and then to the output jacks.

Initially, the large transformer inside was to be used as a step-down, but with the first small batch of supplies some customers were finding them to be mechanically loud, in terms of hum/buzz (I didn't have this issue on my bench when we tested them before shipping, so I think they were sensitive to noise/harmonics on the AC line in some homes).  So now you can't think of it as a step-down transformer.

 

I am aware of Amir and his post on ASR forum.  I've spoken direclty to him about it.   Even with the very small amount of AC leakage via the SMPS charger, the DC output is very clean.  The worst is -115dB at 60Hz (this is only about 20uV at 60Hz for the 12Vdc output.  At higher frequencies, the output is better than -126dB.  That's noise... not a measurement of output impedance vs. frequency.

There have been articles written about the AC leakage via the small Y-caps in a SMPS.  Again, its very low (about 20uV), but it is common-mode and the Belleson will not filter it, and it does creep base the bank switching MOSFETs in the mini.

You'll find on the Uptone forum (regarding their LPS-1 and its SMPS charger) a suggestion by John Swenson to Earth Ground the DC output (-) terminal, thus shunting any SMPS leakage to GND.  You can also try this with the MINI, but it could cause a ground loop with your other equipment. 

 

But can you even notice the 20uV of noise?  Not sure what the SNR of your gear is, so I don't want to speculate yes or no.

The important thing to note is that the VR MINI's 12Vdc output is very clean over a wide freq. range, as is load regulation and output impedance (specs are on the Belleson website).  

 

Quote

Your supply results in a complete lack of low-frequency noise compared to the Nagra supply. I suspect that the output impedance of your supply is much lower than the Li-Ion battery pak and this may cause some interaction with the Nagra's internal voltage stepup circuitry.  Any thoughts?

Glad to hear - it sounds like it is doing what it is meant to do then!

Thank you for your post,

Vinnie
 

[Vinnie Rossi]

*

[sefischer1]

Vinnie

 

I understand from your comments that the SMPS is driving the constant current source used to charge the bank. This implies that the other bank is disconnected (via MOSFET switch I assume) while delivering voltage to the output.   

 

Does this mean that the small AC leakage results from RC coupling between the charging and supplying banks, such coupling resulting from proximity and finite MOS switch open resistance?

[Vinnie Rossi]

Hi sefischer1,
 

Quote

I understand from your comments that the SMPS is driving the constant current source used to charge the bank. This implies that the other bank is disconnected (via MOSFET switch I assume) while delivering voltage to the output.   

 

Correct, the bank in use (not the one that is charging) is disconnected via the MOSFET switches.

 

Quote

Does this mean that the small AC leakage results from RC coupling between the charging and supplying banks, such coupling resulting from proximity and finite MOS switch open resistance?

The AC leakage current comes from the Y-caps used inside the charging supply.  It gets coupled onto the DC output as common mode noise, and a very small amount of it even leaks through the MOSFET switches because a MOSFET is not a perfect switch in that there are still internal capacitances and resistances between its 3 terminals. 

So instead of getting something like -126dB (or better) across the entire band from 0Hz to > 100kHz, there is the AC leakage that shows at 60Hz (or 50hz, depending on where you live) at around -115dB (which is about 20 microvolt of noise per 12V output.  Again, very, very little, but noted), and less of it at harmonics of 50 or 60Hz.   So it is a very quiet supply, and other parameters such as output impedance vs. frequency are not affected, (but are also very important, as audio equipment is rarely acts as a constant-current DC load because the DC current drawn can change over time, even very briefly, and the power supply needs to be able to cope with this).

 

Best regards,

 

Vinnie