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JS-2 Power Supply Installed!

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2 hours ago, Superdad said:

I present our BBQ cat

Wow, I just thought of 3 really good jokes ... none of which would be universally well received.


Innuos Zenith SE --> Berkeley Alpha USB --> Jeff Rowland Aeris --> Jeff Rowland 625 S2 --> Focal Utopia 3 Diablos with 2 x Focal Electra SW 1000 BE subs

 

i7-6700K/Windows 10/HDPLEX 200W/HDPLEX 400W DC-ATX --> ISO REGEN/LPS-1.2 --> iFi iDSD Micro --> Focal CMS50's 

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2 hours ago, Superdad said:

I present our BBQ cat

 

Tastes just like chicken.  


 

Analog:  VPI Scoutmaster / Shelter 501MkII, Sony XRD1 HD FM, Nakamichi BX-300  Music Server:  i7-6700K/Asus RTX2080 OC Gaming, HQPlayer

DACs:  dCS Debussy, Lampizator Golden Atlantic, McIntosh D150 / MCT450 CD/SACD

Digital Add-ons:  Uptone JS-2s and LPS-1s, ISO REGENS     NAA:  NUCs (2), SoTM SMS-200 Ultra / tX-USB Ultra / Network Switch Clock Mod

Preamp:  McIntosh C500P (SS)   Amp:  McIntosh MC452

Speakers:  Wilson Yvette    Signal Cables:  Transparent Ultra Gen V    Power Cables:  Shunyata and PS Audio

GIK Room Treatments   PS Audio P10 AC Regenerators (2)  Dedicated 20 AMP AC circuit

 

 

 

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Would any of these additional tweaks help or would they be detrimental to the sound?

 

Stillpoints ERS sheets glued to the inside of the top plate cover?

MuMETAL Magnetic Shielding Foil or a thick steel divider separating the main transformer from the other components?

EAR SD40AL tape on the heatsinks?

Dynamat Xtreme on the transformers & caps?

 

I know over damping can be a negative in some equipment.

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On 3/2/2019 at 12:00 AM, ThenewGearPPK said:

Would any of these additional tweaks help or would they be detrimental to the sound?

 

Stillpoints ERS sheets glued to the inside of the top plate cover?

MuMETAL Magnetic Shielding Foil or a thick steel divider separating the main transformer from the other components?

EAR SD40AL tape on the heatsinks?

Dynamat Xtreme on the transformers & caps?

 

I know over damping can be a negative in some equipment.

 

The R-core transformer in the JS-2 has an extremely minimal magnetic flux field.  The only significant field in the JS-2 comes from its big inductor/choke, mounted on the right-side heatsink.  However, muMetal would be a very poor choice for shielding it as muMetal saturates too easily.  A 6-10mm thick milled aluminum box around the inductor would be very effective, but that would be costly to have made and there really is not enough clearance around the inductor to mount such a box.

 

As for the rest of the tweak ideas you list: I doubt they will do much good, but nor will they do much harm.  

Just be advised that opening the JS-2 and applying tweaks inside will void your warranty.

 

Cheers,

--Alex C.

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I received my JS-2 just a few days ago and use it together with the MMK on a 2012 Mac Mini. I was really torn for some month to decide the upgrade of the Mac with MMK and JS-2 but i am really happy I decided this way. The combination works really unobstrusive in a technical way and the sound quality made a big step ahead. Even if I take in account all the cost and effort, the Mini/MMK/JS-2 delivers an excellent ratio of "money spent / increased SQ". And it gives the full flexibility to change or improve hardware and playersoftware or use any other tweaks. I really like that!

And with the latest upgrade I can suddenly hear all the influences of boot device, storage device and network connection. So another big playground to maximise sound quality in future.

 

Thanks to Alex and all the staff at Uptone Audio for their great work and customer service! It´s been a pleasure!

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Another 13 JS-2 units built and going out the door today--a day earlier than promised!

Now accepting reservations for the next batch of 12 (half of which are already pre-sold)--for shipment by March 28th.

 

(Not to be catty, but it seems we may build and ship more JS-2s in a month or two than some other premium brands build in a year. :D)

 

Many thanks to all who use and enjoy the hand-crafted JS-2.  

I recently realized how conservatively we rate these (we quote it as 5-7 amps).  Had one on the bench the other day running continuous 8.2 amps (!) at 12V (with 120/240V AC mains input; lower AC input lowers max current at 12V). Was not even hot.  

 

726895805_JS-2March13thbakersdozen.thumb.jpg.d30c87ebf5e2b507bbc63ed17da52f25.jpg

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On 3/13/2019 at 2:18 PM, Superdad said:

I recently realized how conservatively we rate these (we quote it as 5-7 amps).  Had one on the bench the other day running continuous 8.2 amps (!) at 12V (with 120/240V AC mains input; lower AC input lowers max current at 12V). Was not even hot.  

 

 

Hi Alex, I'm glad to hear that these units are selling like barely-warm-at-8.2A cakes. :D 

 

Actually I had a serious question set of questions for @JohnSwenson and you. It has to do not with continuous current, but peak current. Can you compare and contrast how a "conventional" LPS like the JS-2 handles very short current peaks vs. the LPS-1.2?

 

What I'm really wondering is how high a current peak can each sustain, given a short enough duration? Can each deliver 2x, 3x, even 10x the sustained current rating, or is there a practical limit where even for an infinitesimally small interval, max current is limited to some value? Is the amount of headroom - let's define this as rated peak/rated continuous - different for the JS-2 vs. the LPS-1.2?

 

Apologies if this has been answered before - a few searches that I were unfruitful.

 

 

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3 hours ago, austinpop said:

Can you compare and contrast how a "conventional" LPS like the JS-2 handles very short current peaks vs. the LPS-1.2?

 

Hi Rajiv:

That's a great question.  And while neither the choke-filtered JS-2 or the bank-alternating UltraCap LPS-1.2 can be considered "conventional," the physics of peak current handling are quite the same for both--other than that the paralleled LT3045 regulators in the LPS-1.2 are faster--and fairly in common with other power supplies.  

 

Yet the actual answer turns out to be far more complex than your simple question would make it seem.  I just got off the phone with @JohnSwenson about it, and I think it took hime 20 minutes to explain to me.  All sorts of factors, not the least of which are the duration of the current-demand spike, the inductance of the cable (lower is better), the capacitance after the regulators (larger can potentially allow for higher current but dramatically slows the supply down), and the peak current limit of the regulators.  

 

I know that is not an answer, just a list of a few of the factors.  The true answer would requite plotted graphs and many hours of measuring for just a subset.

Perhaps John will have some time to elucidate a bit to give folks a better sense of the topic.  But based on what he explained to me, I would be very wary of power supply manufacturer claims of giant peak-current capability.  Believe me, I would love nothing more than to state that the UltraCap LPS-1.2 can handle brief (10-50uSec) peaks of 4A (it might) and that the JS-2 can handle 20A spikes (it might not).

But things are never so simple...9_9

 

 

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2 hours ago, austinpop said:

 

Hi Alex,

 

Thanks for the clarifications. It would help if I knew what I was asking precisely - which I don't!

 

Perhaps part of my confusion comes from a perception that may be incorrect, that the LPS-1.2 has a "cliff" at 1.1A, so that led me to wonder if instantaneous current demands in excess of 1.1A would be tolerated, and if so, by how much.

 

I am starting to feel more and more that an PSU's sound quality can be variable and heavily depends on the operating point (%utilization of rated max) one chooses. While I haven't done any rigorous listening experiments, I think there is some merit to the idea of massively overprovisioning a PSU for its intended application, so you are running at <50%, perhaps even <25% of capacity. Of course, too often we don't have that luxury.

 

I would agree with this 100%. Not because I have any electrical knowledge, but it just makes sense.


“Waste no more time arguing what a good man should be. Be One.” – Marcus Aurelius

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