JS-2 power cables - difference between red/red and red/black connectors?

[Strojo]

My JS-2 was delivered today and I got two different power cables in the box. One had red connectors on both ends and the other had red on one end and black on the other.

 

Anyone know if there is a difference betwen these that I need to be concerned with? One will be powering a Brooklyn, the other a microRendu.

 

Thanks!

[Superdad]

Hi John:

 

Glad your JS-2 arrived safely (they always do as our packaging system is engineered for a moon landing ).

 

The very fine Oyaide Japan DC barrel plugs we use--the only ones in the world that will accept our 15AWG Belden shielded star-quad wire for soldering--are color coded for size by the red or black rings at their tips.

 

The red-ring tip plugs are 5.5mm x 2.5mm, and that is the correct size to match the JS-2's output jacks as well as your Brooklyn DAC, and lots of other higher-current gear such as computers and DACs.

 

The black-ring tip plug is a 5.5mm x 2.1mm, and that is correct for your MicroRendu, a REGEN, and many other low current devices.

 

You will find that the red-tipped, 5.5mm x 2.5mm plugs will fit into a 2.1 jack--just not tightly--and of course the 2.1mm plugs won't fit at all to a 2.5mm jack. That is because the 2.5 and 2.1mm specify the pin size of the jack and the hole size of the plug.

 

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One other tip:

You will notice that there is printing along the length of the grey jacket of the heavy Belden DC cable. In constructing the cables, we tie the shield to DC ground only at one end, and we prefer that you connect that end to the JS-2.

The shield-tied, power supply end is always the left-end of the cable lettering. That is, hold the cable in your hands so that you read the lettering left-to-right, and the plug end in your left had is the one we suggest plugging into your power supply.

Of course you only need to make that distinction for the red>red 2.5>2.5mm cable, as the red>red 2.5>2.1mm cables always have the 2.5mm PS end on the left already.

 

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As long as I am here--and this is our sponsored forum anyway--I'll take the opportunity to point out a couple of unique aspects to the JS-2 design which sometimes get overlooked:

 

My partner, John Swenson, shared--at the bottom of the JS-2 web page--some details regarding the technical design of the JS-2 in comparison to other approaches. (JS-2 Linear Power Supply – UpTone Audio)

Our choke-filtered design has many advantages--and the results are measurable and audible.

 

In addition to those, and aside from the feature differences such as user-selectable output and mains voltages, 5-7 amp capability, quiet R-core transformer, beautiful casework, and highest quality cable and packing system, I would like to point out a couple of VERY important and entirely unique aspects to the design which I often forget to mention and which prove that there are NO linear power supplies on the market which are similar in circuit function to the JS-2.

 

1) The JS-2's DC output ground is entirely isolated from the AC mains and chassis ground (though our transformer and chassis are grounded to the AC mains for safety). With any other LPS, if you put a continuity meter to the DC output ground and the mains wall ground you will get a "beep." So other supplies are giving a path for noise--and for ground loops. We go to a lot of trouble to isolate the output ground--and we know this matters.

 

2) All other power supplies in this market--both SMPS and LPS--kick noise spikes back into the AC mains. Yes, LPS units do so also as their diode bridges are not conducting over the entire AC waveform (only about 50% of time), so they put harmonics back into the line. With the JS-2's choke-filtered design, we are drawing current from the entire waveform (98%). The JS-2 is the ONLY POWER FACTOR CORRECTED LINEAR POWER SUPPLY ON THE MARKET. Thus we do not kick ANY harmonics back into the AC mains. This is a very big deal.

 

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My assistant was very efficient and productive this month (wish I could say the same; I've been rather distracted with the building of our new production space and with listening tests on a new product), and there are now 6 more built JS-2 units on the shelf just waiting for me to perform final QC, torture/thermal burn-in tests on them. They always sell fast, but at the moment 4 of those 6 are not yet committed. Interested parties just need to send a note via our web contact page to ask for one.

 

Thanks and have a great weekend,

 

--Alex C.

[hieukm]

Hi Alex,

 

Just 2 question for you. I have recently receive your JS-2 and the performance is top notch. Which led me to the following questions:

 

- Will the JS-2 benefited from a balanced AC power input?

- Can i purchase a additional red/black power cord from your side?

- Will you make a bigger LPS say(200-300w) in the near future? (I wanted to connect the JS-2 to my mobo using a PicoPSU but failed as my mobo using around 180w at start up)

 

Best regards,

[Keith_W]

- Will you make a bigger LPS say(200-300w) in the near future? (I wanted to connect the JS-2 to my mobo using a PicoPSU but failed as my mobo using around 180w at start up)

 

Alex, this is a very good suggestion. As you know from my email, my single JS-2 is struggling for power when my CPU maxes out. Having a more powerful LPS would help matters a great deal.

[Superdad]

Hi Alex,

 

Just 2 question for you. I have recently receive your JS-2 and the performance is top notch. Which led me to the following questions:

 

- Will the JS-2 benefited from a balanced AC power input?

- Can i purchase a additional red/black power cord from your side?

- Will you make a bigger LPS say(200-300w) in the near future? (I wanted to connect the JS-2 to my mobo using a PicoPSU but failed as my mobo using around 180w at start up)

 

Hello Hieukm:

 

I'll happy to answer your questions in order...

 

a) I don't think the JS-2 particularly benefits from "balanced" power due to the already balanced construction of its R-core transformer. And it is not picky about power cords (though we recommend a shielded one such as the heavy wire gauge cord we ship with it). A lot of that has to do with the choke-filtered design (making JS-2 the only power factor corrected LPS--it draws from the entire AC waveform thus not generating harmonics back into the mains) and with the RC snubber on the secondary that kills trans ringing--both reducing need for the filtering effect of a fancy power cord (we think special power cords are mostly about filtering what gets kicked back into the power line--not much about delivering "better" power to the component; though in the case of a big power amp it is good to have a cord at least equal to your house wall wire gauge).

 

b) Yes, you can purchase another of our Oyaide/Belden shielded, star-quad, 15AWG DC cables. They are $75, always 5-feet (1.5m) long. Just send a note via e-mail or the contact form on our site.

For others reading, the reference above to red/black refers to the tip rings of the Oyaide plugs (chosen because they are well made and the ONLY DC barrel plug that will accept our big wire). Red rings are 5.5mm x 2.5mm size and black ring is the 5.5mm x 2.1mm size. The JS-2's DC output jacks are 5.5mm x 2.5mm, so one end of the cable is always that size--the choice is at the other end (actually, we do also have a few on the shelf with 2.1mm plugs at both ends; don't think we will see much call for them until I finally put up an order page for our Oyaide/Belden cable).

 

c) Will we make a 200-300 watt LPS in the near future? Absolutely not. Maybe someday. But considering all the factors and cost, it would more likely be a big, expensive UltraCap supply rather than a big, expensive choke-filtered supply. Remember, 250 watts at 12 volts is almost 21 amps! To do that continuos would require a very large transformer and a VERY large choke, plus moving to a regulator with large output transistor design. Would be about a 35 pound LPS.

 

As Keith_W knows, there are other ways to approach this. And as mentioned, we long ago (at the beginning of the little UltraCap LPS-1 development cycle) internally sketched out the design for a really big, 4 output, high-amperage Ultracap supply (code name Dominator), but I am not sure about the market size for a $3,000 DC power supply. Might happen some day, but the initial capital cost for a proper run is not chump change (don't have a free $75K to prototype and do a 50 unit run right now; it all got dumped into our new production space... ).

 

Best,

--Alex C.