wushuliu
100+ Head-Fier
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I suspect an important ingredient to the JS-2 is the choke filter, which the HDPlex does not have...
I suspect an important ingredient to the JS-2 is the choke filter, which the HDPlex does not have...
I agree. Typically a choke of this type is 50 bucks. Where has the 3 times the price gone?
I suspect an important ingredient to the JS-2 is the choke filter, which the HDPlex does not have...
All diode types except Schottkys emit a burst of ultrasonic noise as they turn off. This noise can go forward into the load circuit AND it can go back into the AC line, and it can also excite the transformer resonance. The "slow" diodes still have this ultrasonic noise. Schottkys are the only type which do not have this noise. Schottkys also usually have about half the voltage drop of other diode types and are usually faster. Which type to use depends a lot on what your supply looks like and what you are trying to optimize for.
With a traditional low voltage design with a large cap right after a bridge you get large current spikes, these produce a large amount of high frequency noise which needs to be filtered by what comes after the cap. In this type of circuit the slow diodes can help cut down on the extent of the high frequencies generated by the sharp high current pulse. BUT they still generate the ultrasonic noise.
This is another reason why we like to use the choke-based design. With the choke there is no steep high current pulse, so no disadvantage to Schottky diodes. You get the advantage of no ultrasonic noise, lower voltage drop (so lower power consumption in the diode) and no big massive current pulses.
Well a man's gotta eat.
I think theres an early version js power supply schematic somewhere at diyaudio, so you can build something close for a fraction. That said it's an embarrassment of riches on ebay for audio anything. I'd take any of the mentioned offerings over an smps even the ipower which i consider overrated.
On a separate note, but still about transformers: R-cores don't seem to hum at all. Because of the way the cores themselves are wound, there is virtually no magnetic excitation. Check out this explanation of how the cores are made:Of course R-cores have all sorts of other advantages as well. But even at wholesale from China, they cost about twice what a decent toroid costs, and at least three times a cheap toroid. I know, because I have 25 custom 100VA R-cores en route from China right now. I compared it in my forthcomingJS-2--versus a good 100VA toroid. In fact, this comparison took place with John Swenson here at may place just this afternoon. We went back and forth between the toroid prototype and the R-core in a pre-production chassis I finished assembling last week.We were hoping that my decision to spring for the R-core would prove worthwhile. Wow, did it ever! For my Mac mini it made the bass even more solid and detailed--R-core versus toroid. We were both surprised at how obvious it was (well my system does very good bass). But the knock our socks off moment came when doing the same switch with theJS-2 powering (at 5V) a pre-production BottleHeadDACboard that John had brought along for tests. The effect on clarity and detail (oh, I'm a very unimaginative writer about what I hear) with the R-core was on much more than just the bass. It was a cymbal to vocal to piano to upright bass and horns attack improvement. I am REALLY happy about this as I now feel that the supply could find a even wider market that for computers, drives, and headphone amps. Not that there are that many top-flight DACs that take just a single-ended (+DC) supply.Here are some pics to show what were were doing (click pics for larger version; also, my production R-cores will have the pretty copper electrostatic shield--and some fancy labels I am making):
I agree. Typically a choke of this type is 50 bucks. Where has the 3 times the price gone?
If you are referring to the $925 5-7 amp JS-2 versus the $395 HD-Plex then your multiplication math is a bit off.
And our parts cost (including chassis, packaging, cables, etc.) for the JS-2 is $350. Not including labor, intense QC, support, $50 royalty to my partner J.Swenson, or the PayPal fees we cover for buyers. Or the proven performance as reported by the 300+ owners.
But I admit the HDPlex and many other Chinese supplies are very good values. There is room--and demand--in the market for the whole spectrum.![]()
--Alex C.
Alex - big fan here! You guys deserve every penny. Just wish I could afford one!
Thanks Rob! (I do think there is an UltraCap LPS-1 somewhere in your future though.Once you start experiencing the benefits of breaking "leakage loops" you are going to get excited again. Actually, I think a good portion of what you are hearing that you like with Ethernet components you are using has to do with Ethernet's isolation from the computer end of things.)![]()
Ciao,
AJC
Agreed! I need 9VDC for the Recovery - so no go for the LPS-1. My budget allows $200 max right now for audio gear - wife has put her foot down!
Oh, there are now lots of Recovery users powering it with an LPS-1. From Wyred4Sound's Recovery spec page:
"DC tested safe range: Rev A, 6.5v - 12v; Rev B, 6v - 9v"
But I do fully understand shrinking budgets. I was planning a toy for myself--until I saw our daughter's UCLA tuition bill, compounded with our son at Sacramento State (don't let anyone try to tell you that state college cost is a fraction of a university--it isn't!).![]()
Thanks. I have that Zerozone board earmarked for the PART 5 DIY LPS's. I ordered a MEIYAN, so that'll free up my Breeze LPS for a regulator board swap, first will be the LT3042 0.8uv LDO.Chinese manufacturer ZEROZONE ofer also relatively cheap LPS based on bipolar transistors Toshiba 2SC5200
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LPS board:
http://www.ebay.com/itm/ZEROZONE-Assembled-Ultra-Low-Noise-linear-Power-supply-board-LPS-board-/121760253760
Standard version:
https://pl.aliexpress.com/item/Finished-100VA-Ultra-Low-Noise-linear-Power-supply-ouptut-9v-12v-19v-24v-etc/32468835174.html?isOrigTitle=true&isOrig=true#extend!
Upgraded version:
https://pl.aliexpress.com/item/ZEROZONE-100VA100W-HIFI-Linear-Power-supply-DC-21V-TOP-LPS-for-amp-DAC-PC-sn/32516869764.html?detailNewVersion=&categoryId=63701
Any idea on the noise levels on that Toshiba NPN config? It looks similar to the new TeraDak DC30W.
No, all looks enigmatic, especially the chip in the middle, you will need to ask the chinese seller,
I think about purchase LPS offered by MEIYAN (based on project Sigma 11) to feed my DAC Mytek Brooklyn,
this solution has already been checked by one owner - heard a significant difference,