Hi LC. The shielding is active using wallwart transformer. My worry is active shielding did do some major damage to my CJ350 in the past so i am not so brave to do that😀.
Quan
OK, understood.
But then shielding is not of any use since producer provided it to be active all the way. Why not to disable the shielding completely then by removing it or shorten it into complete isolation from main conductors inside the cable. Is there any schematic of this active shielding cable somewhere on the net?
That's a sad story and hard learning with those burned output devices, understand your caution.
... you soon can play your favorite speakers/cable. CM shown very good functionality and sound reports at the different VSSA threads, maybe save some time and try that first if you have it at hand. Good soldering.Edit: Post 1 says supply voltage +/-40 V to +/-63 V guess you inside spec.
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maybe a thread to disquass it without getting out of topic?i would be interested for some info.
I decided to give-it up with endless fights and boring argues, but:
http://www.diyaudio.com/forums/mult...ductance-mpedance-correction-loudspeaker.html
Hi LC- see below -from SR website re active shielding:
We then experimented with closed circuits, where the shield carried a DC current, with a buffer circuit between shield and ground and separate conductors carrying the ground signal. This closed circuit design not only improved subjective performance, but also made our cables measureably quieter, thus improving detail with greater frequency extension from top to bottom. Since a closed circuit draws current, we could no longer use batteries, as this would drain a battery in a matter of hours.Precision-Ref-Speaker
TESLA LE Precision Reference Speaker Cables combine two high current Tricon geometries, two high current TESLA LE Acoustic Reference geometries, Zero Capacitance Active Shielding, and Quantum Tunneling, for linear detail, speed, and warmth. As with the TESLA LE Precision Reference Interconnect, this cable has a unique ability to reveal an amazing level of inner detail with harmonic structure, due to it’s twin runs of both Tricon and Acoustic geometries. Compared to TESLA LE Acoustic Reference Speaker Cables, TESLA LE Precision Reference presents music that is faster, with enhanced pin-point imaging, and air that extends beyond the boundaries of your listening room. This is the perfect speaker cable for high end tube systems, as it enables music and soundstaging detail without emphasizing or detracting form your systems mid-range bloom and warmth. In high end solid state systems, TESLA LE Precision Reference Speaker Cable presents low frequency control and speed, a holographic sound stage, and transparent frequency extension that makes other detailed speaker cables sound analytical and thin by comparison. Available in silver spade or gold BFA banana terminations, and IFT Bi-Wire.
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I had a look to their web site.
"Active Shielding: Zero Capacitance Apex Active Shielding is the ultimate in detail and transparency, with four active geometries for mid-range warmth, liquidity, and three dimensionality of soundstage."
It is affraying.
About speaker's cables, i use to quote a sentence of Peter Walker, asked by a customer about the cables he recommended for his amplifiers:
"I tend to prefer the ones witch conduct electricity."
Just my two cents if you read my lips.
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Hi quan,
I would try to replace the cables, as you confirmed in the same setup the amp worked fine with other speakers. Just use some usual speaker cables as a test. I understand it's frustrating, but if you do not will to use actual cables as built (and understandable why...) then they have no use at all, IMHO.
Cheers!
I would try to replace the cables, as you confirmed in the same setup the amp worked fine with other speakers. Just use some usual speaker cables as a test. I understand it's frustrating, but if you do not will to use actual cables as built (and understandable why...) then they have no use at all, IMHO.
Cheers!
Member Hose4 has mono SMPS and no hum or his whatsoever.
Very funny 🙂
The reason for the hum is the unavoidable ground loop when a shared supply stereo amp is fed from a common ground stereo source. It is the circulating ground currents from the PS centre point that get fed into the amp clean input ground and cause the issue. With a SMPS these currents are of such high frequency that even if a ground loop exists, the problem won't be audible as hum.
I realise that each and every case of ground loop hum is individual and dependent upon the particular components - transformer symmetry, cap capacitance and ESR and (probably) amp CMRR. Using dual rectifiers may help - should probably try it.
Grounds connected together at the PS and subsequently connected again inside the source - what else would you call that but "unavoidable"?
Can't you imagine star ?
I believe the hum problem is not the one of ground loops, but currents between references points. RFI EMi is an other thing.
Even with two PSU, you'll have such currents (and loop with AC) across them, because parasitic capacitances in the big transfos.
One of the benefit of the SMPS, on my opinion is the parasitic capacitances between ground (or earth) are reduced because trasfo are more efficient, less volumic, so have less surface between primary and secondary coils.
I don't agree with what you said about hum VS EMI RFI with SMPS: The Hypex is not regulated, so the AC ripple is not reduced more than with a linear PSU.
ps: i can't hear any hum in my system. But, yes, it was a fight.
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LC wrote on 9 May 2014:
"Also DC sense error circuit to shutdown SMPS1200A400 in a case of DC potential failure on the First One output will be presented.
Stay tuned "
What's the status of this DC sense error circuit?
Regards,
John
"Also DC sense error circuit to shutdown SMPS1200A400 in a case of DC potential failure on the First One output will be presented.
Stay tuned "
What's the status of this DC sense error circuit?
Regards,
John
Just got the SMPS 🙂
I went for the regulated supply, because it measures very good.
Next week I'll know how it sounds in my system 🙂 if it is better than my F5 (Fairchild, CLC PS) on all areas I'll be very happy.
I'm pretty sure that bass will be better with the FO + SMPS, but the big challenge will be soundstage if it can match or surpass the F5.
Tried to find the best layout for my case, I think this one it will be, it's easy with a big case 🙂
I'll add also a soft start with temperature control, the main reason is that my nice looking switch can't handle the current so it will done by the relais of the soft start.
As speaker protection I'll add something based on the uPC123, simple and works good.
OK, time to drill some holes 🙂
I went for the regulated supply, because it measures very good.
Next week I'll know how it sounds in my system 🙂 if it is better than my F5 (Fairchild, CLC PS) on all areas I'll be very happy.
I'm pretty sure that bass will be better with the FO + SMPS, but the big challenge will be soundstage if it can match or surpass the F5.
Tried to find the best layout for my case, I think this one it will be, it's easy with a big case 🙂
I'll add also a soft start with temperature control, the main reason is that my nice looking switch can't handle the current so it will done by the relais of the soft start.
As speaker protection I'll add something based on the uPC123, simple and works good.
OK, time to drill some holes 🙂
Attachments
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Nice & big casing you have. I am still waiting for mine 😀.
For power supply layout, it will be good if they place 180 degree from each others and by facing DSP aluminum heatsink to first one can help to reduce EMI. 🙂
James
Hi James,
I think I'll add an alu L-profile (40mm) on the other side, so both sides of the SMPS will be shielded, this way I can keep the AC connectors close to the switch.
I think I'll add an alu L-profile (40mm) on the other side, so both sides of the SMPS will be shielded, this way I can keep the AC connectors close to the switch.
Hi John
DC sense PCB-s in production, available from this week on. These will sense DC voltage on output terminals and send a signal to shutdown SMPS1200A400 or any other PSU.
Regards, L.C.
