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Old 4th June 2014, 09:41 PM   #1001
quan is offline quan  Australia
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Originally Posted by Lazy Cat View Post
Cables with active shielding are then the reason of tickling sound, maybe they needs the battery to be connected.
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
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Old 4th June 2014, 09:49 PM   #1002
Lazy Cat is online now Lazy Cat  Slovenia
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Quote:
Originally Posted by quan View Post
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?
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Old 4th June 2014, 10:16 PM   #1003
BYRTT is offline BYRTT  Denmark
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First One - mosfet amplifier module
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Originally Posted by quan View Post
I am a bit reluctant to do that. I used to have Conrad Johnson amp 350 and the active shielding took out the whole output transistors so since then shielding is not used any more with any amps.

Thanks Byrtt. I will take out the bypass caps to see if it is making any difference. I may even try Cap multiplier supply instead to see if the problem goes away.
Quan
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.

Last edited by BYRTT; 4th June 2014 at 10:28 PM.
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Old 4th June 2014, 10:46 PM   #1004
back is offline back  Greece
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Originally Posted by Esperado View Post
Hi, Pinnocchio, I'm afraid it is out of topic here.

Just a serial RLC network to compensate the resonnance of the speakers at its resonnance frequency in free air, and a zobel for the upper part of the spectrum. both connected parallel to the speaker coils.
Target is to have a *flat impedance* curve with value equal to the DC resistance of the coil.

An example here: http://www.esperado.fr/images/temp/a...ll_filterj.gif where Zobel is red, and 'motional compensation' (or resonance) is green. Here, the zobel and the filter's capacitance of the boomer were mixed in a simple 47F value. And the medium/high frequencies driver has a more sophisticated zobel to be flat up to >40Khz.

Of course, passive filters have to be calculated or modified with this flat charge, but is is much simpler. Keep them with the speakers, even with active filters.

You'll never believe the improvement, and, as said BYRTT will never live any more without. !
maybe a thread to disquass it without getting out of topic?i would be interested for some info.
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Old 4th June 2014, 11:26 PM   #1005
Esperado is offline Esperado  France
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Originally Posted by back View Post
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:
Motional and inductance mpedance correction of loudspeaker
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Old 5th June 2014, 01:59 AM   #1006
quan is offline quan  Australia
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Originally Posted by Lazy Cat View Post
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?
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.

Last edited by quan; 5th June 2014 at 02:01 AM.
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Old 5th June 2014, 02:58 AM   #1007
Esperado is offline Esperado  France
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Originally Posted by quan View Post
Hi LC- see below -from SR website re active shielding:....
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.

Last edited by Esperado; 5th June 2014 at 03:17 AM.
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Old 5th June 2014, 04:48 AM   #1008
quan is offline quan  Australia
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Quote:
Originally Posted by Esperado View Post
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.
Yeah , i know
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Old 5th June 2014, 08:02 AM   #1009
metallicus69 is offline metallicus69  Netherlands
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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!
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Old 5th June 2014, 08:36 AM   #1010
analog_sa is offline analog_sa  Europe
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First One - mosfet amplifier module
Quote:
Originally Posted by Lazy Cat View Post
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.
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