Will an Isolation Transformer Help My Digital?
The ARC CD3, at least in its first version, had a specified power consumption of 40W max. I would think it very unlikely that the power consumption of the Mkii version is much higher than that. The wall wart for the QuteHD DAC is described at the Chord site as: 12v 1A 2.1mm connector. Centre point positive 100V- 240V – 50/60Hz, 1A wall adapter suppliedI seriously doubt that it actually draws anything close to 1 amp at 120V (which would be approximately 120 watts) to be able to supply 1 amp at 12V (which would be approximately 12 watts). And the 1 amp output is presumably its max output rating, and what would be drawn by the DAC is undoubtedly a good deal less than that. And correspondingly the AC current drawn by the wall wart would be considerably less than it would draw when required to supply 1 amp at its output. So it’s probably very safe to assume that the AC drawn by the DAC + CDP is less than 100 watts. A 500W transformer would therefore provide a margin of more than 5x, which certainly seems comfortable. Intuitively I would start to feel uncomfortable at less than 3x. If you go to a linear supply for the DAC, though, before finalizing a selection be sure to assess its current draw or power consumption, as it will most likely be a good deal more than the wall wart’s. One thing I don’t understand is why some iso xfmr’s are rated in watts and some are rated in amps.Just a different way of specifying things. For a resistive load watts = volts x amps. So you’ll note that it says in the description of the Tripp-Lite Isolator: Supports combined loads up to 500 watts continuous/4.2A at 120V.4.2 amps x 120 volts = 504 volt-amps, which for a resistive load = 504 watts. Best regards, -- Al |
Thanks to all. And thank you, Al for finding the acoustic noise spec. That unit would need to placed in a separate room. And I knew that it was not a new item, but did not notice the wear and tear on the PC. One thing I don't understand is why some iso xfmr's are rated in watts and some are rated in amps. What size would I need for my 2 digital components...500 watts? Again, I'll refer to the Tripp-Lite... http://www.tripplite.com/isolation-transformer-based-power-conditioner-500w-line-noise-reduction-spi... |
Lak makes a good point about acoustic noise being a potential concern with the Topaz isolation transformer or other comparable devices. I couldn’t find meaningful data on the Topaz model 91095-22 linked to above, but I found this datasheet covering the model 91095-32T, among others, which appears likely to be fairly similar. The spec listed for acoustic noise is "less than 50 db measured at 3 feet from the noise suppressor." Ouch, unless "less than" is actually "a lot less than." I also note, btw, that the particular listing for the 91095-22 indicates "open box," perhaps indicating that the device was previously purchased and then returned, or was obtained by the seller from a previous user. And in fact despite the indication of "unused" in the listing the power cord pretty clearly shows signs of use, and even a bit of damage, when the photo in which it appears is expanded. Best regards, --Al |
Lowrider57, Just remember that if your isolation transformer is going to be located in your listening room, it will generate some heat and some noise (hum). For example, my isolation transformer does run warm to the touch (96 degrees F and produce 55 dB of sound with the reading taken within one inch of the transformers). The noise and generated heat doesn't bother me because the power filtration system is located in a different room. Depending on the size of the isolation transformer, the heat and noise level will vary, however you never know what’s going to happen (noise, heat and filtration wise) until you try it. |
@ptss, thanks! What size would you recommend for use with an ARC CD and a small DAC? I have seen xfmr's rated in watts; shouldn't they be rated in amps? Also, is this Topaz good enough for high-end audio? http://www.ebay.com/itm/191842008876?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT |
@ptss, since there's no budget to change my power conditioning or convert to balanced power, have you ever used an isolation xfmr on upstream components? @lak, Thanks for setting me straight. So you are benefiting by using a CPT PC into a power strip. In my situation, if only the digital was in the CPT/power strip chain, IYO, would that isolate these devices? IOW, no noise bleeding back into the mains? My preamp would need to be on a separate line. (And the Tripp-lite Isobar was a major disappointment. Not at all as advertised). |
Have not reviewed all posts however my experience with Tripplite Isobar Ultra 8 is that it is not suitable for hi-end use due to power constriction and noise. Dampens dynamics. I use three to isolate other digital, non hi-fi items, from the mains power and provide surge protection. I have been extremely pleased my Equitech 2Q and Sound Application units. |
Lowrider57, No, all your equipment doesn't need to have a CPT power cord. I have not done a good job of updating my two systems on Audiogon, sorry about that, I'll have to soon. Anyway, in my second system I have a CT GE high current power cord on my integrated amp and a CPT 300 power cord feeding a power strip that my transport, Dac, and tuner is plugged into. Was a very good improvement. |
@bugredmachine. It's a Chord QuteHD (same design as your DAC). And I got it for an amazing price, so I'm willing to pair a good Linear PSU with it. Yes, the noise coming from the stock switching wall-wart is loud. But my issue is two-fold; it's not only the Chord DAC, my ARC CDP sends interference/noise down into the mains. Maybe it's noticeable because the CDP's output and my amp have very high gain. |
I have been following the CPT thread and find it a most interesting and affordable way to provide balanced power to a system. But wouldn't all the components involved need to use the CPT PC's, in my case the amp, preamp, transport/DAC. Balanced power would prevent any ground-loop and interference. @lak Your audio rig looks wonderful and I have checked out your DIY electrical work and your transformer installations. Am I correct as stated above that all my components would need to use the CPT PCs? @whart I have been looking at linear PSU's, such as Teddy Pardo, but a non-audiophile PSU with a large toroidal transformer is worth a look. Same idea as terry9. |
Another thought, Lowrider - the obvious place for a manufacturer to skimp is on the power supply. But high fidelity begins with pure power, because every bit of garbage, grunge, or harmonic which is generated by a power supply is going to end up amplified in your speakers. You might find that with a lab grade power supply, your equipment sounds better than much pricier stuff with manufacturer's compromises built in. The old lab grade stuff cost many thousands when new, and was used to put men on the moon. I start with heroically (i.e. insanely) overbuilt power supplies for all my home-brew electronics, and it pays off. |
Lak, I have a similar setup, and don't understand why it isn't among the first upgrades on the audiophile radar. My isolation transformers are Plitron. Lowrider, before you spend big bucks, you might want to consider a nice used power supply for the cost of a mid-market power cord. I have bought many a good used piece from Sphere Research in Canada, and never a dud. I would call them and explain the issue, and go with their recommendation. HP power supplies from their glory days, for (Canadian!) pennies on the dollar. |
Whart, you ask a great question which I'm not qualified to answer. I'd love to own the Equi=Tech 10 KVA :-)! I still own an Equi=Tech Q2. Check out http://www.corepowertechnologies.com You could always send an email to Mark at that site or ask that question on the CPT discussion forum here on Audiogon, or phone him. When he sees your question he will answer. It's my understanding that somehow it's balanced power, but that's the limit of my knowledge. LOL! |
Which Chord? I had a similar issue when I had the Qute EX in the system. Bought a Bricasti and with the Chord out of the system the noise disappeared. Tried every trick in the book from isolation transformers, to balanced power transformers, to active and passive ac conditioners. Nothing worked until the Bricasti showed up and now it interfaces with my Audio Magic cond very well. YMMV |
Lak: a question. Is there some kind of transformer in the box of those Core cables? Is the "output" side delivering true balanced power 60/0/60? I am also a big believer in isolation transformers and have several, from a smallish medical grade one that I use for my tonearm air compressor to the Equi=Tech 10kVa (which is sitting in storage, awaiting a new property to install it). |
Lowrider57, Short answer, yes a good Isolation transformer can help front end components sound better. This would also help IMO with or without an isolation transformer: https://forum.audiogon.com/discussions/has-anyone-tried-these-stunning-new-cpt-power-cord This is a bit long, but worth reading: My power filtration for my entire systems is provided by two Extreme Isolation Transformers (5 KVA each). The power goes from my main circuit breaker panel into the Xentek Extreme Isolation Transformers and then into a sub-panel that feeds all eight dedicated AC outlets into my audio systems. The Extreme Isolation transformers have a huge iron core design, noise suppression is -146 and they weigh 129 lbs. each. The isolation transformers actually sit on three 1-1/2" solid brass audio points that are on top of the cinder blocks and the cinder blocks rest on top of three hockey pucks that are on the concrete floor. I hear greatly improved musical response in all areas with no major side effects other than the production of some hum, slight heat and of course any isolation transformer is going to consume additional electricity. The hum and slight heat is not a problem for me since the transformers are located in a different room in the basement. I also think different brands of isolation transformers produce different results and most likely are somewhat system dependent. What works well for one audiophile might not produce the same results for another. The beauty of my power filtration system is I purchased the transformers used and did all of the labor myself. The total cost was well under $1000 (for the used transformers, running 8 dedicated lines and circuit breakers, etc., high end outlets not included). With that said, I improved the sound recently in my secondary system when I attached a CPT 300 power cord to my PLCX0e6 (in my secondary system) and powered my Transport, Dac, and FM tuner and the sound of my front end components were once again improved. See: https://forum.audiogon.com/discussions/has-anyone-tried-these-stunning-new-cpt-power-cord (same link as above). |
Low- on the linear power supply, take a look at the product in the link below. I bought one in part because it was cheap, it has a large toroidal transformer, multiple channels for setting voltage and current limit (with read-outs) as well as a channel with fixed voltage/current. I am not using it for an audio component as such (rather, for one of those Acoustic Revive Schumann resonance generators which may put me in the category of "fringe"/voodoo, I dunno), but it seems like a good value. http://www.loneoceans.com/labs/tekpower/ (Note that the writer compares it to two ’look-alike’ units that are also available, as this one is, on Amazon). |
Lowrider, I'll bet the wall-wart is a switching power supply. If so, it may be feeding noise back into your wall. Why not try an old laboratory power supply capable of the same voltage, instead of the wall-wart? "Old" being the operative word, before switchers became the order of the day. Just a wild guess. |
@lak, Always appreciate your participation. I found a thread where you speak to using an isolation transformer for the entire audio system, as you have done in your own house. https://forum.audiogon.com/discussions/isolation-transformer-2?highlight=isolation%2Btransformer%2Bc... Do you have any thoughts on using a iso transformer on the front-end of my system if indeed digital noise is being introduced? |
Hi Al. See my explanation of the grounding theory. These early units were sold as a set. And you’re correct that the noise was eliminated when CDP was plugged into different and more distant outlets. Given that the noise was considerably less when you used the CDP’s stock power cord instead of the upgraded power cords you tried (the upgraded cords presumably having greater bandwidth than the stock cord, and therefore providing less attenuation of high frequency noise over a significant part of the spectrum)Once again, correct. But, the noise was not eliminated. And now that I’m using a SMPS wall-wart for the DAC, the noise is considerably louder than a dedicated CDP. I intend to upgrade to a linear power supply. |
@bombaywalla , Yes, there is a ground-loop due to the design of the Sunfire amp. I recently had the amp refreshed by Sunfire service and was in touch with Bob Carver who confirmed that the safety ground and the signal ground are tied together and do not meet at the chassis. you've had your system for a while & this seems to be a very recent thing.I started having this interference and hearing the high freq noise in January when I installed a new Atma-Sphere SE preamp (which is star-grounded). Amp into wall, Preamp & CDP into same Blue Circle and Furman. Let me add that I only had the ARC CDP in the system up until then. Almarg diagnosed a ground-loop before that due to the harshness of the CDP. I had a Rogue amp and did not experience any 60Hz hum. I will provide the old link, but be warned, it is very long and goes on and on with tests I performed. Also, the Tripp-Lite Isobar is brand new. It was an attempt to use isolated AC receptacles. Getting back to the current ground-loop, I have removed the Blue Circle and used only the Furman pwr strip. AND, all components are currently using cheater-plugs. The Chord Dac is new and is using a Switched-mode wall-wart as a power supply. Not the cleanest way to provide power. The old link...(jea48 and Almarg provided much time and insight) https://forum.audiogon.com/discussions/isolating-digital-noise-need-help?page=2 I'll leave with an explanation of Bob Carver's grounding design; In the late 90s, the Sunfire 300 amp was mated with a stackable valve pre/pro. The amp used RCA and XLR (unbalanced) and fed it's AC into the pre/pro which was fully grounded to it's chassis. This was the ground potential for the rest of the audio system. |
Hi Lowrider, I read through the prior thread that I think you are referring to, to refresh my memory. Given that the noise was considerably less when you used the CDP’s stock power cord instead of the upgraded power cords you tried (the upgraded cords presumably having greater bandwidth than the stock cord, and therefore providing less attenuation of high frequency noise over a significant part of the spectrum), and given that the noise was eliminated when you plugged the CDP into different and more distant outlets, my guess is that the isolation transformer stands a reasonably good chance of resolving the problem. Obviously, though, I can’t say that with certainty, in part because its specs provide no indication of what frequencies its "35-65 db noise suppression" apply to. So that spec is pretty much meaningless. Also, what was the upshot when the Sunfire tech looked at your amp, with regard to the fact that its chassis was inexplicably not connected to its safety ground? Best regards, -- Al |
I am experiencing noise from my digital components into my system. It presents as high frequency interference thru the speakers once the components are warmed up. This interference is being sent back to the mains and can be heard when music is being played or idle.lowrider57, you've had your system for a while & this seems to be a very recent thing. So, what has changed in your system that created this interference? How are you certain that it's from the digital equipment? All the components you cited are in wide use & mostly modern built meaning that hi freq clocks radiating out of the box is almost a very low possibility. I'm thinking that you have a ground loop somewhere given that you use a power conditioner + a Furman power strip + a Tripp-Lite Isobar. One of these items is coupling to the RF noise & putting it onto your amps such that you can hear it thru your speakers. |
You should contact Ralph Karsten of Atma-Sphere. He has a Power conditioner that weights over 200lbs. It supposed to be installed near the breaker box and you run dedicated lines into the audio room. This is what he has to say about them. They are fully reconditioned by Atma-Sphere. It regulates AC voltage (no need for a variac) and uses a massive transformer to isolate the AC output. There is then a low distortion oscillator that is locked to the AC line frequency- the unit compares this oscillator to that of the output of the transformer and applies a correction signal to a feedback winding on the transformer. The result is a low distortion sine wave all the way up to full power, free of spikes. It puts **all** high end audio power conditioners to shame. I think he sells them about 4500.00 Us dollars for a Single Unit and that is all you will ever need it can handle both your theatre room and audio room and dedicated lines can be sent into your bedroom or office etc etc. Where ever you need Clean Distortion Free Pure Sine Wave. |
Lowrider57, If the Tripp Lite IS250HG Isolation Transformer purchased from Amazon didn’t work I’m guessing you could return it for a refund. Personally, I don’t think it will clear up your problem, but I could be wrong. There are others on Audiogon (jea48, almarg to name a few) that are much more knowledgeable than myself when it come to this type of issue. If I remember correctly, aren’t you using a Blue Circle PLCX0e? As I stated in your other post the PLCX0e works remarkably well in removing AC grit nastiest. I also wonder if the problem could be DC on the line? |
