And power cords. My experimentaion reveals that combining complementary (synergistic) products offers dramatic refinement-particularly for CD enjoyment and preamps. One example is the use of an Equitech 2Q balanced transformer with an MIT Z Stablilizer. I think this is an area that merits our united attention and will effect significant enhancements, far surpassing the use of any one unit or brand. Discussion of the how & why technical factors, i.e. frequency ranges affected, method of the device, could be informative & very interesting if tech savvy members contribute. Hope so.
I believe that each filter I have implemented addresses different areas of AC noise. I can't say which frequencies, and I don't have an oscilloscope to see just how effective they all are. But I can say that I can hear differences with each one in and out of the circuit.
In general, I don;t think you can have too much filtering on your digital components.
A very good thread with excellant information being passed back and forth!!!! This was a area I need to invest a few $$$ to increase low level detail and microdynamics.
I've implemented the following chain of PC's for my DAC:
- Jon Risch power conditioner (choke and cap filtering and varistors for surge supression), into - Jon Risch digital isolation transformer (configured as a step down transformer w/ a cap filter across secondaries into a step up transformer), into - Felix power conditioner (transformer and cap filtering)
Hell, after all that it probably would have been easier to just get a regenerator from PS Audio. Anyway, it seems to be effective and I definitely hear improvements using all 3, and a worsening if I pull one of them out of the chain.
I use an isolation Transformer, then passive parallel filters, then a 193L choke wired into the IEC end of my power cord, to my CDP and my Dac. Great results!!
Any dual core, 480/240-240/120 transformer can be wired (creatively) for balanced AC output because the secondarys are out of phase. Pretty much everything over 1KVA is dual core. If you wire 240V to the 480 primarys(H1-H4), you get +/-60V (referenced to ground) on X1/X4 and connect X2/X3 secondarys. Simple stuff, at least in theory. Transformers can be finnicky. How do you think Equitech got started?
Very high current meant 20A continuous for dual amps, including derating by half for balanced AC output.
The brand I got is GE because this model was fully potted but I have no aversions to any brand, with the possible exception of the Cutler-Hammer aluminum models. Just have to check if it's shielded. It's big and ugly but that's okay in a closet.
Like this: http://cgi.ebay.com/GE-Transformer-5-kVA-5kVA-240-480-120-240-9T21B1004G02_W0QQitemZ370097256785QQcmdZViewItem?hash=item370097256785&_trkparms=39%3A1%7C66%3A2%7C65%3A10%7C240%3A1318&_trksid=p3286.c0.m14
Ngjockey, "Politely"-- A step down transformer is not a "balanced transformer" and will not achieve the same results. What do you mean by "very high current requirement"? Please identify the brand & models you suggest and I will research & post results. Thanks
Before you start looking that up, common mode refers from line or neutral to ground and "differential" or transverse or normal mode refers to noise between line and neutral. Common mode is the big culprit.
A shielded transformer is also a capacitive/reactive inductive load, which filter frequencies beyond 50/60 Hz. I've seen examples (not confirmed) of up to 8:1 spike reduction through transformers as well. What they don't do is regulation, except for motorized autoformers but usually too slowly for our intent. They also don't prevent ground loops because, by code, ground has to be continous.
Chose an industrial step-down transformer because 1) EI cores are not as close coupled as toroids 2) to get balanced AC out of either 120V or 240V 3) Picked up a used one for near pocket change 4) designed for demanding loads, not packaging 5) very high current requirement (5KVA/20A balanced)
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