Tweakers' Asylum

How does its effect differ from isolation transformer?

71.110.249.199

Jon L

In Reply to: RE: hammond 193m - listening impressions posted by rhyno on May 25, 2009 at 08:31:04

"top end extension is not reduced, its more resolved and less forward in the mix (giving the sensation that the mids & bass are 'pulled fwd' in the mix). its a very relaxing presentation"

Your description here is similar to how I hear a good isolation transformer (without "filter circuits") on the AC...

Follow Ups:

Isolation transformers also absorb some noise, - Al Sekela 16:08:50 05/25/09 (0)
but apparently not as much as a properly-sized choke.

The parasitic capacitance and high frequency AC resistance of the windings are what absorbs the noise. If the AC resistance is small, as in a beefy isolation transformer, then it will not dissipate the noise energy and simply reflect it back into the power line or let it pass through to the load. Similarly, if the AC resistance is too high, the device will also not absorb enough energy. There is an impedance-matching effect here.
Since the oerating principles are very different - unclestu52 13:42:14 05/25/09 (2)
there is a different sound. The Hammond mod will also add better dynamics, whereas an Isolation transformer, unless extremely large for the comppoenet draw, tends to slightly squash dynamics. Of course YMMV
Stu

Edits: 05/25/09
- RE: Since the oerating principles are very different - audionutge@yahoo.com 15:03:57 05/25/09 (1)
  Stu
  
  Yes and no...I have been able to throw a 193L on both sides of a isolation transformer and improve dynamics.
  
  Alan
  - I've done the same - unclestu52 17:20:46 05/25/09 (0)
    but using the RGPC devices. I have many isolation transformers, most of which are rated for 8.3 amps or so, but I have a few in the 500 watt range. Still I rarely use my isolating transformers for much audio use, limiting them to front end components. I even run a couple in series for my Plasma. All usages have benefited from the chokes added, however, as your messages seem to imply.
    
    I started experimenting with isolation transformers quite early, way back in 1979. I had several smaller transformers and curiously it had the most profound effect on my TT at the time, a non Valhalla Linn LP-12. At only 500 watts (I still have it) It was marginal for anything else. Eventually I scored a pallet of 1000 Watters and thus could experiment with running them in series and in parallel, and then learned by experience that you need a lot of juice for the amplifiers, but I digress.
    
    Glad to see you recovering from the flu, and welcome back.
    
    Stu

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