• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

If you are looking to try balanced AC power....

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#82
I purchased one of the transformers Ken highlighted in his first post. The transformers are EI, input is wired for 240VAC, output is wired 120-0-120 with two output receptacles, one connected to each 120V leg + ground, capacitors are wired from the 120V outputs to ground + one extra wired with a series resistor taken from one of the 120V outputs to ground, and there appears to be no primary to secondary shielding.

The 120V secondaries are closely matched. I tested their voltages by plugging the unit into a 120VAC outlet and on 1-minute average readings from each secondary to ground read 60.71 and 60.72V respectively. L measurements of the secondaries to ground were both 437.1uH, showing closely balanced secondaries.

Thanks for the tip, Ken!
 
#83
Hi all,
Recently I bought a cheap "multiformat" Samsung player (SMPS) to have a taste of SACD, whose sound was unknown to me. The player is noisy as you guess. I will try to improve it.

A few days ago I asked a local technician to wire a small (around 160VA) EI balanced transformer, with bifilar wound secondaries and electrostatic shielding. I connected it in "technical balanced" mode (with ground to "earth"). Powering the Samsung with it showed improved sonics (it still sounds like s****): less HF noise; more elegant sound; more detailed.

I also powered a CDPRO transport with it and it also showed a gain in resolution and flow. This transport has R-core Tx and ALWSR superregulated digital supply.

I added later a couple of Y-caps from secondaries to earth (10nF). While they cleaned up a little bit the highs, they seem to make midrange and bass lighter and colder 🙁

Just my impressions...

Regards.
M
 
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