GoodSoundClub - Romy the Cat's Audio Site

In the Forum: Analog Playback
In the Thread: The last phonocorrector: “End of Life" Phonostage

Post Subject: Hum again.Posted by AlexBerger on: 5/14/2010

Romy,

I have rebuilt my phonostage (the pictures after update are added to Picasa):

1. Fixed filament. Now a ripple about 1mV (unmeasured by my Fluke).
The filter is: C-L-C-L-C 30000uf-3mH-30000uf-3mH-30000uf.
I put two 3mH chokes & Nichicon capacitors, instead of chip no name capacitors.
2. Put 2M OHm resistor incited of 1.8M + 220K.
3. Put shielding aluminum plate between power supply and RIAA board.
4. Retuning air capacitors.

But hum is steel in the same level as is was before.
I try analyze the problem.
Maybe it caused by antenna effect of strait wires between step up transformer and first stage?
Should I put twisted pair wire instead?

Interesting that sound is changed notable after the rebuild. The sound is lusher and more natural, without metallic ringing coloration in piano as before.
Maybe the chip no name capacitors in the filament damaged sound?

Alexander.

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