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AC power anomalies disrupt only phono stage?

Despite the insertion of a Power Conditioner (Shindo Mr T) for the turntables and preamp in my system……when the street’s power supply is corrupted, the phono stage of my Halcro DM10 preamp is rendered virtually unlistenable?
At the same time…..the line-level inputs (like Tuner and Aux) are unaffected. In fact the sound through the TV (connected to Aux)…..is quite sublime on movie scores.

I am baffled at what could possibly cause the phono-stage to ‘implode’ at these times…..whilst leaving untouched the high-level stages?
128x128halcro
halcro's avatar
halcro OP
2,664 posts
 
Dover,
The soundstage completely collapses with little width and no depth.
The highs become brittle and emphasised at the expense of the midrange and the bass has all the characteristics of an 'out-of-phase' connection.
In other words.....it sounds like the worst of digital!
Thankfully they have stopped messing with the mains down the street.....and 'normal' transmission has been restored.
But it confounds me as to how only the phono-stage can be affected whilst the AUX can sound as beautiful as ever at these times?
nandric's avatar
nandric
4,086 posts
 
Dear Henry, Ever thought about to use a battery powered
pre? I have never such problems with my ASR Basis Exclusive.
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rauliruegas
13,101 posts
 
Dear Halcro: +++++ " In other words.....it sounds like the worst of digital! " ++++++

or the worst of analog.

Halcro, as I told you maybe is time to an up-date. IMHO, that's a design problem on the DM-10s or your unit is out of " specs ". That never been happen in a unit of the DM-10 caliber, there is no reason for taht: something is " wrong " down there.

regards and enjoy the music,
R.
dover
2,250 posts
 
Henry - the Halcro inverts absolute phase in the phono only and not the line stage. Have you factored this into the equation. Also from time to time mains can flip in its phase orientation. Just be happy you dont live in Oamaru. My friends stereo sounds fantastic when the local abattoir ( meat processing plant ) goes on strike.
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almarg
9,670 posts
 
It confounds me as to how only the phono-stage can be affected whilst the AUX can sound as beautiful as ever at these times?
I don't see that as surprising. Unpredictable, yes. But surprising, no.

As you certainly realize, the phono stage uses circuitry that is not involved in the processing of Aux or other line-level signals. And that circuitry is vastly more sensitive, in terms of the signal levels it is designed to process, and provides far higher gain, than the line-level circuitry in the preamp.

Best regards,
-- Al
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