Phono Hum

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IslandPink
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#16 Re: Phono Hum

Post by IslandPink »

Just got the phono back in playing and it's MUCH better. I can only hear some hum quite close to the bass units now. Bass and lower mids have improved, of course !
What a relief after putting up with it for so long.
Just playing 'Don Juan's reckless daughter', as you'd expect.
I also took the opportunity to drill some holes and double-up on output RCA's, it was a bit of a faff, but now the phono is 2-channel-ready :
Phono_extra.JPG
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )
little eddy
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#17 Re: Phono Hum

Post by little eddy »

I see the mechanical isolation, and remember MJ having some ideas in this. Wondering if the maglev units might be a novel option and not too expensive if can keep the weight down?
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
little eddy
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#18 Re: Phono Hum

Post by little eddy »

I see the mechanical isolation, and remember MJ having some ideas in this. Wondering if the maglev units might be a novel option and not too expensive if can keep the weight down?
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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IslandPink
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#19 Re: Phono Hum

Post by IslandPink »

I wouldn't recommend what I did, that's for sure ! It was a desperation measure for hum which at that time turned out to be a broken earth wire down the centre of the circuit.
Maglev sounds very novel indeed :shock:
My next phono intends to have some of the valves soft-mounted using 'well-nuts' ( M3 ) in oversized holes to allow some reduction in vibration.
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )
little eddy
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#20 Re: Phono Hum

Post by little eddy »

How microphonic might the d3a be - it sounds like you think this may not have been necessary?
TD-125/RB250/MC25FL & 'Snail' phono, NAS/SBT with CS4398 DAC, 41MP pre & MoFo Power, still messing with OBs.
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IslandPink
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#21 Re: Phono Hum

Post by IslandPink »

Not bad. Nick uses them in the Reference.
Soft mounting might help a bit - Nick has them in an enclosed box, unlike me.
I have some B&Q tube dampers - didn't put them back on yet, will check. But at present it's just residual hum that's the only audible thing.
"Peridots and periwinkle, blue medallions Gilded galleons spilled across the ocean floor" ( Mitchell )
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