Simplistic NJFET RIAA

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Thanks Salas. It did take a bit of time to even out the highs. I'm glad I didn't rush into adding more to C2Y as the difference between start up and 10 hours or so was dramatic. Must have been the caps I used I guess. It's sounding very good on the highs now, well all through really, and I'm not much for tinkering once I find what I like. I'd rather listen. Thanks again for offer this to the DIY community.
 
After many years research, I accidentally found, that inside toroidal transformer is nylon M6 (M8) screw much better like metal. In case of metal you became inductive antenna which strain buzz. In case of end stage amplifier (3x600W) I found more than 100°C on this metal screw. This working like induction heater. Maybe G-type transformers are much better.
 
I have to apologize, I mean R-core transformer, the best for low noise.
Neue hohe qualitat Audio R core transformator 220 V 30 Watt 12 V + 12 V fur hifi verstarker-in Verstarker aus Verbraucherelektronik bei Aliexpress.com | Alibaba Gruppe


In my former MM/MC discrete current feedback high speed modules, without any phase shifting, I am using switching Mean Well 15+15V, additionally followed with small 25V 2x10.000uF capacitors, after it is also good measure to made two 100E/330uF filters after that for ultra low noise applications. In my end amplifiers and pre modules this is the law. Signal ground on input is 10E up, but chassis ground direct to 0V is normally necessary, then you became quiet nothing.
 
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diyAudio Chief Moderator
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Like those from Selectronic France I used back then (no longer available)
 

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Two PSU became double problems, there is enough one very good source with proposed filters. You have to hearing results, not only imagine in your head, double are double better, but double problems. I am describing full wave rectifying with two graetz bridges and proper capacitors, maybe few steps filtering after. Whenever are formulated good proposal, anyone wants to tweak them.
 
diyAudio Chief Moderator
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Double RAW PSU & double onboard shunt regulators as implemented sounded clearer and wider than single common in my original development of the FSP phono. No extra buzz or hum either. If a next phono board issue comes I will probably have the UltraBiB class shunt regulators outboard so each builder can subjectively choose between common DC source or double DC source feed for the channels beyond my own notes and recommendations.
 
diyAudio Chief Moderator
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In my former MM/MC discrete current feedback high speed modules, without any phase shifting, I am using switching Mean Well 15+15V, additionally followed with small 25V 2x10.000uF capacitors, after it is also good measure to made two 100E/330uF filters after that for ultra low noise applications. In my end amplifiers and pre modules this is the law. Signal ground on input is 10E up, but chassis ground direct to 0V is normally necessary, then you became quiet nothing.

Switching PSU with passive post filtering measured clean noise floor from 20Hz-20kHz in my Chipomatic differential input DC coupled IC phono (CF architecture INA based) but in the end I was disappointed by the out of band switching HF noise making its comeback through wide band integration for elevated audible hiss and much degraded audio quality versus my shunt linear regulator. Although the op-amps in that phono had great PSRR & CMRR spec the sound quality outcome between switching and linear experiments was night and day. Thus in this zero PSRR FSP phono I would expect a total disaster.
 
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P.S.

For your reference that was the measurement with outboard switching charger PSU Philips and local DC/DC switching CUI brand converter plus RC filters for common between channels symmetric supply on that instrumentation IC phono prototype of mine. Test frame chassis was mains grounded.

Chart shows it at 62dB gain including 20dB from balanced impedance input transformer. Zero hum or buzz and negligible THD at 1V RMS output are obvious. Looked prefect, but sounded bad until I switched :))) to linear shunt PSU and became very good. Old school FSP still sounds the more natural though.
 

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