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Simplistic NJFET RIAA
Simplistic NJFET RIAA
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Old 17th September 2013, 11:31 AM   #10131
Salas is online now Salas  Greece
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Simplistic NJFET RIAA
I would use them as paralleled front ends in the simplistic MC channels or in low noise diff amp JFET input stages in other circuits. But I would confirm their matching level first.
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Old 17th September 2013, 11:34 AM   #10132
spinning wheel is offline spinning wheel  Netherlands
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THX , Salas

Will confirm their specs tomorrow ... work is calling grrr

THX ,
Paul
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Old 18th September 2013, 05:48 PM   #10133
rickmcinnis is offline rickmcinnis  United States
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Default Is a line amp needed for buffering?

Hope this is not the fifth time this has been asked but if one does not need the extra gain would there be any reason to use a line stage?

Thanks for letting me stop wondering if I need to use an LCR RIAA filter.

Take care,
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Old 18th September 2013, 06:10 PM   #10134
Salas is online now Salas  Greece
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Simplistic NJFET RIAA
Rick, to give you a practical overview:

I use 63dB voltage gain for a Denon DL-103R 0.25mV LMC cart in my FS PCB prototype. My control preamp is configured for X1 gain (0dB). My CFA power amp for X20 gain (26dB).
My speakers are 94-95dBSPL/W sensitive. They are 8 Ohm but they dip to a 4 Ohm minimum mid-bass plateau. I drive them with the system voltage gain structure I described in 40W MOSFET class A power reserve.

The control preamp's log volume pot gives me practically same SPL either for the Benchmark DAC or the Folded Simplistic at same positions. Some records play louder than the CDs even.
At 12 o'clock I enjoy "loud" peaks at four meters from the speakers that can cover a vivid conversation. Beyond 2 o'clock its just "too loud".

The Folded simplistic has a JFET buffer output stage itself of about 50 Ohm impedance and similar design to a capacitor coupled B1.

I hope that I have given you enough example info to weigh and decide your own configurations.
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Old 19th September 2013, 04:56 PM   #10135
Joshua_G is offline Joshua_G  Israel
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Hi,
What are the recommended power transformer ratings (secondary voltage and current) for the Folded kit? (An E-I transformer will be ordered from a local transformers workshop).
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Old 19th September 2013, 04:59 PM   #10136
Salas is online now Salas  Greece
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Simplistic NJFET RIAA
36VAC 30VA each Tx. Double mono PSU. Are you going to make it point to point or in the PCB?
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Old 19th September 2013, 05:06 PM   #10137
Joshua_G is offline Joshua_G  Israel
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It isn't for me, it's for a person I recommended to the kit. It may well be point to point I'll do the soldering of the Folded PCB and the PSU. Is there a PCB for the PSU?
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Old 19th September 2013, 06:14 PM   #10138
Salas is online now Salas  Greece
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I meant asking about the phono itself if p2p so to know the intention of using external regs of higher CCS or not VS the VA rating of the transformers.
The PSU does not need a PCB. Its very basic. Its ground loop breaking scheme worked for no loops in my system. As in the guide and in the first picture here.
In case it does not in some other systems, then an alternative I can suggest is in the second picture. More I can not predict since the system grounding is a general matter that varies between installations and has not to do with the main phono build.
Attached Images
File Type: png PSU.png (35.1 KB, 298 views)
File Type: png PSU_Alt_GND.png (23.7 KB, 288 views)
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Old 19th September 2013, 06:32 PM   #10139
Joshua_G is offline Joshua_G  Israel
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Thanks, Salas.
The Folded will be installed on the group buy PCB, with the included shunt regulators.
As for possible ground loops, they will be dealt with later, if and when they may come.
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Old 19th September 2013, 06:41 PM   #10140
AndrewT is offline AndrewT  Scotland
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Post10138
In the right diagram the resistor has been omitted from both Disconnecting Networks.
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