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Old 17th October 2012, 06:46 PM   #8221
Salas is online now Salas  Greece
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You could make a Mez. They are brothers. Very convenient, has 6 inputs.

RC, nice, lets see it in the rough and think about tweaks and overall mods worth. Now I have to go, the iron is fired up, got to finish some diy at last, so to have time for the phono too.
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Old 18th October 2012, 03:08 AM   #8222
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Question 'Balanced' Simplistic NJFET ...?

Hi Salas

Thanks for your help a while back, with the cartridge recomendation.
A friend of mine now also wants a new hi-out MC for his setup.
Not sure if the Denon will suit his TT & arm; but if it does, we will both get the same cartridge ( finaly ! ).

I was thinking to make a valve preamp, as you know; and probably will some time in the future.
My friend who wants to improve his setup, however; has made me think your NJFET is best for us now.
Reason being; I would like to help him build his own 'simplistic'.
As it is his 1st project; I think the NJFET is more fun and more SAFE for a newbie.
Also we would like to consider 'balanced'; a bit more agro. with valves.

I have started to order some of the parts for the NJFET and Shunt-Regs; and have some bits in stock already.

The main question, for now; is about constructing a 'Balanced NJFET'. +

I am considering that we both construct 'balanced' NJFET's from the begining.
This I think would be Hi-MC in ( no SUT ), and transformer output for SE or 'balanced' outs.
Since we have old-valve-amps etc. I don't think the full system will be 'balanced' throughout.
But you never know; we might make a whole bunch of Nelson's amps in the future ! ...maybe.

I have searched the thread for 'balanced' NJFET builds; but it's so big now, I haven't had much luck.
I know Felipe made a 'balanced' NJFET ( minus output transformer ); I'm sure there must be others as well.

I see in the photo of Felipe's board; he has only 2 sets of EQ parts ( as you would expect ).
I think I know how to wire this; but if a schematic for a 'balanced' NJFET exists, it might help here.
Also the proposed transformer output; again, I think I know how to wire this; but any recomendations or a schematic of what people might have done, could again be helpfull.
I have here spare Lundahl's 2x LL-1528 and 2x LL-1539, which could be OK to try.

If we do the 'balanced' versions it could be very good for close component matching also; more parts, better match.
Obviously 8x preamps and 4x shunt-regs; is what we would be aiming to make.

Any thoughts, schematics, and EQ advice on a 'balanced' NJFET would be most welcome.
We would like to 'pull out all the stops !' on this one; and go for the best build possible.
Trying to get an idea of final size at present; so it all fits smoothly into a suitable case.

Thanks Salas, Felipe & Ricardo again for your help a while back.

Cheers


Si.
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File Type: jpg Felipe's Balanced NJFET Phono.jpg (149.3 KB, 129 views)
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Old 18th October 2012, 03:25 AM   #8223
Salas is online now Salas  Greece
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If a Denon high out MC is not best suitable to his gear, I had listened to a Benz MC Silver 2mV in a friend's system in the summer and it was a good cart for something like Euro 300.
I have never made the simplistic doubled up for balanced or drawn a config. You are with Felipe for that. Maybe he can draw his configuration and/or give details?
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Old 18th October 2012, 11:10 AM   #8224
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Hi again Salas One more ( or 2 ! ) questions... ...then I shut-up & finish ordering my parts ! 1. Just read the 'Back In Black' thread. The BIBv2 is now the preffered Shunt-Reg for the NJFET...correct ? 2. A guy in the BIBv2 thread asks... ...Will large on-board ( NJFET ) capacitance affect the shunt-reg ? You say...Yes it will slow down the shunt-reg. So... ...If the BIBv2 is supplying ( from enough pre-smoothing caps ) low-impedance, ripple free power... ...Can on-board ( NJFET ) capacitors x3 ( PSU1, PSU2, & LED string ) be smaller polyester types ? I can get 10uF & 22uF polyester; and don't mind paralleling a few up. If OK like this... ...how many uF of polyester would you use in each of the positions ? I plan 1 shunt-reg per channel, by the way. Thanks very much. Cheers Si.

Last edited by The Space Egg Corp; 18th October 2012 at 11:19 AM.
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Old 18th October 2012, 11:21 AM   #8225
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sorry Salas Tried undoing the sentances 3 times Ain't working Get the drift ?
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Old 18th October 2012, 11:28 AM   #8226
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BiB is good for the phono too. Don't tweak the lytics values on the phono for much smaller, those are local to RC filters or LEDs front stage's reference sub system and if the time constant gets small its gonna have unequal filtering as the frequency gets lower in the audio band. Those RC are not slowing down the reg because the R portion buffers the C from being directly parallel to the reg. The LEDS one is separated by a CCS even, and should be big for eating local node noise sufficiently. By having good separate power from channel to channel, only the front stage rail RC can be skipped in the PDF guide circuits.
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Old 18th October 2012, 11:41 AM   #8227
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Thanks Salas.

I thought you would say that.

May as well have Electrolytics in BIBv2 then as well.

People all seemed to want to stuff it with Polyester.

Never mind...I buy good Electrolytics instead...Cheaper !!!

Should I bump-up the on-board ( JFET ) caps ?

( no stupid ! just leave it as be !!! OK !? )

Thanks

Si.

Is BIBv2 in theory lower noise than NJFET pdf shunt-reg...?
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Old 18th October 2012, 11:49 AM   #8228
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I just wondered if I could buy 470uF 50volt for everything BIBv2 & NJFET...and get good bulk deal.
+
1000uF 50volt x10of each shunt PSU smoothing.

Si.
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Old 18th October 2012, 11:54 AM   #8229
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Use polyester in the output zobel of the Bib as per instructions but use 220 to 470uF good ''audio'' lytic for its Vref filtering like Silmic II black sleeve or Nichicon Muse KZ. Bib was made later than the pdf one, the pdf one was sounding good together with the phono, but having pcbs some go for the bib which is certainly not worse.
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Old 18th October 2012, 11:55 AM   #8230
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Quote:
Originally Posted by The Space Egg Corp View Post
I just wondered if I could buy 470uF 50volt for everything BIBv2 & NJFET...and get good bulk deal.
+
1000uF 50volt x10of each shunt PSU smoothing.

Si.
That's good logistics.
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