Simplistic NJFET RIAA

diyAudio Chief Moderator
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This is an open loop minimal circuit. Has 2 main qualities. A. Transparency. It will not show self color so to smother lesser TTs and carts. You can play the best there is. Non the less it will not exaggerate them faults either. Smooth. B. Revelatory. It will throw in to stark relief all components quality. No feedback to tide them up.
Fortunately it is simple, hence low parts count. You can plan a few better components maybe. Clever minimal high quality upgrade, will be: 4 Riken 47K, 2 K40u-9 CCCP 100nF, 2 Auricap 2.2-3.3uF. You can leave the Auricap for later and bypass with 100nF K40u-9 what you have (?) for output capacitors now. What are you RIAA capacitors? Again Ebay CCCP silver Mica there, will be very cheap and great. Even generic carbon resistors will do better than generic metal film if you have access to such. Lee has Grado too, and he is chuffed, so there must be a way you will tune up too. A picture of your build will help recommendations.

Regards
 
for resistor you need to play a little, on the cheap side prp dale resita and kiwane , my best are tantalium , but there are caddok -vishay nude s102
tray, resistor do not cost so much
but caps are more important , percy audio or in canada Parts connexion

buy the best caps you can ,add a bypass for tweek a little , than use a resistor for adjust to taste

ps
in my system Rload

tamtaliun great mid
riken open up too mach for my taste but very good
kiwane rocks solid bass
the serie R are more important
hope this helps
 
Hi guys. I just swapped the 100nF cap from a Mundorf Supreme, to a Russian Paper in Oil 47nF and got quite an improvement! Treble is definitely better and mids seem more open. The soundstage also seems more 3d.

I am really surprised by this, as the Supreme's are really great caps.

Salas, the reg I am using is an SPower. These are the best voltage regs I have yet found, but I don't like to mention them as I don't want people to think I am advertising etc.

As always, I am looking for ways to improve what I have, so that is why I was asking about caps and psu. At the moment I have a large toroid - Schottky diodes - 22,000uF 50v Mundorf - SPower reg - and 2 x 220uF Rubycon ZA's on the phono stage. All resistors are Kiwame, nice and smooth.

I shall try and find some time soon to try the Shunt reg, it will be interesting to compare.

I also got a fantastic deal on a shiny new Jelco sa-750 tonearm, which I should receive next week.

Cheers, Lee.
 
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Thomo said:
Hi guys. I just swapped the 100nF cap from a Mundorf Supreme, to a Russian Paper in Oil 47nF and got quite an improvement! Treble is definitely better and mids seem more open. The soundstage also seems more 3d.

I am really surprised by this, as the Supreme's are really great caps.

Salas, the reg I am using is an SPower. These are the best voltage regs I have yet found, but I don't like to mention them as I don't want people to think I am advertising etc.
...
I shall try and find some time soon to try the Shunt reg, it will be interesting to compare.

I also got a fantastic deal on a shiny new Jelco sa-750 tonearm, which I should receive next week.

Cheers, Lee.

And the CCCP ones I recommended cost peanuts... Did I ever do any ''theoretical recommendations''?;)

SPower maybe very good Series OpAmp controlled high feedback regulators? If so, you know the future comparison story... Make the shunt.:cool:

I am happy for your progress and results so far. Bravo! Expect more.
 

iko

Ex-Moderator
Joined 2008
Here we go...

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Some parts are different between the first and the current version of the prototype.

By the way, are the power mosfets on the regulator supposed to get really hot? :D Mine do.

Guys, many thanks for all the advice concerning better parts. I've already ordered some russian pio caps, and some better resistors. We'll see.
 

iko

Ex-Moderator
Joined 2008
I'm not good at making pretty boards, so at least I hope they're practical, with lots of room. I think I should have left more room for the interstage caps of various sizes. Well, perhaps in version 1.1 :)

The lower trace on the scope is before the regulator, the upper one after the regulator. Too bad I don't have a movie of it, showing the lower one moving up and down, especially when some device turns on in the house. Nothing crazy, but you did ask for a scope pic. I mean, can we really have a serious thread on diyaudio without some scope traces? :cool: Never mind this one doesn't actually carry any information :D

Are you sure about the silver micas? Some people recommend polystyrene in the RIAA filter. Notably, Thorsten, I think. What's your opinion about this?
 
ok,,,I couldn't resist! :D

Thank you ikoflexer very much for the board layout, it gave me the needed info. I've had an itch to lay boards out since I was a kid, I find it quite therapeutic! Back in the bad ol' days with transfers and line tape.... :)

So here is my go at it. I wanted to tweak them to take larger parts. I don't know if I got it quite right, maybe some other eyes can check it. Still not enough space for for the russian teflon 100n's; probably an under-board solution.

Not much news on my RIAA, got busy with work. Collected up some very nice vinyl though...about 80! Oh yeah, the bug has bit!

Right, now maybe I should get some work done!:clown:

-Kent
 
ikoflexer if you do new pcb better use , 0.1mf at input of B+ to avoid pickup rfi from cable
and for gnd you can see the separate signal gnd trace ,this little difference are impontant (separate local loop),walk + and- in pair were possible, and carry a separate wire from psu for gnd ,do not cross on pcb and do not connect the out rca gnd

pcb design is a art ,hope this help and I do not know more :(

from JC discussion the box for bullprof from rfi need alu trick 10mm :eek: with out hole !

Tomo you make a discount on box for Salas gang ?:) or GB ?
 

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diyAudio Chief Moderator
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ikoflexer said:
Are you sure about the silver micas? Some people recommend polystyrene in the RIAA filter. Notably, Thorsten, I think. What's your opinion about this?

Silver Mica sounds smoother to my ears. I am actually very content that you got so far sonically with random generic parts and generic cabling with an MM on a Dual TT. Especially in headphones, it could be a disaster. Expect much better when you tune up. Keep up the good work. The pictures are very nice.
 
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kstlfido said:
ok,,,I couldn't resist! :D

Still not enough space for for the russian teflon 100n's; probably an under-board solution.

Not much news on my RIAA, got busy with work. Collected up some very nice vinyl though...about 80! Oh yeah, the bug has bit!

Right, now maybe I should get some work done!:clown:

-Kent

That's the spirit!

Hint: K40u-9 // 10-20% K72P-6 make an excellent tonal combination if in one's system PIO only is too mellow and Teflon only is too ''monitor''.