Simplistic NJFET RIAA

[Turbon]

Use your stronger for Q3X and 6.2K R3x. Use your medium for Q2x and 27R R6x. Your lower ones for Q5x.

Sorted my 2sk117's.

Q3x 5,2mA R3x 6k2
Q2x 5,0mA R6x 27R
Q5x 3,7mA

Ok?

Regards

 

[Salas]

 

[Turbon]

Leds sorted, 7,65V matched between channels.

Regards

 

[Turbon]

Sorted my 2sk117's.

Q3x 5,2mA R3x 6k2
Q2x 5,0mA R6x 27R
Q5x 3,7mA

Ok?

Regards

According to notes if the batch of fets yields 5mA one should use 33R - not 27R... My misstake.

Will use 33R.

Regards

 

[Salas]

27R would be fine too if it was 4-4.5mA. Not that crucial, this adjustment just keeps the current alike to the prototype's 3LEDs tail CCS for all builds IDSS to ensure better long term reliability for Q2x regarding dissipation since it has much voltage across.

 

[Marra]

I am one happy bunny having spent the past two days listening to several LP's without the crinkly paper noise putting in an appearance.A big thank you Salas for your advice and designing the Simplistic;also to Teabag for his as usual excellent group buy and anyone else who's posts have helped

 

[Salas]

Bravo Marra. Did you comprehend what was the culprit? Found any cold solder joints? I have given green light for the wait list GB just a few minutes ago BTW. Since everybody reports OK here including you.

 

[Salas]

P.S. Do you find you need any C2Y treble level or cart loading adjustments by now it has some hours of play?

 

[Marra]

Nothing that I could actually say for definite although I suspect the led's as they did take some heat what with unsoldering and resoldering.
C2Y is a 220pf polystyrene which sounds fine to my ears no need for any other in my case.I do like the sound of the Simplistic.
For the p/s I used an 80VA Toroidy pl with 4x15V secondaries which I connected in series to give 2x30V.With the higher UK mains I had 32.3V secs which resulted in 43.2VDC so spot on.
I will treat it to a bigger enclosure in the new year so that I can use my better? caps.The pcb's only just fit front to back in the current one.
Thanks again.

 

[Salas]

Try 100 or 150pF instead 220pF at a point also. Just for kicks if the total is not verified with a highly accurate LCR meter.

 

[Erlend Sæterdal]

Critic

Hi a Critic from det old danish " High Fidelity" is going to test this during next week. Hope there is no hum.

 

[Salas]

That is a defunct good old school magazine that was kinda technical like HFNRR used to be? Without any previous hook up test, you never know. Be there with him initially at least having your iron and a couple of alternative polystyrene and bit of GND wire to judge hum and proper treble level in case you need mod it before you leave it to the critic.

 

[Turbon]

A quickie...

Can 1 raw psu drive 2 simplistics? The toroids are 50VA 2*18V. Only one will be active at any time the other on but idle. Should I choose 80VA instead?

Regards

 

[AndrewT]

50VA @ 36Vac will supply 347mAdc continuously and that is just 50% of the rated continuous DC capability.

Two simplistic will not draw 347mAdc.

80VA @ 36mAdc has a maximum continuous DC capability of 1.1Adc.

 

[Turbon]

50VA @ 36Vac will supply 347mAdc continuously and that is just 50% of the rated continuous DC capability.

Two simplistic will not draw 347mAdc.

80VA @ 36mAdc has a maximum continuous DC capability of 1.1Adc.

Thanks AndrewT.

Then I'll use 50VA's if I'm not pushing borders.

Regards

 

[Erlend Sæterdal]

I use a 2x 40 vac R core 200 W . 1/2 for each channel. 22 ohm before diode and 22 ohm between first and second electrolytic. Works perfect 45 -47 vdc for the regulator.

 

[Turbon]

I use a 2x 40 vac R core 200 W . 1/2 for each channel. 22 ohm before diode and 22 ohm between first and second electrolytic. Works perfect 45 -47 vdc for the regulator.

Nice... I need a small footprint for the PSU.

Regards

 

[Marra]

Try 100 or 150pF instead 220pF at a point also. Just for kicks if the total is not verified with a highly accurate LCR meter.

I don't possess an accurate LCR meter so will try different values over the next few weeks.
I found these on Cricklewood's site;wonder what there like?

Cricklewood Electronics - CCTV. CCTV Equipment. CCTV Systems. Digital CCTV Cameras

 

[Erlend Sæterdal]

Marra those are Philips with magnetic end caps. I would go for Polystyren.

 

[Marra]

Thanks.I'll stick with the LCR's from Farnell.