Simplistic NJFET RIAA

[Salas]

ls3-5a-forum.com


for strobe put under a neon lamp

Good idea nicoch46

The stronger the 50Hz flicker is, the easier for the eye will be to follow the sync with the pattern.

 

[Salas]

What I found best to do for tuning the antiskating force, is to play modulation tracks on test records. When the mistracking distortion noise finally appears on the highest modulation bands, that scraping noise should be appearing equal between channels. No worries if the end setting does not tie in grams with the downforce (VTF) used.

 

[merlin el mago]

So that alignment has to be done balanced for all those patterns printed I guess.

For antiskating, the best method is not mechanical check in my experience, but acoustical.

Yes the alignment can be done following the steps of setup.

Important things are:
-1st of all: the screws of the cart must be a little unscrewed to do well the alignment.
-Step 5 be sure that the diamond follows always the arc line from the edge of the disc to the center of the disc.
-Step 6 with the grid check both lines: lateral and front in order that this one parallel with the lateral lines and the lines previous and later(posterior)
-Last: before check the VTA be sure the screws are tight screweds & check the overhang.

The protractors can not check the antiskating.

 

[Salas]

Do not forget to re-enable the antiskating and listen to finally the difference.

That is why I expanded on antiskating.

 

[merlin el mago]

Hi Salas,

Let me know when you do the alignment, when I do mine I can't resist to smile, for half hour more or less of mine time & 0€00....

 

[merlin el mago]

Usefull pictures to check the axis in tonearms:

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With photo-shop programm you can do this:

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Enjoy

Merlin El Mago

 

[merlin el mago]

Hi Salas,

Could I use the Simplistic fono shunt reg. 46V for Low MC because I don't see posted the 45V that you recommend me for gain 63dBs?

 

[merlin el mago]

Hi Salas,

Could I use the Simplistic fono shunt reg. 46V for Low MC because I don't see posted the 45V that you recommend me for gain 63dBs?

If yes wich LSK390 can I use for the shunt regs. ?

 

[Salas]

Hi Salas,

Could I use the Simplistic fono shunt reg. 46V for Low MC because I don't see posted the 45V that you recommend me for gain 63dBs?

http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-281.html#post2018319:

 

[merlin el mago]

Hi Salas,

Could I use the Simplistic fono shunt reg. 46V for Low MC because I don't see posted the 45V that you recommend me for gain 63dBs?

Sorry at this moment I see that you post the information PS regs. in post 2809.

I suppose that for Tx now I need 40V 50VA, right?

Cfilter now will need 63V, right?

Leds for RIAA & shunt regs. can't vary: 1.7V/20mA, right?

Sorry again for these a lot of questions, I am want to be sure 1st to start the Simplistic.

 

[Salas]

Yes to all.

P.S. Leds can be up to 1.9V if you don't mind some more heat on the sinks. You can always fix that by tweaking R1's value.

 

[merlin el mago]

Thks Salas,

Now I will order the BOM to Mouser.

 

[Salas]

Well I suppose that instead an internal dip swicth can be done by a external toggle switch.

I would avoid cabling there. Prone to pick up hum. It can be toggle also, but on the board.

 

[guglielmope]

Hello Salas,
Why do you use in this schematics IRFP9140 and 2N5457 instead of IRFP9240 and 2sk170.
There is any impuvement or I can use the old ones?
Ciao
Thanks
Guglielmo

 

[Salas]

The voltage is high and it will run the BC550 cooler than with a BL. GR are not common anymore. A bit more noise than a 2SK, but less Cgs. Will do OK. If you have a 4-5mA 2SK, use it. 9140 is just a bit better I have found. Can be used always.

 

[merlin el mago]

I would avoid cabling there. Prone to pick up hum. It can be toggle also, but on the board.

OK, thanks.

 

[RCruz]

The voltage is high and it will run the BC550 cooler than with a BL. GR are not common anymore. A bit more noise than a 2SK, but less Cgs. Will do OK. If you have a 4-5mA 2SK, use it. 9140 is just a bit better I have found. Can be used always.

I have 6.5mA 2SK.... can I use it instead of the 2N5457 ?

 

[Salas]

288mW on the BC550. Hmm... better less. Put a 47R between its G,S so to bring down its idss if you don't have any 2N.

 

[RCruz]

Thanks Salas

I have no 2N a some 2sk left...

 

[nicoch58]

Merry Christmas and a Happy New Year from italy to

Salas ,Ricardo,Iko ,Disco and bad boys

best