Simplistic NJFET RIAA

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#2,942
Hola Mago

If the value doesn't need to be exactly 1000 Uf, than use two 2200 in series (negative leg soldered together) and use both + positive leg to get 100 volt .
I did this this with great result in other circuits.

Hay mas maneras para llegar al final ganando! (there are more way's to reach the end )😛

Hasta la proxima,
(cheers)

Audiofanatic 🙂
 
#2,943
RCruz said:
IMO Pana is quite honest sounding and if you use 1000u, you will not loose bass.

I got a lot of 1000u 100v Super Through... I will try those and report the results 🙂

As for the trimmers I guess the max value is 7/150pF PTFE... not enough for the 16n... You will need a third cap (220p smica maybe).

I would try a fixed 330p mica and compare with a 390p mica // CCCP silver mica 15,72nF

Ricardo
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Hi Ricardo,

Sorry I don't explained me well, the trimmers are for fine adjustment to get the exact capacitance value for RIAA.

For mine Salas Phono I see 4.700uF/10V Panasonic FM min. order 5 caps at 0,99€ each.
Link: Panasonic | Pasivos | Condensadores | Condensadores Electrolíticos de Aluminio | Condensadores radiales, hasta 105°C |EEUFM1A472L
R394541-91.jpg


I have to look for if I have some BG 4.700uF/16V used in other DIY audio projects for digital.
 
#2,944
Gracias Audiofanatic

Audiofanatic said:
If the value doesn't need to be exactly 1000 Uf, than use two 2200 in series (negative leg soldered together) and use both + positive leg to get 100 volt .
I did this this with great result in other circuits.

Hay mas maneras para llegar al final ganando! (there are more way's to reach the end )😛

Hasta la proxima,
(cheers)

Audiofanatic 🙂
Click to expand...

Thks for advice, but in this case I prefer only 1 cap.

Congratulation for your Spanish, surely I can not have your same level speaking English.

Best

Merlin El Mago
 
#2,946
I posted most of my mods here so there is nothing new really.

My experiments are based on listening impressions backed up by tech info that I get from here.

I found the 47n obbligato do not have exactly 47n so I am experimenting with small value micas.

In reality if we have less than 47n, we get a bump in the mid freq making the sound too forward in the mids.... I am trying to reach optimum results without a trimmer.

Everytime I do a new mod to improve definition I find it is necessary to fiddle with other parts to compensate.

How is your work going ? did you already built the riaa board ?

Ricardo
PS: It seems DIY is a never ending story... You never quite reach the end... There is always a way to improve.
 
#2,947
For 47nF I bought silver mica, I agre that is best solution a fixed cap to get the right total value but there is some values that aren't standard.

Asked the Shinkoh + Kiwame resistors to Pcx, I want to start next monday the PS, the Phono RIAA will make when resistors arrived.

DIY it's very expensive, but is very exciting do ourselfs the things & if sounds well perfect if not always is possible to up-grade with better parts or changing de schematic.

Merlin El Mago
 
#2,950
Ricardo, the 47nF/500V😉 silver mica pic near the russians so you have an idea how bigs are.

An externally hosted image should be here but it was not working when we last tested it.


RS online: 15€84 each 🙂
Link: | Pasivos | Condensadores | Condensadores de Mica | Serie D

Mouser "no stock", price: 97-186€00 each
Digi-Key "no stock", price: 23-27€00 each

Farnell have on stock but price: 30€25 each🙁

If you have problems to buy in Pcx or Rs online let me know, if you want I can help you.

Felipe
 
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#2,952
merlin el mago said:
Received today the 12 mica caps

As you can see all are tested to know exactly value🙂
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You see, no nominal 15.72n is more or less different than about 15.6n in your batch. That will take a corrective cap addition as Ricardo did. Measure your 47n also. Get a couple of 2.2Meg resistors to test in parallel to each of the 47k for final tuning when the phono will be ready. That will sway the overall tilt enough so to judge how it will go in your system given the total tone with your parts types, values, load, TT setup etc.
 
#2,953
BTW.... It is possible your DMM is not reading correctly because this russian micas have +-0.3% dev so min value should be 15.67 and max 15.77n.

I am very interested in your results using these caps. Hope you get all the parts soon 🙂
 
#2,955
Salas said:
Get a couple of 2.2Meg resistors to test in parallel to each of the 47k for final tuning when the phono will be ready. That will sway the overall tilt enough so to judge how it will go in your system given the total tone with your parts types, values, load, TT setup etc.
Click to expand...

This advice is to try when the fono will ready, so I test with & without resistors and after I can left mine preferred overall tilt ok?
 
#2,956
Yes. Putting the 2.2Meg over the 47k (R3) will get it to 46k. That will move the overall tilt just enough so to let you decide. Just an easy tool to judge and decide your tone trend given the types of parts you are going to use.
 
#2,957
RCruz said:
BTW.... It is possible your DMM is not reading correctly because this russian micas have +-0.3% dev so min value should be 15.67 and max 15.77n.

I am very interested in your results using these caps. Hope you get all the parts soon 🙂
Click to expand...

Never, never trust specified values😡. I remember once used a PRP marked 1Kohm & measured 500ohms😀, other issue is check the parts are not internally broken (rare but possible).

As I remember only: Pcx resistors & 0,1uF teflon russians caps.

I will let you know in mine results, thanks

Felipe
 
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