I am glad you are enjoying your Salas Simplistic so much.... It sounds that good mainly due to your carefull work. Thank you so much for your efforts. I knew you would also hear the differences.
IMO the 318uS zero point is VERY important for the overall Timbre of the instruments.
IMO the 318uS zero point is VERY important for the overall Timbre of the instruments.
So what is the trimmed values network and on what gain machine? So to keep in record and measure on some opportunity. Some sketch pls.
Merlin´s Salas riaa has double paralleled input jfets and works with 45v Vin.
R1 = 3k3r
R3 = 45804r // 4M99 = 45388r
R5 = 1M
So actual R3 for calc purposes should be around 46428r
R4 = 6810r // 1M = 6764r
C2 = 47.01nF
C2 x R4 = 318uS
I am not sure about C3 (15 ~16nF)
R2 under the paralleled input jfets is 15r
As he does not use the source cap bypass I guess it would produce 58dB gain.
R1 = 3k3r
R3 = 45804r // 4M99 = 45388r
R5 = 1M
So actual R3 for calc purposes should be around 46428r
R4 = 6810r // 1M = 6764r
C2 = 47.01nF
C2 x R4 = 318uS
I am not sure about C3 (15 ~16nF)
R2 under the paralleled input jfets is 15r
As he does not use the source cap bypass I guess it would produce 58dB gain.
It is quite difficult to reach the correct values.... I am wondering if you could suggest a combination of smaller caps values so we could reach 15.33nF and 47nF with more precision.
Its good to know you have made what you see on circuit reasonably accurately so to exclude unknown parameters when tuning a cart's load, VTA, VTF, etc. Or when you want to play with the filter itself a bit for your average tone with your records collection, system's tonal synergy, whatever.
Would 1% accuracy to the RIAA equalization components eliminate the need for tweaking values? Or is it always up to a personal taste and adjustment to the preferred tone of the entire system?
The values I give in the PDF are looking good on the simulator and the FFT measurement, also seem to bring acceptable tone judging by anecdotal feedback in the course of the thread with its many builds. With 1% you got a known standard for this preamp. I don't warn against playing with the EQ non the less if someone wants to tune there than elsewhere. EQ is EQ nobody dies if to tamper with. We have done worse.😀
You can adjust the tone by tweaking the riaa filter values but that way you will go away from the perfect riaa curve.
To retain the REAL instruments timbre you should look for the 318uS correlation.
For a 48dB gain you should use 15.33nF on the trebble cap.
For a 57dB gain you can lower it to 15.1nF.
The main riaa filter resistor depends on the output impedance of the first stage and must be calculated for each build depending on the measured resistors values.
To retain the REAL instruments timbre you should look for the 318uS correlation.
For a 48dB gain you should use 15.33nF on the trebble cap.
For a 57dB gain you can lower it to 15.1nF.
The main riaa filter resistor depends on the output impedance of the first stage and must be calculated for each build depending on the measured resistors values.
Be care for 1%, I bought 47nF 500V 1% SM and received one 46nF & the other 47nF (so one of them it's not accurate), each paid 19€39
Only option 1% 15nF & 47nF VISHAY-RODERSTEIN MKP-1837 Metalized Polypropylene Film Capacitor but who knows if it's really 1%
Only option 1% 15nF & 47nF VISHAY-RODERSTEIN MKP-1837 Metalized Polypropylene Film Capacitor but who knows if it's really 1%
It is. I have checked those many times. Polysterene honor their tolerance too. Big international manufacturers in general have the means.
It also depends on the type of cap you are using for the 15n..... And remenber it interacts with the shunt´s output and vref cap choice.... Output zobel is the major factor here when it comes to tone.... Vref deals with extension and control.
For example: 13nF Silver Mica // 2.3nF Styroflex is very different from 13nF SM // 2.3n silver mica.
For example: 13nF Silver Mica // 2.3nF Styroflex is very different from 13nF SM // 2.3n silver mica.
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https://www.rush-on-line.co.uk/cap_index.php
they usually stock what I need. Awful slow service but great availability..
they usually stock what I need. Awful slow service but great availability..