I don't have my JFET book on hand, but it's better the the 5459, and not as good as the 2SK170. I ran a JFET SRPP setup using the 4303 in my system (even with the problems I acknowledged), and never had a noise prroblem using a Grado Gold cartridge. It sounded nice, even if it wasn't the most accurate pramp... This time around, I can get it right. If you're curious about the old circuit, search for the "JFET SRPP" thread - it's documented there.
I will. I like SRPP in tubes too, if the load is right. Its essentially hidden push pull. Needs its 'best' load to shine. Anyway with 47K input load the input resistor's Johnson will much likely dominate. The 5534 circuits are pushed up to 10nV in practice. Anything in the 10 area will do for mm.
For low mc under 5 is good if you have over 92dB speakers. Its good to load such a wimpy mc with 47K too, but with 1K or under, and low ppm resistor you win on noise.
For low mc under 5 is good if you have over 92dB speakers. Its good to load such a wimpy mc with 47K too, but with 1K or under, and low ppm resistor you win on noise.
on psu side ??
in the next 2week for 15$ ska-amp have discrete regulator 50ma max :40 dB better regulation than a LM317 at 10KHz and much lower noise.
Greg (ska-amp) stimate 90 dB from 100Hz -20KHz at 24V from a 28V unreg supply.
I will go for dual mono config , now I need a good unreg psu.....
I ask if can work at 40v...
in the next 2week for 15$ ska-amp have discrete regulator 50ma max :40 dB better regulation than a LM317 at 10KHz and much lower noise.
Greg (ska-amp) stimate 90 dB from 100Hz -20KHz at 24V from a 28V unreg supply.
I will go for dual mono config , now I need a good unreg psu.....
I ask if can work at 40v...
A 317 with 22uF bypassed adj leg resistor will get you to -80dB ripple rejection. You can build an R-C filter before the LM317 if you size your transformer's secondary voltage higher. Just use your DMM for current measurement, see your mA draw and size a resistor to drop 10V to the main filter capacitor. See that you can get 43V on LM's input. Size the setting resistors ratio (see data sheet online) for 37V out. That will add some extra dB rejection and will be damping the current draw from the bridge rectifier reducing power rail wide band switching noise.
In my circuit you will need around 13mA per channel. A 8k2 will drop 10.66V. If you use common supply, a 3k9 will drop 10.14V.
In my circuit you will need around 13mA per channel. A 8k2 will drop 10.66V. If you use common supply, a 3k9 will drop 10.14V.
I need a good psu, dual mono, because despite
provisionally use of a smtp meanwell with 120mvp-p ripple/noise ,in my previous dac (1543) not so big difference to the ear respect battery
, as the absorption in the game are so low I can do
a with a trafo for 36-40vdc out and use the resistance drop in for
24vdc ,right?
provisionally use of a smtp meanwell with 120mvp-p ripple/noise ,in my previous dac (1543) not so big difference to the ear respect battery
, as the absorption in the game are so low I can do
a with a trafo for 36-40vdc out and use the resistance drop in for
24vdc ,right?
I had some boards burned for a low noise switching supply -- it's directly taken from the Linear Tech datasheet so no originality implied or warranted -- promised noise is 100uV or less -- and you can run it from the USB or a wall wart:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128162&highlight=
since we are getting the wrath of a hurricane I won't be out in the garden today, probably just making the SMSP transformer.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128162&highlight=
since we are getting the wrath of a hurricane I won't be out in the garden today, probably just making the SMSP transformer.
nicoch46 said:
If you use 36VAC it will give you about 50V DC after the bridge, on filter cap. Measure you current draw for 24V as it is now. Keep that reading. You may drop 20V on a resistance (Vdrop=I*R) to go 30V and feed a regulator set on 24V. Also Wres=Vdrop*I so to know the wattage burned on your resistor. Keep its W rating 3 times that.
