Hi,
I would like to integrate a simple phono preamp into my lm3886 power amp. The psu for the power amp supplies +/-26 VDC, and the phono preamp (a TL072-design) needs max +/-15VDC.
Is it possible/recommendable to use the same power supply for this? Would for example this ESP "Simple Pre-Regulator" Pre-Regulator be a possible solution?
I hope you have time for this basic question!
Best regards,
Fredde
I would like to integrate a simple phono preamp into my lm3886 power amp. The psu for the power amp supplies +/-26 VDC, and the phono preamp (a TL072-design) needs max +/-15VDC.
Is it possible/recommendable to use the same power supply for this? Would for example this ESP "Simple Pre-Regulator" Pre-Regulator be a possible solution?
I hope you have time for this basic question!
Best regards,
Fredde
With 26 volt amp rails you can just use a three pin regulator such as LM317 and LM337 to get your preamp rails. Most integrated regulators can easily handle your rails without need for a pre-regulator to drop the voltage.
With an appropriate zener diode string to get you 12-15V you can use the ESP circuit you linked to as your regulator if you add a 100-200 uf cap at the output, but I suspect you will get better performance from the LM3xx regulators. Powering a couple of TL072s you wouldn't need TO-220 pass transistors, as the dissipation would be less than .25W. You could save some space and substitute MPSA42 and MPSA92 or if you want a little more margin, MJE340 and MJE350.
You might also consider substituting OPA2134 for the TL072 in your preamp. A bit cleaner sound, just be sure to put the 100nf power bypass caps right at the chip.
With an appropriate zener diode string to get you 12-15V you can use the ESP circuit you linked to as your regulator if you add a 100-200 uf cap at the output, but I suspect you will get better performance from the LM3xx regulators. Powering a couple of TL072s you wouldn't need TO-220 pass transistors, as the dissipation would be less than .25W. You could save some space and substitute MPSA42 and MPSA92 or if you want a little more margin, MJE340 and MJE350.
You might also consider substituting OPA2134 for the TL072 in your preamp. A bit cleaner sound, just be sure to put the 100nf power bypass caps right at the chip.
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So it's even simpler
Space is rather essential here, so I'll be glad to skip unnecessary components. I read in the datasheet that LM317/37 can take 40V which is more than enough.
And yes OPA2134 would probably be a better choice. I have some NE5532 at home so I might go for those. The author of this schematic: Hi-Fi RIAA Phono Preamp also suggests substituting TL072 with either OPA or NE.
Thanks a lot for your info!
/Fredde
Space is rather essential here, so I'll be glad to skip unnecessary components. I read in the datasheet that LM317/37 can take 40V which is more than enough.
And yes OPA2134 would probably be a better choice. I have some NE5532 at home so I might go for those. The author of this schematic: Hi-Fi RIAA Phono Preamp also suggests substituting TL072 with either OPA or NE.
Thanks a lot for your info!
/Fredde
Yes I usually use sockets anyway, it's easier to correct possible mistakes.
I will not use Rod's board since I don't have room for it in my amp chassis, and, so I'll probably make a tight little veroboard design (as usual).
I don't like using premade PCB:s as you can't make modifications or additions very easily, and IMO it simply takes away part of the fun with DIY! My first electronics-project was a velleman-kit phono preamp (the one I'm now about to replace) and when I was finished I asked myself why I just spent much more time and money putting a kit together (bad sounding and with low grade components) than buying a cheap and good sounding factory made preamp. Then I started to read and modify schematics, buying components, breadboarding and veroboarding. Built a couple of synths of variable weirdness, a few guitar effects and finally a chip amp. So much more fun, and a great feeling of success when something works!
And of course, this forum has been, and will continue to be a great resource! Thanks again!
I don't really know what this refection has to do with anything, but I'll let it stand
Regards,
/Fredde
I will not use Rod's board since I don't have room for it in my amp chassis, and, so I'll probably make a tight little veroboard design (as usual).
I don't like using premade PCB:s as you can't make modifications or additions very easily, and IMO it simply takes away part of the fun with DIY! My first electronics-project was a velleman-kit phono preamp (the one I'm now about to replace) and when I was finished I asked myself why I just spent much more time and money putting a kit together (bad sounding and with low grade components) than buying a cheap and good sounding factory made preamp. Then I started to read and modify schematics, buying components, breadboarding and veroboarding. Built a couple of synths of variable weirdness, a few guitar effects and finally a chip amp. So much more fun, and a great feeling of success when something works!
And of course, this forum has been, and will continue to be a great resource! Thanks again!
I don't really know what this refection has to do with anything, but I'll let it stand
Regards,
/Fredde
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