Is it possible to modify 2520 DOA's for +/-24VDC?

[ubxf]

This JLM99V could be good
https://www.jlmaudio.com/shop/jlm99v-opamp-/-24v-to-/-34v.html?display_tax_prices=1

 

[JW]

Thanks,
I've tried nearly all the +/-24V opamps I can find to build. (Not the JLM one due to expense) So far, indeed Pierre Paulo Abbate's APP992 is my favorite. Was just trying to see if it was possible to force the 2520 into this format without building a power supply.

 

[FIX]

The 2520 has a unique sound, so subbing a different amp won't have the same results, and you cannot go above 16V as it is not a self basing op-amp, it is a fixed bias, so it will bake.

 

[JW]

So, may I ask, what value of cap in series with the zener diode to drop voltage. I'll have to research the diode as well. Does this look like a candidate for the diodes? 7.5V drop, 500mW. https://www.mouser.com/ProductDetail/Vishay-Semiconductors/TZX7V5D-TR?qs=oNDV51lhjEPrJGNu9T45Uw==

 

[FIX]

Series Zeners don't always provide a stable voltage if the load changes, I would suggest that you be careful. The 51X thing only gives you 3.5dB more headroom, as +-16 puts out (32Vpp, ideal, no internal drop or PSU diode drops) +23.3 dBu and +-24 gives you (48Vpp, ideal, no internal drop or PSU diode drops) +26.8 dBu. Because the 51X has dual PSU inputs, it uses diodes to steer the different voltages to the circuit, so you can already take off another .5dB. If you then step it up with a balanced output stage, you can add 6 more dB. Most DAW interfaces clip anywhere between +22 and +28, so the effort, expense, fiddling and what ever is a waste of time, as with +-16 you can already blast the hell out of the input as it is.

If you use a 2520, or a 990, both are fixed biases, and you drop the rails down with a 7.5V zeners, you have the same output level out with a regular 500 setup, so why bother?

 

[radardoug]

I once had a client who insisted that preamps needed 100 volt power rails so they didn't clip, and you got more dynamiic range. This was for live work. I then pointed out to him that typical separation on mikes on a stage was 20 to 30 dB, so the extra rail made no difference. And so it is here.

 

[JW]

I'm using the power rails on my console. +/-24V. I don't have a 51X power supply. Another power supply could be built, but I was just hoping I might be able to use the console's power supply rails, but drop the voltage locally at the opamp.

 

[JohnRoberts]

Series zeners to drop voltage will be more stable with load than dropping resistors. Suitable PS decoupling capacitors will firm up the resulting rail.

If you had to, there is enough excess voltage to drop in 3 terminal regulators but that seems unnecessary overkill unless those op amps suffer from poor PSRR (power supply rejection ratio). Do we know the PSRR of these DOAs?

JR

 

[FIX]

What console is it?

 

[JW]

Yamaha Pm2000