JW

Modifying 2520 style opamps for +/-24V
« on: July 22, 2009, 12:23:24 PM »
Hey guys,

I spaced out and ordered 4 2520 kits from classic API to use in the output busses of my Yamaha PM2000 board. Even though the footprint is the same between the original Yamaha opamps and 2520's, I wasn't thinking about the voltage rails being +/- 24V on the PM2000.

Is there a way to modify the 2520 kits so they'll be okay to run on +/- 24V? (They're good at +/-18V, but I don't really want to stress them more than that)


shabtek

Re: Modifying 2520 style opamps for +/-24V
« Reply #1 on: July 22, 2009, 12:33:31 PM »
7v zener in series with 24v=17v
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

owel

Re: Modifying 2520 style opamps for +/-24V
« Reply #2 on: July 22, 2009, 12:42:37 PM »
I bought (4) NE 80100 opamps from 3nity here, thinking I would be able to swap it in/out on DOA sockets.  
(But the legs were too fat and don't fit inside my MillMax sockets.)  

So I haven't used it or even tested it since receiving it.

If you want them, I'll sell it to you at same price I bought from 3nity. $20 each.

JW

Re: Modifying 2520 style opamps for +/-24V
« Reply #3 on: July 22, 2009, 03:30:11 PM »
Thanks Owel, I actually have all the Yammy opamps I need. I was just trying these 2520 kits because they're cheap and something different.

Shabtek,
So, say something like this? http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMstCHp3EWKGl7RSz%2fWB%252byfUxlb19bicrKs%3d

Which way would I orient it at the input of the opamp? Also, I'm wondering if it'll affect the gain much. Not that that's really all that much of a problem.

EmRR

Re: Modifying 2520 style opamps for +/-24V
« Reply #4 on: July 22, 2009, 03:40:16 PM »
It won't affect gain, it will affect headroom, and hardly.  Gain is set by feedback.  Search around for plenty about voltage and headroom. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

shabtek

Re: Modifying 2520 style opamps for +/-24V
« Reply #5 on: July 22, 2009, 03:47:13 PM »
read up on zener diodes. I don't know much. don't think power rating is an issue.  to +18v pin--band facing away from opamp, the other to -18vpin band facing toward opamp.
they are in series with the +/- dc rails.
"really fine players do not use stomp boxes or master volume, they match the amp to the room and turn it up to 11.  Stevie Ray, BB King, Albert King, Duane Allman, Dicky Betts, Louis Armstrong"
   -CJ

JW

Re: Modifying 2520 style opamps for +/-24V
« Reply #6 on: July 23, 2009, 12:24:38 PM »
Awesome

Thanks guys

CJ

Re: Modifying 2520 style opamps for +/-24V
« Reply #7 on: July 24, 2009, 02:21:20 PM »
just put a big heat sink on top of each module, they are about the perdfect size for a cpu sink, they even have cooling tubes now.
fans, whatever.

be the first kid on the block to defy gravity.

serious, i think people have used those chips at the higher voltages, maybe it was a DIY chip with higher value cap ratings, tuff to remember.

hit the search engine or meta for everything API?
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

JW

Re: Modifying 2520 style opamps for +/-24V
« Reply #8 on: July 27, 2009, 12:04:12 PM »
CJ,

What chip are you talking about? These are the discrete kits from classicapi.

CJ

Re: Modifying 2520 style opamps for +/-24V
« Reply #9 on: July 27, 2009, 12:31:38 PM »
well, we used to make those chips all the time.
some freaks even knocked out a couple of deane jensen models.

peter purpose picked a pile of api and posted it properly, do a search on api and peter purpose.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html


 

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