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TS opamp

Started by 23, January 21, 2009, 10:55:24 AM

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23

Ive been reading every thread I can find on opamp stacking and it seems that every thread I read is concerned with stacking opamps for the use of both at the same time. My interest is what dano is doing to switch between single opamps or two at one time. Now i know some opamps selected together can offer good results and others not so good. But if your only selecting one at a time, do you have to worry about the problems with the opamps being stacked and more than one being used at a time?
all of this applies to the TS circuit as Im wanting to build a monster TS with as many mods as I can fit in. also if Dano reads this what value resistor are yuou using for pin 1 and 7 to share the load between the opamps?    I hope this is clear....thanks
put it together, now take it apart

23

i guess I've either been blacklisted or to the "gods" this is just a dumbass question  :icon_question: :icon_exclaim:
put it together, now take it apart

oskar

Quote
My interest is what dano is doing to switch between single opamps or two at one time
Link please...

Quote from: 23 on January 21, 2009, 10:55:24 AM
But if your only selecting one at a time, do you have to worry about the problems with the opamps being stacked and more than one being used at a time?
I guess I need to see the material you're refering to in order to answer properly but generally:
Unused OP-amps need to be stabilised in order to prevent oscillations or whatever to prevent current drain, noise or, perhaps even damage to the OP. You shouldn't just unconnect all pins.


Oskar

23

www.beavisaudio.com    go to projects and then ts
put it together, now take it apart

oskar

Quote from: 23 on January 21, 2009, 10:55:24 AM
But if your only selecting one at a time, do you have to worry about the problems with the opamps being stacked and more than one being used at a time?
What I found on that page was a lot of info and I'm not going to go through it all. Basically Dano is tying the inputs together and switches between the outputs. I'm not 100% sure this will be without trouble. You can try this yourself and measure to see if the outputs are following eachother. If the unused output don't track the output in use you could be facing trouble. Like one OP drawing excessive current or being noisy etc.
But I really don't know. The project was last updated in august 2006 it says. I couldn't see an evaluation on the op-amp switching.

Happy modding!



oskar

MikeH

Basically- yes the inputs are tied together, and the outputs are switched.  I've done it; it actually works pretty well, but doesn't provide any massise sonic differences for how much of a pain it can be to set up.

Here's a thread I did about mine:

http://www.diystompboxes.com/smfforum/index.php?topic=62136.0
"Sounds like a Fab Metal to me." -DougH

petemoore

i guess I've either been blacklisted or to the "gods" this is just a dumbass question
  The gods had their TS Opamps days.
  It's an old question, and we, every one have pondered TSOA {Terrific Sonic Opamp Appreciation}.
  Although the discussion was fiery, and the presentations ranged from flowery to gritty, the actual content among those who tried the opamps gave a light to guide those who haven't tried a few different kinds of opamps, or all kinds off dual opamps, single opamps, dual opamps stacked, 'clean-er opamps, opamps for low power consumption, and the greatest opamp ever to make the pages of magazines...without further adeu', the opamp with the highest frequency of responses and posts, the ultimate TS original:
  4558
  I forget which one.
  JRC4558 is a fine opamp.
  I tried every other one, they're all fine too, socket.
  I soon moved to the diodes and other components that made bigger changes that actually mattered to me.
  TS got pulled from the PB today, sad but true, actually 4 boxes removed !
  ...suggestions veiled as bragadocia: Low Voltage tubes, a Valvecaster '38' [volt supply] went to the pedalboard today.
 
Convention creates following, following creates convention.

23

thanks guys, guess Im just gonna pull the mad scientist and just put every damn switch I can on the box...
put it together, now take it apart

oskar

Just go nuts!                8)

Gila_Crisis

opamp for a TS? put in an OPA2134!!!! in mine (a zendrive, not properly a TS, but the basis is a TS) it sounds like a sharme!