Looking for an opamp between LM4562 and Opa2604 character.

[rodabod]

[Dials DIY bullshit police] "Hello? Hi, yep.... Yep, I've got some serious busllshit going on in a thread here. What? Opamps? Yep, it's another opamps thread.... No, they haven't mentioned their favourite caps yet."

JD 'FFS' B.

Hah!

 

[mulletchuck]

http://www.youtube.com/watch?v=bpTv2jAree8

 

[lagoausente]

It's kinda popular in guitar DIY boutique stuff these days to stack opamps with the same pin out.  It definitely does change the character.  I think I'm using a OPA2604 and a NE5532 in a DS-1.  I can't remember actually.  It does change the sound and slightly increases the gain.

I'm not sure if the strategy is appropriate in things other than dirt boxes for guitar.  Although, I think monteallums.com suggests dual opamps in some eq circuits.

You could certainly experiment.

CC

I do not approve this message..  

Even when paralleling opamps on purpose, the outputs are not shorted together, but combined through some small resistances, with separate negative feedback so they don't fight each other.  

Maybe use a pan pot between the two outputs?

JR

So you were seriusly about the pan?  

  How can decouple ok the AD?

 

[radiance]

  I that case should better to correct the decopling issue if posible. Can you give any tip with that?
 

Well, you can start by soldering a 100nF polyester cap between the +V and -V terminals of each opamp.

 

[lagoausente]

Well, you can start by...

  Thanks for the tip, that "starrt by.."  mean that could be done more things there?

 

[Kingston]

Well, you can start by...

  Thanks for the tip, that "starrt by.."  mean that could be done more things there?

http://www.groupdiy.com/index.php?topic=37307.0

 

[lagoausente]

Thanks! 

 

[JohnRoberts]

NO I AM NOT SERIOUS ABOUT THE PAN>>>

If two opamps sound different in one circuit, either there is something wrong with one or both of the opamps, and/or the circuit.

Step one is to quantify what is different.

Step two is understand why there is a difference between the two opamps.

Step three is change the design or source a better part, or both, to minimize the non-ideal behavior.

If you actually want some coloration or sound effect, do whatever that takes... I am not the right guy to help you.

I primarily focus on making outputs that agree as closely as possible with inputs, with the exception of targeted changes like in the case of EQ.

JR

 

[lagoausente]

NO I AM NOT SERIOUS ABOUT THE PAN>>>

If two opamps sound different in one circuit, either there is something wrong with one or both of the opamps, and/or the circuit.

Step one is to quantify what is different.

Step two is understand why there is a difference between the two opamps.

Step three is change the design or source a better part, or both, to minimize the non-ideal behavior.

If you actually want some coloration or sound effect, do whatever that takes... I am not the right guy to help you.

I primarily focus on making outputs that agree as closely as possible with inputs, with the exception of targeted changes like in the case of EQ.

JR

  If you are right, then my conclusion is that most circuits fail in the same things. I mean,  Before trying the Opa2604  searching give info about about it´s color, and tiny high frequencies, also the 4562 is know for it´s detail in high frequencies and for being very clean.  So that mean that:
    1- Or they really are not ideal opamps so have an inherent frequency response
    2- Or most circuits flaws are near the same, so they flaw in the same directions.
  I never have read about 4562 to be "valve sounding", and Opa2604 to be very clean y high frequencies.
  I guess both things are true, opamps have their own color, and bad circuit design also can do, but I cannot asure that.

 

[jdbakker]

    2- Or most circuits flaws are near the same, so they flaw in the same directions.

That would actually not surprise me very much.

Many such comparisons, at least the ones I've read, tend to focus on a circuit which originally had slower op-amps (like the 5532), but had been 'upgraded' with newer, faster devices. So if one is more sensitive to decoupling than the other, then I expect that the sonic signature (if any) will follow the op-amp if it's plonked into circuits which had not been designed for these parts in the first place.

JDB.

 

[JohnRoberts]

It would take too many words to explain opamp theory and behavior but the short version is yes opamps have an intrinsic frequency response, but this open loop response variation is reduced by "loop gain margin" (ratio of open loop to closed loop gain).  So for most modern opamps at modest closed loop gains their frequency response will be arbitrarily flat thanks to typical gain margins.

Posted subjective impressions about opamps "sound" is a poor substitute for actually measuring the actual response of the opamp in a specific circuit.

Modern opamps often have improved performance but this would only be characterized as having less of their own sound, and sounding more true to the source material.

This isn't rocket science, but there may be subtle interactions from HF perturbations associated with DACs, PS rail noise, etc.  or not.


JR

 

[lagoausente]

   2- Or most circuits flaws are near the same, so they flaw in the same directions.

That would actually not surprise me very much.

Many such comparisons, at least the ones I've read, tend to focus on a circuit which originally had slower op-amps (like the 5532), but had been 'upgraded' with newer, faster devices. So if one is more sensitive to decoupling than the other, then I expect that the sonic signature (if any) will follow the op-amp if it's plonked into circuits which had not been designed for these parts in the first place.

JDB.

   Well, the link provided by Kingstom is antother thread that have some pdf I´ll have to read.
 It has sense what you tell, but I have a question (shorcut before reading all that).  Require much more redesigning the circuits to can get good results? or the cap tip do the job?   If much more redesigning is need is a really nonsense trying diferent opamps, unless liking masochism or trying to get a "diferent colored sound"  coming from blind experiments.

 

[Kingston]

If much more redesigning is need is a really nonsense trying diferent opamps, unless liking masochism or trying to get a "diferent colored sound"  coming from blind experiments.

That's pretty much it.

 

[lagoausente]

It would take too many words to explain opamp theory and behavior but the short version is yes opamps have an intrinsic frequency response, but this open loop response variation is reduced by "loop gain margin" (ratio of open loop to closed loop gain).  So for most modern opamps at modest closed loop gains their frequency response will be arbitrarily flat thanks to typical gain margins.

Posted subjective impressions about opamps "sound" is a poor substitute for actually measuring the actual response of the opamp in a specific circuit.

Modern opamps often have improved performance but this would only be characterized as having less of their own sound, and sounding more true to the source material.

This isn't rocket science, but there may be subtle interactions from HF perturbations associated with DACs, PS rail noise, etc.  or not.


JR

 Well, a whole world inside only opamps behaviour and interaction in the circuits..
 Another shorcut question,  from what slew rate usually are opamps considered "fast opamps".  Aprox.., or just looking at the seller label?

 

[lagoausente]

  And for continue being tiring.., no one is interested on an alternative analog version for this AD?
  Aren´t you tired of preamps and compressors yet? 

 

[jdbakker]

If much more redesigning is need is a really nonsense trying diferent opamps, unless liking masochism or trying to get a "diferent colored sound"  coming from blind experiments.

That's pretty much it.

Broadly speaking, yes.

  And for continue being tiring.., no one is interested on an alternative analog version for this AD?

This thread looks promising.

I have a few designs of my own that I'm working on, but I'm not sure if they're ever going to be released as a project. The main stumbling blocks are (a) for most hi-performance ADCs you need to do fine pitch SMD soldering, and most folks here are still wary of that, and (b) low jitter clock syncing to an external master is not a trivial problem.

JDB.

 

[lagoausente]

This thread looks promising.

I have a few designs of my own that I'm working on, but I'm not sure if they're ever going to be released as a project. The main stumbling blocks are (a) for most hi-performance ADCs you need to do fine pitch SMD soldering, and most folks here are still wary of that, and (b) low jitter clock syncing to an external master is not a trivial problem.

JDB.

  Hell!  September 2009, have realized I must visit the forum more often.
 You could better started giving your project link instead of mock me  

 

[jdbakker]

 You could better started giving your project link instead of mock me  

...but where's the fun in that?

JDB.
[plus you only mentioned the Beis ADC after my first replies, and my crystal ball's back to the manufacturer for an upgrade]

 

[lagoausente]

 You could better started giving your project link instead of mock me  

...but where's the fun in that?

JDB.
[plus you only mentioned the Beis ADC after my first replies, and my crystal ball's back to the manufacturer for an upgrade]

 Fun?  what fun? I didn´t see any fun?  ;D  
  I didn´t want to make much noise about the device name, but finally made a little. Just have to say that sounds very good, and for the opinions of the samples I have tested side by side with Mytek they told was very closed.
  I´´ll have to gather some patiente for reading such things I promised me to read some time ago.
 And thanks for the link.

 Regarding the cap tip, something easy to try, in this case, I should use only the one cap option or the two caps?
http://www.beis.de/Elektronik/ADDA24QS/Images/AD24QS_sp.pdf

 

[lagoausente]

 mm, C8,C9 aren´t the caps you tell?  100n between + and ground,  - and ground. Are not them? Aswell as C17, C18?