Sound of parallel opamps.

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#2
I have played with massively paralleled circuits, including
ordinary op amps, and there are definite improvements to
be had. At Threshold we nearly launched a preamp with 25
parallel stages for each section. Until we costed the parts out.
 
#3
Maybe I misunderstood Bernhard, but I think he meant that he
found the sound better if using only one opamp instead of two
in parallel as in the original design. There are right ways to
parallel op amps and there are wrong ways to do it. Perhaps
posting a schematic will help people to give useful comments
on this observation.
 
#4
In parallel universe maybe!

Nelson Pass said:
I have played with massively paralleled circuits, including
ordinary op amps, and there are definite improvements to
be had. At Threshold we nearly launched a preamp with 25
parallel stages for each section. Until we costed the parts out.
Click to expand...


Nelson....... April fools day is not for 13 days. If that was a practice run the official entry is going to be a real whopper!
 
#6
One sounds better than two.

Here is the schematic, followed all the tracks on the double layer pcb :radar:

😕 Why do they take the feedback before the 150ohm resistors ?

😕 Better remove the muting circuit ?

😕 Better remove the 47ohm resistors on the power supply pins ?
 

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#7
Bernhard said:
One sounds better than two.

Here is the schematic, followed all the tracks on the double layer pcb :radar:

😕 Why do they take the feedback before the 150ohm resistors ?

😕 Better remove the muting circuit ?

😕 Better remove the 47ohm resistors on the power supply pins ?
Click to expand...


the 150ohm resistors are summing resistors. They are there to even out any minor differences between the two amps / gain resistor networks so you don't end up in a situation where one opamp is driving the other like crazy.

You can eliminate the muting circuit if you don't need it.

the 47ohm resistors are for decoupling. yes, you can take them out.
 
#8
One sounds better than two.
Click to expand...

Parallel anything (tube, fet,opamp) sounds different than single. There is often loss of immediacy and focus but there are also some virtues. Many believe that the negative effects can be minimised by precise matching of gain - the resistors in your case.
A commercial product should be able to drive a wide variety of loads - if it sounds better to you single that's how you should set it.

Of course it will sound better without the mute.

Why don't you build a new amp with less comromises using better chips?
 
#11
Mr Pass said:
"I have played with massively paralleled circuits, including ordinary op amps, and there are definite improvements to be had. At Threshold we nearly launched a preamp with 25
parallel stages for each section..."


Analog_sa said:
"...Parallel anything (tube, fet,opamp) sounds different than single. There is often loss of immediacy and focus but there are also some virtues...."

For my knowledge, could you please explain the virtues of parallel amps or indicate a reference document to look at .

Thanks in advance
 
#16
38 ma is the short circuit current. I doubt that the 5532 is able to drive this amount of current without significant distortion. The 150 ohms resistors have probably both purposes (isolation between the 2 x 5532 outputs and for current limiting (with the 68 ohms).

If the goal of paralleling 2 x 5532 is to increase the current available, then it is not the virtue that I would be looking for!
Isn't it better to use a discrete transistor class A amp to allow enough current?
Is there another virtue of parallel op-amps for the sound reproduction?
 
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