Slew rate of a WOPL

[Northwinds]

Inquiring minds would like to know. They are so fast reacting that I wonder what the rating is (if it's been measured)

 

[Gibsonian]

Always wondered that myself, WOPL and original 700. I believe manual stated 12mV/sec for a 700 series 1. Check me on this if someone has a manual handy. Not very fast at all and wondering if the WOPL improved on this (betting it did a little)

 

[marcok]

PL 700 rise time = 1,6 microseconds
PL 700 slew rate = 11V / microseconds
Ciao
Marco
Ps: I don't think it's possible to appreciate differences in the sound reproduction with greater values .
Obviously it's my personal opinion .

 

[Gibsonian]

I would tend to agree. I had an amp that was 45x faster than a 700 per the specs. It did not sound faster or better. It's gone and 700 remains.

 

[marcok]

I have also in my mind the Yamaha 2010 of my father ; the measuremnts are good , but it's has only one issue :
it doesn't sound .
Conclusion : now my father has a PL 700 and the Allison Ones simply fly !!!!!
Why ? I don't know .
Ciao
Marco

 

[Gepetto]

Inquiring minds would like to know. They are so fast reacting that I wonder what the rating is (if it's been measured)

Approx 20V/usec Ron, governed by the minimum slew rate of the OPA134. The remainder of the circuit is limited at approximately 50V/usec making those circuit limitations second order to the OPA.

Full 350W peak to peak response at 20 KHz necessitates at least 9.4V/usec to achieve full power bandwidth. The OPA is more than 2X this and the rest of the circuit is >5X this.

 

[laatsch55]

Is there such a thing as "slew induced distortion"??

 

[Gepetto]

Is there such a thing as "slew induced distortion"??

Absolutely. If the circuit cannot keep up with the slew rate requirements of the frequency and amplitude desired then the sine wave associated with those frequencies becomes distorted. This will show up as harmonic distortion at the output of the amp.

 

[laatsch55]

Ok, if an amp has TOO MUCH , or too high of a slew rate , does that induce distortion also??

 

[Gepetto]

Ok, if an amp has TOO MUCH , or too high of a slew rate , does that induce distortion also??

Not inherently the slew rate itself Lee, speed is usually always your friend. If the amp does not have proper (feedback) control of that slew rate however, excessive slew rate could be detrimental.


High slew rate amps also tend to be wide bandwidth amps as well. Too much bandwidth can be detrimental if the amp design is not low noise or you have noisy source inputs. Wide bandwidth amps may amplify signals of frequencies that you are really not interested in amplifying. This may show up in the N component of THD+N

 

[laatsch55]

Is this where we see overshoot and undershoot in square wave testing??

 

[Gepetto]

Is this where we see overshoot and undershoot in square wave testing??

Yes, correct Lee.

 

[laatsch55]

So the overshoot is an artifact of the amp being slow in the feedback compensation of the excessive bandwidth??

 

[Gepetto]

So the overshoot is an artifact of the amp being slow in the feedback compensation of the excessive bandwidth??

That is pretty much it Lee.

 

[laatsch55]

Brain cramp again??

 

[Gepetto]

Brain cramp again??

???

 

[laatsch55]

When we go off on these sort of tangents, the strain of coming up with analogies that will get the concept across, at times, has caused brain cramps, not exactly how you described it, but close!!

tHANK YOU FOR your patient and thoroughly competent explainations of esoteric ideas....Apple Crown and Oxycotin is a very good mix...

 

[NavLinear]

I suspect the oxy put you a bit over the edge - just saying.

 

[laatsch55]

Ya think???

 

[Northwinds]

Thanks for the info folks. I started wondering about slew rate when I read about some young kid in London finding to monster amps at a recycler. Turns out they are Class A 400w mono blocs (Class A all the time) and they have a slew rate of 800... HOLY FUCK that's fast!!!!! The amps are NRG's. Problem is, I think I read you need a 195v breaker just to turn them on???