Bi wire options

[Julf]

I'm saying amps with low feedback sound better... generally

Your subjective opinion is noted, but it goes against general scientific/engineering consensus and objective measurements.

 

[Julf]

Again, I would have thought it obvious...

Oh, the number of people who have thought their view was obvious who have turned out to be wrong...

 

[Julf]

Only partially relevant but "Interface Intermodulation in amplifiers" R. Cordell, Wireless World Feb 1983 may be of interest

Thanks, will try to find it (I haven't kept my copies), but 1983 was 36 years ago. Here is a somewhat more recent view: Linear Audio: The F-word.

 

[Arkless Electronics]

Your subjective opinion is noted, but it goes against general scientific/engineering consensus and objective measurements.

Indeed it does... but much listening says otherwise! You don't know a "Serge Auckland" do you?

In my experience, designing for lowest possible distortion and output impedance, "doing a Doug Self", results in usually, but not 100% of the time, a grey, sterile, lifeless sound.

 

[Arkless Electronics]

Thanks, will try to find it (I haven't kept my copies), but 1983 was 36 years ago. Here is a somewhat more recent view: Linear Audio: The F-word.

Not quite the same thing...
Yes I'm well familiar with the Bruno Putzys article. It adds nothing new, is generally very good, but there are aspects of it i disagree with based on experience of the likely subjective results... please don't ask precisely which bits as it's a few years since I read it 3 times in succession whilst waiting for someone in a hospital waiting room... for hours...

There's a good paper by E. Cherry that covers some of the same things I've been saying and which Cordell also mentions but I'd have to dig it out to find the title...

 

[John Phillips]

Thanks, will try to find it (I haven't kept my copies), but 1983 was 36 years ago. Here is a somewhat more recent view: Linear Audio: The F-word.

Historical WW copies are available at https://www.americanradiohistory.com/index.htm. The Cordell paper does not support "low feedback is better" theory, at least in respect of interface intermodulation:

"Based on this investigation, it appears that high feedback factor and high open-loop output impedance do not increase the likelihood of interface intermodulation. Rather, what is important is the ratio of these quantities, or simply closed-loop output impedance." ​

Nor does it address nonlinearity IRO single- or bi-wiring.

As it happens I have in my archives from many years ago some SPICE simulations I did of various cable types and my amplifier and loudspeakers at the time. I don't recall anything recommending bi-wiring (IRO linear effects only). That may be my faulty memory of course. I actually did some listening tests of what I simulated and concluded the differences (in my case, anyway) were sufficiently small that anything I heard could have been just my imagination.

I will look up the files but it may take more effort than I want to exert to re-examine them properly. I will see.

 

[Arkless Electronics]

Historical WW copies are available at https://www.americanradiohistory.com/index.htm. The Cordell paper does not support "low feedback is better" theory, at least in respect of interface intermodulation:

"Based on this investigation, it appears that high feedback factor and high open-loop output impedance do not increase the likelihood of interface intermodulation. Rather, what is important is the ratio of these quantities, or simply closed-loop output impedance." ​

Nor does it address nonlinearity IRO single- or bi-wiring.

As it happens I have in my archives from many years ago some SPICE simulations I did of various cable types and my amplifier and loudspeakers at the time. I don't recall anything recommending bi-wiring (IRO linear effects only). That may be my faulty memory of course. I actually did some listening tests of what I simulated and concluded the differences (in my case, anyway) were sufficiently small that anything I heard could have been just my imagination.

I will look up the files but it may take more effort than I want to exert to re-examine them properly. I will see.

Hence I said "only partially relevant"! It does go into issues to do with back EMF from the speaker, which is a part of what I was saying in my lengthy post up thread but which Julf said "I'd like to see some sims of that/evidence for it" or similar (my quotation marks!).

 

[Julf]

In my experience, designing for lowest possible distortion and output impedance, "doing a Doug Self", results in usually, but not 100% of the time, a grey, sterile, lifeless sound.

Nothing wrong with a personal preference for some coloration and distortion.

 

[Julf]

Hence I said "only partially relevant"! It does go into issues to do with back EMF from the speaker, which is a part of what I was saying in my lengthy post up thread but which Julf said "I'd like to see some sims of that/evidence for it" or similar (my quotation marks!).

A reference to a 1983 article in a magazine is not really either.