There's a big difference between checking/simulating the performance and full-bird "buy a finished commercial product". There's not a single serious speaker designer I know of that doesn't rely upon computer modeling and usually also measurement. Why shouldn't electronics be given the same kind of vigor? OPA627 can easily get out of line as it's high-speed.
I'm not saying people shouldn't try different opamps, just that they should take the time to be sure that they're getting the correct performance from a given implementation before deciding what sonic signature to ascribe to a given part. A lot of bad things can sound good at first.
I'm not saying people shouldn't try different opamps, just that they should take the time to be sure that they're getting the correct performance from a given implementation before deciding what sonic signature to ascribe to a given part. A lot of bad things can sound good at first.
Yes a bit more risky with IC opamps. Most of the discrete designs out there are specifically designed to be a drop in replacement for IC opamps. I've had good like with them with my testing.
It is indeed a learning process - but the learning process benefits from an evidence-based approach. Relying on folklore and knowledge "handed down from the masters" was appropriate for the dark ages. We should take advantage of all the engineering and scientific knowledge gained in the last 100 years
But not any random opamp - you have to replicate the critical parameters of the specific opamp you are replacing, and even then the replacement might work in some circuits, but not in others. That is why, as badman pointed out, use of computer simulation to check your assumptions is the rule in circuit design.
Any test results you would be able to share with us?
They were just subjective tests with the Bursons and Sparko's. But sounded better to both my ears and everyone I demoed them to than the LM4562's. Dead silent as well. Connected direct to the DAC cranked to max and sounded like the amps were off. Absolutely nothing coming out of the speakers.
Ah, OK! The word "test" can mean so many different things.
Ultrasonic oscillation is not normally audible, and mostly doesn't come out of the speaker (but stays in the speaker, heating it up). It is rather easily visible on a scope.
It's just "Julf", no Mr needed on nicknames
I am actually having a bit of trouble finding proper specs on the Burson opamps, but the function would have to be analyzed/simulated in the specific circuit setup, and I am not familiar enough with the nc500 circuitry.
Oscillation is really easy to check for once you have a live circuit - just look at the amp output with a scope - even a $200 digital scope will do. All you need is sufficient bandwidth on the scope.
Just to elaborate a bit - in the case of the ncore amps, being class D, they have to have a low pass filtering function to avoid aliasing, so anything above 200 kHz or so will be cut off by the power amp, but might still cause intermodulation. Thus the oscilloscope should be connected to the opamp output (where it is easier to see the oscillation anyway, as the switching noise will make the scope picture messier on the ncore output).
Oscillation between 20 kHz and 100 kHz might still make it out of your tweeter, and annoy your dog or pet bat (named Eric).
Mr = Respect (we were taught this at School)
Thanks, appreciated, but I am just used to someone using "Mr <my family name>" being a sign of me being in trouble...
But do you have a pet bat named Eric?
Then I recommend a cheap digital oscilloscope. Comes in handy for a lot of other stuff too...
Op Amps
All the technical information is available at Burson.com I have been to the site myself and the V5 is according to the site a direct replacement for the LM4562.
I have read many posts and articles and have not seen one instance where someone had a problem with the Burson V5. Also nobody on this site can actually say that there will be.
As you know I am getting some of Boggits NC500 mono blocks and later I am going to buy his uprated buffers with the Burson V5. I am not at all worried about doing this and I have very expensive Scan Speak tweeters in my speakers.
I have the utmost faith in Boggit and his products and am sure he would not sell something which would lead to problems in the future.
All the technical information is available at Burson.com I have been to the site myself and the V5 is according to the site a direct replacement for the LM4562.
I have read many posts and articles and have not seen one instance where someone had a problem with the Burson V5. Also nobody on this site can actually say that there will be.
As you know I am getting some of Boggits NC500 mono blocks and later I am going to buy his uprated buffers with the Burson V5. I am not at all worried about doing this and I have very expensive Scan Speak tweeters in my speakers.
I have the utmost faith in Boggit and his products and am sure he would not sell something which would lead to problems in the future.
I am sure it is - but I couldn't find it when I had a quick look this morning.
If it isn't too much bother, could you post a link to the information?
Indeed, I am pretty sure he will test the amp with the burson opamp, and make sure there is no harmful oscillations etc., especially considering how easy it is to do. No need to speculate, when 2 minutes with a scope will give reassurance.
Nice - I have been a fan of ribbons ever since I came across the original Decca London - especially with the horn removed.
Hi Julf here is the link to the data sheet
https://drive.google.com/file/d/0Bxn23njCr8VCR19ELS1YOTMxV00/view?pli=1
https://drive.google.com/file/d/0Bxn23njCr8VCR19ELS1YOTMxV00/view?pli=1
Thanks! It is not very comprehensive (compare to TI, who even provide a Spice model for their opamps), but while I can't spot any hugely major incompatibilities (the obvious ones are input offset and bias currents that are 7000 and 3000 times as large on the Burson) , I do notice that the LM4562 has generally better specs.
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