Not sure if anyone has provided this link so far https://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=635
And this is a headphone amp that doubles up as a ultralow distortion differential line driver https://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=7&t=825
Available from the guy's company either built, or as a bare board for DIY https://ka-electronics.com/shop/index.php?route=product/product&product_id=67
Although the performance in the above links is just fine the way they are, there is nothing to prevent them driving a line via a transformer.
But note the distortion performance of the headphone amp driving a 1000 foot line at 24dBu at the end of the first link.
And this is a headphone amp that doubles up as a ultralow distortion differential line driver https://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=7&t=825
Available from the guy's company either built, or as a bare board for DIY https://ka-electronics.com/shop/index.php?route=product/product&product_id=67
Although the performance in the above links is just fine the way they are, there is nothing to prevent them driving a line via a transformer.
But note the distortion performance of the headphone amp driving a 1000 foot line at 24dBu at the end of the first link.
At 70 cents , it sounds crap but when its assembeled (crappily) inside a solid mahogany box for 400$, then suddenly it becomes...
"The Grado RA1 is a battery-powered, reference-quality headphone amplifier designed specifically for Grado headphones, known for its warm, smooth, and full-bodied sound, and its elegant solid mahogany case. "
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Translation..
To avoid any confusion, here's a quick German explanation for you!
I have various equipment, several pairs of speakers, several amplifiers, DACs, and network players! I've heard a lot of comparisons, but the TDA7293 with the Burson V7 sounds the best! I was surprised that my Naim couldn't keep up.
I've heard just about every op-amp in my life, but never one like the Burson V7.
Not sure if this link is already shared here - OPA distortion measurements:
https://audioxpress.com/article/modern-op-amp-distortion-tests-part-1-bjt-input-devices
https://audioxpress.com/article/mod...-part-2-a-few-more-bjt-types-and-jfet-devices
"Figure 12 demonstrates the OPA1612 working as a voltage-follower with the usual output loads. Again the 100% negative feedback, and the lack of resistors in series with an input, brings the distortion down so it is barely measurable at 20kHz even when loaded with 500Ω. Much better than the 5532 in Figure 4."
But of course it needs to be used properly. With 10k source resistance it's wasted money. You need to use low feedback resistivity and probably find a tradeoff between THD and noise.
https://audioxpress.com/article/modern-op-amp-distortion-tests-part-1-bjt-input-devices
https://audioxpress.com/article/mod...-part-2-a-few-more-bjt-types-and-jfet-devices
"Figure 12 demonstrates the OPA1612 working as a voltage-follower with the usual output loads. Again the 100% negative feedback, and the lack of resistors in series with an input, brings the distortion down so it is barely measurable at 20kHz even when loaded with 500Ω. Much better than the 5532 in Figure 4."
But of course it needs to be used properly. With 10k source resistance it's wasted money. You need to use low feedback resistivity and probably find a tradeoff between THD and noise.
Thanks for the links - I had not seen those articles. Very useful information, as expected, from Doug Self.
And yes, there are always powerful reasons to minimise driving impedance.
And yes, there are always powerful reasons to minimise driving impedance.
Of a single opamp, sure. And way below the distortion of a loudspeaker.
However, if you have a bunch of them in an active crossover, or a programme equalizer, there is a powerful reason to reduce distortion and noise wherever possible. The 5532 and 5534 still are superb work horses and tough as nails. But opamp performance has moved on from the 5532's introduction in 1979 - 46 years ago.
However, if you have a bunch of them in an active crossover, or a programme equalizer, there is a powerful reason to reduce distortion and noise wherever possible. The 5532 and 5534 still are superb work horses and tough as nails. But opamp performance has moved on from the 5532's introduction in 1979 - 46 years ago.