Stuart, you will also note I've been trying to get JC to cooperate and help us do some Double Blind Tests bla bla.
I can't be certain about Blowtorch.
But Double Blind Tests were an important part of my life for more than 2 decades. We started them in the late 70's with Peter Fryer's test on audiblity of speaker distortions. As part of this, we listened to OPAs over a very long period starting from 741 (Don't laugh!) and have a list of both music & test signals which showed up the audible faults of OPAs. 5534 was the first OPA we were unable to fault in the late 70s. We actually had pre-prod samples from Mullard when it was called TDA1034.
For Blowtorch, I'm doing what JC likes to do and predict performance from the label on the box/chip/bits. ie sighted tests (prejudices). But I'm doing it with 'calculations' on THD including 7th and its performance on Hirata & Quan from his schematic.
I'm confident that eg Blowtorch will do badly on Hirata & Quan and be worse than AD797 on 7th. On audibility, I'm on shakier ground. My true golden pinnae like John Atkinson & Tony Faulkner are all my age and older.
I'm disappointed no one has nominated new younger persons who may be true golden pinnae. Will they all die out and be replaced with pseudo Golden Pinnae?
But you when you do enough Double Blind bla bla, you get an instinct about things. eg I can sense if certain subjects are easily influenced by others which is why in the Wharfedale tests, each subject is tested separately, and the 'tester' is NEVER in the same room.
I have this 'sense', about Blowtorch. Its THD performance is veering on the levels known to be audible in our own Blind Tests and other research too. JC isn't the only person to have played with FETs for small signal.
So to clarify, I contend Blowtorch will sound worse than a properly implemented 4558 device. Quan & Hirata, though poor for Blowtorch, may or may not correlate with its poor sound. They are a smoke screen to
JC's cage and persuade HIM to provide evidence. 7th is in a similar vein but, though Blowtorch will have more than AD797, it's unlikely to be responsible for its poor sound.With JC2 Mk1, I'm confident even on audibility. The decoupling & earthing WILL result in poorer distortion and marginal stability. This is audible even on music let alone the poor noise performance. Scott's AD797 datasheet confirms mine isn't the only experience of this.
Just my $0.02
PMA,
I guess some money counter got in the mix with that connector choice. Can't imagine anyone selecting that connector for a high end product, but perhaps they were trying to save money to pay for all that carved aluminum in the chassis? If this makes waves in the audio press then you will see that connector changed in an instant.
I guess some money counter got in the mix with that connector choice. Can't imagine anyone selecting that connector for a high end product, but perhaps they were trying to save money to pay for all that carved aluminum in the chassis? If this makes waves in the audio press then you will see that connector changed in an instant.
You, of course, trying by yourself, with the same value as my feelings, and in your context.
Looking to your links, i found some noticed differences between NE55xx brands, as well as : "The 5532 has more deep bass also, but has some distorsion in treble".
That seems to correlate what i pretended: Sharper basses sound less 'deep', indeed.
Since 2 decades now i use current feedback AOPs, when i can, and can't differentiate obvious differences with strait wire.
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Waly, as always, its horses for courses. Choose the right device for the application.NO!!!
For some perspective ..
Cyril Bateman in his seminal series(s) on capacitors, (far more definitive than Jung. Sorry Mr. Marsh
) had to make a really ultra supa dupa low distortion oscillator.He recommended 2 OPAs for this application. One of them was 5534. IIRC, this is after the intro of the NI uber OPAs with advertised 1pp zillion THD.
But for the ultimate, supa ultra dupa plus performance, he of course used [drum roll & fanfare] ... AD797
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It won't- the XLR supplied with this amp (it's a power amp) doesn't have a locking tab. So the cables have to be re-seated every few hours. He's tried three different types of cables to see if that's the issue- it's not. He is not a dumb guy, he was a highly accomplished engineer before he moved into management. So it's not a stupid-user issue, it's truly a design flaw that even cheap Chinese equipment manages to avoid.
The dismissive attitude is not the way we would EVER treat a customer. When people give us money for our products, we stand behind them, and when they don't perform to expectation, we make it right. The luxury audio industry is apparently different.
Given your attitude toward the people who put bread on your table, you can be sure I won't.
Kindhornman, the A21 is NOT a super fi amp. It is a MID-FI amp. I will NOT use it in my own audio system. I did not know that the connectors were not Neutrik, but it goes with the territory. For $2500 retail, you get a solid 250W/channel, made to a reasonable standard by the opinion of just about anyone here. We have to produce it in Taiwan at, at least 1/4 the selling price. Try to do this, yourself! In fact, give it to everybody here, giving everybody a credit for at least $5 per hour for their effort. Go for it!
But for the ultimate, supa ultra dupa plus performance, he of course used [drum roll & fanfare] ... AD797
I suspect he wanted not to have to use it after he copied the oscillator from Jeff Smith and me.
Why to copy an oscillator, when it is so easy to design an amplifier stage to get one ?
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There's a very powerful tool in the arsenal for picking up what's going on. And that's to use the "right" side of the brain, the intuitive, to do the "measurements" ...
Unfortunately, the "left" side, the consciously thinking part is very easy to lead astray, it has ego, etc, attached. The more you "focus", try and force the intellectual area in the brain to come to a "correct" decision the worse it often gets. This is obviously what ABX, etc, has evolved to be, to try and get around this problem ... but it has to be extremely well implemented to come up with a meaningful result.
I personally have "learnt" to deliberately switch to intuitive evaluation, this is like listening out of the corner of your ear: Clayton's listening we would call it down under - listening when you're not listening. The intuitive doesn't come up with figures, it just knows when something is right or wrong; and that's how I assess system sound, and one thing the right side of the brain doesn't like is typical hifi sound - it knows that this is really, really wrong ...
Frank
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Pretty poor posture John, surely not a time to be funny, embarrassed maybe and while at it, they should fix the dynamic killing protection circuit too...
That's unbecoming of you, Guru Wurcer!
I'm sure Bateman has the highest regard for you; unlike certain pseudo gurus.
Imitation is, after all, the sincerest form of flattery.
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