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Old 27th December 2011, 05:52 PM   #231
Pano is offline Pano  United States
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My Edirol (now Cakewalk) FA66 does 4 channels of 24/192 duplex.
Seems like a great choice for the price. Well worth looking into, thanks.
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Old 27th December 2011, 05:59 PM   #232
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I am going to spend some money on silicone carbide devices, to try if some difference will be heard or not...
Hate being a grammar cop, but I have seen this mistake so many times in recent days (not just here) that I am compelled to butt in:

"Silicon" is a semiconducting, somewhat metallic-looking, element, bluish in color; devices are now being made from silicon carbide.

"Silicone" is akin to an organic ketone compound, containing hydrogen and oxygen, but with the carbon atoms replaced by silicon. There are many different silicones, all of them oily in nature.

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Old 27th December 2011, 06:04 PM   #233
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Polydimethylsiloxane and its derivatives, to be precise. Tit versus kit.
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Old 27th December 2011, 06:26 PM   #234
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Polydimethylsiloxane and its derivatives, to be precise. Tit versus kit.
Yeah, and since we live in modern California where Holly Wood is going to kill Internet, we should use proper grammar.
By the way, I used before Tascam US-122 D/A that is 96 KHz/24 bit, but now had to switch to M-audio because it does not need M$ Windows and stinkin' firmware download each time I power it on.
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Old 27th December 2011, 06:33 PM   #235
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Only from people who believe that nothing has advanced since 1968.
Not only from them. Also from people who believe that everything had been advanced, so all that was used before have to die.
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Old 27th December 2011, 06:39 PM   #236
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Hi,

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Originally Posted by Pano View Post
Since Class-A runs a such at high idle current and idle temperature, just how much will short term bursts of music change that point? I.E., if the dynamic peaks are only equal to the idle current, the change in current flow won't be high in relation to idle current. Temperature should not change much. Thorsten seems to say that it will, but I ask how much as compared to a low bias amp?
If you run class A and you have a signal just at the edge of class A then one transistor will experience near cutoff, that is it will experience near zero dissipation and the other a doubling of current, that is a doubling of dissipation.

As there is significant thermal resistance between the die and even the heat spreader (have a look at the thermal tracking of the so-called "thermaltrak" transistors) and more of it into the heatsink you can be quite sure that significant temperature changes of the die will be experienced, disregardless of heatsink size.

The precise thermal profile as it relates to the signal will differ for class A and Class AB amplifiers, but both experience significant modulation effects, as do Mosfet's incidentally.

The only saving grace in many cases is that BJT output stages are usually quite heavily degenerated, so the thermal modulation effects are swamped by the emitter resistors... Of course, the lower the emitter resistors, the lower the degeneration...

SE Class A Tubes anyone?

Ciao T

Ciao T
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Old 27th December 2011, 06:52 PM   #237
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Originally Posted by ThorstenL View Post
A major problem is that all these measurement systems invariably involve a lot of averaging...
Not so. Averaging drops the analog detector noise floor, but it's perfectly possible (as I demonstrated in another thread and in some of my published research) to use a single impulse to overcome the objections of unspecified artifacts which somehow get averaged out.
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Old 27th December 2011, 06:53 PM   #238
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Thorsten;

I have both SE class A tube and SE class A MOSFET designs. MOSFET design uses a source follower bootstrapped by another one, and is loaded on counter-modulated CCS. As you can see, variations of power dissipation of the device is minimal. As well as other parameters, such as capacitances.
For SE tube I found the best tube I could, it is 4P1L that is a copy of the tube designed by Telefunken for German army before WW-II. It worth it.
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Last edited by Wavebourn; 27th December 2011 at 06:56 PM.
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Old 27th December 2011, 07:19 PM   #239
a.wayne is offline a.wayne  United States
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So Sy was correct, nothing after 1969 ... for you ..........
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Old 27th December 2011, 07:52 PM   #240
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Hi,

Quote:
Originally Posted by Wavebourn View Post
For SE tube I found the best tube I could, it is 4P1L that is a copy of the tube designed by Telefunken for German army before WW-II. It worth it.
Try the YO-168 or thr german RE-604...

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