John,
I would expect with such a relatively high Zout, there is some sensitivity to interconnect cable parameters. Is that something you have experienced?
BTW Why is it so relatively high anyway?
jd
Yes. If you sift through this thread, you'll find this mentioned while I was wasting some time to analyze this famous preamp.
Perhaps from an engineering perspective, however the market showed it makes a lot of sense
Perhaps from an engineering perspective, however the market showed it makes a lot of sense
No I was asking about the 1k series R; I realize that crippling a line amp with a largish output Z (whether series or parallel) makes a lot of marketing sense as it allows you to distinguish your product from others, and, depending on your reputation, 'different' is often translated to 'better'.
jd
I wish to protest that many 'learned' people here are behaving badly.
First, I didn't choose 1K without consideration of the TRADEOFFS! It is IMPOSSIBLE to go any LOWER, without excessive distortion at operating level, or adding a follower stage of the type that I am famous for. I decided to separate myself from AYRE, the original designer of a preamp topology of this type, by NOT using a follower output stage. This 1/2s the components, reduces the stage count, simplifies the design considerably, and allows a transconductance output that is immune to short circuits.
Since 1K was the standard output impedance of Marantz, McIntosh, Dyna, etc. tube amps of high regard sonically, over the world for decades, I decided that I might try to get away with it, myself. Certainly, the Audible Illusions, with twice the output impedance did OK, most of the time, so 1K would not be a problem with most people. We offered to add a jfet follower buffer, as there was room alloted in the case, (one of the reasons it was so large) for one, BUT we never got a request for one.
It is sad that learned people are too lazy to think it through, before offering criticisms.
First, I didn't choose 1K without consideration of the TRADEOFFS! It is IMPOSSIBLE to go any LOWER, without excessive distortion at operating level, or adding a follower stage of the type that I am famous for. I decided to separate myself from AYRE, the original designer of a preamp topology of this type, by NOT using a follower output stage. This 1/2s the components, reduces the stage count, simplifies the design considerably, and allows a transconductance output that is immune to short circuits.
Since 1K was the standard output impedance of Marantz, McIntosh, Dyna, etc. tube amps of high regard sonically, over the world for decades, I decided that I might try to get away with it, myself. Certainly, the Audible Illusions, with twice the output impedance did OK, most of the time, so 1K would not be a problem with most people. We offered to add a jfet follower buffer, as there was room alloted in the case, (one of the reasons it was so large) for one, BUT we never got a request for one.
It is sad that learned people are too lazy to think it through, before offering criticisms.
1k was a standard, but is not anymore. Could you point to any Stereophile class A ranking solid state preamp of such high output impedance?
I do now understand better why in your experience cables make an audible difference 😀
So? PMA, YOU know my tradeoffs. IF YOU want to make other tradeoffs, then do so.
On this same website on another thread, the same 'learned' people are 'proving' that there are no differences between cables, with the SAME enthusiasm as they are 'proving' here that I should have added a follower or at least, global negative feedback.
Except for the case of EXCEPTIONAL cable capacitance, what is the problem? Impedance matching, electrostatic pickup, DA changes? Try PROVING those assertions on the other thread. The same people will tear you to pieces!
On this same website on another thread, the same 'learned' people are 'proving' that there are no differences between cables, with the SAME enthusiasm as they are 'proving' here that I should have added a follower or at least, global negative feedback.
Except for the case of EXCEPTIONAL cable capacitance, what is the problem? Impedance matching, electrostatic pickup, DA changes? Try PROVING those assertions on the other thread. The same people will tear you to pieces!
PMA, I wish to remind you of a detail that might put you on the right track with this.
As you know, the Parasound JC-2 preamp, my cheaper effort to make a quality preamp, has a class A rating and won 'Preamp of the year' in the 'Absolute Sound' in 2008. YET, my associates and I prefer the sound of the CTC Blowtorch over the JC-2. Several of my associates, and I have compared them. The CTC still sounds better.
The CTC Blowtorch was reviewed by another magazine, as it could not be reviewed by 'Stereophile' because we do not use dealers to sell our product. We don't qualify for a review. Therefore, no rating.
NOW, if I had my choice, I would probably choose between 50-100 ohms output impedance. It just was not possible with this design.
As you know, the Parasound JC-2 preamp, my cheaper effort to make a quality preamp, has a class A rating and won 'Preamp of the year' in the 'Absolute Sound' in 2008. YET, my associates and I prefer the sound of the CTC Blowtorch over the JC-2. Several of my associates, and I have compared them. The CTC still sounds better.
The CTC Blowtorch was reviewed by another magazine, as it could not be reviewed by 'Stereophile' because we do not use dealers to sell our product. We don't qualify for a review. Therefore, no rating.
NOW, if I had my choice, I would probably choose between 50-100 ohms output impedance. It just was not possible with this design.
Good morning, John.
There's absolutely no problem.
I can confirm that when a BT preamp is involved, there are most likely audible differences between cables 😀.
This is one tradeoff I have no problem with. The best pulse generator we ever had was open loop current out with the 50 Ohm termination only at the other end. And yes, cables made a difference.
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