janneman said:
Ja, sehr gut.
Certainly. Push-pull properly biased is in class A since output current (peak) is under 2 x Iq.
When CCS sinked, SE output in fact, it is only to 0.5 x Iq.
Hi PMA,PMA said:
is that Ipk<0.5Iq for a resistor loaded single ended ClassA output stage?
Ipk<1times Iq for a CCS loaded single ended ClassA output stage.
Ipk<2times Iq for a push pull ClassA output stage.
And JLH style different again since the bias current is modulated by the signal level.
You think that there's no role played by hype, legend, marketing, and collector mentality? You must experience a different class of humans there.
AndrewT said:
Not sure, but would expect the bulk to be in the output stage. Maybe Scott can shed some light on that?
Jan Didden
>There is no semiconductor in tubes
>so no depletion mode I'm afraid
Doesn't depletion mode mean the device is on
without bias on the control terminal ?
>so no depletion mode I'm afraid
Doesn't depletion mode mean the device is on
without bias on the control terminal ?
Jan, these would qualify as SMD (ignoring that they're unobtainium), don't you think? (look at the match, for size relationships) 😀janneman said:
@John: Your Siemens EL34's are most probably Philips (Siemens never had a fab, to my knowledge). Or anything else... at that time everbody helped out everybody else in the business and "rebranding" was commonplace. Ie, most today "NOS Telefunken" EL34's are in fact RFT's (if they have a dent on the top, they are RFT. Those are still very good, at any rate).
- Klaus
Ok, let's get back on track here. 😀
I didn't go looking for this, but came across it last night while doing something else. I'd known about it since last year but was reminded of it when I came across it last night.
Steve McCormack on his VRE-1 preamp:
My goal while developing the VRE-1 was to create a preamplifier that would deliver the sound of an original master recording. Working as a recording and mastering engineer has been invaluable in this regard - I have a lot of experience with how even high-end electronics impose their own personality and coloration on our recordings. I wanted a preamp that would transcend merely “good,” or even “great” sound - I wanted nothing less than a true “window" onto the performance. That goal required a degree of neutrality and transparency I had never previously encountered. It took five years of research into all aspects of preamplifier design to find the right circuit topology, appropriately elegant power supply design, the right chassis material and fabrication technique, and the best-possible passive parts. All of this research work ultimately came together to form the VRE-1.
And Robert H. Levi's concluding remarks on the VRE-1 in his review of it for Positive Feedback:
The VRE-1 is a product of innovative 21st Century invention and a horse of a different color. It joins a handful of splendid preamps capable of transporting the listener to the musical event. Steve McCormack has used his enormous genius and creativity in the service of audiophiles and for this we are most grateful. The VRE-1 is a bonafide reference piece for the ages and a cutting edge component for top audiophiles and recording engineers. It's the very best solid-state preamp I've ever heard. I've never said this in print, but here goes …it's cheap at twice the price. The SMc VRE-1 receives my highest recommendation and must not be missed.
High praise indeed. Especially for a preamp that uses... transformers.
And not just input transformers, but output transformers as well. The VRE-1 does use active devices (JFETs), but only as unity gain buffers, the VRE-1's optional +6dB of gain (in addition to -6dB and 0dB) being provided passively by the transformers.
Imagine that. 😀
se
I didn't go looking for this, but came across it last night while doing something else. I'd known about it since last year but was reminded of it when I came across it last night.
Steve McCormack on his VRE-1 preamp:
My goal while developing the VRE-1 was to create a preamplifier that would deliver the sound of an original master recording. Working as a recording and mastering engineer has been invaluable in this regard - I have a lot of experience with how even high-end electronics impose their own personality and coloration on our recordings. I wanted a preamp that would transcend merely “good,” or even “great” sound - I wanted nothing less than a true “window" onto the performance. That goal required a degree of neutrality and transparency I had never previously encountered. It took five years of research into all aspects of preamplifier design to find the right circuit topology, appropriately elegant power supply design, the right chassis material and fabrication technique, and the best-possible passive parts. All of this research work ultimately came together to form the VRE-1.
And Robert H. Levi's concluding remarks on the VRE-1 in his review of it for Positive Feedback:
The VRE-1 is a product of innovative 21st Century invention and a horse of a different color. It joins a handful of splendid preamps capable of transporting the listener to the musical event. Steve McCormack has used his enormous genius and creativity in the service of audiophiles and for this we are most grateful. The VRE-1 is a bonafide reference piece for the ages and a cutting edge component for top audiophiles and recording engineers. It's the very best solid-state preamp I've ever heard. I've never said this in print, but here goes …it's cheap at twice the price. The SMc VRE-1 receives my highest recommendation and must not be missed.
High praise indeed. Especially for a preamp that uses... transformers.
And not just input transformers, but output transformers as well. The VRE-1 does use active devices (JFETs), but only as unity gain buffers, the VRE-1's optional +6dB of gain (in addition to -6dB and 0dB) being provided passively by the transformers.
Imagine that. 😀
se
PMA said:
Thank you !
I realize that the term 'depletion mode' is not usually
used in regards to tubes, but in a sense isn't it
applicable ? Both (jfet and tube) are 'normally on'
devices while bipolars and (most) power mosfets
are 'enhancement mode' and 'normally off'.
I've pondered (more in a metaphysical than
technical sense) if part of the 'magic' of tubes
(and hence jfets) is the fact that a positive signal
in sort of 'releases' the output rather than having to
force (or pull ?) it (as in the enhancement devices).
Thus giving a more 'effortless' presentation......
hitsware said:
That is totally absurd
The reason why some people like valve amps is because of their coloration and not because of some magical quality that can't be measured by normal means. Let me illustrate by way of example. The following is a spectrum analysis plot of a $300,000 tube amp as tested by Stereophile delivering 1 watt into 8 ohms at 50 Hz 
http://www.stereophile.com/images/archivesart/WAVacFIG08.jpg
Note the proliferation of low and high order harmonics right across the spectrum 🙁 Well some people like these artifacts that are not present in the original signal even though as an amplifier it is doing its job rather badly 🙁 However if that is your cup of tea then be my guest 😉
Hi Snoopy,
What's the problem? I always thought that ultra high-end is synonymous with a maximum of harmonic distortion. 😀
Cheers,
Edmond.
What's the problem? I always thought that ultra high-end is synonymous with a maximum of harmonic distortion. 😀
Cheers,
Edmond.
>The reason why some people like valve
>amps is because of their coloration and
>not because of some magical quality that
>can't be measured by normal means.
God save us from seeking truth anywhere
beyond graphs.
>amps is because of their coloration and
>not because of some magical quality that
>can't be measured by normal means.
God save us from seeking truth anywhere
beyond graphs.
john curl said:
Thank you, now I know where to place all my cranial efforts in understanding and taming the native 'flaw' in SS circuits. I always thought it was there, to a large or serious degree, it's just confirmation of what I thought was one of the core/largest non-linear issues. I'm not a circuit guy, but I'm good at understanding electricity itself and the molecular issues involved. I might be able to come up with something. You never know. The usual problem to overcome is understanding the true nature of the question itself-and in that moment-the answer also shows itself to exist.
Theese quotes are from the VRE-1 Manual
My listening tests led me to an exceptionally transparent JFET buffer circuit with no gain.
Jerry Boncer - For all of his help in the past, and for his original design of the JFET buffer circuit that made its way into the VRE-1.
Anybody know the topology of this Jfet buffer?
My listening tests led me to an exceptionally transparent JFET buffer circuit with no gain.
Jerry Boncer - For all of his help in the past, and for his original design of the JFET buffer circuit that made its way into the VRE-1.
Anybody know the topology of this Jfet buffer?
Please, everyone. No personal opinions of an uninformed nature are useful here. At least be informed before offering your personal opinion. I am amazed, as well, the low technical level of the moderators who allow this to be offered, when it is misinformation, rather than fact.
KSTR said:
Yes. Oddly enough, the mechanical/electrical/parts-interactive considerations of loudspeaker design deal with their own equivalences of these SS circuit harmonic issues on a daily basis.
I have designed loudspeakers, perhaps better than most, but that is not my best talent. I worked for years with John Meyer using FFT analysis on loudspeakers as early as 1974. We built a 3 way, time aligned, horn loaded system with transient perfect derived electronic crossovers, and a 14" 'bucket brigade' delay line.
Later, on my own, I developed a 4 way Emilar 800 Hz horn based pro monitor that was mechanically aligned, with a 15" sub, 12" Gauss pro driver driver, with 3 pole Bessel crossovers that was bi-amped for a studio in Paris. It was a disappointment, but the measurements were better than most, even today. After that, I retired from loudspeaker design, but I know a lot about it, so don't try to put anything past me.
Later, on my own, I developed a 4 way Emilar 800 Hz horn based pro monitor that was mechanically aligned, with a 15" sub, 12" Gauss pro driver driver, with 3 pole Bessel crossovers that was bi-amped for a studio in Paris. It was a disappointment, but the measurements were better than most, even today. After that, I retired from loudspeaker design, but I know a lot about it, so don't try to put anything past me.
Charles Hansen said:
I find I am quite limited in implementing extreme quality clocking systems in a given CD player, due to the inclusion of their chips in the given unit. I am a happy guy when none of their chips show up in any CD player I might open up. Direct access and no interference in the clocking function is critical.
john curl said:
Once again, not being a circuit guy, I -just- found a comment on the actual function of 1/f noise..and then this comment from you. It comes to no surprise to me, at that point..that 1/f noise would be more prevalent in a Fet device. I -think- I have a fix I can test this afternoon. I think I can reduce it in severity to a notable degree. Any change at all..will tell me I'm headed in the right direction. I'm just about 100% sure I know the exact source of the noise and how to kill it. Hopefully, without impairing function.
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