- You change the input impedance (that's why HPS is 10ohm...47Kohm || 0pF...500pF)
- You change the pre
Choose the right tool for the job 
You can take this idea down to .6nV with 2XMAT-02 and appropriate feedback resistors. You can extract the values if you do a noise analysis on the Earthworks preamp assuming the classic in-amp architecture. The date on that BTW 1968
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Syn,
I have already answered why I use a bipolar/tube cascode in the RTP phono stage.
The First RTP (~1982) was all tube, and 1/ needed very carefully selected tubes and 2/ very high gain in the line stage (30dB) to have enough gain overall to handle low output MCs.
Later RTP's used a jfet (2SK147)/tube cascode in the front end, which solved the noise issue completely, and increased the phono gain significantly so the line stage could come down in gain to better match CD player outputs.
But this still didn't give enough gain for really low output MCs, so I tried a MAT02 bipolar under the tube, and gained an extra 10dB gain just in the phono stage, and IMO, even better definition.
Clear now? Any more niggles "I haven't confronted"?
We use non magnetic parts because THEY SOUND BETTER - not because they allow us to push up the price. We could use VISHAY bulk foils, which sound even (slightly) better, but at circa $10 a pop, the price would become astronomical.
We also could use $100 teflon caps, but don't find the sonic advantage worthwhile.
Whatever, these are our choices, and the test is in the listening. Until you are prepared to put one of your amazingly quiet preamps up against a RTP, or one of Joachim's designs, or anyone else who has built one and is willing to demonstrate - I say you have no reason to comment - synthesised specs mean nothing to someone who designs, builds and listens to things!
I measured at 1kHz because I had a 16/44 measurement system, so a distortion measurement at 20kHz would be kinda pointless. Now I have a 24/96 system, but a 20kHz measurement is still pointless. And I'm not in a spec contest with you or anyone else - but I'll enter a listening test with confidence.
Regards, Allen
I have already answered why I use a bipolar/tube cascode in the RTP phono stage.
The First RTP (~1982) was all tube, and 1/ needed very carefully selected tubes and 2/ very high gain in the line stage (30dB) to have enough gain overall to handle low output MCs.
Later RTP's used a jfet (2SK147)/tube cascode in the front end, which solved the noise issue completely, and increased the phono gain significantly so the line stage could come down in gain to better match CD player outputs.
But this still didn't give enough gain for really low output MCs, so I tried a MAT02 bipolar under the tube, and gained an extra 10dB gain just in the phono stage, and IMO, even better definition.
Clear now? Any more niggles "I haven't confronted"?
We use non magnetic parts because THEY SOUND BETTER - not because they allow us to push up the price. We could use VISHAY bulk foils, which sound even (slightly) better, but at circa $10 a pop, the price would become astronomical.
We also could use $100 teflon caps, but don't find the sonic advantage worthwhile.
Whatever, these are our choices, and the test is in the listening. Until you are prepared to put one of your amazingly quiet preamps up against a RTP, or one of Joachim's designs, or anyone else who has built one and is willing to demonstrate - I say you have no reason to comment - synthesised specs mean nothing to someone who designs, builds and listens to things!
I measured at 1kHz because I had a 16/44 measurement system, so a distortion measurement at 20kHz would be kinda pointless. Now I have a 24/96 system, but a 20kHz measurement is still pointless. And I'm not in a spec contest with you or anyone else - but I'll enter a listening test with confidence.
Regards, Allen
No; I asked why not cascoding the bipolar with a high voltage SS device (bipolar or MOSFET).
You missed the question about the offset and cartridge current.
You missed the question about the noise contribution of the cascode tube heat.
FYI, THD @ 1KHz is pointless. It is likely the HPS 4.1 distortions @ 1KHz and 20Vp output level are significantly lower than 0.0007%, which is already only a number.
I am ready to put HPS to any fair test against any commercial design, question is who's paying for. Since this is not a commercial (but an "open source") project, I have no incentive to financially engage in such.
About "THEY SOUND BETTER", it's nothing more than a blank claim. You have no facts to support it other than your marketing brochure. But then I'm sure you had to do something to justify the price of this equipment and make a difference to your competitors.
BTW, are you really sure I haven't already done lately comparitive listening tests, with some very reputable brands? Do you need some nice and fancy prose to describe the qualities of the HPS pre?
@ Allen and syn08
Back some 20 years ago or so I was privy to experiments on resistors for use in audio. The first experiment I remember was to make two identical 'H' pad attenuators, one with high quality resistors and the other with the same resistors - but with the magnetic end caps removed. [The resistors used were, now sadly unobtainable, Japanese 1/2 watt Tantalum resistors].
There was a clear advantage in sonic terms for the attenuator with the end caps removed. Not quite night and day, but very significant nonetheless.
One channel of a simple k147 transformer out preamp was then rebuilt using capless Rs and the same differences were noted. There was much more aural space around tones on simple acoustic jazz, small scale string classical music and voice, especially female, was the area of greatest improvement. Large scale symphonic music was less congested and the sound staging became more credible. [ These views were all subjective! The tests were far too haphazard for the likes of Sy, but were sincerely executed. They were based on mono recordings played in true mono using a Denon 102 cartridge. The difference was apparent to all who heard the comparison. As is known to Joachim, it was these experiments which led to a new resistor being designed and produced].
What is (to me) an interesting speculation is whether it was the removal of the magnetic property of the end-caps or was some as yet unsuspected property allied to the end caps mainly responsible for the improvement!
EDIT:
Having just read the post above, I know that my contribution will simply be rejected out of hand. But what DOES worry me is that this thread, which is clearly intended to concern specific designs offered by Joachim is now breaking down into being yet another set of squabbles [as has happened repeatedly on other threads]. Perhaps a new thread could be started by those who want to partake in the spin-off sub-topics regarding phono stage design and implementation?
Back some 20 years ago or so I was privy to experiments on resistors for use in audio. The first experiment I remember was to make two identical 'H' pad attenuators, one with high quality resistors and the other with the same resistors - but with the magnetic end caps removed. [The resistors used were, now sadly unobtainable, Japanese 1/2 watt Tantalum resistors].
There was a clear advantage in sonic terms for the attenuator with the end caps removed. Not quite night and day, but very significant nonetheless.
One channel of a simple k147 transformer out preamp was then rebuilt using capless Rs and the same differences were noted. There was much more aural space around tones on simple acoustic jazz, small scale string classical music and voice, especially female, was the area of greatest improvement. Large scale symphonic music was less congested and the sound staging became more credible. [ These views were all subjective! The tests were far too haphazard for the likes of Sy, but were sincerely executed. They were based on mono recordings played in true mono using a Denon 102 cartridge. The difference was apparent to all who heard the comparison. As is known to Joachim, it was these experiments which led to a new resistor being designed and produced].
What is (to me) an interesting speculation is whether it was the removal of the magnetic property of the end-caps or was some as yet unsuspected property allied to the end caps mainly responsible for the improvement!
EDIT:
Having just read the post above, I know that my contribution will simply be rejected out of hand. But what DOES worry me is that this thread, which is clearly intended to concern specific designs offered by Joachim is now breaking down into being yet another set of squabbles [as has happened repeatedly on other threads]. Perhaps a new thread could be started by those who want to partake in the spin-off sub-topics regarding phono stage design and implementation?
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This would make sense. Realistically though, it won't work. People seem more willing to partake in such discussion around someone's specific design. Human nature?
You've repeatedly dismissed comparisons with your builds based on this excuse, that the test has to be fair and that someone has to pay for it. Can you describe the setup for a fair test, and your estimation of the cost?
I'm sure many of us would like to hear the nice and fancy prose that describe the qualities of the HPS pre. Please don't be shy syn08, do tell us.
I mean, you have the best phono stage on earth, HOW DOES IT SOUND? (I'm not being sarcastic.)
Please discuss here what you think fits. I have no problems with this. On the contrary, it is quite entertaining. I break my laws sometimes too and have worked further on the Echo Extreme although some people do not like the circuit much. Ii sounds graet in my setup and i do this phonostages mainly for me. That was the original intent to start the thread : to do something that pleases me without to much commercial concern.
For the sake of clarity I must say that these were not my experiments but those of a mutual friend of Joachim and me. I was present throughout this period, but in fact all I did was listen - not only to the tests but also to the explanations. [I do know that the same designer refused to use mil. spec. components because they had steel leads!]
It´s the designers choice and the prove is in the listening or the amount of comercial success if that is the goal. As far as i know Allen has a small ethusiast busyness and does not belong into the group of greedy cheaters. You may find technical flaws in his products that can be discussed but the sound he gets is all his i think.
I know at least one maker of cables that uses magnetic nickel and claims BECAUSE they are amgnetic they sound better. If it where that easy !
I know at least one maker of cables that uses magnetic nickel and claims BECAUSE they are amgnetic they sound better. If it where that easy !
Syn,
Somehow I was under the impression that your designs were purely mental synthesized concepts, but on reading your website I see you have actually built all up to HPS4.1
So what's to stop you putting your HPS4.1 in the post to Joachim, or if you want a public figure, Holger (Editor of the German LP magazine) and letting it compete with my and Joachim's designs? Holger is a very well experienced reviwerof extreme hi-end equipment
I'm sure you are not so hard up you can't afford to do that?
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You rail against me using the "sounds good" argument without "proof" - but what about your unproven/no measurement complaint about Al cantilvered cartridges a bit earlier in this thread?
And your use of (my) Neumann 50kHz kink in your RIAA curve. I first presented this to the phono world in my "TubePreamp CookBook" in 1996 - having been taught about it by my "Guru" back around 1978. He optimized RIAA networks by ear!
Many have scientifically argued this extra TC, I use it ONLY because it sounds good - what's your justification?
Regards, Allen
Somehow I was under the impression that your designs were purely mental synthesized concepts, but on reading your website I see you have actually built all up to HPS4.1
So what's to stop you putting your HPS4.1 in the post to Joachim, or if you want a public figure, Holger (Editor of the German LP magazine) and letting it compete with my and Joachim's designs? Holger is a very well experienced reviwerof extreme hi-end equipment
I'm sure you are not so hard up you can't afford to do that?
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You rail against me using the "sounds good" argument without "proof" - but what about your unproven/no measurement complaint about Al cantilvered cartridges a bit earlier in this thread?
And your use of (my) Neumann 50kHz kink in your RIAA curve. I first presented this to the phono world in my "TubePreamp CookBook" in 1996 - having been taught about it by my "Guru" back around 1978. He optimized RIAA networks by ear!
Many have scientifically argued this extra TC, I use it ONLY because it sounds good - what's your justification?
Regards, Allen
If Holger whould like to hear my Low Z MPP with active or shelve inductive Riaa or conventional RIAA, anytime. They are ready (no PCB though), they works fine and sound slighty different (i prefer the inductive shelve version at the moment because it sounds the most transparent to me without edje, i am a detail freak) but it is not ment as a commercial circuit that "beats" anything. I have neather heard a Real Time pre in my place (I could not meet Holger on the scheduled day because something unforseen came in between), nor have i heard any of syn08s designs anywhere. And after i have heard them and they sound better in one or more regards i am eager to find out why. It´s a work in progress.
Good morning, Allen
I may eventually decide to ship a HPS for some subjective evaluations, but not before finding a good answer to the "what's in it for me?" question. I'm in the process of putting together my notes during the listening sessions with a group of local audiophiles (using a garden variety of high end equipment), I'll add them to the Conclusion section of my web site ASAP.
The big difference is that I don't extrapolate my subjective preferences, in particular in marketing brochures.
In my designs, the Neumann pole is optional. Among other famous designers, JC is a staunch oponent to this. Personally, I can't confirm the subjective "brightness" effect on the sound.
That sounds really good to me syn08. I am sorry that you and Allen clash here from time
to time but that tells me that you both have a mesage that is more then skin deep. I simply can not see any superiority of the objective agains the subjective aproach. I measure and when the measurements are good enough i listen. I have phonostages here that got great reviews and measurements (low noise, low distortion, RIAA to +-0.1) that sound uninvolving and sterile. I have other stages with for example some noise that sound great. I can feel it, i am a musician and get the eagerness to conduct or dance when the music plays. This is totally my subjective world but for me it feels more real then a formular.
to time but that tells me that you both have a mesage that is more then skin deep. I simply can not see any superiority of the objective agains the subjective aproach. I measure and when the measurements are good enough i listen. I have phonostages here that got great reviews and measurements (low noise, low distortion, RIAA to +-0.1) that sound uninvolving and sterile. I have other stages with for example some noise that sound great. I can feel it, i am a musician and get the eagerness to conduct or dance when the music plays. This is totally my subjective world but for me it feels more real then a formular.