yep.
Tell me what you found when you measured for cart. electrical resonance(s) of the cart/pre-pre/cable interface and the cart load R? Did you do a MLLSA test on the cart. decay with various loads? Distortion? We need measurements to see what changes rather than guesses, speculation and partial considerations.
OK. Now I'm really sorry JC... its all about your designs..... tell us more.
THX-RNMarsh
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We seriously tried to fully understand phono cartridge characteristics back in the 1970's. We had all the test records, and I used some special equipment to measure the overload characteristics, to determine effective bandwidth of MC cartridges.
In the '80's, an excellent publication called: 'High Performance Review' did a number of extended measurements of phono cartridges. This is probably the best source of measurements for phono cartridges, and their subtle variations between each other.
Today's phono cartridges are either almost junk, or they are hand made to meet some subjective criterion, and are not reviewed by anyone that I know.
In the '80's, an excellent publication called: 'High Performance Review' did a number of extended measurements of phono cartridges. This is probably the best source of measurements for phono cartridges, and their subtle variations between each other.
Today's phono cartridges are either almost junk, or they are hand made to meet some subjective criterion, and are not reviewed by anyone that I know.
For some reason I bought a small stash of Ortofon pickups when they had their anniversary in the eighties... And I also bought pickups of other brands and Ortofon that was supposed to be kind of special in `70`s, `80`s and `90`s. Many of them are still unopened.
Hand made pickups such as by Sugano was needed as I in the `80`s also used a Eminent Technology tangential arm that required custom built Koetsu pickups to perform properly in such arms.
Due to re-tipping have become either extremely expensive or nearly impossible to get done I am now grateful for buying several copies of the pickups I liked the most. When I some years back sent one of my Ortofon Gold for re-tipping it took close to a year before I got it back, it then lay unopened for a couple of more years before I one day opened the box to discover that it was a different model I had got returned...
Hi John, i recently tried a 2N2484 8 pcs (TI) // combination. I was surprised by the incredible quality gain : silence depth first, headroom second. I didn't notice any increase in base current! It seems the device is working as giant quiet transistor, like those early 60' germanium ! I didn't use any aditional emitter resistor. I don't remember who said there were 10 transistors existing types only (marketing , boxing case, pinout are the only differences) ... Remember the old early transistors ? compare the chip size to the currently available transistors : noticed the reduced quantities of embodied material ?
It 's the same with copper ! Available wire from CxxxA is containing more ferrous than copper , at this point it triggers the anti theft alarm loops after cash register ! ;-)
I suspect most of these things will prove not doable due to the non-stationary nature of LP reproduction, i.e. try some time to record the same track twice and line the results up in diffmaker. So let's put everyone's "guesses, speculation and partial considerations" equally off the table for now.
As JC said, the reason for rejecting the topology was it sounded compressed. Taking this literally, would mean even a weak coupling (elect-mech) could be heard. Myself, I didn't hear it that way. I heard other positive attributes. But, that has been the story ever since - compressed.
At same the time, 'virtual' ground, as I understood, would not be the actual terminating Z for the cartridge.... which could be considerably higher... To be further explored.
There are ways to measure this without a TT...if you have the test gear available. And, maybe even thru SIM.
I bring this up here because many are still listening and design for phonographs. And, this area seems to be a last frontier area where any new improvements will be found.
Its for you to take or loose... I dropped LP a long time ago for the potential for lower noise and distortion of CD.... though that has taken a long time also to fully develop. Now I don't buy CD anymore, either... as there are even more direct means from the Master recording to get a bit closer to reality.
I'm interested here in the circuit design topologies, primarily. But, they have been shown for many years now. Mostly for the subtle details that JC uses but, unfortunately, doesn't openly talk about because he still makes his living using them.
Long live the LP and long live this forum.
Thx-RNMarsh
At same the time, 'virtual' ground, as I understood, would not be the actual terminating Z for the cartridge.... which could be considerably higher... To be further explored.
There are ways to measure this without a TT...if you have the test gear available. And, maybe even thru SIM.
I bring this up here because many are still listening and design for phonographs. And, this area seems to be a last frontier area where any new improvements will be found.
Its for you to take or loose... I dropped LP a long time ago for the potential for lower noise and distortion of CD.... though that has taken a long time also to fully develop. Now I don't buy CD anymore, either... as there are even more direct means from the Master recording to get a bit closer to reality.
I'm interested here in the circuit design topologies, primarily. But, they have been shown for many years now. Mostly for the subtle details that JC uses but, unfortunately, doesn't openly talk about because he still makes his living using them.
Long live the LP and long live this forum.
Thx-RNMarsh
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Scott, thank you for your concern. However, I am 1/2 blind, and only drive locally. I perhaps could have taken Bart, but it would have been a trial, and it just was not worth it to try. A few years ago, friends took me a couple of times, but that did not happen this year. I hope you enjoyed it, I will be attending the show in Denver, next week.
Speaking of past testing , Audio Critic's amp power cube test was the one , many pretenders were sent packing ...
Amazing that many high end turntables don't stay on speed. Use a nice Technics SP10 M2 or M3 or a Basis I know AJ's table is on speed.
OK, here is the Vendetta input stage schematic, again for reference.
Now, where is the discussion? Advanced enough for you Scott? Understandable at all, most of you? '-) Yes it works, and has worked for the last 30 years. NOW do you understand WHY I did not publish the schematic, until recently?
Now, in all fairness to most of you here, who are usually repair techs and technical support engineers, the ambiguity of the active symbols might throw you off.
However it is called a COMPLEMENTARY FOLDED CASCODE input stage. And this describes what is shown on the schematic. It is about 100 times lower distortion and with perhaps 40 dB more dynamic range than the original JC-1, with the same input noise. It was originally designed to OBSOLETE the JC-1 type circuits that were still being manufactured. We did NOT call the company VENDETTA RESEARCH for nothing! '-)
Now, where is the discussion? Advanced enough for you Scott? Understandable at all, most of you? '-) Yes it works, and has worked for the last 30 years. NOW do you understand WHY I did not publish the schematic, until recently?
Now, in all fairness to most of you here, who are usually repair techs and technical support engineers, the ambiguity of the active symbols might throw you off.
However it is called a COMPLEMENTARY FOLDED CASCODE input stage. And this describes what is shown on the schematic. It is about 100 times lower distortion and with perhaps 40 dB more dynamic range than the original JC-1, with the same input noise. It was originally designed to OBSOLETE the JC-1 type circuits that were still being manufactured. We did NOT call the company VENDETTA RESEARCH for nothing! '-)
Attachments
John,
I have also used complementary folded cascode JFET stages, but with an integrated (in parallel to the input JFETs) DC servo also using JFETs so I avoided the IC you used for the DC servo.
The reverse engineering done in this link have a lot of errors (but as the drain and source are interchangeable it is maybe not so bad anyway), but if one take into account the DC voltages it is easy to flip some of the JFETs correctly.
http://www.amplimos.it/images/Vendetta.jpg
I discovered this schematic a couple of days ago when you started putting out the pdf files and it was thus I quickly observed it when your pdf´s had the same kind of errors as the reverse engineered schematic..
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Ray, I see where the 'reverse engineered' schematic was drawn with reversed D-S in many instances. I don't normally put D-S markings on the schematic. However, it should be understood that MOST jfets can work about as well with reversed D-S leads, because the jfets are mostly symmetrical in construction. My mistakes were from poor eyesight these days, and the wish to put the schematic up.
wayne
What Scott says is this: When you digitise a vinyl track twice, there is no chance you can match these two digital files down to the sampling interval used, even if you use the sharp waveform of the faintest scratching as the definite starting synchronisation point on each one.
Unfortunatelly it’s not a question of TT brand or model, DD or not.
Analog gear, whether TT or R2R are not designed for and can not achieve the required timing precision down to a few microseconds.
George
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