Mpp

[Audiofanatic]

Dear Joachim,


Now it's my turn to tell you something.
You are a true gentleman just the fact that this grabs you the way it does says clearly that you are a gentlemen and a human being with feelings, and I admire you for that ! (for the record: I know the guy ).

There are few peoples on this globe that get to the TOP like you did, and stay the same simple and humble guy that you are, who wants to giveaway many many ideas to others, for them to learn from you experience in the audio world and from your mistakes also like you thought me a few times

Dear Joachim, just look at it this way, the higher you get the more wind you catch ! The thing is now to keep up the good work and be and stay flexible.

Keep up the good work and if I can help you in any way, don't hesitate to ask and.............. consider it done !

Best regards,

Atb,

José

Audiofanatic

[Joachim Gerhard]

I think it was particular the idea with feeding in the PSU common mode that really bugged him and i must admit that i have not seen that before. The tragedy is that i could not make it work in my circuit and it is not implemented in the playing prototype. Maybe i could make it work after more study but this case is closed for me. Give the king what belongs to the king we say here.

[Joachim Gerhard]

Jose, my stock of "thank you´s" runs out but your response moves and motivates me.

[brianco]

Originally Posted by brianco

IF SYN08 felt offended in any way he would certainly say so in very clear terms! Joachim, you quote Solomon; "nothing (totally) new under the sun" : and as PMA implies,virtually everything designed is in some respects a derivative of some thing else.

The skill is to improve and meet ever higher objectives - and in this success usually comes from examining the objective from every possible viewpoint and stubbornly persisting until what is required is achieved. You have succeeded in this area more than most professionals! AND most professionals do not give any freebie, fully thought out and tested top designs to DIY enthusiasts!

Keep up the good work!!!

LATE EDIT:

I should have added Nelson Pass as being one professional who has the DIY man's interests at heart and who gives very liberally in that direction. I may well have missed some but I keep my interest here to the things of greatest interest to me.

[john curl]

Joachim, I would agree that a common mode servo using the power supply terminals is somewhat unique, but that is NOT what you used, so what is the problem? Also, I am NOT taking credit for a single ended fet or transistor input stage with an op amp second stage, that was standard design even in the late 1960's. Keep up the good work and remember who your 'friends' are, and you might note that I take a lot of 'flack' around here also. Comes with the territory. Feed the animals and some get jealous and bite you. ;-)

[iko]

Can someone explain to the less versed among us, what exactly is original in syn08's circuit?

http://www.synaesthesia.ca/images/HPS51-headamp-sch.jpg

Is the jfet+bjt cascode in the first stage original work? Or the transconductance/transimpedance nature of the preamp? Inquiring minds want to know.

[Joachim Gerhard]

Back to circuit design i put a lot of thought into your proposal that there could be FM modulation in amplifier stages. Last week i made a series of measurements on a RIAA stage.
I started with an input of 0.5mV and raised the amplitude in stages up to 20mV. I observed the ouput with a 1kHz and 10kHz squarewave differentiated by a Lipshitz anti RIAA. I also observed the level of a 1kHz sine and up to 20mV i could not see visible clipping in that particular stage. What i could see was a change in the shape of the squares, first barely visible and then more obvious with rising amplitute. I then made precission measurement of the RIAA acuracy at various amplitudes and i could see chages in the microstructure of the amplitude response. The worst case was a drop in amplitude of 1dB at 20Hz at very high level. I again looked more closly to the squarewaves and i could observe a very slight "kink" in the leading edge at high volume.
My conclusion was that this stage has a slightly varying frequency response and time domain behavious over level. OK, 20mV is very high, my Titan gives out only 0.5mV @ 5cm/sec but the measurements are real and repeatable. I do not know if this behaviour is typical, good or bad because i did not try out how other stages behave under those conditions but my conclusion is that it is not suffient to measure RIAA acuracy to 0.1dB
precission at only one ( arbitrary ? ) choosen level of say 1mV input.

[Joachim Gerhard]

Iko, i already mentioned what i find unique. Maybe i have overlooked something that others find. I also accept the complete circuit as a whole as unique from an holistic point of few as a mix and match of elements that work together for a total result. It is like a new picture from the same caleidoscope. A new twist bringing up an unexpected view.

[analog_sa]

Originally Posted by YWN

If that's the RIAA HF EQ, then the caps must be pretty large (I suppose the resistors are small, thenths of ohms, to keep the noise low).

Hi Joachim

I also find this question interesting. Do you mind elaborating?

[PMA]

Additional resistor noise ==> series resistor must be kept small.