I do not know. Maybe he is not an audiophile. Polypropylen is not the best dielectric concerning temperature stability. A better material in that sense is PPS, itself a substitute for Polycabonate. PPS has low distortion but higher dielectric absorbtion as Polypropylen though. Pick your poison. In my best RIAAs i use Polystyren ( Film-Foil ) trimed with Teflon or Air trimmers.
Hi guys,
Sorry Joachim for hijacking your thread, but I thought this might be the most appropriate thread given the topic. I hope I'm not getting bashed by the moderators. Here we go.
A friend of mine (the designer of DACT CT100) has retired. He has a stash of 2SA1316 GR and BL. Unfortunately not any of the NPN type. If anyone is interested they can PM me and I will help getting you in contact with him. I'm not interested in being in the middle and have no financial interest in this.
Just want to give people the oppurtunity.
Cheers,
Mogens
Sorry Joachim for hijacking your thread, but I thought this might be the most appropriate thread given the topic. I hope I'm not getting bashed by the moderators. Here we go.
A friend of mine (the designer of DACT CT100) has retired. He has a stash of 2SA1316 GR and BL. Unfortunately not any of the NPN type. If anyone is interested they can PM me and I will help getting you in contact with him. I'm not interested in being in the middle and have no financial interest in this.
Just want to give people the oppurtunity.
Cheers,
Mogens
"The body is encased is copper, shielding the resistor body structure against RF interference and magnetic fields. "
Yet, not even a ppm figure...or even a mention of what the resistive element is
The Paradise developed into quite a complex animal.
I think it really stretches the abilities of an average DIY builder to the maximum.
So lately i thought how something simpler can be made that is easier to build but still performs well.
Just for fun i have build two MM stages that are good candidates. One is the High Octane MM stage published in Linear Audio. I still battle a bit with the PSU but i know that it works. Jan Didden build one and he is happy with the result. There is also a thread here on DIY Audio that describes it.
I think it really stretches the abilities of an average DIY builder to the maximum.
So lately i thought how something simpler can be made that is easier to build but still performs well.
Just for fun i have build two MM stages that are good candidates. One is the High Octane MM stage published in Linear Audio. I still battle a bit with the PSU but i know that it works. Jan Didden build one and he is happy with the result. There is also a thread here on DIY Audio that describes it.
The other is the Renardson MM stage found here :
Phono Pre-amp Circuit
Both lack an MC input. Jan uses a transformer but that can get expensive.
So i searched for a circuit that works well but that also is simple and has some historical roots like the High Octane that is a modern interpretation of a Peter Walker design.
A man that i admire for innovation and a clear mind.
I owned several classic Quad amps and speakers and particular the ELS57 changed my view about what good sound is. I even build a double stack with modified Kelly Ribbon and Hartley woofer, a DIY version of the Mark Levinson HQD.
Phono Pre-amp Circuit
Both lack an MC input. Jan uses a transformer but that can get expensive.
So i searched for a circuit that works well but that also is simple and has some historical roots like the High Octane that is a modern interpretation of a Peter Walker design.
A man that i admire for innovation and a clear mind.
I owned several classic Quad amps and speakers and particular the ELS57 changed my view about what good sound is. I even build a double stack with modified Kelly Ribbon and Hartley woofer, a DIY version of the Mark Levinson HQD.
Here you find pictures of this incredible system :
https://www.google.de/search?q=mark...pMajC7AaH6oHABw&ved=0CDQQsAQ&biw=1920&bih=908
I heard it in the 70th with Master Tapes on a Levison modified Studer and that experience blew my mind. It certainly was responsible that i envisioned a career in High End Audio, a choice that i regretted many times but that also gave me great satisfaction and pleasure.
https://www.google.de/search?q=mark...pMajC7AaH6oHABw&ved=0CDQQsAQ&biw=1920&bih=908
I heard it in the 70th with Master Tapes on a Levison modified Studer and that experience blew my mind. It certainly was responsible that i envisioned a career in High End Audio, a choice that i regretted many times but that also gave me great satisfaction and pleasure.
As nice as it is i really do not like the AC coupling much. There are very good caps on the market now and i think that midrange and treble can sound more or less transparent but i always found when i DC couple the bass gets better. More deep, tight, slamming etc. you name it.
The following circuit is at least DC coupled at the input, so one big elcap less.
As far as i can tell it is a Baxandall idea. It works with the fact that a BJT transistor still works when the Base-Collector potential is Zero Volt and the Vce is only Ube ( ca. 0,65V ).
The following circuit is at least DC coupled at the input, so one big elcap less.
As far as i can tell it is a Baxandall idea. It works with the fact that a BJT transistor still works when the Base-Collector potential is Zero Volt and the Vce is only Ube ( ca. 0,65V ).
Attachments
Here the input stage on the left is in a feedback loop including the following opamp.
It can be used in isolation too as only a linear pre-pre without the opamp.
The circuit i am actually building right now is a bit similar but it is DC coupled in and out plus it has a shunt feedback loop from output to input.
As far as i can tell it can be attributed to John Curl. At least that was told to me from the guy that gave me the schematic.
I will tell you more when i have tested the circuit. I have already build one channel and i will put it on the scope in a minute.
Only John himself can clarify that.
It can be used in isolation too as only a linear pre-pre without the opamp.
The circuit i am actually building right now is a bit similar but it is DC coupled in and out plus it has a shunt feedback loop from output to input.
As far as i can tell it can be attributed to John Curl. At least that was told to me from the guy that gave me the schematic.
I will tell you more when i have tested the circuit. I have already build one channel and i will put it on the scope in a minute.
Only John himself can clarify that.
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I found the John Curl Patent from 1977 :
Patent US4035737 - Low noise amplifier - Google Patenter
When i see it again now i am sure : yes that is the topology i am working on.
Patent US4035737 - Low noise amplifier - Google Patenter
When i see it again now i am sure : yes that is the topology i am working on.
Would you believe that this link is not available to UK residents!!! It is claimed that the license fee which we pay does not cover overseas broadcasting!
It is paid for by taxation of our monies - yet we cant use it!!!
One channel of the Curl Pre-Pre is working.
DC offset at the in- and output can be adjusted with one trim and is stable.
It is surprisingly wideband. With a 6 Ohm resistor that simulates the DC impedance of my Lyra Titan and a 160 Ohm feedback resistor -3dB is at 6MHz at a gain of 26.66 x ,
not bad for something so simple.
Square Wave is clean and there is no overshot without compensation.
I will now measure distortion.
DC offset at the in- and output can be adjusted with one trim and is stable.
It is surprisingly wideband. With a 6 Ohm resistor that simulates the DC impedance of my Lyra Titan and a 160 Ohm feedback resistor -3dB is at 6MHz at a gain of 26.66 x ,
not bad for something so simple.
Square Wave is clean and there is no overshot without compensation.
I will now measure distortion.