Does anyone have experience of the balanced phono amp designed by Klaus Boening?
http://www.klaus-boening.de/
http://www.klaus-boening.de/
Klaus' phono amp is a beautiful overkill in a positive sense, very original. I haven't seen anything like it anywhere. I suspect also that only one amp exists, his.
Only his MkIII is a balanced design.
Not my taste. But a phono stage with a balanced input is a nice thing. Since I use one, I won't go back.
Not my taste. But a phono stage with a balanced input is a nice thing. Since I use one, I won't go back.
Hi Havoc,
Can you tell us if the one you'r using is a DIY one and what was the difference? (Sonic wise)
Thanks in advance.
Audiofanatic 😉
Can you tell us if the one you'r using is a DIY one and what was the difference? (Sonic wise)
Thanks in advance.
Audiofanatic 😉
Sort of DIY. It is a design by Barry Porter that was published in ETI. With a bit of luck I can find the date.
Uses 2 LM394 for each input as a front to an NE5532A. Rest is NE5534A balanced to unbalanced convertor. Then RIAA with another NE5534A and a servo loop to get the DC out. Servo loop I added myself, also extra stabilisation to the frontend so the rest can run on +/-20V.
Soundwise it is clear, but the main difference was a lot less hum and noise compared to the previous one. But you may have to re-wire your arm. If you connect the cartridge to a balanced input it may not be connected a ground somewhere. Also the connection to the preamp needs to become balanced.
Uses 2 LM394 for each input as a front to an NE5532A. Rest is NE5534A balanced to unbalanced convertor. Then RIAA with another NE5534A and a servo loop to get the DC out. Servo loop I added myself, also extra stabilisation to the frontend so the rest can run on +/-20V.
Soundwise it is clear, but the main difference was a lot less hum and noise compared to the previous one. But you may have to re-wire your arm. If you connect the cartridge to a balanced input it may not be connected a ground somewhere. Also the connection to the preamp needs to become balanced.
For anyone who cares: it was published in ETI Februari 1987/March 1989. That's what I found on my pcb's (I always put it on the pcb). The last may be an update or so.
I do not know but i should contact him one day because he is living in the same city as i do. (Dresden)
Cheers
Christian.
Cheers
Christian.
Ok, I'll be doing it!
Yes, that is true! My desk is full of parts, lots of them!
Nearly finished the charging pcb for now.
But now I'm running into lots of questions.
1) When matching caps for the passive riaa, do I have to burn them in in any way before measuring?
2) What is the exceptional matching of fet's for? Why not simply matching after IDSS? What will I miss?
3) If some of the 9V accus are used to prevent the caps from switching + and - (see text on his homepage), how can I ever charge the accus safely?
4) One FET is used as a current source; has it the same IDSS, and if so, why?
That'll be lots of fun!
Rüdiger
Yes, that is true! My desk is full of parts, lots of them!
Nearly finished the charging pcb for now.
But now I'm running into lots of questions.
1) When matching caps for the passive riaa, do I have to burn them in in any way before measuring?
2) What is the exceptional matching of fet's for? Why not simply matching after IDSS? What will I miss?
3) If some of the 9V accus are used to prevent the caps from switching + and - (see text on his homepage), how can I ever charge the accus safely?
4) One FET is used as a current source; has it the same IDSS, and if so, why?
That'll be lots of fun!
Rüdiger
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