You hate this use of an opamp, do you ?
I know, it is not without distortion and there are better ways to use an opamp.
It was quite popular though 20 years ago.
I know, it is not without distortion and there are better ways to use an opamp.
It was quite popular though 20 years ago.
Thanks for the links. The designs are all power amps though, any preamp or phono examples?
I agree that op amps are not the best for use in this application.
I am eagerly awaiting Joachim's next circuit, just posted something for discussion till his return.
Jam
I agree that op amps are not the best for use in this application.
I am eagerly awaiting Joachim's next circuit, just posted something for discussion till his return.
Jam
Most of the circuits here are some kind of transimpedans circuits, get the current in, mirror it over, I-V convert it RIAA shape, buffer it and take it out, so many options so many designs. Apart from Joarchims concepts has sergio shown some masters of simplicity.
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PLs look at post 8428
http://www.diyaudio.com/forums/analogue-source/154210-mpp-843.html#post3408743
http://www.diyaudio.com/forums/analogue-source/154210-mpp-843.html#post3408743
tanks for link
now one need very clever ones to turn that in 2 proper drawing whit possibly PCB to boot so one can weld same whatnots and nagh about WTF is not working even whit black (preferebly) whatnots wrong way round 😀
OK--- just don't expect too much Help.... As No time is what i have plenty off.
The circuit here is balanced input, collected to single node out, and than through the nice sounding balanced driver, The Riaa is split, which all my last circuits had been. The treble cut is in the first section- increasing overload margion on the second stage.
I placed a servo in the first stage, This is not so much for the DC, but to alter the working points of the lower and upper section to a place where they have the same gain, Shifting the curve to match.(so to speak)
Its advisable to find good quads/or two matched doubles for the NPN-PNP input transistors. The BD139/140 should be HFE matched.
For the opamp I would advise to consult the Datasheet, as there is a good circuit for nulling the opamp offset.
The circuit here is balanced input, collected to single node out, and than through the nice sounding balanced driver, The Riaa is split, which all my last circuits had been. The treble cut is in the first section- increasing overload margion on the second stage.
I placed a servo in the first stage, This is not so much for the DC, but to alter the working points of the lower and upper section to a place where they have the same gain, Shifting the curve to match.(so to speak)
Its advisable to find good quads/or two matched doubles for the NPN-PNP input transistors. The BD139/140 should be HFE matched.
For the opamp I would advise to consult the Datasheet, as there is a good circuit for nulling the opamp offset.
Attachments
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If you (all) want to know why I am so silent? I need to build 2 stereo amplifier for the High-End 2015 in Munchen, please come and listen to them 🙂
The amps will play here (other side from the road at the main exhibition place)
Zenith - Die Kulturhalle
Lilienthalallee 29
80939 München
Germany
The picture contains:
One full set of boards for one stereo unit
Sorry not all boards available fully stuffed
Left from main capacitor bank
Right front power rectifiers and house keeping
Behind that panel meter mounting board (and lights)
Then 2 pcs of pre-amplifier (same as line stage)
Left/right back, 2 power amps
In-between, left on/off- softstart- and muting- circuit (stuffed)
In-between, right, LED-control board
Center back, 2 x loudspeaker zobel and common-mode filter
The amps will play here (other side from the road at the main exhibition place)
Zenith - Die Kulturhalle
Lilienthalallee 29
80939 München
Germany
The picture contains:
One full set of boards for one stereo unit
Sorry not all boards available fully stuffed
Left from main capacitor bank
Right front power rectifiers and house keeping
Behind that panel meter mounting board (and lights)
Then 2 pcs of pre-amplifier (same as line stage)
Left/right back, 2 power amps
In-between, left on/off- softstart- and muting- circuit (stuffed)
In-between, right, LED-control board
Center back, 2 x loudspeaker zobel and common-mode filter
Attachments
No you did not... 🙂 Think about it. There is a difference between sending the occasional social remark and trying to discus multiple Marantz items. Also, some times I am not in the best of moods and say some things without to much thought (sorry for that).
P.s. There is (actually) a relation between Joachims circuits and this amplifier (even not so remotely).
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