Hi gurus, recommend me some high voltage transistors for a long tailed pair with supply voltage: +-30-50-60V 
I learned how to design discrete op amp and need test
I tested with 549 and 559.
If I decide to use not so simple LTP I would like to add only two more transistors and here is another quest. Up or Down ?
Current mirror or current source/sink ?
Only one! Which is better ? Any recommendations ?
And how to fight this 0.007% THD
I learned how to design discrete op amp and need test
I tested with 549 and 559.
If I decide to use not so simple LTP I would like to add only two more transistors and here is another quest. Up or Down ?
Current mirror or current source/sink ?
Only one! Which is better ? Any recommendations ?
And how to fight this 0.007% THD
Attachments
BC546/556 will cover all your voltages.
On the other hand, you can cascode the collectors with some high voltage transistors like 2N5551/5401.
Then, to lower the distortion in this kind of topology, you can:
- add a current mirror (dynamic load for LTP);
- add an emitter follower between LTP and VAS.
current mirror will give you more advantage, then the current source.
On the other hand, you can cascode the collectors with some high voltage transistors like 2N5551/5401.
Then, to lower the distortion in this kind of topology, you can:
- add a current mirror (dynamic load for LTP);
- add an emitter follower between LTP and VAS.
current mirror will give you more advantage, then the current source.
Tnk u all
My amp sounds fantastic with an op-amp, lets see now with a pair.
P.S. Paralleling 5532 and 072 is very successful, big synergi. bass from 5532 and highs from 072. i soldered "ic on ic", "ic on top of the other".
P.S.2 vzaichenko, what means to cascode a collector ? Firstly i understood to add a current mirror.
My amp sounds fantastic with an op-amp, lets see now with a pair.
P.S. Paralleling 5532 and 072 is very successful, big synergi. bass from 5532 and highs from 072. i soldered "ic on ic", "ic on top of the other".
P.S.2 vzaichenko, what means to cascode a collector ? Firstly i understood to add a current mirror.
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Hey, with current mirror outputs nothing
Aand for newbies -> How to design Discrete Operational Amplifier - Design Guide - Theory - Bart HRK
P.S. oops screenshot error but its the same with the fb connection
Aand for newbies -> How to design Discrete Operational Amplifier - Design Guide - Theory - Bart HRK
P.S. oops screenshot error but its the same with the fb connection
Attachments
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Hey, with current mirror outputs nothing
Aand for newbies -> How to design Discrete Operational Amplifier - Design Guide - Theory - Bart HRK
P.S. oops screenshot error but its the same with the fb connection
You need to add degeneration resistor between the Q3 emitter and the rail, otherwise you don't let your mirror working - it's only 0.7V between the rail and the base of Q3 now.
Hey, with current mirror outputs nothing
Aand for newbies -> How to design Discrete Operational Amplifier - Design Guide - Theory - Bart HRK
P.S. oops screenshot error but its the same with the fb connection
and use PNP with emitter degen.
Better if you add EF helper to feed the VAS. See D.Self and many others.
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just not work
@P.S. look @ this is more powerful
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Attachments
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just not work
P.S. look @ this is more powerfulAn externally hosted image should be here but it was not working when we last tested it.
Now you've got only the emitter follower, but no VAS
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