I never saw a diamond differential before. NP just submit it. http://www.diyaudio.com/forums/showthread.php?postid=687745#post687745
Like full complementary differential, but all the transistors are altered, N-P, P-N. Quite strange to me.
I interested in the part of "where you see the diff pairs operating push pull without limitation to the potential current they can deliver ", "This allows for the current to deliver enormous slew rates.", but advoiding this part "running an input device in Class AB is not a popular approach."
A differential (LTP) is really elegant. Only 2 transistors, but can control the whole amp and can control DC offset.
Has anyone tried this input stage? At a glance it resembles a differential, but it is not. It doesn't do "differential-ing". But it can control the whole amp and can control DC offset, like the main function of a differential.
In a differential, total current (I1+I2) will always be the same. This means if I1 is increasing, I2 will decreasing. In bipolar transistor, if I is rising or decreasing, the VBE value will also follow it.
But in this idea, if I1 rising, I2 will also rising, not decreasing. This means there is no current limiter for the input stage. Current limitation is determined elsewhere (in my drawing it is limited by CCS1 and CCS2). This also helps the input stage to be always biased.
The main fuction is done by transistor A (+C, forming 2 VBE's), in the form of changing voltage between it's base and emitor. If Y is fed by input, then X have to be fixed somewhere. X is fixed by transistor B-D, and with help of transistor C it reaches emitor of A. By VBE drops adding and substracting, automaticly the DC offset will be at ground point. I can expect this, because the current in the path I1 and I2 will always the same due to current mirror, that means all the VBE drops between left path and right path will be the same value(s)
R1 and R2 is needed there, to prevent oscilation. It may be a small valued resistor.
I'm using folded cascode for the next stage, so it perform inverting amp with gain of RF/Rin.
Funny thing is, it doesn't matter where to put the folded cascode. In both path I1 or path I2 it forms the same inverting amp.
A differential will cancel harmonic. Is this idea have the same properties (canceling harmonic), or do nothing to it, or adding harmonic? Anyone can guess what it sounds like?
Like full complementary differential, but all the transistors are altered, N-P, P-N. Quite strange to me.
I interested in the part of "where you see the diff pairs operating push pull without limitation to the potential current they can deliver ", "This allows for the current to deliver enormous slew rates.", but advoiding this part "running an input device in Class AB is not a popular approach."
A differential (LTP) is really elegant. Only 2 transistors, but can control the whole amp and can control DC offset.
Has anyone tried this input stage? At a glance it resembles a differential, but it is not. It doesn't do "differential-ing". But it can control the whole amp and can control DC offset, like the main function of a differential.
In a differential, total current (I1+I2) will always be the same. This means if I1 is increasing, I2 will decreasing. In bipolar transistor, if I is rising or decreasing, the VBE value will also follow it.
But in this idea, if I1 rising, I2 will also rising, not decreasing. This means there is no current limiter for the input stage. Current limitation is determined elsewhere (in my drawing it is limited by CCS1 and CCS2). This also helps the input stage to be always biased.
The main fuction is done by transistor A (+C, forming 2 VBE's), in the form of changing voltage between it's base and emitor. If Y is fed by input, then X have to be fixed somewhere. X is fixed by transistor B-D, and with help of transistor C it reaches emitor of A. By VBE drops adding and substracting, automaticly the DC offset will be at ground point. I can expect this, because the current in the path I1 and I2 will always the same due to current mirror, that means all the VBE drops between left path and right path will be the same value(s)
R1 and R2 is needed there, to prevent oscilation. It may be a small valued resistor.
I'm using folded cascode for the next stage, so it perform inverting amp with gain of RF/Rin.
Funny thing is, it doesn't matter where to put the folded cascode. In both path I1 or path I2 it forms the same inverting amp.
A differential will cancel harmonic. Is this idea have the same properties (canceling harmonic), or do nothing to it, or adding harmonic? Anyone can guess what it sounds like?