I don't think either on them will work very well. The circuit is too dependent on the Vbe drops of the various transistors. It could be that with a zero input the transistor currents will be too large and the devices overheat and burn up.
If so,why certain manufacturer still using them,such as Accuphase???
current-mode feedback stage
It will work, but you really need all 4 transistors inside the same package or it can go into thermal runaway. Or, more correctly, force the VAS that follows it to go into runaway. Transistor arrays are a solution, but what really works is the old LH0002 current buffer. The one in the "N" package is required, because the collectors of the second pair are brought out individually rather than tied to the first stage emitters. It really wasn't meant to be used for that, but it can. Elantec used to make a whole family of current-mode op amps with both input and output stages based on that topology.
It will work, but you really need all 4 transistors inside the same package or it can go into thermal runaway. Or, more correctly, force the VAS that follows it to go into runaway. Transistor arrays are a solution, but what really works is the old LH0002 current buffer. The one in the "N" package is required, because the collectors of the second pair are brought out individually rather than tied to the first stage emitters. It really wasn't meant to be used for that, but it can. Elantec used to make a whole family of current-mode op amps with both input and output stages based on that topology.
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- Differences between this two kind of input stages???