Hi guys,
I'm trying to build a circuit to match NPN and PNP transistor pairs for my SymAsym amplifier. The basis for this exercise is the paper by Ian Fritz, see https://www.dragonflyalley.com/synth/images/TransistorMatching/ianFritz-transmat0011_144.pdf
Since I need +12V and -12V I want to use my lab power supply at 24V and use a virtual GND with voltage divider.
Here is for example the circuit for PNP matching made with LTSpice:
Voltage across the leads on the right side is measured for calculating the mismatch. R4 and R5 values should be as close as possible. I want to use 1% tolerance resistors, that's why I simulate with 99k and 101k.
The NPN version looks like this:
Due to the simple voltage divider the voltages are not +12/-12V but +13.18/-10.82 V for the PNP version and +10.82/-13.18 V for the NPN version.
I don't see a problem with that, except for the difference in current at which the transistor mismatch is measured.
Will this work? Am I missing something?
Best regards,
Jonas
I'm trying to build a circuit to match NPN and PNP transistor pairs for my SymAsym amplifier. The basis for this exercise is the paper by Ian Fritz, see https://www.dragonflyalley.com/synth/images/TransistorMatching/ianFritz-transmat0011_144.pdf
Since I need +12V and -12V I want to use my lab power supply at 24V and use a virtual GND with voltage divider.
Here is for example the circuit for PNP matching made with LTSpice:
Voltage across the leads on the right side is measured for calculating the mismatch. R4 and R5 values should be as close as possible. I want to use 1% tolerance resistors, that's why I simulate with 99k and 101k.
The NPN version looks like this:
Due to the simple voltage divider the voltages are not +12/-12V but +13.18/-10.82 V for the PNP version and +10.82/-13.18 V for the NPN version.
I don't see a problem with that, except for the difference in current at which the transistor mismatch is measured.
Will this work? Am I missing something?
Best regards,
Jonas
I dunno in the real world...
Here is your simulation...
Its surprising in simulation land just how dissimilar the transistors have to be to get a mismatch. Make your simulation dynamic so you can plot the voltages.
The 24 volt supply is replaced by a 0 to 24 volt rising value. Also because it is a simulation you make your virtual ground with 1 ohm or even 0.0001 ohm resistors to get a -/+12v supply but it seems to make little difference (apart from drawing 100,000 amps).
A transistor matching circuit presented at BAF 2024 -
And here is Mark’s video -
And here is Mark’s video -
Here are three examples of very sensitive matchers:
Some time ago, I presented a complementary matcher based on a novel principle:
The same principle applies equally well to identical transistors, and it brings the same advantages: direct comparison between the junctions, with the TUT's themselves performing the comparison and a substantial amplification.
To demonstrate the operation, I have chosen a BC547B and a BC847B, which should be identical but aren't in reality (sim)
This time, no cheat...
The same principle applies equally well to identical transistors, and it brings the same advantages: direct comparison between the junctions, with the TUT's themselves performing the comparison and a substantial amplification.
To demonstrate the operation, I have chosen a BC547B and a BC847B, which should be identical but aren't in reality (sim)
This time, no cheat...