Author Topic: Problem with CROSSOVER RANE AC23...capacitor..operational....  (Read 830 times)

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Offline TasoTopic starter

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Problem with CROSSOVER RANE AC23...capacitor..operational....
« on: November 16, 2023, 02:07:10 am »
Hi, I purchased an analog electronic crossover, i.e. non-dsp, Rane Ac23.
It has a couple of power caps that are a little swollen, so I wanted to change the 6 power caps there.
The power supply is equipped with a voltage multiplier. 10.5+10.5vac enters the crossover (external transformer) which is multiplied by two and then passes through the 7815 and 7915 regulators. The crossover operates at dual voltage +-15 Vdc.

Do you think I can use Panasonic FC for all 6 capacitors even if in different positions? I have the Panasonic FCs in my drawer, but if they don't work well I can buy the ones you recommend.
I attach the diagram.

I ask because I seem to have read that low ESR capacitors, downstream of the regulators in question, can generate oscillations or in any case not be optimal.
I also noticed that one of the operational quads has been replaced with a TL074.
Originally there was one like all the others, namely a 4741cp.
Apart from the 4741cp there are TL072 (double OP), these on sockets.
As per the diagram and are used for input and output.
The TL072 at the input is used partly as an input stage and partly as a subsonic high-pass filter at 20Hz (as per the user manual and declared specifications).
The TL072 is also on the outputs, I think they say it works as a "buffer". Maybe I'm wrong.
In fact there are 3, being 3 ways...6 exits.
So, in total, there are 5 TL072s. Three used for the 6 outputs and two used for the two inputs + two subsonic filters to follow.

Going back to the problem of the TL074 instead of the 4741cp.... From the diagram this opamp works entirely on one channel (right) and therefore I find the asymmetric crossover!

This is certainly not a good thing.
The crossover is 30 years old (maybe 40!). There will also be better opamps.
I would like to intervene to have all the operational ones, obviously the same, I would say BASIC and essential solution.
I would like to mount the sockets for them too and choose which op amps to mount.

I wanted to ask if you can advise me on which quadruple operational amplifiers to mount that are clearly compatible with the scheme and with what they are called to do.
I don't want OPs other than the originals to make the crossover work badly, I don't know... maybe with different cuts from what I set with the knobs!
Thanks for any help.
I have a good desoldering station. It takes me very little to plug the integrated circuits.
I attach some photos of both the original ops and of the TL074 which was placed in place of an original. no good! no good!
I also attach the diagram.


Greetings!

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