Hi everyone 🙂 I've attached the output buffer part of p81 knowing that the project-81 is a intellectual property of rod elliott; bcoz i had no other option. Anyway, my question is about the use of dc blocking cap after VR1(in series with non-inverting input). As you can see tl072 is shown here as output buffer but i want to use bipolar input op-amp like 5532. So my concern is input bias current of 5532, quite high in comparison with tl072. Can i use 1uf film after VR1? I mean here the procedure maybe as same as calculating high pass filters for power amplifiers, preamplifiers?
I'm not sure because as far as i know filters are quite sensitive.
On the other hand since 12db/octave Xovers always invert the phase of one signal, which one would you like to invert? High pass or low pass section??
Regards
Nirupam
I'm not sure because as far as i know filters are quite sensitive.
On the other hand since 12db/octave Xovers always invert the phase of one signal, which one would you like to invert? High pass or low pass section??
Regards
Nirupam
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No one cares!
alright, i think without changing anything 1uf input cap after VR1 will be fine for the HF part.
alright, i think without changing anything 1uf input cap after VR1 will be fine for the HF part.
Tweeter's SPL is usually higher than the woofer so VR1 to the HP would be best. I can't comment on the cap but I can't see it doing any harm if DC blocking is required.
I used the LP section of the P81 in sub processor and have the volume adjustment before mono mixing resistors prior to the buffer op amp U1. The output I used is the same as the first schematic but I had to add a 100K resistor to ground on the output after the 100R. I can't remember the issue but it was noise or DC offset.
I used the LP section of the P81 in sub processor and have the volume adjustment before mono mixing resistors prior to the buffer op amp U1. The output I used is the same as the first schematic but I had to add a 100K resistor to ground on the output after the 100R. I can't remember the issue but it was noise or DC offset.
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thanks for the reply🙂 Yes, HP section would be best to balance the driver sensitivities. I'm not concern about DC offset but large current going through the VR1, maybe it'll make the pot noisy. But it is set and forget type thing so maybe i should leave it as it is.
btw nice op-amps 🙄
Regards
Nirupam
btw nice op-amps 🙄
Regards
Nirupam
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