Potato Cakes
Well-known member
Hello, everyone,
I have been doing various tests and building using the BA283 amps in 1073/84 style circuits and the one of the latest things I've been wanting to do is add a variable HPF/LPF section. In IC based designs there is a buffer amp, then one of these types of filters, then amplifier, then repeat for the other filter. On the 1084 schematic it goes from the HPF section to the LPF then to the BA amplifier before the output transformer. The HF and LF sections of the EQ also share one amplifier and do not use an inductor, and I have no complaints on how those frequency bands sound on a 1073.
I've attached a schematic of what I'm wanting to do. On the 1084 is a 4k7 resistor between the HPF/LPF, but I don't know if that is necessary in my proposed passive layout. I put a question mark in that spot as I am uncertain as to whether or not anything is needed there. To simplify things, I would not add a bypass switch for the filters as the extremes of the filter ranges are well beyond what would be asked of this type of circuit.
This has not been tested yet as I am in the process of moving and have not setup a place to prototype this.
Thoughts?
Thanks!
Paul
I have been doing various tests and building using the BA283 amps in 1073/84 style circuits and the one of the latest things I've been wanting to do is add a variable HPF/LPF section. In IC based designs there is a buffer amp, then one of these types of filters, then amplifier, then repeat for the other filter. On the 1084 schematic it goes from the HPF section to the LPF then to the BA amplifier before the output transformer. The HF and LF sections of the EQ also share one amplifier and do not use an inductor, and I have no complaints on how those frequency bands sound on a 1073.
I've attached a schematic of what I'm wanting to do. On the 1084 is a 4k7 resistor between the HPF/LPF, but I don't know if that is necessary in my proposed passive layout. I put a question mark in that spot as I am uncertain as to whether or not anything is needed there. To simplify things, I would not add a bypass switch for the filters as the extremes of the filter ranges are well beyond what would be asked of this type of circuit.
This has not been tested yet as I am in the process of moving and have not setup a place to prototype this.
Thoughts?
Thanks!
Paul
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