High Pass Filter Racks

[naths101]

Thought I'd throw out an idea for someone to make a rack of high pass filter clones in a 12 or 16 channel configuration similar to the API 215.

It comes from needing such a product for tracking with pres/eq & mixing on consoles where there is little or no filtering. Additionally a low pass filter would be great too.

How easy would it be to build such a thing? When it comes to DIY I'm a beginner and not quite in a position to build it myself at this time...

Cheers,
nath

 

[shabtek]

i believe gustav has some boards for a 2 band hi/lo filter in 500 format

 

[lucidtone]

I guess it depends on what kind of features you wanted your HPF to have - can you elaborate? 

What cutoff slope would you want?  6dB/oct, 12dB/oct, 24dB/oct?
Did you need a single fixed frequency HPF, or perhaps a stepped rotary switch per channel, or continuously variable frequency?

Do you have a particular filter topology that you like, or did you need some advice on what the options are?

 

[naths101]

i believe gustav has some boards for a 2 band hi/lo filter in 500 format

Gustav has the Studer 169 eq if that's what you're talking about? It's a Hi and Low shelf with a mid freq presense.

What cutoff slope would you want?  6dB/oct, 12dB/oct, 24dB/oct?
Did you need a single fixed frequency HPF, or perhaps a stepped rotary switch per channel, or continuously variable frequency?

I'd be after at least a 12dB/oct for HPF and 6dB/oct for LPF.
If it was a switchable 6/12dB that would be even better, obviously.

How possible would it be for a variable frequency? Otherwise a stepped rotary would have to do.

 

[jsteiger]

I do have a module in the works. The switchable HPF and LPF will be 71 series Grayhill's, 5 frequency points per. Both are passive and switchable between 6dB and 12dB. The main purpose for this 500 series module is not for the filters. They are really an add-on bonus to what else is there. If you know me, you can guess what the circuit is based on. ;D

Best, Jeff

 

[ppa]

for making this filter unit can be used:

- a sbalancer input (active)

- an buffer for the HPF filter (12db)

- a balancer output used for the LPF filter (6dB)

the circuit could be made with:

- an IC opamp or DOA for the input sbalancer

- a discrete buffer or an IC buffer

- a balancer output, made with a DOA or an IC balancer or with two IC opamps.

since the circuit is simple could be made with discrete topology, even if a IC opamp can be used for input.

 

[ppa]

I do have a module in the works. The switchable HPF and LPF will be 71 series Grayhill's, 5 frequency points per. Both are passive and switchable between 6dB and 12dB. The main purpose for this 500 series module is not for the filters. They are really an add-on bonus to what else is there. If you know me, you can guess what the circuit is based on. ;D

Best, Jeff

yes, the passive way is the best choise in this case

 

[ppa]

If you know me, you can guess what the circuit is based on. ;D
Best, Jeff

I have many customers that use Jeff's mic pres and they're very happy with them, just my two cents.

 

[dandeurloo]

yeah, this module will be really amazing I have a feeling.