enthalpystudios
Well-known member
In these type of topologies:
API 553
and:
Forssell EQ White Paper
are there any issues with switching out the cap in series with the inductor to change the frequency center to avoid many inductors or multi tapped inductors?
I notice that the pultec switches cap and inductor simultaneously. Is this to avoid a changing the bandwith of the filter section?
It would be cool to use 1 quality inductor per band, but switch the cap for different centers.
Also, in his white paper, Fred describes this circuit as being "a frequency dependent passive attenuator with an output buffer amplifier. The buffer amplifier provides low output impedance for the EQ to drive the outside world properly."
That registers for me but only partially.... it seems the amplifier must provide some gain, maybe not full bandwidth, but at least at some frequencies, during boost control settings.
trying to look at the api553 input section, it appears there may be a padded input first off that runs through the gain trim pins so that it does provide a bit of gain to keep the 2520 more comfortable?
Very cool eq topology in my opinion, however, seems very smart to me.
API 553
and:
Forssell EQ White Paper
are there any issues with switching out the cap in series with the inductor to change the frequency center to avoid many inductors or multi tapped inductors?
I notice that the pultec switches cap and inductor simultaneously. Is this to avoid a changing the bandwith of the filter section?
It would be cool to use 1 quality inductor per band, but switch the cap for different centers.
Also, in his white paper, Fred describes this circuit as being "a frequency dependent passive attenuator with an output buffer amplifier. The buffer amplifier provides low output impedance for the EQ to drive the outside world properly."
That registers for me but only partially.... it seems the amplifier must provide some gain, maybe not full bandwidth, but at least at some frequencies, during boost control settings.
trying to look at the api553 input section, it appears there may be a padded input first off that runs through the gain trim pins so that it does provide a bit of gain to keep the 2520 more comfortable?
Very cool eq topology in my opinion, however, seems very smart to me.
