Pultec filter section question
- Thread starter JPrisus
- Start date
Help Support GroupDIY Audio Forum:
Thanks! I will.
not bad, not bad, hey, this one even designs the indutors!
Thanks Al!
anybody have any experience with the EQ 500?!
man, imagine building an 11 band balanced version with this circuit:
not bad, not bad, hey, this one even designs the indutors!
Thanks Al!
anybody have any experience with the EQ 500?!
man, imagine building an 11 band balanced version with this circuit:
After thinkin about it, i definitely was getting carried away with ideas and maybe we should stick a little closer to the original idea as Jo suggested.
So let's say we keep the original EQP filters (sans Q knob), maybe add a few more frequencies to the Hi cut and low sections, and add the MEQ mid cut with Neve-style frequencies. If we can split it off into two bands, great, if not, no harm done. How does this sound to everyone?
Hope to put more of my own time into this soon, busier this week than i thought i'd be.
So let's say we keep the original EQP filters (sans Q knob), maybe add a few more frequencies to the Hi cut and low sections, and add the MEQ mid cut with Neve-style frequencies. If we can split it off into two bands, great, if not, no harm done. How does this sound to everyone?
Hope to put more of my own time into this soon, busier this week than i thought i'd be.
I am consolidating images so this thread won't bog down.
:razz:
WE WANT MORE! WE WANT MORE! WE WANT MORE! WE WANT MORE! :razz:
if we wanted to blow the doors off the mp we could go fully balanced all the way thru but that would take twice the components said:
actually, i like Manley. why? because their 100 percent tube oriented.
ha! now Your the one thats gonna get sued! (see above posts)
i should have been a lawyer.
:guinness:
i should have been a lawyer.
:guinness:
:guinness:
:sam:
:wink:
OK, were starting to get close to this thang. I see from the owners manual that you can't have cut and boost enabled at the same time on the mp. This means that they are indeed, sharing the cap/inductor filters. Of course! Otherwise, you would have to have 4 times 11 =44 caps/44 inductors, then double that for having the capability to cut and boost at the same time, this means 88 caps/inductors! And it's stereo, so that means 176 cap/inductor combos!
So, they must be switching the cap/inductor filters between cut and boost. This means I don't have to compute seperate values for the cut bell curves! Yipee!
But, in order to get symetrical curves on the cut/boost section, you have to trim the q on the mid cut for every band/frequency. No biggy. I got pretty close, check it out. This is the same cap/inductor combo used for both cut and boost. The cut has a 200 ohm Q trimmer in series with the LC circuit, the boost does not need it. You can leave out the Q trimmer if you want a steeper cut curve than boost.
I lucked out by choosing 1056 ohms as a reactance constant for the filters. IT GAVE ME 90 PERCENT STANDARD VALUES FOR ALL THE CAPS!
The inductors can be wound for any value you want.
:guinness: :guinness: :guinness:
I see that making a balanced filter type eq would be insane, as you would need ten thousand dollrs worth of caps and coils. But, I think I am going to use nalanced makeup amps on this thing. This means a couple of extra push/pull x-formers, but we need to get the noise down. I think the stock EQP-1A makeup amps sound great.
So, they must be switching the cap/inductor filters between cut and boost. This means I don't have to compute seperate values for the cut bell curves! Yipee!
But, in order to get symetrical curves on the cut/boost section, you have to trim the q on the mid cut for every band/frequency. No biggy. I got pretty close, check it out. This is the same cap/inductor combo used for both cut and boost. The cut has a 200 ohm Q trimmer in series with the LC circuit, the boost does not need it. You can leave out the Q trimmer if you want a steeper cut curve than boost.
I lucked out by choosing 1056 ohms as a reactance constant for the filters. IT GAVE ME 90 PERCENT STANDARD VALUES FOR ALL THE CAPS!
The inductors can be wound for any value you want.
:guinness: :guinness: :guinness:
I see that making a balanced filter type eq would be insane, as you would need ten thousand dollrs worth of caps and coils. But, I think I am going to use nalanced makeup amps on this thing. This means a couple of extra push/pull x-formers, but we need to get the noise down. I think the stock EQP-1A makeup amps sound great.
OK, I cleaned up the smaller eq that have been developing.
Just add more treble and mid cut circuits in parallel if you want.
I will get some cap/inductor values for you next week.
The values I have done are for the bigger cousin of this guy.
Just add more treble and mid cut circuits in parallel if you want.
I will get some cap/inductor values for you next week.
The values I have done are for the bigger cousin of this guy.
OK, i cleaned up my posts so this thread will load easier.
Here are all the values for the boost-cut filters.
Here are all the values for the boost-cut filters.
looks interesting!
get that line out of vr 3.
you may have to delete the pot, clean the line and put the pot back.
ditch R7 and see if that hurts anything. i don't think you need it.
get that line out of vr 3.
you may have to delete the pot, clean the line and put the pot back.
ditch R7 and see if that hurts anything. i don't think you need it.
rafafredd
Well-known member
come on...
It´s not a real problem. Use any quiet micpreamp after this and you should be fine.
It´s not a real problem. Use any quiet micpreamp after this and you should be fine.
NewYorkDave
Well-known member
It looks like you're doing you simulations with a "perfect" zero impedance signal source.
Add a suitable series resistance to the signal generator output to see what your curves will really look like.
By the way, you can get similar curves with much fewer components and less insertion loss by using a certain "original design" EQ circuit that was posted a while back... :wink:
Add a suitable series resistance to the signal generator output to see what your curves will really look like.
By the way, you can get similar curves with much fewer components and less insertion loss by using a certain "original design" EQ circuit that was posted a while back... :wink:
You could split up the eq and use two different amplifiers. This is what the MP does.
Or, you could put an amplifier before and after the passive filter. This is
what D.W. Fearn does on his Pultec type eq. This would give you the gain you need.
This would also eliminate the
source impedance problems NYD was mentioning.
Or, you could put an amplifier before and after the passive filter. This is
what D.W. Fearn does on his Pultec type eq. This would give you the gain you need.
This would also eliminate the
source impedance problems NYD was mentioning.
Similar threads
- Sticky
Latest posts
-
-
-
-
Tools to capture electromagnetic fields and alternatives to telephone pickups?
- Latest: abbey road d enfer
-
-
-