Cardinen

Re: Barry Porter "Net EQ"
« Reply #480 on: August 03, 2017, 09:45:50 AM »
I can verify the circuit is working.

Gustav

Hi Gustav !

I'll like to try your design of this eq in the next months, i have a few questions:

- I'll split the channel bypass in L and R instead of stereo ( just using 2 relays) what will the MS do ? (single M-S bypass is possible?)
- Did you used 100uF bipolar caps like the original in the audio path or just standard audio electrolytic ?
- Have you encountered any problems in the project?

thanks  ;)
SSLtech:  "Because not all that matters can be measured, and not all that can be measured matters."


Re: Barry Porter "Net EQ"
« Reply #481 on: August 04, 2017, 08:11:25 AM »
Hi Gustav !

I'll like to try your design of this eq in the next months, i have a few questions:

- I'll split the channel bypass in L and R instead of stereo ( just using 2 relays) what will the MS do ? (single M-S bypass is possible?)
- Did you used 100uF bipolar caps like the original in the audio path or just standard audio electrolytic ?
- Have you encountered any problems in the project?

thanks  ;)


 If you think about how M/S works, you will realise what will happen if you mute one channel.
Think of it in terms of soloing M and S as solo functions if you want to implement that.

I attached an example from a different project showing how I did it around the decoder section. There may be easier ways, but this works..

Bipolars used where called for.

Gustav
« Last Edit: August 04, 2017, 08:24:50 AM by Gustav »

Cardinen

Re: Barry Porter "Net EQ"
« Reply #482 on: August 04, 2017, 03:33:31 PM »
Ok i got it now.

thank you, M/S solo will be a great function!  :D
SSLtech:  "Because not all that matters can be measured, and not all that can be measured matters."

bruno2000

Re: Barry Porter "Net EQ"
« Reply #483 on: August 16, 2017, 07:23:34 PM »
I have built some Net EQ modules and have found that the "linear" implementation of the boost cut ladder (using a switch) does not exactly correspond to the desired boost/cut figures.  I have worked out values for the resistors that come really close (+/- 0.1 dB) for what I wanted.  I'll publish my values if anyone is interested.
Best,
Bruno2000
« Last Edit: August 17, 2017, 01:30:55 PM by bruno2000 »

Cardinen

Re: Barry Porter "Net EQ"
« Reply #484 on: August 29, 2017, 06:25:50 AM »
I have built some Net EQ modules and have found that the "linear" implementation of the boost cut ladder (using a switch) does not exactly correspond to the desired boost/cut figures.  I have worked out values for the resistors that come really close (+/- 0.1 dB) for what I wanted.  I'll publish my values if anyone is interested.
Best,
Bruno2000

Yes i could be interested if you can post it;

« Last Edit: September 01, 2017, 07:30:08 AM by Cardinen »
SSLtech:  "Because not all that matters can be measured, and not all that can be measured matters."

bruno2000

Re: Barry Porter "Net EQ"
« Reply #485 on: September 01, 2017, 08:13:04 AM »
Here you go.
Best,
Bruno2000

bruno2000

Re: Barry Porter "Net EQ"
« Reply #486 on: September 05, 2017, 07:13:40 PM »
My version.
Best,
Bruno2000

5v333

Re: Barry Porter "Net EQ"
« Reply #487 on: September 14, 2017, 09:33:44 AM »
bruno thats sick tight!


i have been planning for a while on my own version of the bpnet eq. i have downloaded this schematic
http://www.collinsaudio.com/NetEQ.pdf
 and i see that it differs some from harpos schematic.
http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_H.pdf

the pots around q, freq, and gain are wired differently and some resistors are different around thoose pots.

is there a right version here?

the gain setting in harpos version seem to disconnect the juction to one of the two summing amps depending on cut or boost operation. seems like a cool idea but shouldnt the disconected end be terminated to ground atleast..?


bruno2000

Re: Barry Porter "Net EQ"
« Reply #488 on: September 14, 2017, 04:54:03 PM »
bruno thats sick tight!


i have been planning for a while on my own version of the bpnet eq. i have downloaded this schematic
http://www.collinsaudio.com/NetEQ.pdf
 and i see that it differs some from harpos schematic.
http://www.hausverwaltung-heger.de/al_leck_trick/Porter_NetEQ_H.pdf

the pots around q, freq, and gain are wired differently and some resistors are different around thoose pots.

is there a right version here?

the gain setting in harpos version seem to disconnect the juction to one of the two summing amps depending on cut or boost operation. seems like a cool idea but shouldnt the disconected end be terminated to ground atleast..?

I used Harpo's circuit, (x5) with a 5k equivalent boost / cut pot with a switch, and did use a 5k resistor from the unused summing amp input to gnd.  Harpo was amazingly helpful with his explanations and spread sheets.  I should have put his name on the front panel as well.........
I also added the M/S encode/decode circuit from Wayne Kirkwood, and the SSL 18 dB/oct HPF.
Best,
Bruno2000



Re: Barry Porter "Net EQ"
« Reply #490 on: March 11, 2018, 05:11:36 PM »
Can someone help me figure out how to make the HF shelf switch allow for selectable freq? Also what is the HF shelf set?

5v333

Re: Barry Porter "Net EQ"
« Reply #491 on: March 13, 2018, 12:30:04 PM »
hi!

the hi shelf freq is set by (1/2πRC) C77+C81 (1nf+6.8nF) and R91+P15 (1K+Pot). when the P15 is turned to minimum resistance, only R91 is part of the formula and sets the freq to about 20Khz.
when P15 is turned for maximum resistance, the total resistance should be about 11K for 2Khz.

the HI shelf and HI bell are separate filter circuits. with the switch, one of them is disconected from the gain pot of that band, while the other is in effect.
« Last Edit: March 13, 2018, 12:37:09 PM by 5v333 »

Re: Barry Porter "Net EQ"
« Reply #492 on: March 13, 2018, 01:38:39 PM »
Thanks that was a great explaination. So my question is that is there a way to put another gain pot in play when the HF switch is engaged to change the freq of the shelf? Also if the HF self is engaged what freq is it set?

5v333

Re: Barry Porter "Net EQ"
« Reply #493 on: March 13, 2018, 02:41:58 PM »
the HF freq is variable - both in the bell circuit and in the shelf circuit - with the same pot. the LF and HF freq pots  are triple ganged.

each band has its own gain pot.
LF bell and shelf shares a common gain pot.
HF bell and shelf shares a common gain pot.

if you want  to separate bell and shelf in any band you need to split the tripleganged freq pot in to one dual pot and one single pot.
if you want to have separate gain for shelf and bell you have to insert an additional gain pot and wire it similar to P14 P11 P8 P5.


Re: Barry Porter "Net EQ"
« Reply #494 on: March 14, 2018, 03:24:59 PM »
Ok that is what i needed! thx Can i ask which set of three connections would effect the shelf?

Ones
toward the outside of board
middle or
 inside board?

5v333

Re: Barry Porter "Net EQ"
« Reply #495 on: March 14, 2018, 03:40:21 PM »
i am only refering to the schematic. i have never seen a pcb...

if you tell us which pcb you have, maybe some one can help you with that.


Re: Barry Porter "Net EQ"
« Reply #496 on: March 14, 2018, 04:09:02 PM »
looks like the pot connections that go to R91.


 

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