Barry Porter "Net EQ"

[assrael]

Yes, per channels a low shelf and a high shelf with separate gain and frequency control and four bands of peaking filters with separate gain, frequency and Q control.
It should be not that difficult to do this. Omit the relays K3 and K4 and go from the shelving circuit via a 2k2 resistor directly to an addition frequency pot/rotary like on the peaking bands. Also an additional frequency pot/rotary is needed for full control. Take a look on the schema and you will understand it.

 

[Nescafe]

Hi,
for the space and lead spacing that allowed consideration, which one is better for bypass cap:

higher voltage X7R
or
lower voltage NP0/C0G

example: 220nF 100V X7R vs 220nF 50V C0G/NP0

Thank You

 

[Harpo]

When in doubt, use same or higher voltage rating than the bypassed cap, IE >=6.3V for bypassing the 1000uF bipolar caps in question (if bypassing is needed at all).
C0G/NP0 is the better/more temperature stable dielectric.

 

[Nescafe]

Hi Harpo,
it's for the transistor coupling C10-C29-C37-C38, sorry for my mistake  so which one do You prefer, X7R with higher voltage or NP0 with lower voltage? And also is that OK if I replace the C19-C20-C21-C22 with Non Polar type?

Thank You.

 

[Harpo]

...X7R with higher voltage or NP0 with lower voltage?

already told you (worst case 12V relais supply voltage across the cap, and doesn't really matter in this spot, so the cheaper one will do as well).
edit: BTW 220nF isn't a c0g/np0 parts value. These are in the pF range.

And also is that OK if I replace the C19-C20-C21-C22 with Non Polar type?

Why would you want this ? (at best similar performance with bigger parts size at higher cost).
As always YMMV.

 

[Nescafe]

Yes, per channels a low shelf and a high shelf with separate gain and frequency control and four bands of peaking filters with separate gain, frequency and Q control.
It should be not that difficult to do this. Omit the relays K3 and K4 and go from the shelving circuit via a 2k2 resistor directly to an addition frequency pot/rotary like on the peaking bands. Also an additional frequency pot/rotary is needed for full control. Take a look on the schema and you will understand it.

Paul Gold have try this, check this link, post no. 40 http://www.gearslutz.com/board/mastering-forum/732670-barry-porter-neteq-2.html

 

[assrael]

Hi Nescafe,

Sampa wrote in an German forum, that the load of the gain stage has to be recalculated if there are these two additional shelving bands. That makes sense to me, but I cannot give any detailed information, because I don’t know the math behind.

Here is the Link to this German thread (#280):
http://recording.de/Community/Forum/Recording_und_Studiotechnik/Do-It-Yourself_%28DIY%29/176376/Thema_14.html

 

[prescott]

Can u guys please help me in the pots....

What type is the 3 gang pot?
Of course I have the BOM, but its a 4 gang pot with switch on it, not a 3 gang type.

How can I use it?

Is it possible to use a dual pot for the bell frequencies, and a single for the shelvings?
Will that work?

thanks!

 

[Harpo]

Of course I have the BOM, but its a 4 gang pot with switch on it, not a 3 gang type.

"The BOM" from Mark (not Barry) was partly confirmed by dagoose (AFAIK his build didn't contain a single pot but switched rheostats). PCB layout seems to be for Vishay/Sfernice series P9 conductive plastic potentiometers.

Is it possible to use a dual pot for the bell frequencies, and a single for the shelvings?

Yes, with the additional advantage of having the oportunity to scale the frequencies more correct, IE the pot(s) at same rotation angle will give different bell/shelf frequency responses. Keep in mind, potentiometers might come with up to +/-20% parts tolerances.

 

[prescott]

Thanks!

Finally I made it with rotary switches like for the first time, but now I found what was wrong at first!

Some wires changed.... 

 

[prescott]

Harpo, can you please tell me where can I find your hop that has the 12 step Q?

I made the switches about a year ago, and now I dont find the source

thanks!

 

[Harpo]

Harpo, can you please tell me where can I find your hop that has the 12 step Q?

this 1st.version ?

 

[prescott]

Yes, thanks a lot!

 

[Majestic12]

Another one done...

 

[3nity]

WOW!
thats one build that makes me wanna build this eq!
Looks really well done!

 

[kante1603]

Very nice looking (and I bet sounding) eq indeed!
Congrats!

Udo. 8)

 

[druu]

I'm just about to start building mine, can someone suggest a choke/inductor for L1 that fits the PCB?

Thanks.

 

[skal1]

do the switches need to be shorting type or can i use no shorting for freq,Q and atten/boost .

cheers

skal

 

[frazzman]

I'm in the process of preparing for this build... First time building stepped pots and actually first project I've looked at that is based on multi deck pots.
Probably a naive question here so humour me, but what's the deal with the dual gang and triple gang pots as outlined in Barry's original layout (I know I'll be substituting these with switched rheostats..)
For a mono channel why the requirement for dual/triple gang on the freq bands ? Usually id only seen dual gang pots used in a stereo application. I'm looking at building a dual mono build but I want to get my head around the original design first... Thanks guys

 

[Harpo]

For a mono channel why the requirement for dual/triple gang on the freq bands ? Usually id only seen dual gang pots used in a stereo application. I'm looking at building a dual mono build but I want to get my head around the original design first...

For the frequency setting pots/rheostats one gang only for the high and low shelfing bands and dual/stereo gang pots/rheostats for all peaking bands. (Using stepped rheostats, the resistor values would better be different between shelfing and peaking bands to match with the frequency frontpanel labeling). In a stereo build and from Barrys schematic, this would be a 6-gang pot/rheostat for the low and high band and a switch to either operate these shelfing or peaking. Your dual mono unit would either have 4 triple gang rheostats for peaking or shelfing adjustment or have seperate knobs for peaking (4 x stereo/dual gang) and shelfing (4 x mono/single gang) adjustment. Both mid bands only use dual/stereo gang pots/rheostats for frequency selection.