porter net eq with some changes

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James HE

Well-known member
Joined
May 21, 2006
Messages
54
Location
Richmond VA US
I started working on the Barry Porter Net EQ as my first big DIY project a few months ago. There isn't that much info on it, which makes for a difficult first DIY. Something just drew me to it, curiosity mostly. I love to think my way through problems - mostly by creating new ones! :D
All the pots are speced as 10k, so easy to find right? Well, the cut/boost pots are center tapped which is an issue, but I think I can find a way around that. (or actually already have options, more on this later) Another snag is the frequency controls on the hi and lo bands. These are three section pots in the original design. I got 20 10k dual lin pots of ebay for a good deal, they are Alpha pots with 12 detents, I paid I think $12 after shipping. So I decided to just use these and work around having to have 3 section pots for the freq.

Since switching to shelving takes the q control out of the circuit, I decided to just use a dual pot there, and use the second section as a shelving freq control, independant of the band freq control. So now it looks like this. (This is just the low frequecy band, the values for C3 and C4 are wrong however)

NETv2.jpg


Good so far? I'll just have to figue out a clever way of marking the front panel for both functions. I decided an led would be really good to have to tell me when I was in shelving and which knob to turn. And decided on a dual color LED. I'm not using relays like in porter's design to keep it simpler, and wasen't sure how to implement the LEd. So that's my stab at that in the schematic. Seems straight foward but I'm unsure. I want to run it from the same + power rail as the opamps, Is this advisable? the original schem has a seperate rail for the relays and LED. And I'm noticing that he has the LED at Ground and not 0V like the rest of the schem. How important is that?

Thanks for any help! I'll try to find the link to the files I found for this design, If not I'll put a copy up.
 
Yeah i tried it a few times. I think I'll have to do a screen shot or something.

Sorry.

I'll get my act together and report back. :green:
 

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