Barry Porter "Net EQ"

[richiyobs]

The number of bands depends on the output capacity of the opamp that drives the filters. It drives the two shelves, which can result in as low as 500 ohms (if LF is set at 200Hs and HF at 20kHz). Each filter has an impedance of 10k. With 6 bands + the two shelves, the load can be as low as 1.75k. Most opamps are capable of driving that, but often with some penalty regarding distortion.
Then there is the issue of noise. The good noise performance of the BPNEQ relies on the use of center-tapped pots, which make sure the noise created by each filter is limited to the strict minimum.

Thanks for your reply and Infos
I d like to have 6 bands in total... 4 parametrics a 2 shelv ... So the load should be lower
Or maybe instead of shelvig using a baxandall configuration
Opamp Will be ne5532 and for Gains pot i ve simulated lorlin 1x12 with PIN 1 to gnd as Harpo s schemo... There s no interaction between bands... But don t know the noise performance about this solution

Thanks for your support
Best

 

[abbey road d enfer]

Or maybe instead of shelvig using a baxandall configuration

A Baxandall is a shelving EQ.

 

[richiyobs]

Always tought It has a different slope/shape

 

[lev s termen]

This is a redraw of the Porter netEQ PCB to replace the exotic format Gerber files circulating around. I tried those at 2 local PCB shops and 2 major Chinese PCB manufacturers and all of them said files were useless. After spending hours trying to make use of these files I concluded that myself but decided to ask companies that are in the business as well. I assume those were deliberately manipulated so that couple of people can sell their PCBs but that's just an evil conspiracy theory of mine.
Fortunately the archive included PCB tracing and schematic which is plenty enough to redraw the whole thing. Now I offer it as a compete and free Sprint Layout PCB project for everyone interested to use as they would like and to modify it to their needs.

Changes I made:
1/ some PCB traces have been optimized and don't exactly overlap the PDF file tracing
2/ included option to use THAT1246 and THAT1646 for input and output instead of the unnecessarily complicated original stages
3/ included is an option for a LM317/337 regulated onboard power supply section
4/ optimized are positions of the onboard 9mm pots in case one wouldn't use stepped attenuators including a footprint for a 10k center tapped 16mm pot available from Aliexpress
5/ all mounting holes and pots/switches distances are in mm of course

ATTENTION: as of August 10, 2022 this PCB is to be considered UNTESTED!

Check the PCB against the schematic and PDF tracing and layout files before you order these somewhere!
I'll be also doing some more checks and post corrections if any.
If you find any mistakes let me know so I can correct them and post corrected files.
To view the files you can download a free Sprint Layout viewer from here:
https://www.abacom-online.de/updates/Sprint-Layout60_Viewer.exe
or get the full software temporarily for educational purposes from...well, you know how.
Note that ground planes are not visible in the viewer.

Last archive update 13.08.2022

hi MM, dear all friends
this is Alex I made your redrawn version of the neteq pcb. Please few questions:
1. there are several components not marked with the values, IE RXX without the ohm value.
2. several discrepancies with original design and so on
Could you send please the schematic and BOM associated to your pcb version.
all the best, A

 

[lev s termen]

Please provide the part/s number/s and how this looks in an actual build and I'll let you know.



I'm sorry if someone got offended by my evil conspiracy theory.
I'm not aware of the project history in detail however the fact is those files in the archive distributed were useless and it was very suspicious to me that all those years a corrected version was not posted.
Now a full PCB project is available and everyone can modify it according to their needs.
I'll be building this in the next month or so and will be able to test the and troubleshoot the board if necessary so if you're not in a hurry you might want to wait some time before you order the boards from somewhere or if you do let us know if you find something that needs to be corrected.

Hi MM I would know some details about your design, Ive made the board and need some explanations. Please contact me Thank Alex