3D "AIR" EQ - "Night EQ" PCB's Complete!

[Whoops]

If you design a PCB...

[veer]
Why not address the quirkiness of the 'filter' sections ?

Making the pots stepped really is the way to go here.

Might also consider proper line receiver and driver (e.g. THAT124x l& 1646).

Or not. Just thinking out loud
[/veer]

I totally understand what you say, tuning the center points with Potentiometers is a pain, the tolerance of potentiometers is quite high.
Using stepped switches would be great, the questions are how many steps? How much dB increase in each step?

Making it true bypass would also be a nice addition

 

[diynamite]

If you design a PCB...

[veer]
Why not address the quirkiness of the 'filter' sections ?

Making the pots stepped really is the way to go here.

Might also consider proper line receiver and driver (e.g. THAT124x l& 1646).

Or not. Just thinking out loud
[/veer]

yes, this is also what I was thinking in the first place, but I think it is better for me to get the original design to work first.. and then tweak from there until I end up with a design I like.
Otherwise I might / probably end up with too many possible error sources

Btw, could someone re-post Harpos excel spreadsheet for calculating the stepped pots resistors?

 

[diynamite]

I totally understand what you say, tuning the center points with Potentiometers is a pain, the tolerance of potentiometers is quite high.
Using stepped switches would be great, the questions are how many steps? How much dB increase in each step?

Making it true bypass would also be a nice addition

0.5 dB steps would make sense, I guess? This would be something like -6 to +5.5 dB or -5.5 to 6 dB with a 24 step rotary encoder if I'm not mistaking.

True bypass would be great!

 

[Script]

Stepped in smaller increments maybe? 6dB can be quite a lot. Could use a set of filters in a DAW to get a rough feel. Harpo' s Excel sheet is somewhere above.

 

[diynamite]

Stepped in smaller increments maybe? 6dB can be quite a lot. Could use a set of filters in a DAW to get a rough feel. Harpo' s Excel sheet is somewhere above.

The last links to the spreadsheet I found are broken, but I can re-check..

I will check on the Mäag EQ VST I bought yesterday (big sale on Plugin Alliance now, if someone is interested)

 

[Whoops]

Btw, could someone re-post Harpos excel spreadsheet for calculating the stepped pots resistors?

Here it is

 

[diynamite]

Awesome, thank you very much!

 

[AllMixedUp]

Anybody happen to have some extra PCBs lying around or the gerbers?

 

[Whoops]

Anybody happen to have some extra PCBs lying around or the gerbers?

to buy PCB's the best place is to post a thread in the Black Market.

For the gerbers you can ask PeterC

 

[beatnik]

Is there any pcb available for this eq with dual ganged potentiometers ?

I would like to use this eq for the sound system in my van

 

[peterc]

Hi Beatnik
The only PCB designs I ever did were for 2 seperate channels, dual mono systems.
Peter

 

[Whoops]

Is there any pcb available for this eq with dual ganged potentiometers ?

You could do it but you will never find dual gang pots for this project with both gangs “matched”, dual gang pots have an high tolerance between both gangs of the same pot, can be 20/30% sometimes.

best way would be to do it with Stepped switches with 1% resistors

 

[beatnik]

You could do it but you will never find dual gang pots for this project with both gangs “matched”, dual gang pots have an high tolerance between both gangs of the same pot, can be 20/30% sometimes.

best way would be to do it with Stepped switches with 1% resistors

The Alps RK27 series has pretty good channel matching but unfortunately isn't available off the shelf in 500K rev log.

With stepped switches it might become quite time consuming and expensive which isn't really worth for this kind of project.

I should probably look into something else, any suggestions are welcome

 

[Script]

For listening in a car environment, I'd say, noise is omnipresent while moving and noone sits directly in the sweet spot anyway. Ergo not exactly matched pots is rather a no-brainer.

Unit can be modded for 50K rev log.

WTH, why not even lin pots and no '0' marking, as the knobs will get continuously tweaked to gusto anyway

 

[MVee]

Here's everyting I have on this project : https://we.tl/t-6iQaqbnDkN

Hi I know it's been a while but would you still have the files ? I'm trying to trouble shoot a used unit I purchased and might need to recreate the PCBs. Thanks a bunch!

Mike

 

[dasnevestheo]

sorry i missed your post, here you go, hope that helps ! 53.39 MB folder on MEGA

 

[fragletrollet]

The Alps RK27 series has pretty good channel matching but unfortunately isn't available off the shelf in 500K rev log.

With stepped switches it might become quite time consuming and expensive which isn't really worth for this kind of project.

I should probably look into something else, any suggestions are welcome

500k log

Edit: sorry that's Log not RevLog.

 

[Script]

Pots need to be rev-log.

Switches can be had comparably cheap from AliEx'. They are not necessarily top-notch but they 'work'.

Using C50k (rev log /anti-log) instead of C500k lowers noise and might be (generally) more readily available. But that requires on-board resistors around filters and gain stages to be scaled accordingly.

 

[peterc]

Thanks for that Theo! Slipped me mind completely

 

[3nity]

Hey guys. I've been trying to open the Harpo spreadsheet but no luck on page 55 theres one document with the excel and pdf extension..but fails to open..any other source available?