3-band parametric EQ

Posted by on 11 January, 2011 Leave a comment (13) Go to comments

Here’s my first attempt at a parametric equalizer. I combined parts of the graphic equalizer I did previously with information on how to make gyrators from R.G.Keen at Geofex. There’s a schematic and a vero layout, and I haven’t verified either yet. Updates to come soon.

Update (13.01.2011): Correctly labeled C1 as 150nF and not 150pF.

Update (24.02.2011): Built this circuit yesterday and I can hereby verify it as working.

Update (29.03.2011): Boxed this effect last night with a friend. This is my second take at using a transparent film for artwork and labeling, and it came out a lot nicer now. Only thing missing is a few (many!) knobs.

Update (20.10.2011): Fixed dead picture links.

Build, Equalizer, Layout, Moderate, Schematic, Verified
Leave a comment ?

13 Comments.

  1. Alex 23 December, 2012 at 16:51

    Hi Harald,
    I was trying to make the equalizer more bass-friendly but I don’t know which caps to change. I’ve found these infos on bass frequencies:

    http://www.diyaudio.com/forums/instruments-amps/32205-bass-guitar-frequency-range.html

    Could you suggest me what to do from them?

    Thanks

  2. Alex 8 December, 2012 at 12:08

    Hi Harald,

    I don’t know if this could be useful but I’ve found some informations about bass frequencies here:

    http://www.diyaudio.com/forums/instruments-amps/32205-bass-guitar-frequency-range.html

  3. Harald 6 December, 2012 at 00:39

    Hi Alex. Thanks a lot for the great offer, but I’m going to regretfully have to decline. I already have too much going on as it is and I likely wouldn’t be able to do it justice. But it would be a great idea having a collective space where everyone could add layouts. Hmm. Again, where’s the time…

  4. Alex 2 December, 2012 at 22:38

    Hi Harald,

    It was for a friend and I don’t know much about bass either.

    I really love your website and I can’t thank you enough for it.
    I’ve been drawing some circuits using the same DIY Layouts program you use.
    Some are those that some people have requested you and I’ve already verified them (Marshall ShredMaster, Death By Audio Robot,…).
    If you want I can send you the original layouts files and, once you’ve double checked them and possibly corrected them, you can put your name and add them to the website.
    I wouldn’t want my name to appear on them.
    It would be just a way of thanking you for your great work.
    Please, let me know if you could be interested.

    Thanks Again

    Alex

  5. Harald 2 December, 2012 at 21:20

    You will probably need to swap out a few caps to shift the frequencies down. I don’t know that much about bass guitars. What frequency spectrum does a bass cover and what’s the center frequency?

  6. Alex 2 December, 2012 at 15:40

    Hi Harald,

    Any modification instructions for bass?

    Thanks

  7. Harald 21 February, 2012 at 06:02

    Chris. I can’t remember what they are at the top of my head (and I didn’t write it down either), but try this calculator and you can come up with your own frequencies even: http://www.muzique.com/lab/gyrator.htm

  8. Chris 18 February, 2012 at 11:06

    Hi,
    This site is amazing!
    I’m planing to build this for tone-shaping.
    Only one question: Could you please me about the Low/Mid/Hi Frequency Range?

  9. Harald 24 November, 2011 at 15:50

    You should probably adjust the frequencies for bass, it’s set up for guitar as it is now. Let me think about it for a bit and I may add some modification instructions to the post.

  10. Didiet 24 November, 2011 at 12:50

    hi Harald,

    can i use this eq for bass guitar..?? how about the frequency range, is that dedicated for bass guitar too..??

  11. Stefan 12 October, 2011 at 12:34

    Hi Harald,

    You are right the components are labeled different. That was confusing me a bit.
    Thanks

  12. Harald 11 October, 2011 at 14:11

    Hi, Stefan. Thanks for the input, but you have to excuse me. I’m not entirely sure what you mean. Do you mean the polarities or the fact that I mislabeled almost all of the components compared to the schematic?

  13. Stefan 10 October, 2011 at 20:10

    Hi,
    I noticed that C12 and C13 are interchanged in the vero layout.
    Best regards and thank you for this great site.

Leave a Reply