7 Band EQ

classic Classic list List threaded Threaded
10 messages Options
Reply | Threaded
Open this post in threaded view
|

7 Band EQ

Stevel
Hi y’all, long time lurker first time poster.

I recently came across (snigger) these ICs from China,
5 PCS LA3607 3607 7-Band Graphic Equalizer @ £1.88.
Used the datasheet to make my first proper vero, seems to work ok,
if anyone is interested or has any tips for the layout please let me know.




I used this site to calculate the Frequencies http://www.muzique.com/lab/gyrator.htm
R1 – 68000 (68K) & R2 – 1200 (1K2) as per datasheet.

I’ll attach the DIYLC v2 file & Datasheet

Apologies to IvIark for the standing resistor (lol).

7-Band_EQ_-_DIYLC_v2.diyLA3607.pdf
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Alex
This post was updated on .
Great job Stevel!
With an extra link and a few cuts you could avoid the standing resistor and make it 21 x 12 by cutting the first 2 rows on top.
Something like this:
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Stevel
That's better, thank you Alex, don't know how you have the patience for the larger boards, took me long enough with this small circuit but very satisfying when it works.

Cheers
Steve
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

strassercaster
nice job guys. how a out a video? so would it be fair to say these cap ranges are pretty much universal for most eq setups?
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Stevel
This post was updated on .
Thanks for the interest strassercaster, no video I'm afraid, not equipped for that at the moment.

I based this on the frequencies shown on a BOSS GE-7 with Q around 1.5,  however I have since found the correct Fs & Qs (thanks Mark, 4th May 2014).


 C2           C1           F         Q
390n       82n   98.52 3.45
220n        39n  190.21 3.17
100n       22n  375.63 3.53
47n          10n    812.69 3.47
22n          5n6   1587.34 3.80
10n       2n7 3390.73 3.91
5n6         1n4 6292.41 3.76

I also created an Excel Sheet for the calcs, (the one Mark posted seems to have disappeared).
EQ_Frequency_&_Q_Calculator.xls

There are also 5-Band chips around and all can be joined together for more. The original post showed my first attempt, I have since changed the values and tried values for the Mesa 5-Band (all in the attached Excel).

Cheers
Steve
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Stevel
This post was updated on .
They were lined up, try again.

 C2      C1         F         Q
390n   82n      98.52   3.45
220n   39n    190.21   3.17
100n   22n    375.63   3.53
47n    10n     812.69   3.47
22n    5n6   1587.34   3.80
10n    2n7   3390.73   3.91
5n6    1n4   6292.41   3.76

Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

cylens
that's really interesting, thank you!

it's +/- 12 dB per band, if I got it right. might be interesting to "double the bands" and make a 3 band +/-24 dB...
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Stevel
Yes according to the datasheet it's +/- 12 dB per band, don't know if you can double the cut and boost, but you can connect several ics for more individual bands.
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Mark SL
In reply to this post by Stevel
Has anyone actually built this with good results?
Reply | Threaded
Open this post in threaded view
|

Re: 7 Band EQ

Stevel
This post was updated on .
I built one with the values I originally posted but I think the bands (Q) are a little narrow, required quite a twist of the pots for any effect.

Tried a 5 Band with the Mesa values and that worked rather well, I haven't tried the updated Boss values yet (Q 3.5 - 4.0)

Download the EQ_Frequency_&_Q_Calculator.xls I uploaded and have a play, it's a Gyrator in a chip or try something like this http://tagboardeffects.blogspot.co.uk/2014/05/4-band-gyrator-eq.html

Hope this helps.