[Goobley]

I'm thinking of attempting this for my next project, but there appears to be very few resources on the subject. I keep coming back to the same site, which doesn't seem the most reputable, however I expect the guy just copies the schematics out of some old book.


 


3 different ways of going about this have occurred to me but I don't know about the pros and cons of each type.


 


1) an IC designed for the task (quite how good quality these are I don't know


ex:





http://www.free-circuit.com/2010/04/12/5-band-graphic-equalizer-with-ic-ms226p/


 


2) Individual filters and buffers for each band


ex:





http://www.free-circuit.com/2010/03/02/6-channel-audio-graphic-equalizer-circuit-with-tl074/


 


3) Filtering then 1 opamp per channel


ex:


 





http://www.free-circuit.com/2011/03/22/stereo-pre-tone-control-circuit-with-ic-ne5532/#more-1058


 


The best design - to my untrained eyes - would appear to be the second, unless there are some very good quality all in one eq chips. If I was to build something like the second I'd obviously double it (as the schematics only one channel), but I'd also update it to use OPA2134 as they're cheap and very good quality. I'd power it off the same psu as my next amp, as they'll both want +15/-15V.


 


Any ideas or input on equalising projects would be very welcome,


Chris

 

[nagrive]

Interesting.. I will sit behind and listen to this thread..

 

[Goobley]

I'm back!
This has been a project that I have been mulling over and working on over the past couple of weeks (including learning to use PSPICE to simulate a few things). I came up with a shopping list of features that I'd like and decided to integrate Linkwitz's/Chu Moy's/Tangent's Crossfeed Module. The preamp and tone control designs are based off of Rod Elliott's work (Project 97), I'm still waiting to hear back from him whether I can work of his design, if not there are a few things that I'll change. I decided due to personal preferences to go with tone control rather than an equaliser.
 
Heres the schematic:
 

The molex connectors are obviously used to be connected to the pots/switches giving a very wide range of possibilities.
 
Along with my rough PCB design (done in eagle for wima FKP/MKS2 caps):
 

top:
 

bottom:
 

 
I'm not yet happy with the ground plane as I have very little experience laying out PCBs, can anyone advise me on this?  have included the sch file (zipped) if any of you are brave enough or just have nothing to do.
 
I think/hope this may be quite a useful project for the diy community (even if the principle isn't very audiophile) and look forward to sharing it's evolution with you.
Cheers,
Chris