amek m2500 eq schematics...

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electrichild

Active member
Joined
Aug 12, 2008
Messages
35
Location
italy
Hi,
I'm planning to make an EQ based on the amek m2500 eq section. On the schematics I find on the forum there aren't the original bell/shelf switches I would implement...Adding resistors and switches in the HF and LF path between R6/C5 and R45/C20 will affect the curve of Q pots?
Which values are right?
Respect
Electrichild

http://www.gyraf.dk/schematics/amek_m2500_eq.gif
 
[quote author="jdbakker"]Have you read this thread, and the older threads that its first post links to?

JDB.[/quote]

Thanks for reply.
Yes I read all posts inherent but it's not clear which are the values of the resistors. I imagine 220k would be ok for HF and greater for LF.
Have anybody really realized a good working eq based on that schematic?
 
the schematic from jakob site have the mods for the shef/bell sw.
http://www.gyraf.dk/schematics/amek_m2500_eq.gif

IIRC you must make a shortcircuit in R137 (one half of the 50 rev log) and add a 1M resistor between r144(pot) and R50.

I have some schematics for LTspice if you want to play :razz:

cheers
Rafael
 
[quote author="12afael"]I have some schematics for LTspice if you want to play :razz: [/quote]
I'd be interested!

[quote author="electrichild"]LTspice? What's?[/quote]
Linear Technology's free SPICE-based circuit simulator. you can download it from their site.

JDB.
 
here are the simulation files and some models needed for the simulation. the models IIRC were from the yahoo ltspice group.

http://www.twin-x.com/groupdiy/albums/userpics/amek2500_nemek_Harrisonfilter.zip

Enjoy :razz:

Rafael
 
tantalium or a small esr cap should do the work, 1uF film should work too.
I also put a small film cap in the power pins of each tl074.

39nF shouldn´t be so hard to find, but yes, you can use four 10nF in parallel.
 
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