amek m2500 eq schematics...

electrichild

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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
 

electrichild

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[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?
 

12afael

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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
 

electrichild

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[quote author="12afael"]

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

[/quote]

LTspice? What's?
 

jdbakker

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[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.
 

12afael

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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
 

12afael

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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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