Pultec HLF3c

[matthias]

I'm looking for a schematic of the Pultec HLF3c EQ

I searched the whole web and got nearly no info...

http://www.danalexanderaudio.com/OutboardPic/PultecHlf3c.jpg

what is meant by "constant "k" circuit ??


thanks,
mat

 

[gyraf]

I'm pretty sure that there's no schematics out there for this one. But if you find it - be sure to post it here as well!

Jakob E.

 

[PRR]

Filter equations have far too many variables for humans to comprehend.

One popular simplification is to divide-away the gain of the filter, "K", so that you can compute the shape of the filter and worry about gain later or in another stage.

It is a mathematical tool and should NOT be a boast on the box spec-sheet. In fact there are disadvantages to using an unmodified Constant-K filter, and I'd be more concerned how they handled that.

I guess what they are saying to the practical user is that gain is unity except where it is cut.

http://www.du.edu/~etuttle/electron/elect31.htm

http://my.core.com/~jematz/filters.html

http://www.radio-electronics.com/info/circuits/lc_highpassfilter/lc_hpf.php

http://www.edn.com/article/CA505069.html?industryid=2853

 

[PRR]

You want a schematic??

From the curves on the cut-sheet, just use loudspeaker crossover filters scaled up to Line impedance and your desired freqs.

http://www.carstereo.com/help/Articles.cfm?id=11

 

[CJ]

Don't waste time with anything but the classic EQP-1A.

 

[ciminosound]

The old Tremain book has the K filter equasion , doesn't it?

Mine's packed away right now... :sad:

The Audio 'Cyclopedia......

 

[gyraf]

Hi Matt,

I actually had the filter schematic from a friendly person who sent it to me some months ago. But I had so much work to do at the time, that I completely forgot about it.

Well, here it is, now added to gyraf/resources under Equalizers:

http://www.gyraf.dk/schematics/schematics.html

Direct link:

http://www.gyraf.dk/schematics/Pultec_HLF3.pdf

Many thanks to the supplier!

Jakob E.

 

[CJ]

This software is the bomb, ******!

I reversed the massive with this bad boy:

http://www.filter-solutions.com/