5003 eq building and help.

[outoftune]

thanks alex, i will give it a try.

curious what freqs/values you swapped to.

anyone experimented with a zobel or with adding a loading resistor to the output as indicated here?

I have built mine stock but am considering doing a few little changes to make them better suited as an eq for masterbus.

if on/off/on switch is used, this defeats the band when on the off position, correct?

 

[alexc]

My changes were about more about maintaining the approx centre frequencies where I had changed the inductors to ones which gave me a better noise floor.

I used inductors I had at hand and so I needed to change the filter RC values to compensate.

They basically corresponded to calculated values but not exactly as you have to parallel caps within the constraint of the pcb layout, to get as close as you can to your desired values.

My main problem was in taming a too high Q value due to the inductor values I had available, particularly in the mid band - so I had to experiment somewhat around my calculated values to give me a tradeoff between the centre freq and a usefully broad Q.

I ended up with  :

low - 120Hz and 340Hz,  mid - 1KHz and 1.5KHz , high - 8KHz, 12KHz


And yes, mid position of an on-off-on removes the contribution of a filter band from the eq.

Cheers

 

[outoftune]

thanks for the reply.

do you notice much of a sonic difference with the unused filter bands switched out?

 

[alexc]

I didn't implement the on-off-on switches for each band, using just dpdt switches I had lying about.

 

[benlindell]

Has anyone tried to implement a zobel to tame the ring? how/where would one go about adding one?

 

[desol]

http://www.groupdiy.com/index.php?topic=32441.0

 

[desol]

Has anyone tried to implement a zobel to tame the ring? how/where would one go about adding one?

Hey Ben. Did you manage to get a zobel figured out for your eq's?

 

[benlindell]

Has anyone tried to implement a zobel to tame the ring? how/where would one go about adding one?

Hey Ben. Did you manage to get a zobel figured out for your eq's?

I haven't had a chance to pull them out of the rack to mess with, plus I'm not very confident in knowing where exactly/what values to start with for implementing a zobel.

 

[Govinda Doyle]

After a bit of playing around and testing, with the ed transformers (i'm not sure of others) they are definitely phase reversed, no big deal it goes RED then Brown for perfect phase alignment! Now if I wired up the OP tranny wrong this could explain this haha!
I love this eq when you turn it off you miss it, it adds some weight to kick snares and brings vocal forward, im not 100% sold on the frequency choices but I'm going to have a play around and see if i can get the lows down to 60hz with a 6.8uf!
I have a calculator here for this, don't know if the inductors will cope but I will listen and see!
oh la la!

 

[AudioCommand]

Any one have a frontpanel file for this?

 

[desol]

It's not that hard to make your own. (frontpaneldesigner)

I contacted one person about some 500 panels but they were hugely expensive.

 

[AudioCommand]

Hey Desol,

I know, it's easy to use frontplattendesinger....! But I whant the dimensions on the right place on the pannel, and I don't know how I can do this...!


_Thank's dom

 

[peterc]

For some reason, I cannot find the front panel design files, so I will measure it this evening at home.

Peter

 

[AudioCommand]

peter that's wonderfull many thank's

 

[mylesgm]

Hey govinda, how'd you go altering the low freq. points?

 

[AudioCommand]

hey peter ...
you have the measure?

thanks dom

 

[desol]

It would be nice to find a way to make the inductors more quiet (wrapping in mu cans or foil) or find some other inductors that
would work for this circuit...

 

[shabtek]

Does anyone have the part #'s for the switches--especially the 4p2t

 

[peterc]

Shabtek

I think the 4pdt is this one
http://za.rs-online.com/web/p/push-button-switches/7582102/
I am not at my PC this week so I am not 100% sure......

Also known as Schadow (sp) switches. I think the pitch was .1" between pins and .2" between rows.
Peter

 

[jensenmann]

I´ve used the straight pin version, not snap-in as Peter mentioned. See here: Alps SPUN 194700 http://www.alps.com/WebObjects/catalog.woa/E/HTML/Switch/Push/SPUN/SPUN_list.html

btw, Peter, thanks a lot for this project. These EQs rock so much, it´s insane. If I only had 10 more of these....