Best/Simple 500 Series EQ 4 band with mid sweeps

[Spencerleehorton]

Hi,

Looking to eventually build 16 or so 500 series EQ's, wanting to keep the budget around the £1600 or so.
Something API-ish would be great but simple and cost effective.
What do you guys think?

regards

Spence.

 

[sahib]

Have a look at my EQ ONE
http://groupdiy.com/index.php?topic=52444.0

Build thread
http://groupdiy.com/index.php?topic=53044.msg702864#msg702864

 

[Fablab]

Ian has realised some old eq project (helios, EMI REDD). They are not in API 500 format but you can adapt them
Another interesting project may be the Studer 169 EQ. This one is in API 500 format, the sound is really good ... and it is not expensive

 

[Spencerleehorton]

HI,

EQ ONE is way too big and is NOT what i would call a simple EQ.
I'll take a look at the EMI REDD, have considered the Struder 169.
thanks for your thoughts.

regards

Spence.

 

[Spencerleehorton]

Hi,

is there anyway i can alter the Struder 169 to have 2 x dual pot swept mids and HF and LF?
Happy to make my own design and pcbs just need some advice on how to alter the circuit.

regards

Spence.

 

[Spencerleehorton]

this is the BOM i'm going by if someone could check please!

1 x Neutrik NTL1
4 x pots - 22K lin, 2 x 10K lin, 2 x 100k reverse log
1 x pcbs -
1 x switch DPDT
DOA - pins

resistors
2 x 10R
8 x 10k
2 x 20K
2 x 3.3k
2 x 1.8k
2 x 680k
2 x 22R

caps
4 x 47pf
2 x 22pf
15nf
4 x 100nf
10nf

electrolytics
3 x 100uf/35v
2 x 10uf/25v

IC
2 x 5532
4 x 5534

psu - +/- 16v

regards

Spence.

 

[Krcwell]

Get a bunch of 0R for jumpers if purchasing the pcb's. The studer needs a few. I guess you could use trimmed leads as well.

 

[Spencerleehorton]

i'll be making my own pcbs i reckon, i have loads of 0R for jumpers.
Looks like a great EQ if i can tweak it to my needs.

Spence.

 

[peterc]

Spence

S800 in 500 series will work, I could do a run if there was enough interest, about 60 pieces of PCB....

http://groupdiy.com/index.php?topic=29759.680

Peter

 

[weiss]

nice! didn't notice that before

 

[TheJames]

A fully parametric EQ requires three controls per band.

Sounds like what you want is like on a small mixer, HI and LOW shelf, Low-Mid/Hi-Mid with frequency select and gain.  For that to work you need two controls for high/low shelf and two controls for each mid  band for gain/freq,  That's six controls.  Lay that out on a 500 series panel and see if you can make that work. 

You need to try to find pots that will do what you want too.  Consider concentric pots or push/pull pots, or maybe concentric switch+pot to save space on the front panel space.

You could add a fourth band to the 169 by adding a second mid-stage to it.  You'll want the hi-mid to be first, followed by the low-mid.  Tweak the values to shift the range of frequencies for hi-mid and low-mid (unless you want two of the same range).  Watch the output polarity.  I'd suggest adding an output level control.

 

[Spencerleehorton]

Hi,



Nice peterc the S800 seems the perfect EQ for what I'm thinking, will look into BOM and put some thought into layout as it may well be that the studer 169 with another mid frequency is also a good choice.
I won't need 100hz roll of as already have this on most of my pre amps, just need on/off switch.

Regards

Spence.