API eq kits????

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Elco,

I am interested in a pair myself. Once again, please keep me in mind. I look forward to an update on how things are going with the 553 project!

Thanks,

Jason
 
if I were doing this, Id lay out the pcb's to accomodate lundahl transformers. lots of people have a ton of api shit and I would bet that edcors dont sound a world different than the profile thats in there. Using lundahls on a circuit like this would give you something pretty unique.

dave
 
OK guys it's still in the works and progressing, but my studio work takes precedence. I'm pretty busy doing 12+ hour days.

I'll dust off the layout and see if I can squeeze in some Lundahl transformers that Dave suggested. What do you think? 1517's? 5402's? Maybe a combination of the two? I'll have to investigate further.

Cheers,

elco
 
How about the Sowter transformers sold by our hosts, Prodigy Pro?

http://www.groupdiy.com/detail.aspx?ID=326
http://www.groupdiy.com/detail.aspx?ID=325

A little spendy, but could be nice.
 
[quote author="elco"]OK guys it's still in the works and progressing, but my studio work takes precedence. I'm pretty busy doing 12+ hour days.

I'll dust off the layout and see if I can squeeze in some Lundahl transformers that Dave suggested. What do you think? 1517's? 5402's? Maybe a combination of the two? I'll have to investigate further.

Cheers,

elco[/quote]


Don't forget to change the edge connector to a 15 pin.

--Vince
 
hi there,

I just went trough this tread from the begining, and this kind of equalizer is just what i need to complete my stereo preamp.

If boards are coming, i'm intersted in a pair of these babies.

Thanks to keep us updated on this !!!

Cheers,
 
So elco, I know you're busy, and I also wouldn't want to ask a million options, but any chance these will have api/profile trafo compatibility? those 4804's are some damn good trannies, and I suspect there'll be quite a few floating around this place with that api/cinemag group order.

Billy
 
[quote author="enthalpystudios"]So elco, I know you're busy, and I also wouldn't want to ask a million options, but any chance these will have api/profile trafo compatibility? those 4804's are some damn good trannies, and I suspect there'll be quite a few floating around this place with that api/cinemag group order.

Billy[/quote]

I'm in the process of re-doing the board layout. The boards will be double sided, solder masked, silk screened and gold fingered.

Oh yeah, I decided to ditch the Edcor PC transformers. In it's place will be the 2503, Profile 4804, Cinemag CMOB-2S/CMOQ-2S, Edcor XSM600:600 (without the metal channel) sized transformer.

I still have room for a Lundal as an alternative, but I don't have experience with them so I'm open to suggestions as to which model.

For the input I'm going to stick with the Burr-Brown INA134/137. If you use a 1:1 transformer on the output use the INA134 (G=1). If you use a 1:2 transformer use the INA137 (G=1/2)

That's it for now. At best this is still about 2 months out for the full proto.

Oh and I learned how to count to 15 now! :wink:

Cheers,

elco

elco
 
Here's what I got on the board now.

Input. you have a choice of DRV134/137, Lundhal LL1540 or Cinemag CMLI-15/15B w/PC pins. Optional -6dB T-pad for transformers.

Output. 2503/CMOB-CMOQ sized or Lundahl LL1517. Jumpers for 1:1 or 1:2 selection on the LL11517.

My Fastron inductors should be in my mailbox today. I'm still waiting for various transformers.

Cheers,

elco
 
I'm pretty partial to the URS 1084 EQ plugin. Yesterday I did some measurements on a URS. I assume they accurately modeled the eq curves..

What I got was a Q of .6 on broad and a Q of 1 on sharp. They are a little broader then I assumed, but I guess all you have to do is add a little resistance to broaden up the Q.

I'm going to shoot for a Q of .6 or .7 on broad and a Q of 1.2 on sharp for my first prototype. Freq. of 350, 700, 1.6k, 3.2k, 4.8k and 7k.

Cheers,

elco
 
Wasn't there a shootout on here a while ago between various makes of inductor? For some reason I remember reading that the consensus on the Fastrons was "just okay" sounding. What other options are out there that people can readily buy in small quantities that actually sound good?

Brad
 
What other options are out there that people can readily buy in small quantities that actually sound good?

That's the problem. I haven't found any other shielded inductors in the 10 mH to 1H range available for low quantities, expect MCM Magnetics, but those are $6-$8 a pop and are physically large. Wilco BSL inductors would be ideal, but they have a steep minimum order.

One of the design goals for this eq is to be cheap to build.

Cheers,

elco
 
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