NYD's passive EQ, ghetto edition

[edanderson]

[quote author="newyorkdave"]Do you have a link to data on the core (AL value and such?)[/quote]

no, unfortunately i don't have any info on the epcos (former siemens) N38 core material, and i wasn't able to find anything about it searching the net either. however, the link with the winding instructions that i posted did say that the wah inductor they were making was 520mH at around 30 ohms DCR using #33 wire. i would think that even if you have to go down a wire size or two to get all the turns on for your highest L value, you'd still be well under the DCR limit you are shooting for.

please let me know if steve gets back to you. he's here in brooklyn, y'know.

ed

 

[analag]

Individual coils give cleaner boost/cut response and overall better performance than one big inductor full of taps.

 

[NewYorkDave]

please let me know if steve gets back to you.

I haven't heard from him yet, but I just sent the email last night. I'll let you know.

he's here in brooklyn, y'know.

I was born in Bushwick. Has it been annexed by Billyburg yet? :wink:

In other news, I received an email reply from Wilco (after moaning about the pricing). They said to contact them when I'm ready to buy and they'll try to work something out with me. That's good news, but I'd still like to look into the feasibility of the DIY option. It's always good to avoid a single-source situation if possible.

 

[NewYorkDave]

I heard back from Steve. The AL value of the core is 2900nH, +30% / -20%. This isn't too far out of line with what was said on http://www.arielfx.com/inductor_guide/guide.htm about somewhat less than 550 turns being needed for ~520mH. (If the AL value were exactly 2900, it would take ~423 turns for 520mH, ~532 turns for 820mH if I figured it correctly. But how accurate is the inductance range on the guy's cheap DMM, anyway?). The core size is 18mm x 11mm, height is 7.2mm.

 

[solder_city]

roger how much did the custom sowters cost you?

 

[alk509]

After seeing Dave's EQ, I got inspired and decided to come up with my own passive EQ, which I finished designing on paper/sim last night at 3:45AM... It has 3 inductors (low, mid, high) each with multiple taps..... With that in mind:

[quote author="analag"]Individual coils give cleaner boost/cut response and overall better performance than one big inductor full of taps.[/quote]

What's the reasoning behind this? I've read the same thing once before on these fora, and I'd be interested to learn more, if anyone cares to ellucidate... Please? :grin:

[quote author="solder_city"]roger how much did the custom sowters cost you?[/quote]

Sowter's web site says GBP 37.49 for custom wound inductors... What's that, like 60 bucks? HTH!

Peace,
Al.

 

[analag]

In the NYD's new revision I see where three inductors could be used each having three taps, since only one tap can be used (at a time) per inductor the response would be just as smooth as if individual coils were used. The pot core from CWS bytemark are very workable in this application. I have calculated the turns and core sizes. The inductors (6) can be built for less than $60.00.

 

[NewYorkDave]

I intend to kludge this fine antique into a manual coil winder. With a gear ratio of about 4:1, it shouldn't be too tedious to wind a few hundred turns.

 

[Gus]

Are you going to use the old cheap calculator counter mod?

 

[NewYorkDave]

Actually, I was thinking of a resettable mechanical counter. I've seen a couple of inexpensive ones on the web.

 

[AnalogPackrat]

Another (slightly less primitive) hand winder is born! Looking forward to seeing your results on this one, Dave. Your EQ might just have to be added to my list. Wind on, Garth! :thumb:

A P

 

[Bauman]

Do you think a M4 lams core can be good for inductors ??

 

[alk509]

I think M4 would work, but distortion would be higher than ferrite... I remember reading somewhere that for values up to 1Hy, you should use ferrite, and for values higher than 1Hy, you should use iron. I don't remember the reasoning behind it, but I suspect that it just has to do with iron's higher AL value...

I'm going to attempt to wind a ~1.7Hy inductor on a fat ferrite, though... wish me luck! :?

[OT]

[quote author="Bauman"]

[/quote]

Tha looks HOT, Fabio! Care to share the recipe? :grin:

Man, I LOVE hot sauce - I must have about a dozen different kinds of it in my kitchen!

[/OT]

Peace,
Al.

 

[analag]

[quote author="alk509"]I'm going to attempt to wind a ~1.7Hy inductor on a fat ferrite, though... wish me luck! :?
Al.[/quote]

Why do you need 1.7H, what kinda frequency are you targeting with that.

Analag

 

[alk509]

[quote author="analag"]Why do you need 1.7H, what kinda frequency are you targeting with that.[/quote]

32Hz. 1.64H, to be exact.

Peace,
Al.

 

[analag]

Viitalahde tell us about this wonderful rendition of the NYD Passive Q that's got everyone fired up, got the DIY juices flowing.

Tell us about the supporting circuitry. You said it sounded better with a 2:1 ratio transformer? Now that you have it working in it's intended application what other enhancement(s) have you applied to the circuit.
Do tell.

Analag

 

[Bauman]

Al,
you got a PM :thumb:

Well, the ma$$ive pa$$ive eq uses nickel for its inductors right? Just not sure it is for all of them. Worth a try

 

[Viitalahde]

[quote author="analag"]Tell us about the supporting circuitry. You said it sounded better with a 2:1 ratio transformer? Now that you have it working in it's intended application what other enhancement(s) have you applied to the circuit.[/quote]

Sure. My first impressions with the testing were that a LL1528 in 5:1 configuration smeared the sound too much. Don't know about other trafos, but at least that I didn't like. I just happened to have the 2:1 Sowter around I felt happy with it.

In general, it is pretty basic NYD EQ. I do have extra steps in the level controls (1dB steps instead of 2dB, done by simply dividing the resistor values) and an extra step too, being the -1dB point where I rememeber using a 1k7-and-something resistor.

Three bands as you know.. loaded with 600ohm resistor as ment to be. I think I'll add some resistance for the highest band, it might be a bit too sharp now. Not much, just to tame it a little.

The amp is just a BA283 output stage with Brazilian iron.. sound cool. Not transparent, but doesn't smear things bad either. Great for mastering most rock, not that good for jazz, and for some metal it might be too sweet sounding. That's mostly the amp's fault.

What can I say, I highly recommend building one. EQ like this wouldn't be my only EQ, but it fills my Sontec clone perfectly. In the high end, the NYD eq is smooth in an airy way, the Sontec is smooth in just bringing the existing high end up. Sound confusing? :razz:

 

[analag]

[quote author="Viitalahde"] Sound confusing? :razz:[/quote]

Nope, I think I know exactly what you mean.

Analag

 

[Viitalahde]

[quote author="analag"]I think I know exactly what you mean.[/quote]

Cool!

Also, in the low end range the NYD EQ is obviously really smooth. When the NYD EQ says "easen up, will you???" to the low end, the Sontec says "Get a grip! Suck that gut in and get you spine straight!!!" :green:

I think I have read that inductors tend to alter their inductance slightly with incoming AC. I quess this is one of the reasons why a jumpy, nervous bass tames down when boosted with this one.