analag

NYD's passive EQ, ghetto edition
« Reply #140 on: March 01, 2006, 09:32:47 AM »
Had to revive this thread. I just finished winding an EQP1A inductor with an added 70mH on top of the 150mH for a 2k frequency select (220mH total). I used a P-3622-77 pot core, from CWS Bytemark. A few minutes of experimental winding showed me  AL=6665 not 7680 as they claim on the website. I calculated all my turns based off of this value and swept all the frequencies with the appropriate caps in place and only the 16k sweep was a few Hz off(capacitor related), everything else was dead on.   Total resistance is 2.3 ohms. It took me all of five minutes to do it by hand, with some #26 wire I had lying around.

analag
Audio engineering suffers from misinformation, disinformation, and downright lying more than most fields of endeavour.


Viitalahde

NYD's passive EQ, ghetto edition
« Reply #141 on: March 01, 2006, 09:57:01 AM »
Damn, I still need to wind my own some day.. Well done!  :thumb:

NewYorkDave

NYD's passive EQ, ghetto edition
« Reply #142 on: March 01, 2006, 10:07:19 AM »
Good info, Rowan. I was considering those cores, myself.

alk509

NYD's passive EQ, ghetto edition
« Reply #143 on: March 01, 2006, 10:14:08 AM »
Good job, Analag! :thumb:

You gotta keep in mind that those pot cores are spec'd with a 20% tolerance. So, 7680*.8=6144. I'm going to be doing some winding as soon as I get a counter and a hand-drill I got off eBay (thanks for the inspiration, NYD! :thumb:). My plan is to overwind using Al=6144, and then remove turns until I hit the sweet spot.

My EQ will have 10 bands - 1 band per octave, or 32Hz (shelf), 64Hz, 125Hz, 250Hz, 500Hz, 1KHz, 2KHz, 4KHz, 8KHz and 16Khz (shelf) - with selectable shelf or peaking response on the 64Hz, 125Hz, 4KHz and 8KHz bands. :cool:

I'll try to document the build for the group's perusal.

Peace,
Al.

Lest laziness get the best of you!

analag

NYD's passive EQ, ghetto edition
« Reply #144 on: March 01, 2006, 10:22:12 AM »
Quote from: "NewYorkDave"
I was considering those cores, myself.


It a damn good looking core too. Comes with a white plastic nut, bolt, washer and bobbin.
When winding, take all your taps from the same slot, including the begining and end.
Audio engineering suffers from misinformation, disinformation, and downright lying more than most fields of endeavour.

Viitalahde

NYD's passive EQ, ghetto edition
« Reply #145 on: March 02, 2006, 06:43:49 AM »
BTW, I just added some series resistance to the highest band, thought it was too sharp. I ended up with a 200ohm resistor, way better now. I reckon it took about 3dB away from the maximum boost. Didn't even bother to measure.  :razz:

NewYorkDave

NYD's passive EQ, ghetto edition
« Reply #146 on: March 05, 2006, 04:04:32 PM »
I drove right by the Fair-Rite factory the other day. If I'd planned ahead and left in some extra time, I could have stopped in and asked for some samples  :?

analag

NYD's passive EQ, ghetto edition
« Reply #147 on: March 05, 2006, 06:56:36 PM »
Hey Dave, it's better if you roll your own to the required specification of what you're building.
Audio engineering suffers from misinformation, disinformation, and downright lying more than most fields of endeavour.

NewYorkDave

NYD's passive EQ, ghetto edition
« Reply #148 on: March 05, 2006, 07:20:56 PM »
Fair-Rite sells cores, not complete inductors.

radiance

NYD's passive EQ, ghetto edition
« Reply #149 on: March 06, 2006, 07:39:00 AM »
Dave: Looking at your scematic I was wondering if it's possible to make a very simple version of your EQ, one with only 1 frequencie selector switch with 6 positions (2 X low, 2 X mid and 2 X high) and 1 cut/boost rotary switch.

I'm in the proces of "thinking of building" a 10 X  stereo channel active summing box and a very simple passive EQ would be a nice addition.
It will be all stereo EQ's so I'll need some hefty rotarie switches.
(this "thinking of building" proces will be taking some more years  :grin: )
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan


Viitalahde

NYD's passive EQ, ghetto edition
« Reply #150 on: March 06, 2006, 07:47:40 AM »
Then you'll feel pissed off when you need both low and high.  :wink: I'd suggest that you make instead a 2-band version with fixed, wide frequencies. Same amount on knobs. Low shelf at, say, 100hz and a w i d e 12-14k peak?

radiance

NYD's passive EQ, ghetto edition
« Reply #151 on: March 06, 2006, 07:58:58 AM »
Yeah, that would also be an option.On the other hand, this EQ will only be for  mild coloring, not for hefty EQ tasks.
One thing that I want to get rid of is that 2 pole 12 position rotary (I don't think it's possible though) ...when building a stereo version it will be 4 pole 12 position and quite costly  :sad:
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

Viitalahde

NYD's passive EQ, ghetto edition
« Reply #152 on: March 06, 2006, 08:01:06 AM »
Well, if you're not going for heavy EQ'ing, you could go with less maximum boost/cut..? That would make the switch requirements simpler.

But the boost/cut switch only needs to be a two-decker for stereo material.

radiance

NYD's passive EQ, ghetto edition
« Reply #153 on: March 06, 2006, 08:19:44 AM »
Quote from: "Viitalahde"

But the boost/cut switch only needs to be a two-decker for stereo material.


Maybe I don't have the latest schematic, but mine sais that for the high bands (5k, 10k and 15k) I need a 2 pole 12 pos rotary for boost/cut and a 2 pole 3 pos for frequencie selection...(for a mono version that is)
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

radiance

NYD's passive EQ, ghetto edition
« Reply #154 on: March 06, 2006, 03:45:37 PM »
Viitalahde: looking at your version of NYD's EQ I don't see any 4 deck rotaries. Your's is also a stereo version right?
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

alexidoia

NYD's passive EQ, ghetto edition
« Reply #155 on: March 06, 2006, 03:49:16 PM »
Quote from: "donnysparks"
i wish i had saved more of your scematics rather than bookmarking the threads

I just thought the same eating my fingernails... :)

I understand NYD althought this a difficult decision to make. Having said that  he said he would give it out to regular members of the forum, so no need to be sad.  :)

NYD: have you thought about the GPL licenses ? Maybe that would be a good think to keep your work public.

I am very new here, but already love this forum. I took on a electronic course and bought some books. I always wanted to do DIY audio but did not think I would manage anything until I met you guys.

Thanks.

Viitalahde

NYD's passive EQ, ghetto edition
« Reply #156 on: March 06, 2006, 04:06:19 PM »
Quote from: "radiance"
Viitalahde: looking at your version of NYD's EQ I don't see any 4 deck rotaries. Your's is also a stereo version right?


Yes. You only need one deck per channel.

radiance

NYD's passive EQ, ghetto edition
« Reply #157 on: March 06, 2006, 04:09:19 PM »
Quote from: "Viitalahde"
Quote from: "radiance"
Viitalahde: looking at your version of NYD's EQ I don't see any 4 deck rotaries. Your's is also a stereo version right?


Yes. You only need one deck per channel.


GREAT :thumb:
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

NewYorkDave

NYD's passive EQ, ghetto edition
« Reply #158 on: March 07, 2006, 01:48:45 PM »
The two-deck switch on the high band is because I wanted peaking boost and shelving cut. If peaking boost AND cut is acceptable, you only need a single deck.

Viitalahde

NYD's passive EQ, ghetto edition
« Reply #159 on: March 07, 2006, 01:54:56 PM »
Ah, now I got it - Radiance was referring to that pretty new schematic.  :thumb:


 

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