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Hello all
Is there a schematic for the N1200 crossover that negates the use of the tapped inductor and uses an equivalent circuit instead?
I have considered using the 4333/S300/L300 equivalent bandpass circuit schematic, but wondered what changes i would have to make to this schematic to make it work for my set of drivers (130A, LE175DLH, 075).
Thanks, Barry
To the best of my knowledge, an equivalent circuit ( omitting the tapped inductor of the N1200 ) has not been developed or published .Quote:
Originally Posted by Barry H
For Review ( here's Giskards' N333 equivalent for 3 ways ) ;Quote:
I have considered using the 4333/S300/L300 equivalent bandpass circuit schematic, but wondered what changes i would have to make to this schematic to make it work for my set of drivers (130A, LE175DLH, 075).
Thanks, Barry
http://www.audioheritage.org/vbullet...1&d=1052963079
The N333 was designed for the longer 2312 (HL92) horn . Using the 2307 ( HL91 ) or the 2301/05 ( 1217 masher ) means some changes are warranted in the HP portion of the horn circuit .
You'll need to buy extra LC components so that you can build up a bunch of variations on this theme . Choose the one that sounds best to your ears .
For some ideas as where to go, here are a couple of Toddalins kludged 3-ways ( which I believe started as N333 equivalents ) ;
2-pole UHF ( HP )
http://www.largescaleonline.com/eima..._Crossover.jpg
- A 3-pole UHF ( HP ) variation
http://www.largescaleonline.com/eima..._Crossover.jpg
Some mods to the Zobel used in the woofer section of Todds network ( as suggested by RobH3606 ) . ( 2 ohm resistor ??? with 10uF cap ) vs the ( 10ohm resistor with a 3 uF cap ) . I'm not sure what has Todd settled on .
http://www.audioheritage.org/vbullet...1&d=1195017294
The change in the lowpass response for Robs' suggestion is seen here ( Robs' suggested changes in blue result in flatter response for the woofer, out to the crossver point ) ;
http://www.audioheritage.org/vbullet...1&d=1195017309
I'd suggest that you get some free testing software( with the necessary USB hardware ) so that you can tweak the LC values for your own situation .
http://www.hometheatershack.com/foru...ine=1159694603 is very good ( free ) software .
- You'll need to sign up as a member of the "Shack" to be able to download it .
- It along with a Behringer sound card like the http://www.parts-express.com/images/.../248-599_s.jpg and the http://www.parts-express.com/images/...245-262_Si.jpg ( test mic ) from Galaxy are all you need to test Frequency Response ( pretty accurately up to 8K ) .
- Radio Shack SPL meters also work just fine ( with REW & the UCA202 soundcard ) . http://rsk.imageg.net/graphics/produ...266248w345.jpg
- Generic Calibration Files are available for these SPL meters over at http://www.hometheatershack.com/imag...cklogo_alt.jpg.
- The calibration files are necessary to increase the accuracy of these meters so that they are useful for making believable measurements .
- The UCA202 only has line-evel ins & outs / this is why you must use a SPL meter type mic / since these SPL meters will output line level directly into the sound card .
<> cheers
I think I ended up with a 24 mfd and 10 ohm resistor on the Zobal. Also the mid went back to the 1.5 mfd low pass.
Recognize that this is designed with an ~800 Hz crossover point and the long horn in mind and you really want to use 1,200 Hz with the DL175. This circuit may leave a "hole" in your sound.
Assuming your 130A is pretty ancient and still has the original cone/voice-coil / you could use most of LC elements from the original N1200 design .
- For L2, use a regular 1.1 mH inductor .
- I'd add an 8 ohm variable Lpad ( 50 or 100 watt ) right before the le175 driver and a series ( 2 to 3 ohm ) resistor after the 1.1.mH coil ( before the LPad ). This will result in a load impedance of between 11 to 13 ohms / which is about right for this driver in that FR area .
- You'll need to "best-guess" at the values necessary for the low-pass portion to be used with your horn/driver combo .
- I'd first start by trying out a .27mH coil and 1.5 uF cap ( copied from the N333 ) / with both put in place just after the 3 ohm series resistor, and before the 8 ohm Lpad .
- Copy the UHF section shown in either the N333 or Todds 3-pole design ( they're about the same ) .
http://www.audioheritage.org/photopo.../500/N1200.PNG
<> cheers