Crossoverless Khorn

[Different]

For something completely different from what has been printed here before, I decided to walk where PWK already walked a long time ago. I remember reading somewhere that the first Khorn Paul built was a two-way horn system without a crossover. So I decided to go back to the future and repeat this. Using my Khorns and a tube amp with ground, 4,8,16 ohm taps, I wired directly from the midrange Atlas k-55-v driver with soldier lugs (specially modified by PWK for more extended high end) to the 4ohm tap and ground. With a second set of wires, I went directly from the woofer to the 16ohm tap and ground. This type of wiring is nothing new, and there is nothing electrically wrong. It reduces the midrange driver by 6db to match the output of the woofer (bi-wiring). NO CROSSOVER AND NO TWEETER (crossoverless). The amplifier must turn on and turn off without sub-sonics and not have hum.

The Atlas midrange driver is rated full power at 250hz (120db) 40 watts and with a simple 6db filter would be at 102db at 30hz. So if I don't go above 102db (very loud), not use a turntable (subsonics) or tone controls or test tones everything should work fine crossoverless. The sound was good, better then a stock AA networks, but not great. I next removed the bug screen, and screen holder from the k-55-v with soldier lugs and reversed the polarity of the driver. Without a capacitor on the midrange the driver has to have reverse polarity to have proper phase. The sound was very good. I then shorten and separated my speaker wires, and interconnect to as short as possible and after opening the curtains, it sounded EXCELLENT. The above method sounds complex to implement, but it's really very simple.

This method could also be used for La Scalas, Belles, and even Cornwalls.

1. No capacitor, inductor, autoformer, or resistor colorations.

2. No impedance mismatch.

3. No time alignment problems between midrange and tweeter.

4. No tweeter.

5. Not Complex, Simple.

6. No money.

If you play your Khorn above 102dbs, have turn on, or turn off noise or hum you can add a high quality 40uf in series with the k-55-v midrange unit with soldier lugs and not reverses the polarity but this will hinder the sound. You can also add a 14 gauge 2.5uH air coil inductor in series with the woofer if it's too wooly sounding, but this to will hinder the sound but tighten the bass.

For EE's or crazies who want the very ultimate Khorn sound you should passively bi amp, solid state amp on the bass with a 2.5 uH air coil inductor and a small SET tube amp directly connected with reverse polarity to the k-55-v with soldier lugs without bug screen. Passive preamp to a hi quality cd player and your done. I have been using this method for about 6 months and I love it, thank you PWK.

I hope someone will try the above method, but as always you try it at your own risk.

[ZAKO]

The bug screen is there to keep iron particles out of the voice coil gap.

[TBrennan]

I think this bugscreen removal thing is a placebo, especially with bullhorn drivers like the K-55. Hell, I can't tell a difference removing the screens in high quality drivers like tangerine Altecs and JBLs.

Just for the record I did remove one screen in the last set of Cornwalls I owned, didn't hear a damned thing different.

[djk]

"I remember reading somewhere that the first Khorn Paul built was a two-way horn system without a crossover."

http://164.195.100.11/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=2612558.WKU.&OS=PN/2612558&RS=PN/2612558

There was a crossover, it was built into the amplifier.

[Different]

Thanks for the replies received so far.

I have grille cloth on my Khorns so I don't have to worry about iron particles or foreign materials getting on the voice coil gap, but you must be very careful when removing the bug screen that particles from the screen do not fall into the driver.

The bug screen sonic improvement is not a placebo. Many people have removed bug screens from compression drivers on the audio asylum forum with the vast majority hearing the improvements. The Cornwalls that you removed the bug screens from were probably the k-55-v with spring clips and single slot phase plug, not the ones with soldier lugs and double slotted phase plug for extended high end. The tweeter, autoformer, inductor and capacitors were still being used, so it would be hard to hear an improvement.

DJK, thank you for the paper on PWK patents. The crossover was built into the amplifier and it was a two way system.

PWK did remove the crossover from the woofer at one time to reduce inductance load on the amplifier but it was later put back in for protection from high-powered amplifiers.

So the only new information in my post is the removal of the highpass filter on the k-55-v with soldier lug. (This greatly reduces the beaming of this horn driver combination)

I wish someone could duplicate this driver with the modifications and at the specifications that PWK was using. (Reduced diaphragm to phase plug spacing, and double slotted phase plug)

My original posting on a crossoverless Khorn is simple, it works extremely well and costs nothing. This is what a hobby is all about, sharing everyone's information.

[djk]

"PWK did remove the crossover from the woofer at one time to reduce inductance load on the amplifier but it was later put back in for protection from high-powered amplifiers."

PWK tried running the type AA network without the woofer inductor as a result of my bi-amping a pair of Klipschorns. His thought was that the only advantage of bi-amping was the removal of the DCR of the woofer inductor. He was, of course, wrong.

I do tend to agree with PWK though, that the average person will screw it up so bad that they are better off leaving things stock.

"So the only new information in my post is the removal of the highpass filter on the k-55-v with soldier lug. (This greatly reduces the beaming of this horn driver combination)"

Beans. The beaming is a function of the wavelengths involved and the physical dimensions of the horn. You changed neither.

"I wish someone could duplicate this driver with the modifications and at the specifications that PWK was using. (Reduced diaphragm to phase plug spacing, and double slotted phase plug)"

You got enough money, Atlas will make them for you.

"My original posting on a crossoverless Khorn is simple, it works extremely well and costs nothing. This is what a hobby is all about, sharing everyone's information."

It's going to sound different for sure, poor bass due to a bad plate load with a 4R woofer on the 16R amplifier tap, and 3dB more attenuation than stock on the mid driver, no tweeter. With a flea powered SET it won't hurt anything.

[Different]

I completely agree about bi-amping and I even tri-amped for a number of years.

I also agree with you and PWK that the average person will screw up bi-amping; this is why a crossoverless Khorn is the way to go. (simple)

The worst thing about a stock Khorn is beaming. I've never heard a large valued series capacitor or a small autoformer that did not pitch the sound. Going crossoverless will greatly reduce this driver-horn combination from beaming. Altec driver-horn combinations have much less beaming, but most require a tweeter.

With the efficiency of a Khorn, it is much less detrimental to put the woofer on the 16 Ohm tap than putting the midrange driver through a small autoformer. (Everything is a compromise.)

The combination of the 13uf motor run capacitor (high series resistance) and the autoformer reduces the midrange driver by 4dbs (108 dbs - 4dbs = 104 dbs).

Most people believe a stock Khorn has too much midrange and reducing it by another 2dbs is just about right.

A flea-powered amplifier with a midrange driver of 108 dbs and without a bug screen will knock your socks off. If you have big feet then bi-amp.