EV 15wk - only horn loaded?

[ned]

Hi,

I just pulled a beautiful clean EV 15wk from an old homemade (1950s) corner horn. I am considering using it as a direct radiator with a low watt guitar amplifier - for playing guitar.

The EV spec sheet is pretty clear that it is intended for use in a folded horn enclosure but I notice that the first generation of Cornwalls used this driver.

What is the consequence and performance of using this as a direct radiator?

Thank you very much,

Ned

(I should mention that I have K-horns and know the wonders of horn-loading a 15" speaker)

[twistedcrankcammer]

Ned,

Buy a second one and run them in your Klipschorns. You did not mention if the EV 15W-K you have is Alnico, or Ceramic?

The EV 15W-K is a 4 ohm speaker with very little excursion. Inside the horn loaded bass bin of a Klipschorn, La Scala, or Belle, the amplifier sees a load of 16 Ohms because of the resistance of the slot in the motor board. There are much better suited drivers for what you want. These EV drivers are very beutiful unless you have one of the newest versins with the white magnet structure and no chrome on the basket. The ceramic versions of this driver is in the toilet right now on prices, and as such, I suggest putting it on top of one of your Klipschorns as a conversation piece or until you can match it and put them in your Cornerhorns. If you are lucky enough to have an Alnico, let me know, as there are two different models and there is a slight difference in value. In my oppinion, these Alnicos are the best ever put in a Klipschorn, works of beauty. You could sell it to pay for the driver you want for a guitar, or look for a second on ebay.

Roger

[ned]

Thanks Roger. Finding a second will be a trick, but I recognize that you are correct that guitar would not be its best use. Selling is an option, shipping will be a bit of a trick - it would need to be bolted into a wood crate inside a padded cardboard enclosure, and I still would be concerned about it bouncing around.

I assume it is alnico. Judging by the cabinet construction, the homemade crossover, and the other horns/drivers, cost was no object. The crossover is tunable and must have 18 oilcan capacitors. It was made by aguy in Los Alamos in the 50s.....need I say more?

The EV is beautiful - cast and chromed basket, brown hamer tone on a the largest cylindrical magnet I have yet seen ( maybe 8" in diameter, 4 inches deep). measures 3 ohms across the voicecoil. weighs ~50 lbs. Condition is like new.

So, imagine I found a second (I gave up looking for mate to my Fisher 55a after a few years), I expect I would need to do some crossover work to keep the balance of my Khorns...true?

How did Klipsch get away using this in the Cornwall?

Thanks again for the resopnse.

Ned

[twistedcrankcammer]

Ned,

You probably have an Alnico if it is truely 1950s, and not 1960s. Is the manet housing steel, or cast aluminum?

Does the magnet housing have a polished bow tie with the badge in the middle, or is it just hammer tone copper painted with the badge in the middle? If it is the steel housing, is the back plate pinch spot welded to round section, or does the back plate have two large flat faced machine screws counter sunk in place? If you have any other questions, you are welcome to call me (419)-358-0137 Home, Cell is dead

Roger

[ned]

alas, I am at work, and the speaker is at home.

it is 1950s.

it is a steel housing with welds.

there is no chrome on the magnet. Four mounting bolts. 4 digit code on the cone, typical speaker codes no redilly on the framee.

the serial number is 3 digits.

That's all I can recall. I'll pick this topic back up in 8 hours or so.

Thanks again - I am curious about this fine thing.

Ned

[twistedcrankcammer]

Ned,

Sounds like you have the second series of Alnico woofer on your hand. The first series is more of a brownish copper tone hammered finish pait, and the back plate is held on by two machine screws, these are the rarest and bring the most. Yours sounds like the second series Alnico, which has the back plate pinch spot welded on in two places. (I own two of these in totally restored shape) The third edition of these has an aluminum cover that is held on by a single machine bolt under the badge, and has what appears to be a polished aluminum bow tie with the badge in the middle of the bow tie, but it has the same chrome plated basket. The aluminum cover houses a ceramic magnet. The fourth, and newest series which is also the least valuable has the same aluminum basket, but it is bare aluminum, neither polished nor chromed, and the aluminum cover still has the raised bow tie, but the whole thing is just painted white.

Now we have to discuss condition of your woofer to establish value. It would be easiest if you could email me pictures at rgordon@ watch tv.net

I need to know if the cone is smoot or ribbed? What color is the surround? What the dust cover looks like, is there anything printed on it? What condition is the cone and surround in? Does the voice coil rub at all when freely moving the cone in and out? Does it make any funny noises at high volumes? What shape is the chrome in? Is there any copper showing through? Any thin chrome where nickle is showing through? Nickle is still silvery and shiny but is different in appearance and is the coat between the copper and the chrome. Is the basket marred up where the bolts were tightened to the motor board?

Answer to you question is all of the Klpschorn from that period on have had 4 ohm drivers. Only the very early Klipshorns had 16 Ohm drivers. If you find another similar driver, and they both have the correct cone and coil, you can bolt them in as direct replacements for the drivers you have in your Klipschorns now.

As for Cornwalls, I was not familiar that they ever used this driver, and if they did, why not use an EV 15W which is the same thing except it has an 8 Ohm coil.

Roger

[Kenhorns]

Here's a pic.

[Kenhorns]

This one's a little better...

[twistedcrankcammer]

Ken,

Is this a picture of your driver, or Neds??

That is a second generation Alnico EV

Roger

[ned]

That's Ken's. I'll post some pics once I get from work.

N

[Kenhorns]

Here's a pic of Cornwall Ser# 229, 1960 Vertical, this one has the rear backplate porting up and down the center, and it has a Jensen 15PLL 15" woofer.

Notice the small woofer opening on the motorboard.... the shadow in the grill cloth. It looks much smaller than a 15" diameter circular cutout.

Was PWK loading the woofer using a smaller cutout???? If so, why???

Based on my Forum readings and study:

CWI was introduced in October 1959 - EV15WK and Jensen P15LL were the offered woofer options. By end of 1959, a few short weeks, the K33J Jensen (the P15LL) became the standard supply on CWI. (The K33J started use on Khorns in April, 1960.) PWK is reported to have treated the surrounds on the P15LL with DBP (dibutlyphalate) to lower free air resonance. The K33M (believed to be Eminence) did not come along to replace the P15LL/K33J on CWI until September, 1967.

I can find no mention of the P15LL ever being designed to Klipsch specs - meaning 3.6 Ohm DCR. Any information will be appreciated!

On Khorns, the EV15WK is 1st used August, 1950, and used until March, 1961 - replaced by then used K33J.

The P15LL began use as early as 1949, the year 26 Khorns were produced.

Stephens 103LX2 was used from August, 1953 on Khorn, replacing the Stephens P52LX2 which began use in 1949 on 2 way Khorns. Both of these were built to Klipsch spec of 3.6 ohm DCR.

[ned]

Great post.

I based my question on a search that turned up this link

http://www.klipsch.com/na-en/support/faqs/do-you-have-heritage-reference-data-available-details/

Here is listed the 15wk from Octover of 1959 to "late" 1959. Maybe the WK wasn't up to the task.

N

[Kenhorns]

Actually, I tend to think it was probably more about cost than performance. Chromed castings had to cost more to produce.

I hope someone will chime in and answer: Why were most all the original 1940-1950s woofers produced as 16 ohms vs 8 ohms, and why did PWK spec them to be essentially 4 ohms? This apparently continued in the late 60s-and 70s when Alnico went to ceramic and 8 ohm seemed to become the standard while PWK still specified a 3.6 ohm DCR making the 8s in fact 4 ohms speakers?

[twistedcrankcammer]

Ned,

I agree with Ken here. I own like 35 or 40 Klipsch 15 inch drivers with at least 9 different models and 5 different models specifically for Klipschorn or La Scala, and I like the EV 15W-K Alnico the best. The industry switched to ceramic from alnico because ceramic is cheaper as well, not because it is as good as, let alone better then Alnico.

I will try to help you determine the value of your driver in case you descide to sell it. I may be interested in a purchase if you sell it cheap enough, but I will try to tell you actual market price on what you have value wise when condition is established. I personally think you should buy a second and see how you like them, and as previously stated, they make a pretty piece of Klipsch history to display on top of a Klipschorn as well.

As for Kens question on loading the Cornwall woofer, that is exactly what I would say he was doing. From a mfg standpoint, I will bet Pauls production levels were low enough at that early stage that in order to gear up for the specific woofer that he needed from electro- voice, in order to manufacture them to his specs, he would need a minimum run order, as well as he might get a price break on a run of X many. It would make sense to load the woofer and use it as such, and nothing else I can come up with makes sense to me.

Roger

[LarryC]

Here is listed the 15wk from Octover of 1959 to "late" 1959. Maybe the WK wasn't up to the task

EV discontinued the alnico 15WK, apparently in 1959, and my recollection is that Klipsch had to scramble to find a satisfactory replacement. The 15WK was superlative, and today still has astonishing mid-range clarity and musical realism, IMO.

Re using an EV 15W in non-horn app's, the 15WK worked very well in the Shorthorns, which were direct radiators like the Corns.

[twistedcrankcammer]

Here is listed the 15wk from Octover of 1959 to "late" 1959. Maybe the WK wasn't up to the task

EV discontinued the alnico 15WK, apparently in 1959, and my recollection is that Klipsch had to scramble to find a satisfactory replacement. The 15WK was superlative, and today still has astonishing mid-range clarity and musical realism, IMO.

Re using an EV 15W in non-horn app's, the 15WK worked very well in the Shorthorns, which were direct radiators like the Corns.

Larry,

I agree on the Alnico, but why did EV continue 15W-K production of ceramic drivers well into the 1960s??

Roger

[LarryC]

I agree on the Alnico, but why did EV continue 15W-K production of ceramic drivers well into the 1960s??

Darned if I know. Klipsch sent me one because I begged for a 15WK to match the alnico I had. It was pathetic by comparison. Maybe they thought they had a continuing market to supply before they gave up?

[Kenhorns]

Larry's 1959 date for EV15WK alnico end is interesting....

Per my Heresy history research, Model 8 (Heresy) was intro'd in 1957 as a center channel for Khorns with an ElectroVoice SP12B, 16 ohm alnico used on some units. The EV12WK, the 12" model, was also offered from 1957-1959 (12", alnico, 16 ohm modified for Klipsch with a DCR of 3.2 ohm). Then an EV, SP12B "variant" 16 ohm, alnico, with red surrounds is reported showing up and labeled a K22 in the "early 1960s".

The next mention of a Heresy woofer occurs in 1972 when a CTS 16 ohm red surround alnico d shaped small magnet is offered as a K22.

I wonder if PWK convinced EV to build the SP12B as a Klipsch spec 4 ohm as a result of maybe both the EV15WK and EV12WK going from alnico to ceramic at the same time????

We need some old timers to set us straight????

[Kenhorns]

SP12B Pic....this one has a red surround

[twistedcrankcammer]

SP12B Pic....this one has a red surround

The red surround is the orriginal EV cone. The EV replacement cones had black surrounds and EV on the dust cap.

Question is, even after the change to ceramic, why spec the SP 12B instead of the SP 12A? Only thing that makes sense again is cost?

I always felt that if I owned a pair of Heresy, that I would recone a set of EV 12W to 4 Ohm spec and install them. That is a really nice motor unit for a 12 inch driver.

Roger