Replacing K-55-M or K-55-M/horn in 1985 KHorn

[Lawrence H Wesson]

I have recently purchased a pair of 1985 Khorns (type KB00). They have the K-55-M midrange horn, AK-2 crossovers and the K-77 high freq horn.

Because the K-55-m driver is no longer made, instead of replacing the diaphram (don't want to force another diaphram to fit the K-55-M driver), what driver can I use to replace the K-55-m driver on the end of the existing horn..or would I need to replace the entire horn/driver? Would they fit in place of the existing horn in the speaker? Does Klipsch have a replacement horn/driver for the K-55-M/horn? What would be some of my options?

[Coytee]

I don't know all your options (I don't know the variety of K55's that were made) but...you should be able to simply unscrew your existing driver and replace the driver only with a new driver of your choice (according to what the experts here suggest would be best for you)

You replacing BOTH K55's or just one? I wonder if that might be an issue.... (having the network rebalanced for a different driver than what you might put in)

[*-)]

[gaspr]

I suggest you contact Bob Crites. bobcrites@century.net He will answer all your questions and give you all the options...

[Lawrence H Wesson]

Both K55s. Sounds like I can just screw onto the end different drivers....suggested that I email Bob Crites.

Thanks

[Groomlakearea51]

Theoretically, unless Bob or someone else has additional data, you should be able to screw on a vintage K-55V or an Atlas PD-5VH.

Oct 1983: The Type AK-2 network was introduced to accommodate the new Ceramic Magnet K-55-M mid-range driver. This Electrovoice sourced driver was essentially the same as the previous K-55-V with a ceramic magnet and a smoother response.

See: http://forums.klipsch.com/forums/p/103886/1048788.aspx#1048788

[Guest " "]

Theoretically, unless Bob or someone else has additional data, you should be able to screw on a vintage K-55V or an Atlas PD-5VH.

Oct 1983: The Type AK-2 network was introduced to accommodate the new Ceramic Magnet K-55-M mid-range driver. This Electrovoice sourced driver was essentially the same as the previous K-55-V with a ceramic magnet and a smoother response.

See: http://forums.klipsch.com/forums/p/103886/1048788.aspx#1048788

I have the subject horn and drivers.....they both use the same 1 3/8 TPI mount.

They only issue I recall of the AK-2 from the 1985 khorns I had, is the use of soldered heavey guage monster wire. The K-55-M's and AK-2's are soldered throu out and there are no screw terminals on the crossover board to remove the leads and no terminal spades on the driver side to disconnect. Easy to cut off the wires, but difficult to solder back on unless you use a 30 watt soldering gun or higher. The heavey wire transfers heat away from the solder point so it takes some work.

There's been mixed opinion about circut changes needed to move from K-55-M to K-55-V and back, I pesonally find no difference in their output, but others claim that there is one. Graphs on the fourm of the sound patterns show the wigglely lines to be different, but only in the locations of peaks and valleys rather than actual sound levels.

The onl other consideration is the phase plug in the K-55-V. The solder terminal version made in NJ (altlas was in NJ during the early 80's) are dual phase plug like the k-55-M. The solder terminal version made in TX (current version) are single phase plug.

If you go with the K-55-V's, take note that connection #2 is positive when used in the Khorn. There are minature numbers at the connection point. Most folks assume that connection #1 is positive.

[Blvdre]

If my memory serves me (and often it doesn't...) The Atlas PD-5VH is not always a viable swap, depending on where your tweeter is x'd-over. I believe the PD-5VH doesn't extend out much beyond 4.5KHz. Not a problem if you have Bob's Tweeter, but not so good when using the K77, which is normally crossed at 6KHz.

[Groomlakearea51]

As Fritz pointed out. I have swapped the K-55M's with K55V's on my 87's, but cannot tell any difference, per se. I did remove the original cabling to the drivers and replaced it with fresh 13 gauge as the original was turning "green". When I had Bob convert the AK2's to AK-3's, the whole soldering thing became a moot point because he installed terminal blocks on the crossovers.

[Guest " "]

If my memory serves me (and often it doesn't...) The Atlas PD-5VH is not always a viable swap, depending on where your tweeter is x'd-over. I believe the PD-5VH doesn't extend out much beyond 4.5KHz. Not a problem if you have Bob's Tweeter, but not so good when using the K77, which is normally crossed at 6KHz.

To your valid point about the K-55-V. The issue is the single
vs double phase plug. The push-pin terminalversion of the PD5HV's
has a single slot phase plug which has issues in the frequency range
your talking about. The solder terminal pd5hv comes in two flavors.
The ones made in NJ have a dual slot phase plug and work better in the
frequency range we are talking about. The ones made in TX, are
singleslot phase plugs and have the same limitation as the push-pin
model has.

About the tweeter, My take is that the K-77 not working below 4500 is subjective. Klipsch currently cuts the K-77 at 4500hz. The EV documentation for the T-35 says 3000hz.

The subjective part has to go with power levels. The lower you crossover, the lower the power rating. The slope of the crossover is another factor. AL-4 xovers which have the 4500hz crossover have a steeper slope than prior models.

[Blvdre]

SF, thanks for filling in the blanks.

[BEC]

First, all the versions of the K-55 make it to 6 khz. The K-55M is smoother than the K-55V (single piece phase plug) and the K-55V (two piece phase plug is smoother than the K-55M.

On the ability of the K-77 to go low, I have one test I did on that subject. I put 1/2 watt if continuous sine wave power into one of those at 3 khz. I started at 1/2 watt intending to increase the power from there to see when the diaphragm went away. Problem with that is I started it out too high. The diaphragm popped in a few seconds with 1/2 watt at 3 khz. So what can we see from that? Assuming 1/2 watt is the maximum amount (and seems it is even lower), if we have a 1st order crossover and want to have (for instance) two watts into the tweeter at 6 khz, that would give us the 1/2 watt at 3 khz and that would be too much for the tweeter.

I think that is the reason that Klipsch changed crossovers from the Type A to AA. The type A has a 1st order tweeter filter and the AA has a 3rd order. With a 3rd order filter, you could put two watts into the tweeter at 6 khz and only have a few hundredths of a watt at 3 khz.

Bob Crites

[Guest " "]

"and the K-55V (two piece phase plug is smoother than the K-55M. "

Interesting.

[Groomlakearea51]

"and the K-55V (two piece phase plug is smoother than the K-55M. " Interesting.

Very interesting. I like the 55V's more than the M's. Guess it's what your individual "ear" likes.

[JohnA]

You have 5 choices for a direct replacement driver. A spring-terminal K-55-V, a Solder-terminal K-55-V, A K-55-M, A K-55-X (the newest) or an Atlas PD5-VH (the same as a spring-terminal K-55-V/-X). I prefer the sound of the K-55-V (and the -X and Atlas Driver by inference). The slder-terminal driver has superior measured performance, so I've converted all of my speakers to it.

There is no reason you cannot get a diaphragm, now, for your K-55-M or for several years down the road. If it needs a diaphagm, and you replace it, you can expect it to last for 50 to 75 years, barring abuse. {My Bad. Apparently Klipsch no longer stocks the -M diaphragms. This is a surpie to me as they were in production until just a few years ago.}

My La Scalas were mismatched when I got them. There is more difference in the crossover's sound than between the K-55-V or -X and the K-55-M.

Now, if you don't like the sound, that's a different song altogether, ...............

[Guest " "]

""You have 5 choices for a direct replacement driver. A spring-terminal K-55-V, a Solder-terminal K-55-V, A K-55-M, A K-55-X (the newest) or an Atlas PD5-VH (the same as a spring-terminal K-55-V/-X). I prefer the sound of the K-55-V (and the -X and Atlas Driver by inference). The slder-terminal driver has superior measured performance, so I've converted all of my speakers to it. "

On paper there are 6 chioces, but in fact, we are talking about 4 drivers with 6 possible label configurations.

a. Push-pin k-55-v

b. Solder terminal K-55-V with the nade in NJ tag. This would be the dual phase plug version.

c. Solder terminal K-55-V with the made in TX tag, this would be the single phase plug version.

d. k-55-x Not really a choice from the perspective of being different other than the tag, but solder terminal k-55-x with the made in TX tag, this is no different than "c" since they are both single phase plugs. There are no K-55-X's made in NJ. All are single phase plug.

e. PD5HV is also not really a choice from the perspective of being different other than the label since they are either the same as (a) or ( above, the only difference is the absence ot the klipsch tag. Atlas made versions of the K-55-V's for klipsch.

f. K-55-M dual phase plug made by EV.

[JohnA]

"Solder terminal K-55-V with the made in TX tag, this would be the single phase plug version."

This is a new one on me. I have my 2 spare solder-terminal -Vs in my hands and I cannot find any mark that might id the factory of origin.

[BEC]

Here is what Klipsch said about that.

Bob

[Guest " "]

Bob

Your post about when the dual phase plug went into production is not in dispute. Events since 1980 need to be understood. Klipsch switch to the EV K-55-M driver later down the road. When they switch back to Atlas manufactured K-55-V's, these do longer were dual phase plug. So the statement which was true at the time (1980) that the dual phase plug could be identified by solder terminals, is not longer true today. The K-55-X is a single slot phase plug driver. So are all K-55-V's with solder terminals made after Klipsch ended their relationship with EV to produce the K-55-M. The dual slot phase plug drivers where produced by atlas in NJ. The single slot drivers were produced by atlas in TX.

[BEC]

What simplifies this a lot more than talking about New Jersey and Texas versions, is to simply say if you have a Klipsch K-55V with solder terminals on it, you have the dual phase plug.

Klipsch did not switch back to the K-55V. Klipsch switched back to the Atlas PD-5VH and called it the K-55X.

Bob

[JohnA]

What simplifies this a lot more than talking about New Jersey and Texas versions, is to simply say if you have a Klipsch K-55V with solder terminals on it, you have the dual phase plug.

Klipsch did not switch back to the K-55V. Klipsch switched back to the Atlas PD-5VH and called it the K-55X.

Bob

This is how I know the history. Klipsch switched to the -X right after the -M, with a short period of almost 2 years when there was no Heritage production, though it was not an official halt in production.