Mid Drivers: K-55-V or K-55-M?

[BEC]

K-55V push pin.

Bob

[Deang]

Blows that theory out of the water, if you know what I mean.

[BEC]

Dean,

I probably listen to more different varients of the K-55 on the same horn of the same Cornscala test box more frequently than anyone else other than BroMike.  There really just isn't a dimes worth of difference between them.

Bob

[BEC]

"Yeah, I do. I guess they decided 4dB down was still too hot, so they went 5dB.

If we tap out on 3, we're only 1dB off. Just a thought."

Oh, and by the way, you got that backward.  They went from 5 to 4.  Within one db of tap 4.

Bob

[EarsOnly]

Hello HarrO. I could use one. Still got it? Happiness always,

Earsonly

[Deang]

Oh, and by the way, you got that backward. They went from 5 to 4. Within one db of tap 4.

Figures.

You mean they had it right the first time and screwed it up.

[NOSValves]

All I know is the K77M sounds like dung on any Type A network I have listened too at anything but low convesational levels. I say that driver is way to hot for that network. I can still feel the nails in my forehead[] In fact the best type A I have ever heard was the original Type AA I wired as Type A's with the original 1940's lossy caps to tame that over bright mid frequency LOL!! I bet it would sound great with Jensen PIO's in one.

Craig

[HarryO]

Yea, I still got one V.

HarryO

hbailey1@earthlink.net

[Bacek]

Does any of you checked how this two piece phase plug looks like or it is too much integrated in the driver? Does old k-55 can be modified some how to have this two piece phase plug?

[freddyi]

here's a push terminal K55V vs an old SAHF, both on Heresy horn (no baffle) - K55V has two deep dips leaving a 9Khz area - I'll probably use the ancient SAHFs on fake La Scala with 511 (in another thread ALK suggested a deep notch filter for this style K55V)

[BEC]

Does any of you checked how this two piece phase plug looks like or it is too much integrated in the driver? Does old k-55 can be modified some how to have this two piece phase plug?

You could probably change the phase plug in a single piece phase plug K-55V. But where would you get the 2-piece phase plug? Probably would cost $10,000.00 to get the mold made to make them. Atlas could probably make them again and probably still had the original tooling to do it, but they are not interested in doing that. It talked to them about it.

Bob Crites

[Invidiosulus]

Does any of you checked how this two piece phase plug looks like or it is too much integrated in the driver? Does old k-55 can be modified some how to have this two piece phase plug?

You could probably change the phase plug in a single piece phase plug K-55V. But where would you get the 2-piece phase plug? Probably would cost $10,000.00 to get the mold made to make them. Atlas could probably make them again and probably still had the original tooling to do it, but they are not interested in doing that. It talked to them about it.

Bob Crites

What does the 2 piece phase plug look like anyways?

I know I've got some in my solder terminal K-55V's but I'm in no hurry to open them up as they are working fine.

Anybody have any pics?

-Josh

[BEC]

I can show you that. This driver was junk. I think it had been underwater for a long time, so this was the one I decided to dissect. I hope yours would look better than this one.

Bob Crites

[BEC]

Another pic

Bob

[BEC]

Phase plug apart.

Bob

[BEC]

Now the one piece phase plug.

Bob

[Bacek]

Bob,

I saw your tutorial on rebuilding k-55-m. For me it looks like k-55-m also has double piece phase plug. But advanced k-55-v measures better than k-55-m. Have you madded measurements of k-55-m with k-55-v diaphragm? Did they look the same as original "M" (at the top end)?

Regards,

Bacek

[Groomlakearea51]

Listen to Bob...... Listen....... It's argumentative, but a new single phase plug Atlas PD5VH will, by nature of diaphtagm rigidity, etc. new materials that have not been flexed for 30 years, etc. will sound better, regardless of measurement specs. Besides, any old measurement specs are just that.... old. They have not existed (except in the "Nexus") for years.....

Juat my opinon...... humble..., but I try to be practical....

[H]

[BEC]

The K-55M does have a 2 piece phase plug and tests very close to the
K-55V with 2-piece phase plug. For a couple of reasons, though, I
think the K-55V with 2 piece phase plug is a better driver than the
K-55M. But, as I said, they are close.

Bob Crites

[Bacek]

I saw your test here:

Squaker Driver Tests ...

original M looks smoother but it is little bit shorter at the top end than V versions.

But what after diaphragm change :

K-55M Rebuild

Does k-55m tests look exactly the same with new Atlas PD-5VH diaphragm , or there are any changes?

Regards

Bacek