La Scala rehab, part 2

[Fjd]

I was referring only to the K-55V drivers (and not to the much later k-55-X). There are a number of things that don't make sense in the above post. The soldered K-55 V's (with the re-designed phase plug) were around for many years - they are not uncommon. 

 

But the bottom line is that the soldered K-55V (soldered and with the fancier phase plug) is the preferred version of the K-55. My memory may have slipped on this, perhaps DJK or someone more know knowledgeable than me can clarify this.

 

 

 

Additional information from Dennis and a call in to Klipsch.  The point from the quote in my prior post was the solder terminal dual phase plug (two port).

 

 

All K55s have phase plugs. The only question is, is yours a one port or a two port? The K55V with push button terminals was a one port, the solder terminal K55V and the K55M are two port.

http://www.atlas-soundolier.com/techLib/slsheets/SL2.1551.PDF

The peak at 9Khz will be a little more pronounced in the K55V as Klipsch has Atlas reduce the spacing between the diaphragm and the phase plug.

http://www.atlas-soundolier.com/techLib/slsheets/SL2.1561.PDF

This driver is the same except it has a bigger magnet and more spacing between the diaphragm and the phase plug. Note that the dips from phase cancellations due to phase plug design are at exactly the same frequencies.

http://www.atlas-soundolier.com/techLib/slsheets/SL2.1552.PDF

A smaller phase plug spacing, note the dips are shifted higher in frequency.

 

 

I called Klipsch again and I guess I didn't understand them the first time. I was told that the older K-55-V driver goes to 6,000hz and that the modifier version goes to 7,000hz. Because the modified version has a higher frequency range the transition over to the tweeter is suppose to be a little smoother. However, it sounds like they are very similiar and not worth the bother of swapping out the older drivers for the newer ones. They must have made the older version for quite a while since I have them in these old Klipschorns I just got and a pair of 77 Heresys. I think the Klipschorns are from the 60's.

 

 

 

A while back we were discussing this. I contended the PD4 was less efficient and had less high end. Someone else thought otherwise.

Atlas says the -10dB point on the HF is 7Khz vs 10Khz and the difference in SPL is 2.2dB (the chart shows 3dB, but that must be adjusted for the difference in maximum power).

http://www.wvi.com/~vintage/ATLAS2.JPG

After I get my scanner figured out I will post response graphs I made about 20 years ago. They show about:

6dB less output at 4Khz

12dB less at 5Khz

15dB less at 6.3Khz

and a peak at 12.5Khz only 3dB down from the 4Khz level

Both were on the same CD horn (JBL 2370), the 12.5Khz peak would be much worse on any Klipsch midrange horn (due to narrowing HF pattern at HF).

The PD5 was the MR version (two port phase plug, K55V solder terminal type), and shows a very smooth roll-off above 6.3Khz.

 

 

 

.

Edited January 24, 2016 by Fjd

[Matthews]

CUT THE TOPS OFF!!!! or at least I would

 

That is INSANITY, Dude!!!  ...pure insanity

[The Dude]

CUT THE TOPS OFF!!!! or at least I would

That is INSANITY, Dude!!! ...pure insanity

Insert mad scientist laugh.

Sent from my SM-N920P using Tapatalk

[Matthews]

Very interesting information concerning the K-55.  Originally I was planning on keeping the spring loaded versions and putting the solder lugs up for sale (preferring the push springs ease of use).  However, from what I am reading, the solder terminal driver is the one to install in the keepers?

 

Thank you for sharing, fella's

[Deang]

I stand by my original post.

[ZEUS121996]

From my 73  CWs, obviously replaced

 

Mark

[Bossman]

Deang, in YOUR opinion, what are the sonic differences between the K55 with spring loaded terminals and the K55 with soldered terminals. It seems like you are familiar with both of them. What is the difference in sound and the differences in the measurements? 

[Ceptorman]

You should start a La Scala rebuilding business

 

Love the pics.

 

Nice work.

[ricktate]

Would it just be better all around to put in Crites tweets and change crossover to 4500. That takes the load of the mid driver and gets you a better tweeter. I did this on my 72 k-horns and seems to sound better to me.

     The Scalas you got there have the base shoe molding they came out with in late 80 right after I got mine with the flat ugly trim. I finally changed that when I veneered my Scalas .

      Did you change the mid driver gasket with the flat kind or did you try my O-ring idea?

[Matthews]

You should start a La Scala rebuilding business Love the pics. Nice work.

 

Thanks Ceptor   - I do have to say, it is A LOT of work.  Have a very good feeling about this pair.  If I could only find a little sander that would fit inside the dog house walls.  Pneumatic, electric, anything...  that is the worst part of this entire process.   Getting inside that dog house by hand, UHG!!!  And so, that is where I shall start this morning.

 

Did you change the mid driver gasket with the flat kind or did you try my O-ring idea?

 

New, flat gaskets from Crites.

[Frzninvt]

I was referring only to the K-55V drivers (and not to the much later k-55-X). There are a number of things that don't make sense in the above post. The soldered K-55 V's (with the re-designed phase plug) were around for many years - they are not uncommon. 

 

But the bottom line is that the soldered K-55V (soldered and with the fancier phase plug) is the preferred version of the K-55. My memory may have slipped on this, perhaps DJK or someone more know knowledgeable than me can clarify this.

 

They were not readily available!  They were only used late '80 to '83 before being replaced with the K-55M.  They and the K-51V (dual phase plug equivalent) ceramic version are more desireable and not that common at all as compared to the spring terminal K-55V.  I am certain they were more expensive and the decision to go with the K-55M was most likely a financial one.

 

I have them in most of my Heritage speakers.  At least the main five anyway.

Edited January 24, 2016 by Frzninvt

[Matthews]

I seem to gather you like to fix up old LaScala's to sell.

 

Indeed, the pair I just finished will be for sale soon, in stock form.  All the "Hot Rod" goodies will go into the current restoration and they will be keepers   - for years to come.  After this, I am done for awhile.  Time to sit back and enjoy

[PrestonTom]

 

I was referring only to the K-55V drivers (and not to the much later k-55-X). There are a number of things that don't make sense in the above post. The soldered K-55 V's (with the re-designed phase plug) were around for many years - they are not uncommon. 

 

But the bottom line is that the soldered K-55V (soldered and with the fancier phase plug) is the preferred version of the K-55. My memory may have slipped on this, perhaps DJK or someone more know knowledgeable than me can clarify this.

 

They were not readily available!  They were only used late '80 to '83 before being replaced with the K-55M.  They and the K-51V (dual phase plug equivalent) ceramic version are more desireable and not that common at all as compared to the spring terminal K-55V.  I am certain they were more expensive and the decision to go with the K-55M was most likely a financial one.

 

I have them in most of my Heritage speakers.  At least the main five anyway.

 

That is interesting and now that I think about it I have just discovered something.

 

I have owned a number of Heritage series cabinets and they have usually had the K-55V soldered mid drivers. Now that I think about, they had another thing in common - they were usually from the early 80's vintage. Seriously, I had never noticed my pattern.

[Matthews]

OMGosh, think my mission just got a little easier    

http://www.harborfreight.com/air-angle-sander-93629.html

[twistedcrankcammer]

 

I was referring only to the K-55V drivers (and not to the much later k-55-X). There are a number of things that don't make sense in the above post. The soldered K-55 V's (with the re-designed phase plug) were around for many years - they are not uncommon. 

 

But the bottom line is that the soldered K-55V (soldered and with the fancier phase plug) is the preferred version of the K-55. My memory may have slipped on this, perhaps DJK or someone more know knowledgeable than me can clarify this.

 

They were not readily available!  They were only used late '80 to '83 before being replaced with the K-55M.  They and the K-51V (dual phase plug equivalent) ceramic version are more desireable and not that common at all as compared to the spring terminal K-55V.  I am certain they were more expensive and the decision to go with the K-55M was most likely a financial one.

 

I have them in most of my Heritage speakers.  At least the main five anyway.

 

 

 

A TSCM's Top Hat has a K-400 horn but instead of a 1 inch throat like in LaScalas or Klipschorns, these K-400 horns have a 2 inch throat and a K-4 adapter with four K-55 drivers screwed into the adapter in every one of them. Multiply that by 7 TSCM's, and I am pushing 28 of these buggers. TSCM production started in 1982, so I have a lot of them and some of the later M versions as well

 

Roger

[twistedcrankcammer]

OMGosh, think my mission just got a little easier    

http://www.harborfreight.com/air-angle-sander-93629.html

 

 

Hope you have a big compressor, those little buggers will go through a lot of air

 

Rog

[Matthews]

Hope you have a big compressor, those little buggers will go through a lot of air

 

Yeah, just hoping it is available for in-store pick up.  Otherwise, as many of you know, I don't waste any time.  NOT waiting on shipping.  By the end of the day my fingers are likely to be mere nubs

[Matthews]

Here is a little triangle sander that is just what you are looking for, electric. Other brands are available. http://www.homedepot...cB&gclsrc=aw.ds

 

Oh Boy!!!  -  PERFECT!!!   thank you so much "wdecho", not sure how I missed that little guy in my search, but I did

 

On my way...      

[Matthews]

WOW    -  got a lot more done this morning than I expected.  The WORST is over -YAY- 

 

Inside the dog houses, sanding complete down to #220  -  This old man is worn out!!!

[MookieStl]

You can't sand down 3 pairs of La Scalas in the past three months and act surprised at the amount of work every time. As for you being old, I am pretty sure I have socks older than you! Now breaks over, I see plenty more to sand!

Hang on to that k400 for me.