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New K55X vs Older K55V?


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Does anyone have any information as to whether a brand new pair of PD-5VH would offer any sonic benefits vs an older and existing unit?

I own a pair of 1977 KHorns (plus 81 Cornwalls & 79 Heresys)

The drivers in my 81 Cornwalls have the phase plug vs the 77's not having it.

Any opinions or measurable facts regarding which if either offer any kind of measurable or sonic benefits?

The data sheet on newer PD-5VH's indicate it does have a phase plug.

I've spoken with Atlas but no one has any information as to what kind of tweeks the PD-5VH may have undergone over the years. It would take someone that has been with either Atlas or Klipsch for 30 years+

Klipsch is stil working off of older but new units becaise they have not ordered any from Atlas in about 10 years.

Thanks for any feedback.

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Does anyone have any information as to whether a brand new pair of PD-5VH would offer any sonic benefits vs an older and existing unit?

I own a pair of 1977 KHorns (plus 81 Cornwalls & 79 Heresys)

The drivers in my 81 Cornwalls have the phase plug vs the 77's not having it.

Any opinions or measurable facts regarding which if either offer any kind of measurable or sonic benefits?

The data sheet on newer PD-5VH's indicate it does have a phase plug.

I've spoken with Atlas but no one has any information as to what kind of tweeks the PD-5VH may have undergone over the years. It would take someone that has been with either Atlas or Klipsch for 30 years+

Klipsch is stil working off of older but new units becaise they have not ordered any from Atlas in about 10 years.

Thanks for any feedback.

I'm no expert, but ......

  • I think your '81 Cornwalls have Atlas drivers with phase plug modified by Klipsch, rather than by Atlas.
  • Google " 'Speaker Builder' Klipsch Interrview" or the like. In that interview, PWK describes the modification, as well as why they later temporarily stopped using Atlas drivers (I think)
  • There was a Dope from Hope (c. 1980) on the difference in the frequency response due to the new phase plug.
  • Atlas may have later adoped the mod themselves, or improved on it.
  • I think the K55X in AK4 Klipschorns is made by Atlas for Klipsch, but Klipsch gets it out of there by crossing over to the K77 at about 4.5K (instead of the old 6K), with steep slopes (compared to the old ones) at the crossover. I don't think the X has the phase plug mod (?), but it may not need it because of the new crossover frequency. The X may sound like the X is supposed to sound only if you have steep slope crossovers at 4.5K, or close to it..
  • Somewhere there is a printed history of all the changes in the Klipschorn ... maybe on this forum.
Edited by Garyrc
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Does anyone have any information as to whether a brand new pair of PD-5VH would offer any sonic benefits vs an older and existing unit?

I own a pair of 1977 KHorns (plus 81 Cornwalls & 79 Heresys)

The drivers in my 81 Cornwalls have the phase plug vs the 77's not having it.

Any opinions or measurable facts regarding which if either offer any kind of measurable or sonic benefits?

The data sheet on newer PD-5VH's indicate it does have a phase plug.

I've spoken with Atlas but no one has any information as to what kind of tweeks the PD-5VH may have undergone over the years. It would take someone that has been with either Atlas or Klipsch for 30 years+

Klipsch is stil working off of older but new units becaise they have not ordered any from Atlas in about 10 years.

Thanks for any feedback.

I'm no expert, but ......

  • I think your '81 Cornwalls have Atlas drivers with phase plug modified by Klipsch, rather than by Atlas.
  • Google " 'Speaker Builder' Klipsch Interrview" or the like. In that interview, PWK describes the modification, as well as why they later temporarily stopped using Atlas drivers (I think)
  • There was a Dope from Hope (c. 1980) on the difference in the frequency response due to the new phase plug.
  • Atlas may have later adoped the mod themselves, or improved on it.
  • I think the K55X in AK4 Klipschorns is made by Atlas for Klipsch, but Klipsch gets it out of there by crossing over to the K77 at about 4.5K (instead of the old 6K), with steep slopes (compared to the old ones) at the crossover. I don't think the X has the phase plug mod (?), but it may not need it because of the new crossover frequency. The X may sound like the X is supposed to sound only if you have steep slope crossovers at 4.5K, or close to it..
  • Somewhere there is a printed history of all the changes in the Klipschorn ... maybe on this forum.

sounds like an expert answer to me lol

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The old K-55-V (spring loaded terminals) and current K-55-X are both made by Atlas and utilize a single phase plug. Though the K-55-X has solderable tabs, both drivers are identical.

PK had Atlas create a dual phase plug design, which was also known as the K-55-V, and it made its short lived debut in 1980. A ferrite magnet version materialized, known as the K-51-V (Atlas). PK approached Electrovoice to see if they could produce the driver for less - and that would be the K-55-M.

There is no functional or performance difference between the current Atlas PD5-VH and the K-55-X.

The purpose of the crossover change was due to a desire to achieve a smooth power response by matching the polars. We have K-55-V (single phase plug) plots out wazoo showing a stable response to almost 6kHz on horns that collapse the verticals (K-400, 401, Trachorn, Fastrac-K, Eliptrac 400, etc.)

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Does anyone have any information as to whether a brand new pair of PD-5VH would offer any sonic benefits vs an older and existing unit?

I own a pair of 1977 KHorns (plus 81 Cornwalls & 79 Heresys)

The drivers in my 81 Cornwalls have the phase plug vs the 77's not having it.

Any opinions or measurable facts regarding which if either offer any kind of measurable or sonic benefits?

The data sheet on newer PD-5VH's indicate it does have a phase plug.

I've spoken with Atlas but no one has any information as to what kind of tweeks the PD-5VH may have undergone over the years. It would take someone that has been with either Atlas or Klipsch for 30 years+

Klipsch is stil working off of older but new units becaise they have not ordered any from Atlas in about 10 years.

Thanks for any feedback.

I'm no expert, but ......

  • I think your '81 Cornwalls have Atlas drivers with phase plug modified by Klipsch, rather than by Atlas.
  • Google " 'Speaker Builder' Klipsch Interrview" or the like. In that interview, PWK describes the modification, as well as why they later temporarily stopped using Atlas drivers (I think)
  • There was a Dope from Hope (c. 1980) on the difference in the frequency response due to the new phase plug.
  • Atlas may have later adoped the mod themselves, or improved on it.
  • I think the K55X in AK4 Klipschorns is made by Atlas for Klipsch, but Klipsch gets it out of there by crossing over to the K77 at about 4.5K (instead of the old 6K), with steep slopes (compared to the old ones) at the crossover. I don't think the X has the phase plug mod (?), but it may not need it because of the new crossover frequency. The X may sound like the X is supposed to sound only if you have steep slope crossovers at 4.5K, or close to it..
  • Somewhere there is a printed history of all the changes in the Klipschorn ... maybe on this forum.

The last letter "E" in K-48-E = they were made by Eminence on the woofers. Pyle made the "K" series for Klipsch. Klipsch had several different woofer vendors over the years.

Example: K-33-E would be the "Klipsch", part type 33 (15") woofer from Eminence. The suffix letter code generally referred to the Klipsch assigned origin/ manufacturer of the driver.

B = CTS (Chicago Telephone Supply), Brownsville TX

P = CTS in Paducah KY (woofers only)

R = Rola (an additional "R" either stamped or handwritten also indicated replacement (often seen on K22's and K- 24's)

D = K-77-D; From 2006 to the present. Essentially a K-77-F (see below) with an integral recessed mounting flange. Permits flush mounting of the tweeter from the rear, per the “Z” brackets for pre Feb 1983 Klipschorns (KH Update kit: part # 1006969)

F = Philippines supplier that purchased the EV tooling (e.g. K-77-F)

EV = Electro Voice (early K-33's e.g. "EV-15WK", also EV 1828 was used as the K-56 for Cornwall in 1974)

G = Atlas (for K-55-G for Cornwall 1981-1983)

J = Jensen (Also used for University drivers in mid- 1950s; e.g. K-5-J - University model 5A HF, and SAHF)

H = Heppner (K-52-H in Cornwall-II’s)

K = Klipsch (Pyle - Klipsch purchased Pyle and drivers were assembled in Hope Arkansas and at Pyle in Huntington, Indiana)

E = Eminence (Primarily woofers)

V = Atlas (see also notes below)

M = Electro Voice (also for the Eminence K-33-M in 1967)

X = Atlas (e.g. K-55-X)

Ti = Titanium series (new design with titanium diaphragms)

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  • 2 weeks later...

the stuff you learn in this forum is amazing... thank god.

Yes it is!

Does anyone have any information as to whether a brand new pair of PD-5VH would offer any sonic benefits vs an older and existing unit?

I own a pair of 1977 KHorns (plus 81 Cornwalls & 79 Heresys)

The drivers in my 81 Cornwalls have the phase plug vs the 77's not having it.

Any opinions or measurable facts regarding which if either offer any kind of measurable or sonic benefits?

The data sheet on newer PD-5VH's indicate it does have a phase plug.

I've spoken with Atlas but no one has any information as to what kind of tweeks the PD-5VH may have undergone over the years. It would take someone that has been with either Atlas or Klipsch for 30 years+

Klipsch is stil working off of older but new units becaise they have not ordered any from Atlas in about 10 years.

Thanks for any feedback.

I'm no expert, but ......

  • I think your '81 Cornwalls have Atlas drivers with phase plug modified by Klipsch, rather than by Atlas.
  • Google " 'Speaker Builder' Klipsch Interrview" or the like. In that interview, PWK describes the modification, as well as why they later temporarily stopped using Atlas drivers (I think)
  • There was a Dope from Hope (c. 1980) on the difference in the frequency response due to the new phase plug.
  • Atlas may have later adoped the mod themselves, or improved on it.
  • I think the K55X in AK4 Klipschorns is made by Atlas for Klipsch, but Klipsch gets it out of there by crossing over to the K77 at about 4.5K (instead of the old 6K), with steep slopes (compared to the old ones) at the crossover. I don't think the X has the phase plug mod (?), but it may not need it because of the new crossover frequency. The X may sound like the X is supposed to sound only if you have steep slope crossovers at 4.5K, or close to it..
  • Somewhere there is a printed history of all the changes in the Klipschorn ... maybe on this forum.

The last letter "E" in K-48-E = they were made by Eminence on the woofers. Pyle made the "K" series for Klipsch. Klipsch had several different woofer vendors over the years.

Example: K-33-E would be the "Klipsch", part type 33 (15") woofer from Eminence. The suffix letter code generally referred to the Klipsch assigned origin/ manufacturer of the driver.

B = CTS (Chicago Telephone Supply), Brownsville TX

P = CTS in Paducah KY (woofers only)

R = Rola (an additional "R" either stamped or handwritten also indicated replacement (often seen on K22's and K- 24's)

D = K-77-D; From 2006 to the present. Essentially a K-77-F (see below) with an integral recessed mounting flange. Permits flush mounting of the tweeter from the rear, per the “Z” brackets for pre Feb 1983 Klipschorns (KH Update kit: part # 1006969)

F = Philippines supplier that purchased the EV tooling (e.g. K-77-F)

EV = Electro Voice (early K-33's e.g. "EV-15WK", also EV 1828 was used as the K-56 for Cornwall in 1974)

G = Atlas (for K-55-G for Cornwall 1981-1983)

J = Jensen (Also used for University drivers in mid- 1950s; e.g. K-5-J - University model 5A HF, and SAHF)

H = Heppner (K-52-H in Cornwall-II’s)

K = Klipsch (Pyle - Klipsch purchased Pyle and drivers were assembled in Hope Arkansas and at Pyle in Huntington, Indiana)

E = Eminence (Primarily woofers)

V = Atlas (see also notes below)

M = Electro Voice (also for the Eminence K-33-M in 1967)

X = Atlas (e.g. K-55-X)

Ti = Titanium series (new design with titanium diaphragms)

Interesting....

Thanks for posting Moray!

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  • 1 year later...

The dual phase plug K-55V is one of the best midranges Klipsch ever produced.  I would not change them.  I tried to buy them for all my Heritage speakers but have a couple of pair to go.  They get pricey on eBay since a lot of people know they are desirable.

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The dual phase plug K-55V is one of the best midranges Klipsch ever produced.  I would not change them.  I tried to buy them for all my Heritage speakers but have a couple of pair to go.  They get pricey on eBay since a lot of people know they are desirable.

You wouldn't happen to have drawings or photos of these two drives insides would you? Seems to me they have been posted but I can't find them. Thanks.

Edited by moray james
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https://community.klipsch.com/index.php?/topic/115376-are-these-horns-from-a-klipsch-speaker/

 

Klipsch was not happy with the Atlas ceramic magnet version of the two exit port PD5, the ones I saw were marked K51V and wound up in the Cornwall. The EV version had the plastic back chamber, the only Atlas version I saw of this had a metal bumped back chamber that looked like an ash tray glued on the back of the driver. Atlas had a whole skid of these that Klipsch refused to accept. I bought some of these from Atlas as the PDMR. They did not measure as smooth as the EV made K55M in the 4Khz~6Khz region, but they worked great for PA (especially for $24 each).

Klipsch was hot to reduce the cost of the midrange driver for the Cornwall and Heresy. The Atlas PD5 not only had an alnico magnet, but also required quite a bit of machine work in the magnet assembly. Hepner had long been providing ceramic magnet midrange and tweeter horns with 1" coils to Cerwin Vega. These had stamped plates in the magnet assembly making them dirt cheap by comparison with the Atlas and EV products. The new 1-1/2" VC midrange/HF driver proved suitable for the Cornwall/Heresy product, but was not deemed 'enough' for the K/B/LS . The stamped magnet assembley tweeters were not efficent enough to keep up with the horn loaded LF of the K/B/LS either, and the EV tweeter was retained. The KG2 was the first Klipsch speaker to use a Hepner tweeter, virtually the same one sold to Cerwin Vega.

Ray Hepner died and Klipsch took over the payroll and kept production going. Eventually Klipsch bought the tooling and moved it to Hope.

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DJK: would you care to share your thoughts on the sonic qualities of the different k55 drivers? Their strengths and weaknesses and what they are each best suited for? Also I am curious to know if all the K55 versions all shared the same exit angles and compression ratios and such or do they vary ? Thanks for posting the above info. Best regards Moray James.

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At one time Bob Crites had a very detailed thread on all of them.  With disassembled photos, plots and all.  Too bad the "Search" function is all but useless.

 

 

I find that when I search for certain word combinations and fill in the author I have better luck.  Just did "squawker driver tests" and "BEC" and came up with this thread. 

 

https://community.klipsch.com/index.php?/topic/73483-squawker-driver-tests-k-55v-k-55m-k-51v-k-52h/page-1

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