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Technical Information on EV T-35 (K-77)


WMcD

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Questions come up occasionally regarding the K-77.  It is a rebranded EV T-35  which passed strict Klipsch QC.  According to an article, PWK selected the EV after EV adopted the Avedon phase plug.  It was first used in a K-Horn in October 1959.  University eventually acquired EV and published a spec sheet which is more elaborate than what EV published.  My read is that horizontal coverage is greater when the unit is oriented with the long axis vertical -- i.e. that the patterns shown were obtained with the unit oriented as shown in the picture.

 

Per the timeline for K-Horns: The first three-way Klipschorn incorporated a Jensen RP203 tweeter. This tweeter came from the famous Jensen G-610 Triaxial 15" driver and required considerable negotiations with Jensen. It was not until mid-1952 that all Klipschorns were three-way. A two-way Klipschorn with response to 12Khz was generally adequate for program material up to that time. The University MID-T- 4401 replaced the Jensen unit as the tweeter of choice later in 1951.

 

WMcD

T35A University Spec Sheet.pdf

T35A EV Spec Sheet.pdf

Avedon Design Patent on T35.pdf

Early T35.pdf

EV Avedon T35.pdf

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Thanks DizR.  I should not have jumped to that conclusion.  There is some information on EV on Wikipedia but I don't find anything informative about University Sound on the Internet.  It does seem safe to say that Mark IV acquired University, based on the spec sheet.  The address given is the same as for EV.  Probably they were sister corporations for a time.

 

My thought is that maybe Mark IV used the University name to market EV drivers and take EV out of that line of business to the extent it still existed. 

 

WMcD

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The dispersion of the T-35 is wider with the long axis vertical, below 5000 Hz. 

 

T-35_Disp.thumb.jpg.e0753835d556f9993c1654acc7964b5f.jpg

 

If you look through several of the documents, you will see that the T-35 also got the T-350 diaphragm at some point.  I think it was when the K-77 turned into the K-77-M.  From that I deduce the K-77-M gets the T-350's 10 watts continuous/50 watts Program/100 watts peak rating.  Naturally, the peak rating is a uselessly short duration.  I wouldn't test it. 

 

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While looking at my mono speaker the other day wondered why the Wolverine by EV T-35 was oriented vertically and positioned behind the woofer

some mounted to the floor of speaker by a bracket that looked not homemade. It is a smallish lower slot ported speaker that as a 2 way is well,

wonderful. Interesting!

Edit: TW-35

 

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12 hours ago, billybob said:

While looking at my mono speaker the other day wondered why the Wolverine by EV T-35 was oriented vertically and positioned behind the woofer

some mounted to the floor of speaker by a bracket that looked not homemade. It is a smallish lower slot ported speaker that as a 2 way is well,

wonderful. Interesting!

Edit: TW-35

 

 

Billy,

 

Would you be able to post photos of your EV speaker?  EV’s history as a  Michigan company, as well as its association with Klipsch, has always  interested me.

 

OBTW, the T-35 (K-77) was always intended by EV to be vertically oriented.  The dispersion was said to be better.  Early on, PWK decided it didn’t “make a dime’s worth of difference” so it was rotated 90 degrees in Klipschorns so as to be able to produce a single model for stereo pairs, rather than mirror imaged pairs with vertically oriented tweeters to the left or right of the squawker horns ( as did Speakerlab in their knockoffs).  In this case he was right; it did not make a dime’s worth of difference sonically, while saving many many dimes in production and marketing costs.

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Some good history Neil. Not certain about the Vertical Cornwalls  but, may have the K-77. Do think it is real that the TW-35

has a smaller magnet than the K-77, as mentioned in an advert saw online recently. Photo I have on this computer has files

scattered about but will try and find. Hope I do not stray far from OP's original intent.

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