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Electro-Voice 12TRXB vs. SP12B & T-35

"b" version EV's

Originally the "b" version of EV speakers were a more affordable version of their big brothers with the enormous magnet structures. The advantage of these huge magnets was higher efficiency, superior transient response and better high end response on the full range models SP8, SP12 and SP15. These big magnet guys needed either horn loading or very large bass reflex cabinets to take advantage of their highly damped moving mass.

The more affordable "b" versions are better in smaller enclosures simply 'cause the're not so highly damped and have a better balance between highs and lows. An SP12 or 12TRX needs at least 6 cu. ft. of reflex loading to realise it's great bass potential.

Later on, the the outer suspension was changed to an orangish impregnated fabric and VC travel (Xmax) was increased. Gordon's right ,these are better speakers than the earlier version with the pleated paper surround. There was a drop in efficiency with the longer VC travel but who cares; technology has given us affordable high power that more than offsets the power demands of a few db's drop in efficiency.

I can't imagine what today's cost would be to manufacture those huge alnico magnets with the chrome plated baskets on the non "b" versions. :thmbsp: Dave
 
Squidward- where did you find a set of them? I've had mine for quite a while and love them. I have E-V liteerature on them and was told they have the SP12-C. Very, very flat responce curve. By the way, what did yoy pay if you dont mind me asking? I finally got my bass bin speakers about ready to help them out on the bottom end. I'm gonna see how the sound passivly powered before I go with the plate amp.
 
Well, I have a pair of 12TRXBs, a pair of Sentry IIA with the SP12B with the white cast aluminum basket in them, and I'll soon have a pair of cinnamon colored SP12B to round out the collection. I just pick them up where I see them, and I try not to spend too much on any particular item. Thanks to Redboy, tho, who's helping me out with the match to my SP12B!
 
The EV SP12 and TRX are twice as efficient as the b and c. But you have to get SP 12's or TRX's that still have thier full magnet charge and that have not been abused by clipping amps or poor storage. Someone in VA told me they stored their speakers magnet to magnet, that's a huge no no. While they can be remagnetized at Great Plains Audio, I don't know how you could remagnetize the TRX without removing the T-35 tweeter from the polepiece of the woofer. That would require removing the felt and unsoldering the tweeter. Reassembly might alter the sound unless it is done perfectly.

I had a pair of orange surround, white magnet 12 TRX's purchased in 1964 with Marquis cabinet kits, still have the reciept. They would literally shake nick nacks off the shelves when played with a garrand A turntable and Eico stereo 40 amp, (twenty watts a channel) and they were clean and clear. They seemed to be nearly as loud and dynanic as a set of K horns but not as horny. Wish I still had them, they were lost in a fire and every pair I have bought since then don't seem to measure up. My Kef Reference 3's sound much better than any old speaker I have heard, they just don't play as loud on 20 watts. 93 db vs. 102 db.

The DL12x from the 80's-90's was a lower distortion speaker than the SP12 or b and c versions and were very efficient, about 99db 1 watt/1meter. The newer EV DL series are totally different, different baskets, spiders, surrounds, cones.

Speaker manufactures used to say that if you could keep the excursion to a minimum, underhang the voice coil and keep the magnet gap to a minimum then the distortion would be low and the efficiency high.

I have original NOS EV recone kits for the SP12C and original voice coils for the SP12 8 ohm if anyone needs them. The SP12 used to have 2 1/2" epoxy glass voice coil formers and later had Kapton whereas the B and C had 2" coils.

I own two pair of original EV 12 TRX 16 ohm, one pair pink with chrome baskets orange surrounds, the other white with painted baskets orange surrounds, two pair of 12TRXB 16 ohm one pair newer style the other older style both with orange surrounds, one NIB 12TRX 8 ohm orange surround, three SP-12's, one pair NIB 604-8G and a pair of NIB Altec 515-8G HP. And a pair of new T-35-T350 16 ohm replacement diaphrams.
 
EV SP12 Coils

This post is for skypilot_one. Do you still have the EV SP12, 2.5" voice coils available? I assume these are the glass-epoxy versions? Are the tinsel leads firmly attached? Also, do you have other EV-SP12 parts, cones, whizzers, spiders? Please feel free to contact me at migoblue1986@sbcglobal.net. It would be great to discuss the old EV products.

Mark
 
EV speaker parts

skypilot_one said:
I have original NOS EV recone kits for the SP12C and original voice coils for the SP12 8 ohm if anyone needs them. The SP12 used to have 2 1/2" epoxy glass voice coil formers and later had Kapton whereas the B and C had 2" coils.

Hello,
Do you still have 2 1/2 inch voice coils and spiders for EV SP12's?
thanks
Doug
tonecat@shaw.ca
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