Yeah, Right ! - djk - High Efficiency Speaker Asylum

High Efficiency Speaker Asylum

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Yeah, Right !

djk

In Reply to: Efficiency using transformer posted by Kenny Brant on July 1, 2002 at 05:28:50:

You followed the recipe all right, except you used baking soda instead of baking powder and garlic salt instead of celery salt. Does it sound kinda funny? If you hung a KSN1016 on the 10W tap of a 70V line transformer without the 68R resistor I stipulated you will have a 125R load at 10Khz on the secondary and it will reflect back as 2R to the primary. With an 8R in series with the primary 80% of the voltage is dropped across the resistor and only 20% getting to the tweeter. 10V from the amp / 2V to the load = 5(log)=.7 .7*20 = 14dB. Congratulations, you have constructed a 14dB pad at 10Khz. How much gain does the transformer have? 8.944V = 10W/8R, 8.944V/70V=.1277 .1277(log)=.9 .9*20=18dB So, by attenuating it 14dB and then boosting it 18dB you gained about 4dB. Let us see what doing it right can do. The 5W tap on a 25V transformer is 125R, not a bad match for the 64R of the piezo at 20Khz plus the 68R resistor we added in series. The 5W tap is 35.35V with 8.944V on the 8R primary. 8.944/35.35=.253 .253(log)*20=12dB So, a 92dB/2.83V KSN1016A + 12dB=104dB/2.83V (in the 10Khz region. The KSN1016 generally rises another dB or so at 20Khz even with the transformer and 68R series resistor). A JBL2440/2441 on a 90* horn from 1Khz~4Khz is about 107dB/2.83V (110dB/W/16R). If you use the 4R tap as the primary you will pick up another 3dB, but this will sound too hot for the 2440/2441. The 8R/5W taps are about 104dB, but this sounds too hot for a Klipschorn. For the 1982 and newer Klipschorn I use the 8R/10W taps, 101dB. I usually use a zobel of 10R+100ÂµH across the 8R tap and then treat it as an 8R load for the crossover design. 3.3ÂµF+.26mH+10ÂµF=4Khz/18dB, 2.2ÂµF+.26mH=6.3Khz/12dB

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Follow Ups Full Thread

Topic - when are piezo arrays of 4 or more useful? - how to best impliment? - freddyi 01:18:22 07/01/02 (9)

Re: when are piezo arrays of 4 or more useful? - how to best impliment? - djk 02:10:45 07/01/02 (8)

Re: when are piezo arrays of 4 or more useful? forgot to ask -End Fire? - freddyi 09:34:02 07/01/02 (0)

Re: when are piezo arrays of 4 or more useful? - when to impliment Zoebel? - freddyi 09:19:39 07/01/02 (0)

Efficiency using transformer - Kenny Brant 05:28:50 07/01/02 (5)

Yeah, Right ! - djk 01:40:31 07/02/02 (2)

Re: Yeah, Right ! - Kenny Brant 17:57:36 07/02/02 (0)

Re: Yeah, Right ! - many thanks for the xformer math lession ! - freddyi 02:30:09 07/02/02 (0)

Re: Efficiency using transformer - freddyi 14:28:36 07/01/02 (0)

Re: Efficiency using transformer - Kenny Brant 05:40:36 07/01/02 (0)

Follow Ups

Yeah, Right ! - djk 01:40:31 07/02/02 (2)

Re: Yeah, Right ! - Kenny Brant 17:57:36 07/02/02 (0)

Re: Yeah, Right ! - many thanks for the xformer math lession ! - freddyi 02:30:09 07/02/02 (0)

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