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#1
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ID'ing old Magnavox console components
I'd like some feedback regarding specifications for some speakers &
crossovers I have. A few years back, my parents gave me their old '60s Magnavox console stereo after it "died" because I'd mentioned interest in those HUGE woofers and horns. I had no interest in the dead control/amplifier units so I merely scavenged the speakers and crossovers, chunked the dead hardware and used the cabinet for fireplace kindling. I never thought to notice this unit's model number. But now that I am wanting to put these thing to use, I cannot determine what the speaker/horn specs are nor the values of the unmarked crossover components. I'd like to know what these speakers are rated at & whether they are 4, 8 or ohm. I'd like to recreate the original x-overs. I've tested a couple of different sets of commercially produced x-overs (connected to 4, 8 & 16 ohm outputs) but like the sound better through the originals. Here is what I do know: This unit was one of Magnavox's first solid-state versions ca. 1965. It was about 6 feet long with removable sliding wooden panels on the top. The control unit and record-changer were in the right-hand side. An album storage bin and speaker selector switch were located in the left-had side The amp was 50 watts and was remotely located in the bottom of the cabinet. The woofers are 15" in diameter and say, "Magnavox 581515-1 719" The horns are 11.5"x5" aluminum and about 12" long (no markings). The tuner was AM/FM/Multiplex. It sported a Gerrard record-changer. The x-overs were actually combined on one cardboard circuit board. There was no baffling for the speakers... the cabinet acted as one giant plenum. |
#2
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Testing will be required, obviously. I'll refer you to the library for
the correct procedure. You will need only that test equipment without which you don't belong fooling with this stuff. (Nothing terribly expensive.) |
#3
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- - : R A T B o y : - - wrote:
I'd like to know what these speakers are rated at & whether they are 4, 8 or ohm. An ohmmeter will get you a close (20%) read on the impedance of a speaker. Other than comparing the physical size of the voice coil and magnet to known speakers, not sure how to identify power rating. |
#4
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Thanks, Bob.
The system was advertised at 50 watts. Possibly it was 25 wpc. So, I expect at least 25w. This is the least of my worries. A set of frequency curves would help me build substitute x-overs. I figure Magnavox used a variety of speaker suppliers and models so I am hoping the previously described markings will mean something to someone. Also, I measured the individual speaker resistances: The horns show 11ohms resistance and the woofers 7.6 ohms. According to your suggestion 20% variances approximate the following: 4 ohms +/- 20% = between 3.2 & 4.8 ohms 8 ohms +/- 20% = between 6.4 & 9.6 ohms 16 ohms +/- 20% = between 12.8 & 19.2 ohms This suggests that they could possibly be 16 and 8 ohms... would the old crossovers have compensated for this? They were very simple (a big cap, a ferrite coil and a wound resistor (big rectangular clay thingy). Obviously, an audio frequency generator and a o-scope would allow me to plot my own curves... fat chance I'd pop for these. I do, however, have a stereo FM signal generator... but I do not know if this could be used for audio. "robert casey" wrote in message link.net... - - : R A T B o y : - - wrote: I'd like to know what these speakers are rated at & whether they are 4, 8 or ohm. An ohmmeter will get you a close (20%) read on the impedance of a speaker. Other than comparing the physical size of the voice coil and magnet to known speakers, not sure how to identify power rating. |
#5
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- - : R A T B o y : - - wrote: snip Obviously, an audio frequency generator and a o-scope would allow me to plot my own curves... fat chance I'd pop for these. I do, however, have a stereo FM signal generator... but I do not know if this could be used for audio. If a good look at the front panel does not sufficiently answer this question you are too _stupid_ for this hobby. But seeing as this is also true of many, many regular posters to this NG it would at least put you in good company. |
#6
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FM signal generator... but I do not know if this could be used for audio. If a good look at the front panel does not sufficiently answer this question you are too _stupid_ for this hobby. But seeing as this is also true of many, many regular posters to this NG it would at least put you in good company. You'd make an excellent candidate for ambassador at the UN; hurry and submit an application as I hear there's an opening there now...... If the FM stereo sig generator doesn't have an audio output jack, use a receiver to get the audio. |
#7
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Or buy a audio generator like a non-idiot.
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#8
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Calcerise,
If you'd actually READ the original posting you could have saved yourself the effort of trying to put me in my place. You are a sophomoric ****head! Talk to the TWIT filter because the newsreader 'aint listening. wrote in message oups.com... ... If a good look at the front panel does not sufficiently answer this question you are too _stupid_ for this hobby. But seeing as this is also true of many, many regular posters to this NG it would at least put you in good company. |
#10
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THese were 8 ohm speakers, if this is the SS update of the original tube
based unit that was made into the mid 60's. From your description it sounds like the identical console unit I picked up at a garage sale for $1. Did you save the magic eye tube? Woofer frequency only goes down to about 45 hertz, then they start frequency doubling. Original tube unit was biamped--no xover. Used a P-P for woofers, and SET 6V6 in triode mode for horn tweeter. Xover was at about 1100Hz accomplished with a tunable hound wound inductor circuit feeding the driver tube for the SET 6V6. I suspect they just used an external xover to try to duplicate tube bi-amp response. Probably sounded like crap. Good choice to junk the SS hardware/ Original was quite a marvel in design. I've got the scematic for it somewhere. Now if it had been the tube version--you'd have something. I rebuilt one and ran it for awhile--really an amazingly good sounding unit for it's time. Also, the cabinet is valuable these days. I sold mine to a vintage shop who converted it to a mini-bar and sold for good $$. "- - : R A T B o y : - -" - - : R A T B o y : - wrote in message ... I'd like some feedback regarding specifications for some speakers & crossovers I have. A few years back, my parents gave me their old '60s Magnavox console stereo after it "died" because I'd mentioned interest in those HUGE woofers and horns. I had no interest in the dead control/amplifier units so I merely scavenged the speakers and crossovers, chunked the dead hardware and used the cabinet for fireplace kindling. I never thought to notice this unit's model number. But now that I am wanting to put these thing to use, I cannot determine what the speaker/horn specs are nor the values of the unmarked crossover components. I'd like to know what these speakers are rated at & whether they are 4, 8 or ohm. I'd like to recreate the original x-overs. I've tested a couple of different sets of commercially produced x-overs (connected to 4, 8 & 16 ohm outputs) but like the sound better through the originals. Here is what I do know: This unit was one of Magnavox's first solid-state versions ca. 1965. It was about 6 feet long with removable sliding wooden panels on the top. The control unit and record-changer were in the right-hand side. An album storage bin and speaker selector switch were located in the left-had side The amp was 50 watts and was remotely located in the bottom of the cabinet. The woofers are 15" in diameter and say, "Magnavox 581515-1 719" The horns are 11.5"x5" aluminum and about 12" long (no markings). The tuner was AM/FM/Multiplex. It sported a Gerrard record-changer. The x-overs were actually combined on one cardboard circuit board. There was no baffling for the speakers... the cabinet acted as one giant plenum. |
#11
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Yep sounds like the one I scraped some time back.The 15 inchwoofers are
CTS,the horns are Magnavox/Jensen.The xovers are nothing special.The horns are sold on line often.The woofers would make alot of sound of so so quality.I was thinking of a guitar cab for them. WesJ........ |
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