With all due respect, if I connect a good pair of speakers to the amp output this unit sounds great, so I don't believe there are limitations of the preamp or (especially) the amp. The open design of the speaker placement leaves a lot to be desired, granted, but I can live with the shortcomings if I could just get a nice, strong, balanced amount of treble to go with the mid and woofer. The mid is really loud and strong so I've wondered about just trying to build a 3 way crossover based on the values of the drivers to see if that would solve it.
That takes us back to the beginning of the thread. The bass driver can be run direct from the amp terminals. The mid would benefit from having a capacitor in series with it and, in addition, an L PAD attenuator to reduce its sound level. The tweeter remains as at present with the 2.2uF series capacitor.
If you want to try this approach, we can suggest component values for the mid's series capacitor and L Pad.
To be clear, my suggestion is to reduce the level of the mid somewhat to bring it into balance with the level of the existing tweeter.
The bass has to be excluded from the mid by a series capacitor in order to make the L pad attenuation a viable prospect.
The bass has to be excluded from the mid by a series capacitor in order to make the L pad attenuation a viable prospect.
Agreed. I've had a few Magnavox solid state Astrosonic models and the electronics are fine. Some of the others, like my Clairtone in the living room, not so much.
Wise Old is correct about the boom, it sure sold consoles.
I find the highs usually very rolled off at the speakers. Perhaps that was to mask a lot of the noise from AM radio and the surface noise of the records. Good luck with the new tweeter and keep us informed!
Wise Old is correct about the boom, it sure sold consoles.
I find the highs usually very rolled off at the speakers. Perhaps that was to mask a lot of the noise from AM radio and the surface noise of the records. Good luck with the new tweeter and keep us informed!
Agreed. I've had a few Magnavox solid state Astrosonic models and the electronics are fine. Some of the others, like my Clairtone in the living room, not so much.
Wise Old is correct about the boom, it sure sold consoles.
Along these lines, I've finally gotten the turntable to a decently-performing place by altering the RIAA curve on the preamp slightly to raise the overall rolloff curve by a couple of db. By itself the phono input seems even more rolled off than the tape input probably to, as you say, hide record wear back in the day.
I wanted to be able to use the phono input as to not lose the auto shutoff. I have a vintage Shure Premier cartridge installed with a modern Jico DJ stylus, and the Collaro turntable will track as light as 3-5 grams so I'm okay with this - I know a lot of people freak out at that much VTF but in my experience heavier tracking especially with a conical stylus does far less damage than a microline tracking at a halfa gram or whatever. So the turntable goes into a modified Hagerman Bugle, which is tucked in the back of the cabinet, and it's then plugged into the phono input, and the power is run into the switched outlet on the preamp. Works beautifully, and does well with 78s (via stylus change) as well.
It would be nice to know the impedance of the mid driver.
Could you at least disconnect the mid from the circuit and measure its dc resistance?
Failing that, I will supply ball park figures for experimental purposes.
Could you at least disconnect the mid from the circuit and measure its dc resistance?
Failing that, I will supply ball park figures for experimental purposes.
in the original configuration it seems the tweeter and mid (running fullrange) are side firing while the bass is out the front or have i got that wrong and it's the other way around.... either way phase is likely wonky and mudding the high end perhaps
I can measure the ohm rating with a multimeter, I think - let me pull the back off later this afternoon and I'll see what I get.
John
Magnavox consoles used side-firing woofers in many models, horns, tweeters, were always in the front.
In a few "upper end" consoles, they actually used a "tunnel" across the whole console for the woofers.
And in some solid state (Astrosonic) models, even encased the woofers in a styrofoam sealed box at either end (air suspension design).
Do me a favor John, get me the model number (2Sxxx?) and amp/preamp chassis numbers (ink stamped on chassis) for this unit.
I'll dig out my Magnavox Master Service Manual and do some investigating.
I used to be an authorized servicer of those buggers.
so if the bass driver on the side is running fullrange how is it the response of the mid high is not affected? with no filter involved and at mid to high frequencies there's two sources firing at right angles from each other( across a cabinet corner to boot)
Running the woofer full range was typical in consoles of the era. And as you are usually 90 degrees off axis to the woofer, its own top end doesn't interfere much. It will splash a little mid range off the walls. All in the goal of a big, house filling sound.
If that's working, then I suspect the original phono input is for a ceramic (crystal) cartridge which don't need as much amplification or EQ as a modern magnetic cart. It's a good solution.
If you supply the model number, Wise Old can tell you for sure. I don't know when consoles started using moving magnet carts, but none I've owned had them.
fleece and pooh are different but you can fill a house with both 😀
don't get me wrong i'm a fan of vintage consoles but some designs where lemons but still became widely purchased, RCA went through the same phase.
don't get me wrong i'm a fan of vintage consoles but some designs where lemons but still became widely purchased, RCA went through the same phase.
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