Adding a Headphone Jack

John L Root · by **John L Root** » Sat Sep 04, 2010 1:17 am

I have a 67 Maggie Console Astrosonic with the 100 watt amp, and was wondering if I could add a headphone jack like my newer Astrosonic from the 70's and how would I go about it,I am willing to use the part off the other Astro which is located on the back side ( this also has the terminals for the external speakers) Would doing this harm the Amp?

Bobby Basham · by **Bobby Basham** » Sat Sep 04, 2010 4:51 pm

I might get reprimanded for this (LOL), but it is possible. I'd be worried about damage to your headphones and ears. I have an old mono Rheem/Califone classroom recordplayer and reel-to-reel. Their headphone/extension speaker outputs are tapped directly from the speaker, but they have that muting function. You wouldn't need that muting since you have an internal/external speaker selection switch, and you could easily mount a headphone jack close to the selector switch located over by the record storage compartment.

If you look at your speaker wiring diagram pasted somewhere inside the cabinet, you'll see everything and all you have to do is tap off those three(?) wires and connect them to your headphone jack. That way, your original external speaker connections will still be intact should you decide to use them. Just switch to external, which serves as your mute, and enjoy your headphones. Be careful of the sound level, since the signal is not padded down. --BB

Bobby Basham
Tucson, Arizona

by **Ron Rich** » Sat Sep 04, 2010 5:59 pm

Bobby,
OK--I'll "spank" you--a little, on this (LOL-'cause you "asked for it")--It may be possible to do what you suggest, but I would be more inclined to worry about impeadence mis match, causing harm to the amplifier portion of the set--depending on what type of output device, is used, and what type of "phones" are used. Ron Rich

Bobby Basham · by **Bobby Basham** » Sat Sep 04, 2010 11:22 pm

OUCH!!! LOL

Well I knew that I forgot something. The impedance did cross my mind for a hot second, but didn't give it anymore thought. I've got a set of Sennheisers that are 32 ohms and an Audio-Technica set that's probably several hundred ohms. I personally would not want to tap in on 100 watts to run headphones, yet I'm suggesting how to wire up things so that folks can destroy their systems...MY BAD.

Okay, John must have one of those Astro-Sonic 100s with the separate ampliflier. I have a pair of those pictured below. I paid $25 bucks for the first one and the second one was free. I don't know the reasoning behind using two styles of woofers for these units...Heavy-Duty 20 oz. vs the Super-Sonic 48 oz. These are from a 1966 Brochure, and they weren't cheap back in the day. $595 vs $650, and that didn't include an optional reel-to-reel for $249.90

: Picture 18.jpg (78.39 KiB) Viewed 799 times

: Picture 19.jpg (121.36 KiB) Viewed 799 times

: Picture 20.jpg (119.15 KiB) Viewed 798 times

I also have a 70's Magnavox that has a separate amp and receiver plus 8-track, and it does have a headphone jack. Oh, and those big bullet-shaped styrofoam enclosures, too. Maybe trace the headphone connections on the newer 70's receiver and see how you can modify the older. Just don't drill any holes in those pretty face plates. All the inputs are passing through the receiver and putting out a signal to the amp, so you may be able to tap into that part of the chain and be able to mute the audio output when using headphones. I haven't gone that deep, but you may also need something to boost that tapped signal.

Again, I apologize for inaccurate/damaging info. --BB

Bobby Basham
Tucson, Arizona