Muntz Stereo-Pak 4 track - Schematics? Coverting to AC?

[Megachunk]

Hi all.

I have an old Muntz stereo I took out of my Lincoln years back, and have a number of tapes as well. Stuff like Frank, Don Ho, Herb Alpert, etc. Cool stuff. Anyway, the unit itself has a 5 pin connector that, from what I remember, has everything - power, common, and speakers.

Anyway, I know I'm going to have to make a power supply of some sorts, (12V to 120V? - Could I get one at Radio Shack?)  but I'd like to make a pre (tube!) with outs so I can digitize this stuff, or play them through my stereo. Something about the headroom and bass on tape... My ears just go "ahhh..." and if someone is familiar with these things and know the pinout, or knows how I can go about testing the sockets, I'd be much obliged. Shot in the dark, but hey, gotta pull the trigger to hit something.

Thanks mucho.
Mega
MikeG.

[PRR]

Open it up. Much of it may be "obvious". +12V goes to power switch and then to a 1,000uFd 16V e-cap (probably now oozing all over). -12V may go to chassis -OR- it could be an agnostic (positive or negative ground) design, but will arrive at the "-" end of the main e-cap. There may be a choke and a fuse along the way. And if you are tapping it for home use, you don't need speaker pin-out.

You will also find that the main drive belt has rotted off. And the high-traction rubber pinch-roller is hard as titanium -or- crumbled to dust. Good luck.

> to make a pre (tube!)

Lot of work; and the wheezy transistor preamp is part of the sound that makes your ears just go "ahhh...". Find the volume control, dual pot. The end strapped together across the two sections is common. Each other-end is live signal for a channel. This is approximately correct level and EQ to go right into a Line Input. Try that (with a cap-job in the preamp) before you go nuts building an overkill preamp. (If you do: the EQ was nominally NAB 3.7ips, but really had massive bass "EQ errors".)

Without the loudspeaker sections, you need at least 12V 1A. Radio Shed used to be a good source for 13V 3A car-replacement power supplies to run car CB radios in the home. Be generous. The track-change solenoid is a BIG CHUNG. A lightweight power supply may play, but punk-out or even quit at track-change. If the loudspeaker stage is just two big transistors on BIG heatsinks, you may need 5A just to bring it up. Don't go over 15V no-load.

Search eBay first. Mostly old 8-tracks are not worth a buck, but Muntz was THE first, and just might be modestly collectible. Not so you get rich, but enough to hack gently to preserve its historical value.

[PRR]

> old 8-tracks are not worth a buck, but Muntz was THE first

Actually, Muntz was 4-track. Didn't invent it, but Muntz got the rights and promoted the heck out of it. Lear took a ride with Muntz, took a distribution deal, but also improved the format into 8-track. And it was Lear's 8-track that Ford bought into.

Muntz was notoriously nuts:

"he contemplated joining the Communist Party in order to get more exposure. He dressed up in red longjohns and a Napoleon hat"
Not someone who could do a deal with FoMoCo.

4-Track (and broadcast cart) has a big hole in the bottom, no rubber-roller IN the cartridge, a big LOAD lever. 8-track has no such hole, a rubber-roller built-in instead, and notched sides so you just shove it in and spring-levers sorta hold the internal roller to the player capstan. There -may- be 4/8 machines, there sure were adaptors to fit 4-track tapes in 8-track players (Lear was not gonna re-release every tape Muntz already had on the market).

4-Track may be interestingly collectible. Like $11 instead of $10 for a cherry 8-track.

[Megachunk]

Mad Man Muntz! Didn't he have a car stereo that played 45 records?

Thanks a bunch for the insight. I will go through the thing and replace the necessary items. If I get it running, I'll let you know how it sounds. It worked fine when I puleld it out about 8 years ago.

Thanks again man for giving me the ideas.

MikeG.
Mega.