Maggie 81-01

[bigtuna]

Ok just acquired this amp on bartertown, says working, I bought without tubes, have sourced some, others on the way, that being sAid couple questions, I'm in the process of building a dim bulb tester, after I test this , will be able to just turn it on whenever I want to use it. Or is there a ritual of slowly warming it up every time to use it, plans are to run the phono pre through it to just power the turntable, I'll try and post pics.

 

[gadget73]

With new caps, you turn it on and go. The slow warmup thing is to hopefully keep it from blowing up with old caps. For reliable use, it really wants new caps.

Pretty sure this is one of their bi-amp rigs. It needs a separate woofer and tweeter with no crossover at the speaker side.

 

[bigtuna]

The ad says serviced and modafied, also says full compliment of tubes and it will be plug and play, guess I can live w/11 seconds. Lol.

 

[gadget73]

well, that doesn't look serviced to me. Those certainly appear to be circa 1960 wax filled paper capacitors, which are almost always shot. I do see modern speaker jacks added to the back but it looks pretty original otherwise.

 

[century tek]

I have never heard that particular Magnavox but it is a biamp. Not sure if the original woofers were full range but those outputs under the chassis are for the highs and you're going to want to find a pair of those metal Magnavox horns for it to shine.

 

[bigtuna]

Interesting, I see a set of those horns on flea bay $25.00, but I don't see building a set of speakers around this particular amp. Just trying to get my feet wet, then move up the food chain.

 

[cademan]

It probably won't sound right without its original speakers or at least some that are fairly efficient but if you wanna get your feet wet then I would simply recap it, get it working correctly and/or normally, and then sell it for something better.

 

[bigtuna]

Yes, I believe this will be the plan.

 

[gadget73]

If you have speakers that can bi-wire, or just a pair of 2 way speakers with a similar crossover point, you can use those. Just bypass the internal crossover and feed off the amp directly. I believe the crossover point is around 1100hz but you can test that fairly easily with a signal generator and a voltmeter.

 

[bigtuna]

I appreciate everone chiming in, since being a green horn, I have an old pair of radio shack bookshelf speakers, actually don't sound bad running thru the Scott rec. But each speaker has one rca jack and the 2 screws for bare wires,

 

[gadget73]

To properly mate with this, you'd have to open it up and access the internal wiring. If its a two-way, there will be a pair to the tweeter and a pair to the woofer and a crossover to seperate the frequencies. Could be as simple as one cap to act as a "bass blocker" for the tweeter. either way you'd have to bring the leads out individually to run properly with the Magnavox amp. Basically that thing has 4 amplifiers in it, two bass amps and two treble amps. A "normal" stereo amp has two amps that cover the full range.

 

[Lavane]

To properly mate with this, you'd have to open it up and access the internal wiring. If its a two-way, there will be a pair to the tweeter and a pair to the woofer and a crossover to seperate the frequencies. Could be as simple as one cap to act as a "bass blocker" for the tweeter. either way you'd have to bring the leads out individually to run properly with the Magnavox amp. Basically that thing has 4 amplifiers in it, two bass amps and two treble amps. A "normal" stereo amp has two amps that cover the full range.

I dont think ive seen this one before. I thought it was the three channel amp when I first looked at it. Kind of cool.

 

[bigtuna]

Guess I didn't pick a very good one to start with. Just wanted a very simple vintage amp to run my turntable thru. That would power 2 speakers.

 

[bigtuna]

Not sure what opt is.

 

[bigtuna]

B320041-2 Sound right??

 

[bigtuna]

You need that #as well

 

[bigtuna]

Ok I see 2 more on the bottom and 2 larger ones on top. Thanks for you interest, I'm heading to work.

 

[bigtuna]

Ok now I'm startin to smell what your steppin in, not a bad idea.

 

[gadget73]

How about doing it externally on the amp with a 500-700hz high pass coming off the treble OPT to block the bass from driving back down the treble tranny, and then just paralleling outputs ala the ST-70 mono-izing. Wonder what the impedance rating of the old speakers is for each channel?

Might work but I envision weird phasing issues trying to do that. If its got global feedback on both sides, you'd have to be absolutely sure neither amp drives back into the other, especially if the phasing ends up imperfect. Also just seems like a messy solution having what amounts to 3 crossovers in the mix. One at the front end of the amp, one at the output, and another inside the speakers. Honestly I think a better solution would be to remove the front end crossover and the treble amp entirely and run it as a full range amplifier.

Wild guess, 4 ohm woofers and maybe 8 or 16 ohm horns.

 

[bigtuna]

Ok, re-read the post I bought this from says stereo, or bi. New speaker post 2 marked stereo, 2 marked bi., says there a switch to go one of the other, and there is. Well see. When the tubes arrive, oh says runs dead quiet 0 hum, we will see,