Magnavox console pulls- differences.

[2litre]

Hi All,
I'm new to tube radios and amplifiers.

This summer I picked up an old Wards Airline AM/Phono and a Magnavox console. They both still work.

I initially picked up the console for the speakers. I pulled them am are using them Open Baffle in my garage. Thankfully I didn't junk the console. Its a stereo unit with 2x6BQ5, a 6EU7 and a 6CA4.

While trying to find info on it I found my self walking away from the internet with more and more questions about tube amps, Magnavox amps in particular.
I guess my biggest question about Magnavox console pulls is;

-What is the big differences between the 6V6 or 6V6GT amps and the ones like I have with the 6BQ5's or EL84?

See, I want to have a tube stereo (AM/FM, phono and aux/CD) system and I want to learn what its all about. I don't want to pay through all orifices for one so I' going to start by using console pulls. I'd just like to know a bit more about what circuits to look for. Some are obviously better than others. I haven't done a back to back comparison of PP vs SE (yeah, like I know what I'm talkin about there!) so I'm not even worried about that yet, but I think I'm leaning toward PP.

Thanks for any insite you can give,

Jim

 

[audiodyssey]

I can't personally help you with any of the technical stuff, but you are on the right track starting here with the Maggie amps from old consoles. I find these babies for next to nothing at garage sales, thrifts etc. I then go to Antique Electronic Supply and copy the circuit onto a new chassis from them, with new wire, socket caps, resistors etc. and now there's something to talk about. My experience is with 4-6bq5's / 2-6eu7's and the 6v6/12ax7 pp version. I prefer the 6v6 push/pull. It sounds better to me and you will notice some very definite differences. The 6v6 has a more open sounstage, deeper lows and very good seperation (?) It sounds like you have a single ended version. These are alot fun to work with, have very simple circuits and sound good.

 

[2litre]

audiodessey,

That's my intention too. I understand you might not be familiar enough with them to give a techno comparison, but what gives you the impression I have a SE version? Tube count? It also seems that the one I have is a bit smaller than the ones I've seen on e-Bay.

Its still in the console for now. Silly I know but I have my digital camera charging for some reference pic before I pull it. I don't want to get ahead of myself. I found some good reading on a site called aikenamps.com. Pretty easy for a beginner like me. Might just see how the wiring compares with some of their tech diagrams.

I guess I should try them both and, like you mentioned, find the one that sounds best to me. What doesn't sound that good to you might sound great to me.

Thanks,

Jim

 

[Tom Bavis]

If it's stereo, with two 6BQ5s, it's single-ended. It would need two pairs for push-pull. Sounds like the AMP83 series (check for number on the amp). If so, email for a schematic - tbavis(at)rochester(dot)rr(dot)com

And if you find a model number for the Airline, let me know, as I might have it or know where to get it.

 

[2litre]

Tom,

The console knobs have FM, FM-AFC and FM stereo. So is that a good rule of thumb to remember - 2 output tubes is probably SE and 4 output tubes is probably PP?
My Magnavox amp has only two numbers on it: 8601-20 and 221283
FWIW the console number is 1ST296R.
Also I finally saw one on e-Bay that looks like mine with a smallish, more compact spacing of components on the chassis.

The Airline is a model: 25GHM-2012-A
Tubes: 35W4, 50C5, 12AT6, 12BA6, 12BE6
I looked for it on Nostalgia Air and exchanged e-mails with a Puget Sound Antique Radio Association (PSARA) member and couldn't find a schematic for it. Hope you can find some info on it because I really like that AM radio and would love to keep it up to snuff.

Thanks for the help,

Jim

 

[Tom Bavis]

You have it right about SE and push-pull.

The Maggie 8601 is in Sams #550-12 (1961) - I don't think I have it or I would have scanned it already. I do have a scan of the 83 series (very similar), if you want a copy

The Airline (Montgomery Wards) is in Sams 256-4 (1954). I'll see if I have it. DON'T plug anything external into this one - with those tubes, it's not isolated from the power line! No such problem with the Magnavox, which has a transformer. If all the tube numbers start with 6, it has a transformer. The series string tubes add up to 120V, and run without a transformer. (50+35+12+12+12=121)

 

[2litre]

Tom,

Great info. Every little bit helps when on a learning curve. I'll e-mail you for any schematics you might have.

I don't intend to plug anything into the Airline. I removed the ragged old phonograph and intend to shorten up the casing accordingly to make it a nice AM radio (you know, the 'first success' thing). The only mod I have done is to series wire in an additional 4ohm oval speaker. No apparent negative effect. I don't touch now since I noticed a big crack down the side of a very prominent old black capacitor(?) inside the chassis. I will put it into regular service after I replace those items that should normally be replaced (hints?).

Good to know about the SE/PP design visual que. I revisited AikenAmp and found that their schematic of a SE did indead have only one output tube and the schematic for the PP had two output tubes. I didn't put 2 and 2 together on that as I was focused on interpreting symbols by memory.

So I guess I should look for a PP unit to compare against so I can see if I hear the difference that Audiodyssey was talking about.

As for the Maggies, any benifit to either design? I mean, which one is generally considered the better of the two designs as far as sound quality, 'proper' electronics and wattage? Or is the sound more personal or subjective and the wattage comparable between the two?

Thanks,

Jim

 

[wa2ise]

The Airline is a model: 25GHM-2012-A
Tubes: 35W4, 50C5, 12AT6, 12BA6, 12BE6
I looked for it on Nostalgia Air and exchanged e-mails with a Puget Sound Antique Radio Association (PSARA) member and couldn't find a schematic for it. Hope you can find some info on it because I really like that AM radio and would love to keep it up to snuff.

Thanks for the help,

Jim

That sounds like an "AA5" (All American 5ive) AM tube radio. See my web site http://www.geocities.com/wa2ise/ and scroll about half way down the page to see a schematic that is likely to be very similar to yours. Replace all wax caps and the electrolytic if it's in a cardboard tube. Metal can ones may still be good.

 

[2litre]

wa2ise,

Thanks! Cool site and beautiful pics. I'll print the schematics and compare. I
'll let you know.
I'm pretty sure I can find all the capacitors but I keep hearing about the 'electrolitics', is it / are they obvious? They must be the ones that look plastic coated or modern compared to the wax / cardboard ones, right?

Tom suggested it was an AA5 also. With both of you suggesting that, it's probably dead on.

Thanks a bunch. Like I said, I like that radio. Simple and pleasent to listen to. Sounds great listening to Sinatra/Martin and Como on my local 'real' oldies AM station.

R/

Jim