Farmall Cub

OK now you might be thinking why in the world am I posting this on a Farmall Cub forum. Well the honest answer is because we are a great group of people who respond to questions very quickly!

I have a 64 Magnavox Astrosonic stereo console that is in need of some help. Everything works OK, but there is a noticeable hum. Normally this is filter capacitors that need to be replaced, but this system is way beyond my abilities in electronics. Hey what can I say, I do better with tractors!

Does anyone have someone they know who works with vintage stereo equipment and would be willing to help me?

Thanks!

Jason - you are probably on the right track by suspecting the filter condensors. Is this an olde tube type system or one of the early solid state units?
The filter condensors are not terribly hard to replace if you are handy with a solder gun and if you can still find the parts.

Bring it to the tug, you would be amazed at the talents that show up there. put the brand and model number (should be a tag on the back) in a Google search, and you will probably be able to find a diagram on line. Of that vintage the filter capacitor is probably a metal can mounted on the metal chassis. Looking underneath it will have 3 tams going though slots and twisted with one soldered to the chassis, and in the hole in the chassis you will probably see 3 or 4 wires soldered to it going to 2 or 3 different terminals. that is the filter capacitor, and probably one section is bad. values will be marked on the metal can. If you do not see that type can, the filter caps will be individual units wired to terminal strips under the chassis, and having a wire on each end. Markings on either one will be on the order of 250uf 50V. sorry, but I could not find a symbol for mu. You are bringing back memories of a former life that I would rather forget (working in a tv shop).

Bigdog wrote:Jason - you are probably on the right track by suspecting the filter condensors. Is this an olde tube type system or one of the early solid state units?
The filter condensors are not terribly hard to replace if you are handy with a solder gun and if you can still find the parts.

This is a very early solid state unit with Germanium transistors. The sound is very close to tube sound. Once they moved on to Silicon the sound went down the hole. I am mostly a tube amp dude myself, but I have to admit that my parents 64 and this 64 have a real cool tube like sound. My Mother's Mother still has her very early 60s tube unit, and that to me has the BEST sound. I am still convinced that nothing beats tube sound!

I have built a few tube amps in the past, but this is a bit beyond my skill set. However, I did manage to find a gentleman in Alabama who can go though the unit. I think he was a bit surprised that I understood how the filter capacitors worked. I am sure a lot of people who bring in their items have no idea of the technology behind it.

John *.?-!.* cub owner wrote:Bring it to the tug, you would be amazed at the talents that show up there. put the brand and model number (should be a tag on the back) in a Google search, and you will probably be able to find a diagram on line. Of that vintage the filter capacitor is probably a metal can mounted on the metal chassis. Looking underneath it will have 3 tams going though slots and twisted with one soldered to the chassis, and in the hole in the chassis you will probably see 3 or 4 wires soldered to it going to 2 or 3 different terminals. that is the filter capacitor, and probably one section is bad. values will be marked on the metal can. If you do not see that type can, the filter caps will be individual units wired to terminal strips under the chassis, and having a wire on each end. Markings on either one will be on the order of 250uf 50V. sorry, but I could not find a symbol for mu. You are bringing back memories of a former life that I would rather forget (working in a tv shop).

Finding a correct schematic for this model Magnavox is difficult. For one thing just because it is an Astro-Sonic does not mean that the one you find will match your amp and tuner. Astro-Sonics had several different amps and tuners based on what model console you purchased. Mine is the absolute top of the line. Remote control unit, automatic tuner with the push of a button, and the larger woofers and horns. The cabinet is the largest Magnavox I have ever seen. I guess this same cabinet was also used in the models that had a TV. Mine just has the Record Changer and AM/FM tuner. Before I found this one I never even knew they made ones with remote control.

This model has a few different types of filter caps. There are two cardboard tubes that come up from the amp chassis, and then a few in the chassis itself. Finding them is not that hard, but doing the solder work myself would be a bit of a pain. There are some pretty cramped quarters in both the amp and tuner that I am just not comfortable doing myself. However I did find someone in Alabama who said it would be no problem. He has 40 years of experience so he has about 40 years over me! I did a few tube amp kits back in college and am thinking about doing another. I would love to have a new tube amp for my home office HI-FI. This Maggie console is in my living room. I am still shocked how these units will fill a room with sound. Once it has been gone though I bet I will be shocked and amazed even further.

I just finished having all my 70's audio gone over by these guys. They brought my Sherwood receivers(2), Hitachi cassette deck, Philips turntable and 3 pairs of EPI speakers all back to life.
They came highly recommended, and I would do the same.
Their store location is just 2 minutes off the Morse Road exit of I71.
They do accept items shipped in.

STEREO LAB SERVICE and COLUMBUS SPEAKER
4532 Indianola Avenue
Columbus, Ohio 43214
Phone: 614-268-5500
Fax: 614-268-5584
http://www.stereolabservice.com/

My setup is, (much to my wife's consternation), as rockin as it was in 1977 ! It rattles the dishes in the china cabinet all the way from the basement !!
Tom Kent is even a little green over my gear and album collection !
"Far out man" !

Hope you get your Magnavox up and running !

Marion(57 Loboy) wrote:I just finished having all my 70's audio gone over by these guys. They brought my Sherwood receivers(2), Hitachi cassette deck, Philips turntable and 3 pairs of EPI speakers all back to life.
They came highly recommended, and I would do the same.
Their store location is just 2 minutes off the Morse Road exit of I71.
They do accept items shipped in.

STEREO LAB SERVICE and COLUMBUS SPEAKER
4532 Indianola Avenue
Columbus, Ohio 43214
Phone: 614-268-5500
Fax: 614-268-5584
http://www.stereolabservice.com/

My setup is, (much to my wife's consternation), as rockin as it was in 1977 ! It rattles the dishes in the china cabinet all the way from the basement !!
Tom Kent is even a little green over my gear and album collection !
"Far out man" !

Hope you get your Magnavox up and running !

Sounds good! I just shipped the items to Alabama yesterday, so I should be good to go in a week or so. I will post back what things sound like then. I have booked marked the site you posted. My Dad's system could use some work, and they would be much closer to them for shipping. I was lucky to find someone so close to me to ship to.

Very interesting read....I never even thought about the sound with tubes and this is the first I have heard anyone even mention it....looks like my 53 Seeburg model G high fedelity with seperate woofer and tweeter control will rock when she comes back to life.
Robert (too many projects) Miller

It has been a long time since I worked on this type equipment, but the old Germanium transistors conductivity would fall off over time like a tube. do not be surprised if they contact you and state that to bring it back to original levels it will require more than just capacitors. In other words, get the big check book out. For several years when I worked in a 2 way radio shop, and for a while when working for the phone company I ran a small business after hours repairing specialty audio equipment. I mainly did 2 types of equipment, the intercom, PA, and projection equipment for the local schools, and the high end audio for individuals. I live in a rural low income area and the school budget was pretty tight, and I did their work for practically nothing. A number of people would go to the city (no internet back then) and buy high dollar audio and radios, then when they failed (they were much less reliable than everyday gear) they could not find anyone to work on them, so I repaired their gear and charged them enough to cover the repairs on the school equipment.

dakcub wrote:Very interesting read....I never even thought about the sound with tubes and this is the first I have heard anyone even mention it....looks like my 53 Seeburg model G high fedelity with seperate woofer and tweeter control will rock when she comes back to life.
Robert (too many projects) Miller

Yep sure will! You would be surprised of the sound of a good tube amp vs the newer solid state units. There can even be a huge sound difference between the early solid state units and the later solid units. All all depends on the transistors used.

You would be surprised at the differences in sound. When I grew up, my first stereo was an RCA Victor console that my parents gave me when I was about 15 or so. They upgraded to a much newer solid state unit. The sound that came from the tube amplifier in that Hi-Fi was outstanding compared to my parents new solid state Grundig with an outboard turntable and Sony reel to reel. I loved that old RCA. When I went to Inuvik, well there wasn't much there. There was a really good audiophile shop surprisingly. I bought a Pioneer 9000 series amp, tuner, cassette, equalizer and turntable. Cost me a bundle along with some really cool JBL speakers. I also added a pair of AKAI GSX reel to reels... which are simply awesome. However, no matter how much I played with this setup I could not get the mellow full bodied sound that I was used to on the RCA H-Fi. The only time I have ever been able to equal the sound of that RCA unit was when Em and I were posted to Lahr in W Germany back in the early 80's. We had a Grundig Stereo console complete with turntable, tuner, amp and reel to reel tape deck which was also a tube unit. The sound that came out of that was like listening to the Moody Blues live at the Royal Albert Trully full bodied sound.

I still have much of my solid state stuff from the 70's along with my Uncle's Marantz Quadraphonic amp which I want to set up again. My Technics stereo just isn't the same quality as the solid state 9000 series from the 70's, and is not even in the same aural class as the tube units, even though it was one of the best available at the mid 80's period.

I have some really cool tunes .. I have a very large vinyl collection as well as mag tape.. and it is about time I start putting that all back together again. It is amazing at what you put away/aside when you have kids

Surprisingly as well, I have an almost full Yaesu FT-101E series HF Transceiver in my ham shack. The quality of the tone and body of the audio amp section is far superior to pretty much any of the completely solid state gear around. The FT-101 series was partially solid state with vacuum tube in the finals and the audio section. My old RCA AR-88 superhet HF receivers are also top notch.. I much prefer them to solid state HF receivers. Vacuum tubes have much going for them and I am glad that there is still parts available for these old units.

The reason I started looking for a Magnavox was I had a bunch of vinyl and 78s I could not play. My parents have a 64 but of course they are not willing to part with it now, so I had to find my own. As luck should have it I found a good rare one! Right now things are in the techs hands so I just have to sit and be patient. I love doing things myself, but this one was beyond my skill set.

CANNOT BEAT TUBE SOUND! I plan on purchasing a tube amp kit just to play round with. Maybe I will build another set for the living room. Never hurts to have more then one set.

I remember all the complaints in the stereo magazines when CDs first came out. They said the sound quality was really harsh. Using a tube amplifier was supposed to improve it a lot.
Someone gave me a broken 1955 Zenith console TV when I was going to electronics school in the mid 80s. When got it working, it had the best sound quality I've ever heard on a TV. It had one 10" speaker, and you could hear it clearly all over the house. A very rich and smooth sound.
A genuine 'hi-fi' stereo from that era must have been awesome...

Ronny Bailey wrote:I remember all the complaints in the stereo magazines when CDs first came out. They said the sound quality was really harsh. Using a tube amplifier was supposed to improve it a lot.
Someone gave me a broken 1955 Zenith console TV when I was going to electronics school in the mid 80s. When got it working, it had the best sound quality I've ever heard on a TV. It had one 10" speaker, and you could hear it clearly all over the house. A very rich and smooth sound.
A genuine 'hi-fi' stereo from that era must have been awesome...

They were, and are!

Well I have the radio back and have to get the cabinet done for install. As soon as I have everything in I will update on what it actually sounds like. From what I understand they had to replace about 30 capacitors. I think the job was much bigger then the guy thought it would.