astro sonic trebel issue

Hi, I have a 1966 Astro Sonic and I have to turn the trebel all the way up to have the sound decent. I know little about repairing these things, but certain I could do it. Does this sound like a easy fix and anyone know what part it cold be?

Well, an "easy fix" question is always a stop sign to me--
If one has invested in the education, and test equipment necessary to fix this (or any) problem, it COULD be "easy"---I have fixed a whole lot of electronic problems in the last 40-50 years, but I don't think I would tackle this one, as I have never seen the Astro Sonic insides, nor do I have the schematic that I would need to figure out what is going wrong. My "easy fix", would be to locate a qualified repair person, and get it done right--the 1st time.
Without appearing as too much of a smart arse---I suggest that--Since you are in SF, there is a Palm Reader, who's sign, in the front window, I have seen on 19th and about one, or two blocks, north of Sloat--she might have the answer ??
Ron Rich

I totally agree with Ron.
And being an experienced tech, and having worked on Astrosonics, I cannot possibly advise on what the issue is, from 3000 miles away.
No one could, over the internet.

But I bet ya that the ton of websites and blogs out there are full of "mechanics" just waiting to spew their uneducated opinion on what the problem is.
I read such garbage mainly for amusement.

Normal deterioration of some components naturally happens over decades.
That is a fact.
So as Ron mentioned, the best solution, and also the time-tested one, is to have a tech knowledgeable with the Magnavox line, do the needed and proper restoration procedures.
Just be sure the tech is reputable, and not one of those online gold-diggers or tinkerers - they'll slop up your set real fast.

It's funny how this topic, more than any other involving these old consoles, keeps coming up.

I have a set of schematics for the 1965/66 models that have AM-FM-Phono. If you P-M I'll upload them and send links.

These machines were designed at a time and for a market that regarded a bassy, "plush" sound with a recessive treble as "Hi-Fi".

I remember these sets as a kid. My Grandmother had one as did her neighbor, along with the ones I heard in the showroom at Bloomingdales all had the same sound. Even though I liked it as a kid (and later bought one) I knew by comparison with the Fisher, A.R. and KLH systems we had at home that these sets were not exactly accurate.

I rebuilt and modified my 1965 magnavox in Jan 1990. I did a full set of alignments on the tuner and plotted the response of the amp section.

The amp's treble response while it has the typical somewhat tinny-zippy high end of early transistor amps, the overall response is OK. The rolloff occurs mostly in the speaker system

The horn "tweeters" used are really only effective as midranges and they are also "padded" (attenuated) in the simple crossover used.

If your set has terminals for external speakers as mine does, connect a set of speakers that you are familiar with and see how it sounds. Be reasonable with volume levels as there is only about 8 watts/rms per channel.

You'll probably find that the tuner sounds reasonably good but the phono is dull.

These mass market sets all used a mediocre ceramic phono pickup and that along with the fact that most people would not bother to connect a decent FM antenna led manufacturers to try and cover up these deficiencies with filtering the treble where most of the resulting distortion occurs.

With a bit of work you can greatly improve these sets, but taken as-is you are looking into the world of mid-sixties mass produced, hi-fi.

Rob/NYC

gbhumphrey wrote:Hi, I have a 1966 Astro Sonic and I have to turn the trebel all the way up to have the sound decent. I know little about repairing these things, but certain I could do it. Does this sound like a easy fix and anyone know what part it cold be?

Yes Rob, the bassy sound was a selling point of older consoles.
Meant to define a sense of "power" against the average table radio - and impress the potential customer into buying one.

Yes, that was "hi-fi" back then.

I never did like some of those Magnavox speakers - the metalic "ring" of those famous "1000 cycle" horns gave me a headache.
Like running fingernails down a chalkboard.
I much preferred a dome/cone type tweeter for their smoothness and sparkle.
Back in 1972 I landed my first decent speakers - the Smaller Advents, and had them for a long time.

And yeah, most anything can be "upgraded" to provide better performance, as long as it's done right.

I can think of two easy checks.

Did some kid turn the sound all the way up and blow the tweeters?

Are the electrolytic nonpolarized crossover capacitors bad?