McMartin AM tuner

[Studio1]

McMartin made a fixed frequency AM monitor - AM-1 or AMR-1 or such number.

Anyone know where I can find one?

 

[RadioMan203]

I saw one a handful of months ago on ebay - wouldn't you be better off with a newer tuner that isn't 30+ years old?

 

[BobOnTheJob]

I saw one a handful of months ago on ebay - wouldn't you be better off with a newer tuner that isn't 30+ years old?

Don't write off the McMartin too quickly. It had a wide enough AM bandwidth that it sounded better than virtually anything made today. Still, it's a McMartian...a fact that can't be totally ignored.

 

[Studio1]

Yeah, I've been watching Ebay...

I don't want it - I'm just enquiring on behalf of a tech associate who doesn't have internet access..

I'd probably just use a Technics tuner, for what it's worth.

 

[greg.hahn]

I saw one a handful of months ago on ebay - wouldn't you be better off with a newer tuner that isn't 30+ years old?

Don't write off the McMartin too quickly. It had a wide enough AM bandwidth that it sounded better than virtually anything made today. Still, it's a McMartian...a fact that can't be totally ignored.

They do sound good, but I had some trouble at a station with an AM transmitter on-site. My station was 1330 at a kilowatt, and my EBS primary relay station was on 1440. I could never reliably get my own audio completely out of the EBS receiver.

 

[RadioFixerCLE]

I saw one a handful of months ago on ebay - wouldn't you be better off with a newer tuner that isn't 30+ years old?

A lot of the older analog tuners were just better built than most of the new gear available today. Not to mention they allowed for fine tuning.

If the 30 year old tuner is of good quality, what does it matter how old it is?

 

[greg.hahn]

I saw one a handful of months ago on ebay - wouldn't you be better off with a newer tuner that isn't 30+ years old?

A lot of the older analog tuners were just better built than most of the new gear available today. Not to mention they allowed for fine tuning.

If the 30 year old tuner is of good quality, what does it matter how old it is?

Well no, Stephanie, if it's of good quality I don't think it does matter how old. But my argument is that the old McMartin wasn't that great.

And it had no fine tuning at all. It was crystal controlled with no provisions to change it to a different station. This was a single rack-mount beige box with a fake woodgrain face. It had absolutely nothing on the front except an on-off switch and MAYBE a red LED to show it was turned on. (But I remember the on-off switch lit up, so probably it didn't have the LED.)

On the back it had a BNC connector for the antenna and a terminal strip for the audio. That's IT!

And I'm betting the bandwidth was wide enough that stations now transmitting HD would sound as bad as any Chrysler!

I'd try a CCRadio from C Crane company. In fact..I have tried that and it works great as an EAS receiver for AM.

 

[RadioFixerCLE]

Greg, Ahhh.... OK. Yeah, I was picturing something along the lines of an old Pioneer or Marantz with the big fly-wheel knobs.

Now that I picture what you describe, I take back my comment.

 

[greg.hahn]

Greg, Ahhh.... OK. Yeah, I was picturing something along the lines of an old Pioneer or Marantz with the big fly-wheel knobs.

Now that I picture what you describe, I take back my comment.

No take back necessary... your point is actually well taken.

 

[RadioMan203]

I saw one a handful of months ago on ebay - wouldn't you be better off with a newer tuner that isn't 30+ years old?

... If the 30 year old tuner is of good quality, what does it matter how old it is?

As mentioned before me, McMartin wasn't the greatest product line out there. I remember being at a station in Massachusetts and the McMartin EBS system going on the fritz ... every time the jock opened the mic the system would randomly go and unmute. Not exactly the thing you really want to happen.

The other thought when I made my comment was that the unit should be rehabilitated with new caps before being returned to service.

 

[NoTimeForSleep]

McMartin made a fixed frequency AM monitor - AM-1 or AMR-1 or such number.

Anyone know where I can find one?

It is the AMR-1 receiver. Had one, but it worked better as a doorstop then it did at picking up a 50K about 12 miles away.

 

[Studio1]

McMartin made a fixed frequency AM monitor - AM-1 or AMR-1 or such number.

Anyone know where I can find one?

It is the AMR-1 receiver. Had one, but it worked better as a doorstop then it did at picking up a 50K about 12 miles away.

I'll pass your thoughts on to my associate. Having seen what the McMartin FM mod monitor looks like inside I sure wouldn't want any of
their other 30+ yr old stuff.

 

[greg.hahn]

McMartin made a fixed frequency AM monitor - AM-1 or AMR-1 or such number.

Anyone know where I can find one?

It is the AMR-1 receiver. Had one, but it worked better as a doorstop then it did at picking up a 50K about 12 miles away.

Oh see now I never had that problem. I had another one of these units that picked up WHAS, a 50 K that was about 40 miles away (I was in southern Indiana) and it totally worked great. But no AM RF field within several miles of me.

I agree with the guy that said you must recap it. The caps in the originals weren't that good.

And the unmute problem. I remember that too. Had the same issue, but I don't remember why that happened, just remember it did.

 

[Freq Band]

(first post on this forum)

Maybe I'll give this tuner a go....see what results I get.
I just got one, $5.

http://i5.photobucket.com/albums/y177/Midiot/DSCN2912.jpg

I'll re-cap it first thing. I have no experience with AM tuners, but I do have a full home electronics lab though.

Maybe someone can tell me a few things...
1) How do I set the receiving frequency? (see pics linked below)
2) recommended antenna ?
3) this unit connects directly to my (50 ohm) hifi preamp inputs, correct ?..... or do I need to match impedance somehow ?

http://i5.photobucket.com/albums/y177/Midiot/DSCN2913.jpg
http://i5.photobucket.com/albums/y177/Midiot/DSCN2916.jpg

I live in Los Angeles, w/some surrounding foothills. I'd like to tune to 640 (KFI).
Thanks...

=FB=

 

[Freq Band]

http://i5.photobucket.com/albums/y177/Midiot/amr1_fmr5_datasht.jpg

=FB=

 

[littlejohn]

McKay - Dymek used to make a nice line of AM tuners which were fairly widely used as monitors. You might find one for cheap on eBay.

 

[Freq Band]

I said, "I'd like to tune to 640."
Lo-and-behold, I noticed a stamp on the unit's exterior marked, "640.00".
Go figure the luck ?
(haven't fired it up yet)

Here's what a web-friend "PRR" posted on another forum:

> I want AM

WHY???

I'm not just being wise-ass. In most civilized areas, AM radio means major compromises. What you want AM for determines what the radio must do.

As sad as they are, the general run of $2 AM radios do about as good a job as is possible. You need some special situation to do better.

If you are "close" to a strong station, a wide-band AM tuner can reveal a spectacularly faithful reproduction of what they put in the transmitter. Much more treble than you expect. Can't avoid the fact that most AM today is grossly over-compressed. That's the only way they can keep their business going.

If you are far out in the desert, and want to pull Denver or L.A., you want a decent antenna, ample gain, and lots of selectivity, to the point that you don't hear anything over 3KHz.

If you are near town, and "your" station is not very much stronger than others, about the best you can do is a little gain and a LOT of filtering to knock the crap down. Any non-junk $2 radio will do that. (Yes, there's some real junk on the market.)

I spent several years tweaking on a golden-age Stromberg-Carlson.

In my suburban area, antenna and gain were non-issues: a loopstick or 2 feet of wire pulls-up more noise than you know what to do with.

Wide-band opens up the treble, but also opens up monkey-chatter from every adjacent-channel station in the US and Canada (and Mexico too, if the Canadians weren't overwhelming Mexico in my area).

And you can't avoid the fact that AM does not lock to a signal(*), so you get every same-channel station underneath the one you want. (There are no "clear channel" allocations any more: one former clear-channel broadcaster in NYC now has 17 other western hemisphere stations on the same channel, from 25 watts to 25KW.)

(*)Actually, a synchronous detector can give some AM lock-in. My father the old-time radio geek didn't believe it at first, because sync-det was just way-difficult back when AM was king. It is still a very difficult problem. The only practical answer is a chip. Maybe someone has done that. I notice that none of the marketed radio chips do anything fancier than ceramic filters and a buffered detector.

> Is it possible to build a "higher quality" AM band receiver, than I can buy?

If you have a Strong Local Station, a crystal radio will give great results, and is certainly a DIY thing. Understand that most listeners don't want quality, so the broadcaster hammers-up the sound to stop them in their tracks. You'll mostly hear how modern broadcast limiters can slam everything into a 3dB dynamic range without getting fuzzy.

A TRF with a large (10 foot) loop can give sharp sound a bit further out, but parts for a TRF are hard to source. If there is ONE station you want, it is maybe doable. But tuning a 3:1 band is hard work even if you can find the gang-caps.

People DIYed superhets, but it seems to be a lost art. And certainly you can't get the parts without scavenging a radio, you can't get the good parts without scrapping a good radio, and it is surely easier to fix the radio than re-engineer it.

I've heard the GE and Tivoli are good. These and the Golden Oldies are surely better bets for all-round AM use than any DIY except a crystal set.

(In Los Angeles) sensitivity and antenna are nearly non-issues. Aside from the universal earth-made static, cities are full of man-made noise, and also chock-a-block with AM signals. And even in sprawling LA, you can't get very far from a transmitter, or at least you have a choice of nearly equivalent programs from near and very-near towers. A foot of wet macaroni will pull enough atmospheric noise (and signal) to overwhelm the worst input stage's self-noise.
PRR

 

[greg.hahn]

(first post on this forum)

Maybe I'll give this tuner a go....see what results I get.
I just got one, $5.

http://i5.photobucket.com/albums/y177/Midiot/DSCN2912.jpg

I'll re-cap it first thing. I have no experience with AM tuners, but I do have a full home electronics lab though.

Maybe someone can tell me a few things...
1) How do I set the receiving frequency? (see pics linked below)
2) recommended antenna ?
3) this unit connects directly to my (50 ohm) hifi preamp inputs, correct ?..... or do I need to match impedance somehow ?

http://i5.photobucket.com/albums/y177/Midiot/DSCN2913.jpg
http://i5.photobucket.com/albums/y177/Midiot/DSCN2916.jpg

I live in Los Angeles, w/some surrounding foothills. I'd like to tune to 640 (KFI).
Thanks...

=FB=

I'm trying to figure out what is that greenish cylindrical thing with the square ends? It's right next to the screw hole above the rear terminal strip.

Connect it to your hifi inputs. They aren't 50 ohms, more like 10K. But that's a good thing, because this box wouldn't like 50 ohms.

Glad it's already on 640, otherwise we'd be guessing between L1 and L2 for the local oscillator. My guess would be L2.

 

[Freq Band]

I'm trying to figure out what is that greenish cylindrical thing with the square ends? It's right next to the screw hole above the rear terminal strip.

It's a reed relay.

Thanks for replying.

=FB=

 

[greg.hahn]

I'm trying to figure out what is that greenish cylindrical thing with the square ends? It's right next to the screw hole above the rear terminal strip.

It's a reed relay.

Thanks for replying.

=FB=

Of course, the carrier fail relay! Thanks for answering that. It's so funny to see that box after all these years. Thanks for the pictures.