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Best Tube Radio You Ever Owned/Tuned

Steve Green NEPA

Steve Green NEPA

I'd have to say it was one of my buddy's radios. His Dad owned an electronics repair shop,and my pal got to DX off a few refitted tube radios.

I'd say
a) American Bosch.
Incredible selectivity. We'd get things like 1470 from Connecticut all day despite being pretty near the main beam of local WHOM 1480.

b) Atwater Kent AM-SW.
I knew little about selectivity/sensitivity when I spun the dials on this earlier gem. But it separated ZMB1 1235 Bermuda very nicely from adjacents 1230 and 1240, and had the best frequency determination I ever had the glee of exploring. Every AM frequency and many short-wave spots had each frequency demarcked with a small and accurate slash.

Am fuzzy about the age of either. Let's say mid- late-Forties.
The Atwater-Kent used a longwire, and the Bosch used an outdoor diamond loop.
 
My 1959-vintage Hammarlund HQ-145 was probably the best tube radio I ever owned. In fact, it was the only tube radio I ever owned. ;D

Seriously, it worked fantastic on the AM and lower shortwave bands, not so great above 12 MHz. Excellent audio quality, decent selectivity (one crystal with a phasing control that actually gave decent single-signal reception on CW and SSB), and a decent "feel" typical of all the Hammarlunds of the time. Excellent AM broadcast reception, even with the 20-foot indoor dipole fed with TV twinlead that I used back in the early '70s.
 
Fisher AM-80 tuner - still amazes me with its sensitivity.

Hammarlund SP-600JX - the extra tuned RF stage makes this one the hottest AM / SW receiver I have ever owned.
 
It used to be that tubes would amplify and oscillate only up to a certain frequency. Even transistors had their limits. In later years that increased with tubes designed for VHF and UHF frequencies. I think one problem was that tubes that were electrically more than a certain percentage of wavelength in size would start to radiate harmonics that got into other stages. Tubes got smaller before solid state took over.

My favorite tube radio is a Westinghouse table radio from 1938 that was in the family. I hooked up a 100+ foot long wire antenna to it. The first time that I ever heard KPMC Bakersfield, now KNZR, was on that radio. It was after WQXR, now WQEW, signed off at 12:07 AM. The radio sounded great. It has an electromagnet speaker. Any suggestions on replacing capacitors would be appreciated. Would just replacing the filter capacitor be enough to have it not blow up? Should I get a VARIAC and slowly build up the voltage? The filter capacitor was leaking years ago.
 
I never owned anything that high-end. I did have a late 1940's model RCA tabletop
five-tube that could really pull 'em in. Sounded great too (still have it but have not
fired it up in some time)
 
The best tubed radio I owned was a 1937 vintage RCA, Model ACR-111. That monster had 16 tubes in it and covered 540 kc to 32 mc. It was a true Communications Receiver that weighed a ton. I used it mainly for Broadcast Band DXing when living in Southern California in the early 1960's. The antenna was just a random length of wire in the backyard. Some great DX was had with that rig including Australia (2NR) and Japan (JOIB) plus several Hawaiian and Alaskan stations. WLS from Chicago came in like a LOCAL every night, not to forget all the 50kw Clear Channels of the period. I got that radio from a high school classmate whose grandfather was W6AA, one of the earliest hams in California. In the late 60's, while in college, I was forced to sell it to pay bills! I wish I still had that beast!
 
A McIntosh MR-55A AM/FM Tuner (16 tubes).

The AM section had 15 µV sensitivity, selectable audio bandwidth down 3 dB at 2 kHz, 6.5 kHz or 9.5 kHz, and a 10 kHz adjacent channel carrier notch filter with 70 dB rejection.

WJR AM and FM simulcasted back in the 1960s. The MR-55A dial scales were such that 760 kHz and 96.3 MHz were at the same physical location on the scale. Switching tuner modes for WJR between their FM and their AM at 9.5 kHz audio BW gave a nearly instant comparison of the two, with nearly identical audio.

Listening location was a basement apartment across Lothrup Street from the Fisher Building, Detroit (the studios/offices of WJR), and about 16 miles from the WJR AM transmitter site.. The AM antenna used was a 20 ft piece of hookup wire in the room, and the FM antenna was 30" of hookup wire.
 
Schroedingers Cat said:
Any suggestions on replacing capacitors would be appreciated. Would just replacing the filter capacitor be enough to have it not blow up? Should I get a VARIAC and slowly build up the voltage? The filter capacitor was leaking years ago.
Click to expand...

Reviving an old tube radio can be risky business. First and foremost, put your own safety ahead of the radio. Better for it to be destroyed than you get injured.

Bringing up the voltage slowly with a variac is highly recommended. If you don't have one, you can make a fixture using a light bulb socket and various wattages of light bulbs - until the government makes it impossible to buy bulbs of differing wattages, I think 100W are already gone, I don't know about 75W and 60W. I skipped CFLs and went straight to LED, but that is off-topic. The principle of the multi-light bulb fixture is to allow you to have some impedance between the wall outlet and the radio. If all the power is dissipated in the bulb, then it is a safe bet the radio is shorted, or the secondary of the transformer is shorted through the cap.

I am not a purist. For me, when it is anything running off AC - my philosophy is to make it safe by putting in the latest technology in capacitors. You can replace the filter cap, which is usually multi-section, with good axial lead single value capacitors. I just mount under the chassis, because they are usually much smaller than the dried out multi-section they are replacing. I leave the old multi-section cap in place on the chassis for looks only, if I took it off there would be an ugly hole where it went. I replace all the old wax paper foil capacitors with a newer technology film capacitor. They are usually a fraction of the size and are much better. I resist replacing wax paper foil with ceramic, because the old caps have a shielding characteristic ceramics don't, but occasionally if a cap was dropping from a tube socket pin to a lug on the chassis, it is OK. Its a bit of a judgement call, plus a little experience with this sort of thing. Resistors are another matter - I don't just jump into shotgunning old carbon resistors for metal film, but be sure to measure them. If they have changed over time and are out of tolerance, it is better to replace them.

I have a controversial mod that I do - I find that my old tube gear works better if I get rid of the old rectifier tube and use a couple of 1N4007's instead for the rectification. I just leave the tube out of the socket and wire the diodes directly to the tube socket pins. The issue here is that the B voltage is usually a bit higher than it was before, but I've never had a problem. The tube gear warms up better.

I also modify tube gear I use a lot so the filaments are always heated. This wastes some power, but the equipment powers up immediately. And it extends tube life - filaments burn out when power is cycled a lot. They last a lot longer if always lit. Old CRT televisions worked that way, the filament was always on. Better to waste some power than replace a CRT. CRT televisions virtually never lost a picture tube due to filaments burning out.

There are some oddball components in tube gear, multi-plate high voltage rectifiers, chassis mounted power resistor ladders, etc. All can be replaced with more modern components like a diode for the multiplate rectifier and a string of resistors for one of those tapped chassis mounted power resistor ladders.
 
I'd say the two best I've owned are a Hammarlund HQ110 and a Scott Philharmonic. The Scott could do 50 Hz - 15 kHz and had about 30 tubes. It also had a downward expander and a peak unlimiter!
 
Thanks for the information rbrucecarter.

I actually ordered a schematic a few years ago, so I can look at what the filter capacitor value(s) are. I used the thing right up into the mid 1980s until I got married and the thing hasn't been used since. Someday, I may have more time to work on it.

My wife bought me this old Farnsworth console that had been somewhat restored, but some of the fixed trimmers soon went bad in the oscillator section and are intermittent. Bangs in the audio as it goes out of tune, but nothing serious. It has six presets, which is good because the variable capacitor either shorts out from a bent plate or has metal whiskers that short it out below a certain frequency around 1100 kHz. I cannot see what it shorting it, and got the schematic but I need time to take it apart to see what's wrong. I got some ceramics at RS to replace the trimmers but never had the time to put them in. Any suggestions on those? It changes frequencies when the trimmers go out, that's how I know it must be in the oscillator section, though I guess it could be in the IF section. If it were in the RF section, it would just get less loud I would assume. As they heat up, I assume that the lead pulls away from the plate of the capacitor and efectively takes it out of the circuit.
 
Schroedingers Cat said:
Thanks for the information rbrucecarter.

I actually ordered a schematic a few years ago, so I can look at what the filter capacitor value(s) are. I used the thing right up into the mid 1980s until I got married and the thing hasn't been used since. Someday, I may have more time to work on it.

My wife bought me this old Farnsworth console that had been somewhat restored, but some of the fixed trimmers soon went bad in the oscillator section and are intermittent. Bangs in the audio as it goes out of tune, but nothing serious. It has six presets, which is good because the variable capacitor either shorts out from a bent plate or has metal whiskers that short it out below a certain frequency around 1100 kHz. I cannot see what it shorting it, and got the schematic but I need time to take it apart to see what's wrong. I got some ceramics at RS to replace the trimmers but never had the time to put them in. Any suggestions on those? It changes frequencies when the trimmers go out, that's how I know it must be in the oscillator section, though I guess it could be in the IF section. If it were in the RF section, it would just get less loud I would assume. As they heat up, I assume that the lead pulls away from the plate of the capacitor and efectively takes it out of the circuit.
Click to expand...

Your tuning capacitor likely opens up at the bearings when you rotate it lower in frequency. Removing the cap from the radio can be tricky, but if you do you can soak it in solvent, then address each issue individually. The best place to make contact is a leaf spring that contacts the shaft. If you can unsolder it and take it loose, clean it with a pink eraser. There may be a conductive component in the dust. I would resist the temptation to blow it out with compressed air, as compressors are capable of seriously bending tuning capacitor plates with 100 psi or more. If you can regulate the pressure down to 30 psi or less, then it is probably safe to use compressed air.

If by trimmer caps you are talking about the little trim sections on the tuning capacitor, they cannot be replaced by fixed ceramic capacitors. Any ceramic capacitor you use for fixed values should be NPO / COG dielectric, not X7R. If you think the trim capacitors are really bad, you can strip off the screw, brass spring, and mica, but you should have a very good trim capacitor to replace it with. Some are ceramic based with metallization on them, and will work well. If they don't offer enough range, you can add small fixed ceramic capacitors in parallel to get the range you need. Also - if you can find silver mica caps, they are excellent for working on front ends.
 
To Schrödinger’s Cat

I agree with rbrucecarter5’s comments, especially about safety. I think you may know most of this already but I’m passing it along in case someone else is reading this thread.

If it is original, your radio has neither a grounded power plug nor a fuse. A 1938 table radio may or may not have a power transformer depending on the model. Some of the inexpensive (5 tube) sets were commonly called AC/DC or All American 5 and they do not have a power transformer as they are powered directly from the AC power mains. Some of them used a resistance wire as part of the power cord to drop the voltage for the series filament string.. The chassis, including the volume control and tuning control shafts of these sets may have 120 Vac that can bite you depending on how the plug is plugged into the wall outlet. The external wire antenna is another source of electrical shock depending on the condition of the radio and polarity of the power plug.

Old electrolytic capacitors, even if they seem to be good, can fail. If your set has a power transformer, a filter capacitor failure may destroy the transformer. Not good. Even if the electrolytics were replaced years ago, they are likely to be not up to snuff today.

Recommend at a minimum, you replace the filter capacitors.

Other capacitors and resisitors may need replacement but you may be able to get the set to “play” without replacing multiple components. Also, the tubes, if they were working properly when the set was removed from service, are probably OK. Tubes that test weak on tube testers will still function in most sets. Your radio probably has rubber covered wire which most likely is cracked and brittle. Be careful.

I use a Variac and have found that tube equipment will power up and operate with 80 volts out of the Variac. The set will warm up slowly and not be as loud as it could be but if everything is working, it should “play” at 80 or even less volts. Bringing up the set slowly with a Variac may help you determine the condition of the set but I would not power it at the full 120 volt power line voltage without taking care of the filter capacitors.

Have fun and let us know how your Westinghouse set is doing.

-Bill
 
If you are going to replace the capacitors be sure to check the working voltage of the caps. HV capacitors are getting difficult to find.
 
hammarlund sp-200. Talk about overbuilt. Woulda kept it, but it was a wartime model that only tuned down to ~1230 khz.
 
Philco 116-X from 1936. Liked it so much I bought another to put on the other side of the fireplace, so I'd
have "matching" stereo audio if I ever get around to making a Kahn-type AM stereo transmitter.

I have some ideas for doing this using 262.5 khz IF transformers and mixing up to the desired frequency.

If there's another contender, it would be the Collins R-390A. I have to get off my butt on this one and
figure out if it was the filter caps that munched the 26Z5 rectifiers.... I miss using this radio and the teletype machine.
 
A friend of mine recently gave me a Hallicrafters S-38E.
So far I haven't done much with it (haven't even hooked up an antenna) but I heard 1070 KNX with it moderately well, from about 111 miles away, at midday.

There's also my bro's Hallicrafters S-53A sitting on a shelf in my room currently, and my parents have a Zenith K731 as well. I haven't used either of those much, recently.

I think I'd really like to get my dad's Stoddart NM-20A working again, though. I wonder how good of a tube radio THAT might be, if it's properly serviced, and how tough it might be to get it up and running?
 
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