Look what crawled out of the woodwork...

[VintagePC]

Originally Posted by wa2ise

Sounds like me when I paid a wad for this Aussie tube radio, a Tasma 1001 Baby. Love the looks. And the little map of Australia in the center of teh dial is cool. And the fact that I didn't spend much on old radios in the past several months let myself spend the bucks. It was already restored, though I replaced a resistor to improve reception a little (a screen supply to the 6A8 and the IF tube drifted high, feeding too low a voltage and made local strong stations distort too much). It's happy with American 240V@60Hz, which I ran a special circuit from the breaker panel to a very old American made Aussie pattern outlet

If memory serves, you can easily run 50Hz equipment on 60Hz. The problems occur when you try to do it the other way around - the 60Hz transformer doesn't need to be as beefy for a given wattage, and is incapable of producing sufficient power at 50Hz.

[zenith2134]

That's correct, 60Hz will handle 50Hz in most cases (i.e., if the supply is at all adequate for its intended purpose)

[Steve D.]

I like that Sparton. Not a real common brand. Looks like a nice clean full door console. You might take a chance and power it up on your visit. If there's no snap, crackle or pop and the picture tube provides a raster, quickly unplug it and buy it. You only live once, so enjoy.

-Steve D.

[electronjohn]

You said you had access to a Variac...why not whip up a dim-bulb tester to bring along? Something you'd probably use in the future as well.

[maxhifi]

Originally Posted by VintagePC

Agreed.
I'll keep you folks posted on any developments. In my case though, it's 'beggars can't be choosers'... been wanting to get in to TVs since my tube radio project, and have seen exactly zero for sale within the area since then. I'd be satisfied with owning just one... so if the price drops within my means, you'll see a resto thread on it shortly.

I was thinking the same way... a year ago I had an old tube colour TV I acquired nearly 20 years ago, and came to this site wanting to repair it. In day to day life, it's very rare to see an all tube TV around here, too. (Edmonton Alberta, Canada)

Started keeping my eyes open (and reading all about TVs on here nearly every day), and now I have 5 all tube tv's, including the original one. They are out there! That said, considering you'll likely spend dozens and dozens of hours working on it, if you value your time, I don't think spending a bit more up front for something nice is a bad idea. (think old cars) Just make sure you buy one you actually want, and not because of rarity... they are large, and hard to get rid of.

[bandersen]

I say go take a look at it too. Maybe you can negotiate a lower price ?

One bit of warning though. If the CRT is bad, replacements for those early 16" CRTs (16KP4/16RP4/16TP4) can be a little hard to find.

[wa2ise]

Originally Posted by VintagePC

If memory serves, you can easily run 50Hz equipment on 60Hz. The problems occur when you try to do it the other way around ....

To a first order approximation, the higher the frequency the smaller and less turns you need for the primary and secondaries for the same voltage. A 50Hz transformer running at 60Hz can take a higher input voltage before its core saturates, roughly 6/5 higher. But a 60Hz transforemr run at 50Hz can take only 5/6 the input voltage, unless it was overdesigned with enough margin to avoid care saturation. Sometimes you find a power transformer made for 25Hz, it can take 12/5 higher input voltage (assuming the insulation inside it can take it, especially the B+ windings). But if you do that, all the secondaries will have proportionally higher voltages too. Sometimes you find mil surplus equipment that was used in airplanes, and airplanes used 400Hz, speciffically to keep the weight down. You cannot use those power transformers on regular 60Hz, unless you only apply about 18V to the 120V@400Hz primary. 60/400 And the secondaries will also deliver only 6/40 as much voltage, not too terribly useful...

[old_coot88]

When i was 15 i built 50 watt CW transmitter from the schematic published in a Heathkit catalog, then decided to Heising-modulate it (plate modulate the final) for voice. Used a pair of 25 cycle TV power transformers hooked back-to-back (primary to primary), with the HV winding of the first tranny run by push-pull 6L6s, and the HV winding of the second tranny in series with B+ feeding the RF final stage (two 6DQ6s in parallel). The trannys had pretty sharp rolloff above 5 kc (kilocycles in those days), ideal for voice while keeping the bandwidth tight. The modulator was on a separate chassis from the transmitter, with its own power supply.
At that age i didn't understand about core saturation but apparently the big trannys avoided it, as the rig ran spectacularly well and the modulation envelope scoped at 70% with no sign of clipping.

[VintagePC]

I'll definitely see about going out to take a look - I haven't heard back from them since the initial response.

[Penthode]

My RCA TV was made in Canada in the late '40's. Toronto hydroelectric power from Niagara was still 25Hz and radios and the earliest Canadian TVs had to contend with large transformers.

I photographed the mammoth 25Hz power transformer of my RCA 8T243. The set was built in Montreal in 1949 and is claimed to be the first television manufactured in Canada. Certainly, it was the first RCA television made in Canada. The set is essentially the same as its Camden counterpart except for the power supply and the Video IF transformers. Note the Canadian sets had brass threaded screw adjustments and the Camden sets had threaded ferrite slugs.

TV broadcasting did not begin in Canada until September 1952, when CBC stations CBLT (Toronto) and CBMT (Montreal) commenced. My set from Toronto would have initially been tuned to the sole signal in the area, WBEN (Buffalo Evening News) channel 4, which then carried NBC, CBS and DuMont programming.

Note also the label which was affixed to all Canadian TVs until about 1953 warning forfeiture by His/Her Majesty if you did not pay the licence fee.

[VintagePC]

Whelp... this journey is at an end for me. I tentatively ran the idea of acquiring a tube tv by the house "management". This was the almost immediate answer:


Boy, do I need to find my own place soon... hehe.

[Sandy G]

Sorry to hear that-I was looking forward to yr purchase & restoration of said Sparton...I'm sort of the same situation as you are in a way-There ain't DIDDLEYSQUAT for old TVs here...We didn't have a local station til '54, so you virtually NEVER see an interesting REALLY early set "In the Wild"...About the best you can hope for is scoring the odd RCA "8PT" style set from '56 or so...MAYBE a beat-to-Sh!t old color roundie...But that's about it.

[Electronic M]

Penthode, that transformer looks be bigger than the CRT!

VintagePC, I laughed so hard at that photo.

[VintagePC]

That's not a transformer you want to drop on your foot... for sure.

Sandy: well, at least this doesn't end with me buying it followed by an "Ah HATE yew..." I've been spared from the hate!

Electronic: Yeah, it's from a collection of what are called "rage faces" (More info). Despite being generally simplistic in style, they capture the exact expression(s) involved very well. - and that is the face I was more-or-less met with along with the answer.

[Penthode]

Comically massive transformers on the older 25Hz radios and TVs were very unique to sets made in Canada .

I often wondered why 25Hz remained so long in Toronto. Certainly it offered a degree of trade protectionism since you could not back then buy a radio or TV in the US and simply plug it in in Toronto.