These were made to couple between a big semi-con PA amplifier and a high-Z long wires distributed (usually multi-speaker) system. You could measure the turns ratios or just guesstimate that the 4 Ohm tap is maybe 100 Watts, so 20 Volts. Call it a 1:10 turns ratio. The problem for using as a low ratio output transformer is that they're not air-gapped.
All good fortune,
Chris
All good fortune,
Chris
Measure winding continuity to check if they are tranformers or auto. Several of those was autotransformer for better performance and lower cost, wheight and size for equal power in the core.
Quite possible being auto trafo’s - at that power level amps were often used to directly drive 70 and 100 volt lines, so isolation may not be required. The only reason to think they may be isolated is the fact that the terminals are on opposite sides of the bobbin.
As far as using it for tube amps, that BIG of a core might be able to stand some DC. Not a lot, but I bet you could get a few watts out of it. The better ones to use are the ones with the HV line tapped at 70, 100, and 140 volts. Then you can push pull. If by chance you connected between A and C and saw 106 volts (I wouldn’t hold my breath) I would say you hit paydirt. As long as the other side were isolated, of course. It’s just a possibility, since 70.7 + 70.7/2 = 106.05. It may even be properly interleaved if that’s what they did.
As far as using it for tube amps, that BIG of a core might be able to stand some DC. Not a lot, but I bet you could get a few watts out of it. The better ones to use are the ones with the HV line tapped at 70, 100, and 140 volts. Then you can push pull. If by chance you connected between A and C and saw 106 volts (I wouldn’t hold my breath) I would say you hit paydirt. As long as the other side were isolated, of course. It’s just a possibility, since 70.7 + 70.7/2 = 106.05. It may even be properly interleaved if that’s what they did.
Hint found on-line:
https://www.usedprice.com/items/pro...15470a-329414.html?q=Watt+transformer&x=0&y=0
15470A Altec Lansing 1997-1998 Description: 400 Watt Transformer.
400 Watts at 4 Ohms is 40 Volts
70.7V at 400 Watts is 12.5 Ohms
212V at 400 Watts is 112 Ohms
So-- 4:12.5:112 Ohms, 40V:70.5V:212V
None look tube-friendly even at the obscene 400W level. Nothing center-tapped for simple push-pull.
4r:12.5r might be useful for mix-and-match in large amplifiers and speakers.
The standout application: best power economy in pair-wire cable is often near 100 Ohms; 112 is "near". Lower needs more copper and higher needs more rubber/PVC. We would rarely over-volt the wire even at 400 Watts, safety may suggest not pushing too hard. So 4r (ordinary transistor audio amp) to 112r for audio delivery at long range at low cost. (Or 70V because the warehouse is full of 70V parts and the difference in loss is pretty small.)
BTW: 212Vrms times 1.414 is 299.8 volts peak, and 300V is a number sometimes seen in wire insulation standards.
IMHO these will be isolation, not autotransformers, because of the risk of a one-side ground. Floating windings are maybe safer in this voltage class. But if it may matter, CHECK!
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found on same trawl, for possible future seekers:
15480 Altec Lansing 1997-1998 Description: 100 Watt Transformer.
15075 Altec Lansing 1997-1998 Description: 150 Watt Transformer.
15567A Altec Lansing Description: 300 Watt Autoformer.
15070 Altec Lansing Description: 75 Watt Transformer.
https://www.usedprice.com/items/pro...15470a-329414.html?q=Watt+transformer&x=0&y=0
15470A Altec Lansing 1997-1998 Description: 400 Watt Transformer.
400 Watts at 4 Ohms is 40 Volts
70.7V at 400 Watts is 12.5 Ohms
212V at 400 Watts is 112 Ohms
So-- 4:12.5:112 Ohms, 40V:70.5V:212V
None look tube-friendly even at the obscene 400W level. Nothing center-tapped for simple push-pull.
4r:12.5r might be useful for mix-and-match in large amplifiers and speakers.
The standout application: best power economy in pair-wire cable is often near 100 Ohms; 112 is "near". Lower needs more copper and higher needs more rubber/PVC. We would rarely over-volt the wire even at 400 Watts, safety may suggest not pushing too hard. So 4r (ordinary transistor audio amp) to 112r for audio delivery at long range at low cost. (Or 70V because the warehouse is full of 70V parts and the difference in loss is pretty small.)
BTW: 212Vrms times 1.414 is 299.8 volts peak, and 300V is a number sometimes seen in wire insulation standards.
IMHO these will be isolation, not autotransformers, because of the risk of a one-side ground. Floating windings are maybe safer in this voltage class. But if it may matter, CHECK!
-------
found on same trawl, for possible future seekers:
15480 Altec Lansing 1997-1998 Description: 100 Watt Transformer.
15075 Altec Lansing 1997-1998 Description: 150 Watt Transformer.
15567A Altec Lansing Description: 300 Watt Autoformer.
15070 Altec Lansing Description: 75 Watt Transformer.
Hi John
Finding a good use for these may be a little difficult. If you are into transformer winding it may be possible to make something more useful out of the cores. Can you see how thick the lamination are? A lamination thickness of 0.35mm or less is typical for Hi-Fi audio. If rewound the cores could be used for power transformers, chokes or output transformers.
Finding a good use for these may be a little difficult. If you are into transformer winding it may be possible to make something more useful out of the cores. Can you see how thick the lamination are? A lamination thickness of 0.35mm or less is typical for Hi-Fi audio. If rewound the cores could be used for power transformers, chokes or output transformers.
They used transformers in some early models to support push-pull with the same device type. Also I think it was a slight step up to use devices that did not have a high C-E voltage rating.
Thanks for all the info...
When I first saw the Altec Lansing label, I got a little excited....then saw the voltage taps (thought maybe the 70v taps could serve as the Ultra-linear 40% taps) but no centertap, so likely not Push Pull, maybe a single ended output transformer? So after all this guessing, I thought I would let you all educate me...thanks!!
Anyway I will let my friend know not much Audio-wise can be done with it
When I first saw the Altec Lansing label, I got a little excited....then saw the voltage taps (thought maybe the 70v taps could serve as the Ultra-linear 40% taps) but no centertap, so likely not Push Pull, maybe a single ended output transformer? So after all this guessing, I thought I would let you all educate me...thanks!!
Anyway I will let my friend know not much Audio-wise can be done with it