I have an old transformer which I am told was taken from a tape recorder with ECC83/ECL86.
it has 3 wires on one side Brown, Blue, Red (primary), And 4 wires on the secondary side Green, Black, Yellow, red.
Brown - Blue 71.7 Ohms
Brown - Red 80.8 Ohms
Blue - Red 9.2 Ohms
Yellow - Red 0.6 Ohms
Yellow - Green (No read)
Yellow to Black (No read)
Red - Green (No read)
Red - Black (no read)
Green - Black 194 Ohms
Can anyone tell me how to work out what the expected outputs would be and how to figure out how its wound from the results? also, which of the input pairs would have been for 240V?
Thanks.
it has 3 wires on one side Brown, Blue, Red (primary), And 4 wires on the secondary side Green, Black, Yellow, red.
Brown - Blue 71.7 Ohms
Brown - Red 80.8 Ohms
Blue - Red 9.2 Ohms
Yellow - Red 0.6 Ohms
Yellow - Green (No read)
Yellow to Black (No read)
Red - Green (No read)
Red - Black (no read)
Green - Black 194 Ohms
Can anyone tell me how to work out what the expected outputs would be and how to figure out how its wound from the results? also, which of the input pairs would have been for 240V?
Thanks.
It looks like a dual voltage input type: 220V/240V or 117V/127V, probably the former in your case since you are UK based.
Thus, for the input I would use brown and red, and measure the secondaries.
Yellow red is probably a heating winding, 6.3V or maybe 5V.
Green black is the HV winding, and you need to measure it too.
Use a light bulb tester for maximum safety, and if you you want to evaluate the respective power of each winding, refer to this thread:
https://www.diyaudio.com/community/...multi-winding-transformer.247758/post-3745504
Thus, for the input I would use brown and red, and measure the secondaries.
Yellow red is probably a heating winding, 6.3V or maybe 5V.
Green black is the HV winding, and you need to measure it too.
Use a light bulb tester for maximum safety, and if you you want to evaluate the respective power of each winding, refer to this thread:
https://www.diyaudio.com/community/...multi-winding-transformer.247758/post-3745504
Please be very careful you're working on high voltage!
I think the brown and red is for 240V. Connect it to a DBT (Dim Bulb Tester) with 40Watt incandescent light bulb, red to live and brown to neutral.
If the bulb dimmed, the transformer should be safe to connect directly to the mains.
Now you can measure the voltage across brown and blue wires, probably it's the 220V tap.
Next to measure the voltage across green and black wires, that should be the HV.
Then measure the voltage across yellow and red secondary wires and that is the filament supply.
Group them by gauge of wire. The heavier wires are filament most likely. Measure between the greens and one of the blacks will go with them. Same with the yellows and a black. Pay attention to wire gauge to know what goes with what. The thinner reds and yellows might be the HV, two wires and a ground. You can sort them out easier by picking one wire to connect to your ohm meter and going through all the other wires to find each group. Move on to another and so on until all wires are found. You will not have filament sets with two colors, it’s always two of the same color and a black if it is center tapped. Happy hunting!
here is what i will do.....inject 3volts ac on the yellow-red wire, then measure voltage on the green-black wire, and others....i will make a schematic as to which wires go with what...
Connected to the mains at red and brown,
Green to Black: 253v
Red to Yellow: 7.5v
The Yellow and Red heater supply wires are quite stout. I'm wondering how much current they'd be able to take. This would have been designed for a mono amplifier obviously. Wondering if I could use that winding to power 2 valve heaters? Say, single ended stereo amp with 2 with ECL82 (6.3v, 0.78a).
Green to Black: 253v
Red to Yellow: 7.5v
The Yellow and Red heater supply wires are quite stout. I'm wondering how much current they'd be able to take. This would have been designed for a mono amplifier obviously. Wondering if I could use that winding to power 2 valve heaters? Say, single ended stereo amp with 2 with ECL82 (6.3v, 0.78a).
Try to measure the diameter, or alternatively measure the resistance accurately with a 4-wire milliohmmeter
I will connect a 10ohm resistor (10watt or higher) to the filament winding and measure the voltage, if not drop below 6.5v, use a 5ohm resistor and measure again. If voltage still higher than 6v, it should be safe to supply about 1.2A.
I=V/R
You can use 8ohm resistors (dummy load) or whatever on hand.
I=V/R
You can use 8ohm resistors (dummy load) or whatever on hand.
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congratulations!!!!
good results, now you are good to go, do not let that 7.5vac annoy you, use it for your 6.3 vac tubes and they will just be fine, you have plenty of dc resistance in the windings to even out voltages.....
it looks to me you have enough juice to get something working... good job!!!