A multimeter would answer the question pretty quickly I think. I think this is a PP transformer.
T1 and T2 are taps - probably screen grid for UL operation.
IP - I think is the in phase plate (relative to the tap used for feedback on the output)
OP - I think is the out of phase plate (relative to the tap used for feedback on the output)
CT - Center tap
If you need assistance for their thoughtful disposal just send them to me....
T1 and T2 are taps - probably screen grid for UL operation.
IP - I think is the in phase plate (relative to the tap used for feedback on the output)
OP - I think is the out of phase plate (relative to the tap used for feedback on the output)
CT - Center tap
If you need assistance for their thoughtful disposal just send them to me....
The ratios can be calculated since the impedances are known, my suggestion was mostly to confirm by resistive measurements whether my basic premise was correct or not.
Carrying it a step further and determining the ratios would be useful to determine the % tappings of those two taps and indeed that they are connected to the primary winding. Also of course it would verify that the transformers are electrically good before proceeding with a fairly expensive project without that assurance.
They should be very nice transformers..
Carrying it a step further and determining the ratios would be useful to determine the % tappings of those two taps and indeed that they are connected to the primary winding. Also of course it would verify that the transformers are electrically good before proceeding with a fairly expensive project without that assurance.
They should be very nice transformers..
Hi
Measured the resistances:
Opt 1:
CT - T1 = 114,6R
CT - T2 = 94,8R
CT - IP = 475R
CT - OP = 472R
IP - OP = 948R
Opt 2 showed a break at first between CT - T2 and OP...
Opened it but it looked very fresh and I measured at the solderings - it came alive so there is a bad solder joint somewhere. I'll take care of that later.
CT - T1 = 116R
CT - T2 = 94,8R
CT - IP = 484R
CT - OP = 484R
IP - OP = 971R
The outputs shows 1R 1,1R and 1,2R on both.
So they are probably ok
I will make the AC test in the weekend.
Will an AC wallwart be ok? How much current is needed?
Regards
Measured the resistances:
Opt 1:
CT - T1 = 114,6R
CT - T2 = 94,8R
CT - IP = 475R
CT - OP = 472R
IP - OP = 948R
Opt 2 showed a break at first between CT - T2 and OP...
Opened it but it looked very fresh and I measured at the solderings - it came alive so there is a bad solder joint somewhere. I'll take care of that later.
CT - T1 = 116R
CT - T2 = 94,8R
CT - IP = 484R
CT - OP = 484R
IP - OP = 971R
The outputs shows 1R 1,1R and 1,2R on both.
So they are probably ok
I will make the AC test in the weekend.
Will an AC wallwart be ok? How much current is needed?
Regards
Hi
Measured the resistances:
Opt 1:
CT - T1 = 114,6R
CT - T2 = 94,8R
CT - IP = 475R
CT - OP = 472R
IP - OP = 948R
Opt 2 showed a break at first between CT - T2 and OP...
Opened it but it looked very fresh and I measured at the solderings - it came alive so there is a bad solder joint somewhere. I'll take care of that later.
CT - T1 = 116R
CT - T2 = 94,8R
CT - IP = 484R
CT - OP = 484R
IP - OP = 971R
The outputs shows 1R 1,1R and 1,2R on both.
So they are probably ok
I will make the AC test in the weekend.
Will an AC wallwart be ok? How much current is needed?
Regards
i see nothing unusual here....just do the ac tests, injecting a low voltage of say 6 vac in the secondary will show if you have equal voltages across the primary windings wrt CT, and this is more important than dc resistance alone...
Transformers don't have impedances
They have winding ratios
They have optimal impedances that depend on losses, thermal resistances, electrical breakdown voltages, inductances, saturation voltages, and also limited by required bandwidth and parasitic inductances and capacitances.
No current really required.... I use a wall wart as well..
Saturation can be a problem with smaller transformers. Make the test as fast as possible.
I found some time to make sort of an AC test. The smallest I have gives 7,5V 300mA. Covardly I divided it by means of 2k+1k so the final AC was 3,85V.
The outputs between CT and
T1 = 0,525V
T2 = 0,525V
IP = 2,64V
OP = 2,64V
IP - OP = 5,25V
I expected more so the current must be to weak I think... My resistor network might be too resistant
OTOH T1 and T2 are 20% of IP and OP...
Regards
The outputs between CT and
T1 = 0,525V
T2 = 0,525V
IP = 2,64V
OP = 2,64V
IP - OP = 5,25V
I expected more so the current must be to weak I think... My resistor network might be too resistant
OTOH T1 and T2 are 20% of IP and OP...
Regards
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I think the readings are fine, you put much less current through them than you could have, but the readings look useful.
I think the UL taps are around 20% if I haven't confused myself.
I think these would be good for use with EL84s in something similar to the Mullard 5 - 10 design, although the gain is too high for modern amps unless you are using it as an integrated.
You could use the UL taps rather than pentode connection, and operate between 250V - 300V, fixed bias is an interesting possibility as well.
I think the UL taps are around 20% if I haven't confused myself.
I think these would be good for use with EL84s in something similar to the Mullard 5 - 10 design, although the gain is too high for modern amps unless you are using it as an integrated.
You could use the UL taps rather than pentode connection, and operate between 250V - 300V, fixed bias is an interesting possibility as well.
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