I have a xfrmer I pulled from a console. The console was a hybrid. SS amp, tube tuner/preamp.
I'm measuring 45-0-45, 130-0-130, and 0-6.3 on the secondaries.
can I connect the 260v and 90v secondaries in series to get a higher voltage? 350v?
I'm thinking of using it in a SE amp with a pair of 6l6s or el34s. I'd not use the center taps and use a bridge rectifier.
I'm measuring 45-0-45, 130-0-130, and 0-6.3 on the secondaries.
can I connect the 260v and 90v secondaries in series to get a higher voltage? 350v?
I'm thinking of using it in a SE amp with a pair of 6l6s or el34s. I'd not use the center taps and use a bridge rectifier.
Yes, but the available current is limited to the lower of the two.
The relative phasing must be right, or you'll get 170VAC instead.
can you post dimensions of the traffo?
what was that traffo used for in that console, what tubes and how many...
what was that traffo used for in that console, what tubes and how many...
The series connection of the 45 & 130Vac windings will give you ~500Vdc.
You could have the two 45Vac windings tapping off to give you a choice of voltages.
260Vac >> 370Vdc
305Vac >> 430Vdc
350Vac >> 500Vdc
You could have the two 45Vac windings tapping off to give you a choice of voltages.
260Vac >> 370Vdc
305Vac >> 430Vdc
350Vac >> 500Vdc
130V windings are probably too weak. Measure their resistance, and calculate current for about 6...10V drop!
Hi,
Its highly unlikely the current of the taps match.
The 130-0-130 taps are highly unlikely to be able
to support a valve SE power amplifier in any sense.
rgds, sreten.
Its highly unlikely the current of the taps match.
The 130-0-130 taps are highly unlikely to be able
to support a valve SE power amplifier in any sense.
rgds, sreten.
yes, it is easy to speculate about possible voltages,
but without knowing the dc resistance of the windings,
this is a stab in the dark...
working with tubes, it is not the unloaded voltages that matters,
but the final voltage when everything has stabilised at the operating point...
but you also need the unloaded voltages to
know what filter cap voltage ratings to use...
laws of physics rules......
but without knowing the dc resistance of the windings,
this is a stab in the dark...
working with tubes, it is not the unloaded voltages that matters,
but the final voltage when everything has stabilised at the operating point...
but you also need the unloaded voltages to
know what filter cap voltage ratings to use...
laws of physics rules......
The xformer is almost the exact weight and dimensions of a Hammond 270hx which happens to be next to it on the bench. I considered that transistors might not present the kind of load tubes do. I've been unable to find a schematic on this console, to know for sure. I do have an old rca transistor manual and I looked at some of the specs and it looks like tube like currents are not unheard. But I don't know what transistors these are so it's all speculative. There are 9 tubes all in the tuners and preamp section. and the amp appears to have have 4 output/power transistors.
As rayma pointed "the available current is limited to the lower of the two." This is the 130V section. Knowing current of the 45V section is kinda useless. But measuring a resistance is very simple and useful. So why not doing it?
You could roughly estimate the current capacity of the 130VAC winding by loading it
until its AC voltage drops by around 10% from the open circuit value.
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then you have a capable traffo, go ahead and do it....
if you know the part numbers of the tubes, you can add up the total loading
on the filament winding, my guess is, it is big enough...
Or simply by measuring its resistance. Everybody has a DMM and it is a safe measurement. But if somebody trusts more guestimations... mass and dimensions... looking for unknown transistors...
Transformers do. What about you? ;-)
What about ohm's law? Why can it be ignored?
And which other law applies to this transformer such way that you can calculate maximal load from the given info?
What about ohm's law? Why can it be ignored?
And which other law applies to this transformer such way that you can calculate maximal load from the given info?
What sreten said (tm)
You can´t use this transformer to feed a Tube power amp, *any* Tube power amp, period.
130-130VAC stinks of full wave rectifier, supplying some 180V DC, fine for preamp and tuner duty.
How much current?
Probably not more than 2 or 3 mA per tube, maybe 20 to 30 mA total, IF that much.
The bulk of that transformer must have been dedicated to the SS Power Amp, of course.
If the console is as old as described, wouldn´t be surprised at all with 45-45V winding being meant also for full wave rectification (2 diodes) for single supply , output capacitor coupled Stereo power amp , around +62V single rail so some 30W per channel into 8 ohms.
Which must have been a very respectable Audio Console back in the day.
You can´t use this transformer to feed a Tube power amp, *any* Tube power amp, period.
130-130VAC stinks of full wave rectifier, supplying some 180V DC, fine for preamp and tuner duty.
How much current?
Probably not more than 2 or 3 mA per tube, maybe 20 to 30 mA total, IF that much.
The bulk of that transformer must have been dedicated to the SS Power Amp, of course.
If the console is as old as described, wouldn´t be surprised at all with 45-45V winding being meant also for full wave rectification (2 diodes) for single supply , output capacitor coupled Stereo power amp , around +62V single rail so some 30W per channel into 8 ohms.
Which must have been a very respectable Audio Console back in the day.
without proper documentation, all we do is speculate, and that is not helpful at all...
OP says: http://www.hammondmfg.com/pdf/EDB270HX.pdf
at 176 VA capacity, he has more than enough iron on the power traffo to make an SE amp if that is what he wants....
hey this is after all DIYAUDIO, and we diy'ers can think out of the box....
then all the more a 5 watt per channel 6L6 SE is possible........
OP says: http://www.hammondmfg.com/pdf/EDB270HX.pdf
at 176 VA capacity, he has more than enough iron on the power traffo to make an SE amp if that is what he wants....
hey this is after all DIYAUDIO, and we diy'ers can think out of the box....
then all the more a 5 watt per channel 6L6 SE is possible........
Exactly.
Yes. But what about copper on 130V coil?
No information about it yet, however it takes 30 seconds to measure resistance.
This is very probable.
without knowing the dc resistance of the 130-0-130 it will be hard to say for sure....
if that is less than say 70 ohms more or less, then is is possible.....
if that is less than say 70 ohms more or less, then is is possible.....
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