Hey Anyone,
There used to be a link here to an article "Rating Unknown Power Transformers."
But it seems to have disappeared. I want to use an Eico ST70 power transformer in Poinz's EL34 MM but using 6550 instead of EL34. I want to get closer to the 35 watt capability of the Eico OPT's. the original tube compliment of the ST70 totals about 300ma. I would need closer to 400ma for the outputs. (I will run the 6GK5's from a different power supply.)
From what I remember of the article the parameters necessary are much the same as the transformer data entered in PSUDII. My question is this, if you design a power supply using PSUD if you are overtaxing the B+ windings will it know? And will it tell you?
Kevin
There used to be a link here to an article "Rating Unknown Power Transformers."
But it seems to have disappeared. I want to use an Eico ST70 power transformer in Poinz's EL34 MM but using 6550 instead of EL34. I want to get closer to the 35 watt capability of the Eico OPT's. the original tube compliment of the ST70 totals about 300ma. I would need closer to 400ma for the outputs. (I will run the 6GK5's from a different power supply.)
From what I remember of the article the parameters necessary are much the same as the transformer data entered in PSUDII. My question is this, if you design a power supply using PSUD if you are overtaxing the B+ windings will it know? And will it tell you?
Kevin
From para4.Was this common?If only two high-voltage leads are found, check to see if the centre-tap is grounded internally.
Is it done with modern EI transformers?
My question is this, if you design a power supply using PSUD if you are overtaxing the B+ windings will it know? And will it tell you?
Kevin
It won't tell you explicitly as far as I know, however the B+ voltage will continue to drop as you increase the current draw. After measuring the unloaded voltage, you can assume that the voltage regulation is typically 5-10%, giving you a reasonable voltage window.
I've measured a few unknown transformers based on the article, and it will get you somewhat close. Measure the DCR of the secondary and look at the graph.
Thanks Boywonder,
I checked the Eico per the article instructions and it should be good for about 250ma. The original tube compliment totals about 265ma. So I'm in the right neighborhood. I plan to have Heyboer build me another power transformer so I can build a pair of 6550C MM monoblocks. They'll have 438 volts of B+ at 94ma per 6550. With 188ma for the outputs and 24ma for the CCS 6GK5's, at 212ma the transformer will have some nice headroom. The amp should produce a little over 30 watts. With the Z out of 4k the 16 ohm becomes 8 and the 8 ohm becomes 4. Thanks for the help so far!
Kevin
I checked the Eico per the article instructions and it should be good for about 250ma. The original tube compliment totals about 265ma. So I'm in the right neighborhood. I plan to have Heyboer build me another power transformer so I can build a pair of 6550C MM monoblocks. They'll have 438 volts of B+ at 94ma per 6550. With 188ma for the outputs and 24ma for the CCS 6GK5's, at 212ma the transformer will have some nice headroom. The amp should produce a little over 30 watts. With the Z out of 4k the 16 ohm becomes 8 and the 8 ohm becomes 4. Thanks for the help so far!
Kevin
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