I've got a different Edcor transformer (XPWR005). I don't recall anything unusual about the voltages. With no load on the TX, the primary made 695VCT on my 126VAC line. It's rated 660VCT for a 120VAC line, so the math agrees (2.75:1). I don't seem to have any notes where I documented the heater voltages - maybe I can go back and measure them for you. Regardless, I would expect an Edcor power transformer to perform pretty much exactly as rated. It's not like a Hammond, where there is a reputation for running too high.
Your mains voltage is a smidge high, but only by 3.3%. In other words, I'd expect to see your 6.3V winding running around 6.5V, and the 5.0V winding at 5.2V. If they truly are as high as you note, it probably will reduce the life of your tubes. When you get the amp up and running with all the tubes in place, check those voltages again and see where they are. If they are still high, I'd try to find a way to get them down to spec.
An amp is born
wow wow it sure does sound good I'm blown away with the sound. I have been trying it out on my old mourdent short ms10 small bookshelf speaker 8ohm ~88db and cant wait to try it on my main speakers (diy lineup's really nice!) but boy does it get hot the tubes would prob take your skin off!
The steel top that the tubes are fastened to it gets to about 68C is this normal or is this a symptom of my over voltage I will see if I can take some readings again but its more difficult now that its all boxed up, I can see the underside ok if I turn it on its side. BTW is it ok to run the tubes sideways?
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cheers😀😀😀😀😀
wow wow it sure does sound good I'm blown away with the sound. I have been trying it out on my old mourdent short ms10 small bookshelf speaker 8ohm ~88db and cant wait to try it on my main speakers (diy lineup's really nice!) but boy does it get hot the tubes would prob take your skin off!
The steel top that the tubes are fastened to it gets to about 68C is this normal or is this a symptom of my over voltage I will see if I can take some readings again but its more difficult now that its all boxed up, I can see the underside ok if I turn it on its side. BTW is it ok to run the tubes sideways?
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cheers😀😀😀😀😀
68^C is not unusually hot. Some chassis ventilation would help extend the life of some of the components, such as the capacitors. Don't touch hot tubes. 🙂
Many tubes are perfectly fine running in any orientation. Check the tube data sheets to be sure. Anything you can put into the Simple SE will be fine. Just be gentle while turning it over. Transformers are heavy and you don't want to drop the thing. I might recommend turning it on the side before you power it up, just to avoid accidents.
You want to avoid "short cycling" the power. After you turn it off, wait at least 5~10 minutes for the tubes to cool off before you turn it back on. If you turn on the power while the rectifier is still hot, you virtually guarantee arc'ing it out.
thanks for the tip I think that that's what happened to the rectifier tube as I listened to the amp a few mins switched off to adjust something then switched back on and FLASH! oh well you live and learn.
I will turn the amp on its side to do some readings whilst powered up to see if the voltages calm down a bit, will post results asap.
BTW I think a Current Limiter in the circuit would be a good idea they seem to be a bit hard to find in U.K the one I can get at good cost is NTC 120 Ohm - 7A would that be suitable also i have read in this forum people fit them in different places how many do I need and where is the best place to fit
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cheers
7A is way too much. The Simple SE will never draw that much current, and the IRCL will never properly heat up. You want something like the CL-90, which is 120 ohms cold and less than 3 ohms once you draw at least half of its rated 2 amp capacity. A CL-130 would probably work pretty well, too.
CL-90 GE Sensing / Thermometrics Thermistors - NTC
Digi-Key - KC009L-ND (Manufacturer - CL-90)
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thanks managed to order some of the above.
H ave been volt testing whilst amp is running
rectifier pin 6 and 4 is 397vac
but cant get a reading for heaters, meter reading not steady this is on all tubes so guess that's normal (lot to learn with this black magic electricery😱)
when testing the leads at the board connectors I get
799vac
7.15vac
5.95vac
so it's come down a little but still high?
haven't done fitted any thing else just listened to it (Fantastic!!)
does anyone think its worth doing any mods to reduce the voltage or do I just live with it
Perhaps I have bought a Monday morning transformer!
Those are with the amp on and fully-loaded? The transformer is running about 15% "hot" (voltage wise). Does it get hot temperature-wise after a few hours? The heaters running high like that can shorten the life of the tube cathodes somewhat. What is your line voltage?
It might be worth an email to Edcor just to see what they say. That transformer is supposed to be designed for a 240V primary. Your mains are only 3.3% high. The HV secondary is 6.5% high, and the heater windings are 13.5% and 19% higher than spec. Either your meter(s) is(are) telling you lies, or somethings wrong.
I wouldn't want to run the heaters on my tubes that far over spec for any length of time.
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