A couple of questions

a 3W single ended EL84 amp for home, work & school

Re: A couple of questions

Postby GrahamJ » Thu Oct 22, 2015 12:37 pm

Hello again,
Nearly there, with the bucking transformer in place the voltages for the Budgie are a lot better.
301v on the 6P14P anodes, 9.3v cathodes and all heaters now about 6.5v. I'm a lot happier with those numbers.
But, the bucking transformer is buzzing quite loudly, even loud enough to be heard during quiet passages of music. Probably my metal toffee tin enclosure isn't helping but the intensity of the buzzing seems quite a lot to overcome. I would be grateful for possible solutions.
I still can't understand why the mains transformer failed so miserably as it would be the standout transformer to use for those of us with 220-240v mains???
Thanks again to Mike and Tom for your help which is very much appreciated.
Graham
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Re: A couple of questions

Postby mike567 » Thu Oct 22, 2015 3:11 pm

Welcome.
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Re: A couple of questions

Postby GrahamJ » Fri Nov 27, 2015 1:52 pm

Thanks to Tom and Mike 567 for helping but I was not happy with the 369JX transformer as it seemed to be getting far too hot.
I decided to speak to the UK Hammond agent and he suggested that I would be better off with a 370DAX (250v c/t @ 104 mA and 6.3v @ 3.5A. Fortunately he helped me with a good deal.

I now however have over-voltage issues.
I have resolved the heaters with a 0.1R 3w w/w resistor in each secondary lead to the pcb.
But I am having problems with the high voltage secondary. Namely, 318v on the 6P14P plates. I think it is just as well that I am using the Russian tubes as they appear to be quite tough and I am happy to stay using them.
Does anyone please have any tips that would help me to lower that voltage or is it even worth bothering?

Through it all by the way the amp sounds great.

Graham
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