6.3V 2a3 heaters

pre65 · Post by **pre65** » Sat Mar 26, 2011 2:40 pm

I know it's not correct to heat more than one DHT with the same transformer winding, but can one heat a 6.3V 2A3 and a D3a from one 6.3V AC winding ?

If not, could I use one winding for both but convert one to DC ?

Or, any other suggestions.

The PSU is on an umbilical and that has HT and 6.3V AC

Is the D3a + 2A3 circuit shown elsewhere (like wot Bizzie is doing) suitable for 6.3V heater types like 6S4s ?

Mike H · Post by **Mike H** » Sat Mar 26, 2011 5:57 pm

If the D3A has insulated heater then feasible. Only one way to find out!

pre65 · Post by **pre65** » Sat Mar 26, 2011 6:06 pm

I've changed plans now, and the ex WAD transformers I'm using (from that nice man in Laindon) only have one 6.3V winding.

However, I could use my DIY hi-fi modules (when I find them

) powered by a separate 9V toroid.

Must only use bits in stock if humanly possible.

Mike H · Post by **Mike H** » Sat Mar 26, 2011 6:07 pm

Ahh!! Those ones

Post by **Nick** » Sat Mar 26, 2011 11:06 pm

If the D3A has insulated heater then feasible. Only one way to find out!

Yes, but the d3a seems to be very sensitive to noise on its heater.

pre65 · Post by **pre65** » Sat Mar 26, 2011 11:20 pm

Nick wrote:
If the D3A has insulated heater then feasible. Only one way to find out!
Yes, but the d3a seems to be very sensitive to noise on its heater.

OK. I've got the message.

I have found the two DIY-hi-fi ultra low noise modules which will be powered by a 9v toroid, and the mains transformer 6.3V ac is centre tapped.

So, best to use the modules on the D3a ?

Post by **Nick** » Sun Mar 27, 2011 2:37 am

AC is fine in my experience on the d3a heater, what it doesn't like is noisy AC or DC.

cressy · Post by **cressy** » Sun Mar 27, 2011 1:52 pm

hi phil, ive got 2 transformers that have 2 6v 2.5a windings per transformer. i use one of these to heat the 6s4s in my amp. they dont seem to mind the lack of point 3 of a volt. i'll send one on if that'd help. one transformer does both valves.
they arent centre tapped so youd have to put a couple of resistors across the heater to make a centre tap
cheers ant

pre65 · Post by **pre65** » Sun Mar 27, 2011 2:32 pm

cressy wrote:hi phil, ive got 2 transformers that have 2 6v 2.5a windings per transformer. i use one of these to heat the 6s4s in my amp. they dont seem to mind the lack of point 3 of a volt. i'll send one on if that'd help. one transformer does both valves.
they arent centre tapped so youd have to put a couple of resistors across the heater to make a centre tap
cheers ant

Thanks for the offer Ant, but I've sussed it out now.

D3a = 6.3v AC with centre tap grounded.

6S4S = DIY hi-fi low noise module fed by separate 9V toroid.

All from parts in stock.

audio-talk

6.3V 2a3 heaters

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