audio-talk

OK, a bit at a time. To get a center tap I would connect 4 & 2 togther and ground them as 0v then take your voltage from 1 & 5. So connect the middle two together and ground that, then take your volatge from the outer two pins to the anodes of the rectifier. I just checked, I recently did sa...

OK, primary first, looks like you want pin 7 = live and 11 = neutral for UK operation. Next up we'd need to know what you want out of the it? Looks like you can get 270-0-270, for HT, similarly 50-0-50 etc. You've also got various combo of 6.3v and 5v etc for heaters. Looks like quite a versatile be...

That's about it, but you need to buy a NAS that supports SlimServer, use EAC to rip to FLAC (I do two copies, a VBR MP3 for the icrap and FLAC for the SB). I use the NLSU2 which is dirt cheap but marginal in the speed dept, very marginal. I think other suggestions have been made, however, which may ...

Good explanation, Nick. One of the best videos I ever saw and a good example of this, was how the Canadians, during lulls in serious ice storms, use a helicopter to clear the ice of power lines so the pylons don't collapse under the weight of the frozen water hanging off the lines, when the pylons g...

If you plan to DC heat then I reckon there's no issue, or if your AC heating a rectifier valve as in Philip's question, then again, you're going to rectify anyway so noise isn't an issue. Sure, in any TX that shares a dual primaries, one for heating and the other for B+, then the noise will still be...

Nick wrote:When I want to be neat, I use the schema drawing part of expresspcb

http://www.expresspcb.com/

I have a set of valvie symbols that you can add to it. I think its from Duncans amp pages.

I use Linear's LT Spice, again a link from Duncan Amps, Google should find it.

cheers,

-- Andrew

Sorry, just got it, you've got dual secondaries. Are you using the 12v for heaters? I think mixing heater and rectified B+ can cause problems, Nick and I found at his place that the noise from the rectifiers was getting capacitively coupled back into the secondary and appearing a grunge on the other...

Hi Al,

For a 12v 3 amp toroid wouldn't RS/Farnell be cheaper? Or am I missing something obvious.

cheers,

-- Andrew

I'm unable to phrase a counter argument, to Nick's point, perhaps due to lack of understanding, I need to digest this some more. I will say this might be a case of the pentode's missing gain :oops: The LCR remains on the shelf for the time being as being a step too far! However, I'm hoping understan...

I did parafeed once .... why should it be that much better ? Andrew the 1st. I'm not saying it better, its just something I've been wanting to try really. With 6EM7 you need to have a largish cap on the cathode bypass, say 47uF on the Barker/Kaufman design. I had an idea to try a constant current s...

Oh for having too much gain....I always seem to have too little.

How about one of the older DHT's other than that didn't Nick uses something that fits the bill on the input to his 6N6P Aikido 300B driver? Or was that too high mu as well?

cheers,

-- Andrew

Excellent. I have a pair of OPT on the way from the good Mr Slagle, I have IXCP10M45S via Buddam from Digikey, I have the bits for C4S and some cheap 6uF caps for parafeed duty. If I don't like parafeed I can restack the OPT to take DC at the expense of some inductance, or so I am told. I hope to co...

Bit more of everything, higher mu, higher gm, higher miller, higher anode dissapation and higher cathode current. I was very impressed with the lack of any colouration at all in Nick's anode follower; they sounded good in the LCR, but not quite enough gain when compared to the E810F. I suspect its s...

I agree, D3A makes both a nice triode and a good pentode should be a good driver for 2A3, plenty of headroom either way.

In fact, it should be easy enough to try both and decide which you like best.

cheers,

-- Andrew

-- Philip, My take is.... Have you found your ideal valve the one you like the sound of, (tho' I have to say there's no perfection just a series of suitable compromises) if not then, yes, go-ahead build/lashup/knock together/ and generally build whatever takes your fancy as cheapy, or as well, as yo...