CCDA SE output stage?

Navyblue · 18th July 2012, 05:02 PM

Say I have a typical SE output stage, with an OPT loaded on the anode of a triode.

Would it make any sense, to have another identical triode to do nothing apart from to draw current in opposite phase from the triode driving the OPT? Which would make the current draw appear constant to the PSU? If it would work at all, is it actually beneficial in practice?

Thanks.

DF96 · 18th July 2012, 05:09 PM

I'm sure this question, or a similar one, came up a few months ago. Yes it would work, after a fashion. To do it properly you would need an identical loudspeaker in an identical room fed by the same length of identical cable, but acoustically isolated from the room you are in. No it would not make any sense, even less sense than the normal CCDA.

Navyblue · 19th July 2012, 12:38 AM

So I guess, you are not a fan of normal CCDA?

Say it is to be used with unregulated power supply, where a current draw would correspond to a voltage drop. While it is not possible to have 2 identical triodes driving 2 identical loads, wouldn't it help minimizing current draw fluctuation? But of course if it is in fact an audible improvement is another matter.

DF96 · 19th July 2012, 11:03 AM

I can't see the point of normal CCDA, especially the constant current aspect of it. I can see some merit in cancelling supply noise (the other feature of CCDA) but cancellation is always a risky thing to do as it relies on a balance between two nasty things remaining balanced. Power supplies can cope with current variation, so why double the number of valves just to minimise something which doesn't matter? When you load the CCDA the current balance disappears anyway!

18th July 2012, 05:02 PM	#1
Navyblue diyAudio Member Join Date: Mar 2012	CCDA SE output stage? Say I have a typical SE output stage, with an OPT loaded on the anode of a triode. Would it make any sense, to have another identical triode to do nothing apart from to draw current in opposite phase from the triode driving the OPT? Which would make the current draw appear constant to the PSU? If it would work at all, is it actually beneficial in practice? Thanks.

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18th July 2012, 05:09 PM	#2
DF96 diyAudio Member Join Date: May 2007	I'm sure this question, or a similar one, came up a few months ago. Yes it would work, after a fashion. To do it properly you would need an identical loudspeaker in an identical room fed by the same length of identical cable, but acoustically isolated from the room you are in. No it would not make any sense, even less sense than the normal CCDA.

19th July 2012, 12:38 AM	#3
Navyblue diyAudio Member Join Date: Mar 2012	So I guess, you are not a fan of normal CCDA? Say it is to be used with unregulated power supply, where a current draw would correspond to a voltage drop. While it is not possible to have 2 identical triodes driving 2 identical loads, wouldn't it help minimizing current draw fluctuation? But of course if it is in fact an audible improvement is another matter.

19th July 2012, 11:03 AM	#4
DF96 diyAudio Member Join Date: May 2007	I can't see the point of normal CCDA, especially the constant current aspect of it. I can see some merit in cancelling supply noise (the other feature of CCDA) but cancellation is always a risky thing to do as it relies on a balance between two nasty things remaining balanced. Power supplies can cope with current variation, so why double the number of valves just to minimise something which doesn't matter? When you load the CCDA the current balance disappears anyway!