Quad II - Can 6P3S-E/GU50 be used as KT66 direct replacement?

pwan · 25th March 2010, 06:12 PM

Hi

Two questions:

I've got a pair of Quad II cloned OPT and interested in building Quad II (KT66). The KT66 is quite expensive, however, just wonder if the 6P3S-E can be used as KT66's direct replacement?

ALso, beyond the heater requirement, can GU-50 can be used in this Quad II (KT66) schematic too?

Thanks.

Rod Coleman · 25th March 2010, 06:46 PM

ГУ50/GU50 sits in a different socket, and likes higher voltage than KT66. I wouldn't try that.

6П3С-Е/6P3S-E should be fine, so long as you can adjust the anode current.

pwan · 25th March 2010, 07:12 PM

Quote:

Originally Posted by Rod Coleman

ГУ50/GU50 sits in a different socket, and likes
6П3С-Е/6P3S-E should be fine, so long as you can adjust the anode current.

Thanks for your response. What is the suitable current (KT66 originally ran with 65ma per tube)?

Can chinese "6L6-GC" is pretty inexpensive (though the quality of builds appearently is not as good as 6P3S-E) be used as its output tubes too?

Rod Coleman · 25th March 2010, 07:17 PM

65mA is allowed for the 6П3С-Е, but see that the anode voltage is low enough. At 20W disspation, the 6П3С-Е lasts forever. you can run it higher than this, but the life will go down.

The 6L6GC Shuguang that I received a few weeks ago was made to the old 6П3С (not -E) design, meaning rated for lower voltages. The assembly looked very rough, and the valve compares badly to the 6П3С-Е.

pwan · 25th March 2010, 08:53 PM

Quote:

Originally Posted by Rod Coleman

65mA is allowed for the 6П3С-Е, but see that the anode voltage is low enough. At 20W disspation, the 6П3С-Е lasts forever. you can run it higher than this, but the life will go down.

The 6L6GC Shuguang that I received a few weeks ago was made to the old 6П3С (not -E) design, meaning rated for lower voltages. The assembly looked very rough, and the valve compares badly to the 6П3С-Е.

Thanks Rod. I think the disspation is roughly ~ 20W which is max in spec - though my experience Russian mil tubes should run fine with that.

Look like your recommentation is 6P3S-E ( 6П3С-Е ) then. Thanks!

Cheers,

bigwill · 25th March 2010, 09:32 PM

6P3S-E is good but as said, don't go above 20w on its plate

stevieg · 25th March 2010, 10:04 PM

It's going to be a quad II type amplifier, not a Quad II. NOS KT66 are expensive - modern retro are not, and they can sound very good. It's like replicating a speaker design but using different speakers and cabinet.

405man · 26th March 2010, 07:40 AM

Where did you get the output transformers

Stuart

25th March 2010, 06:12 PM	#1
pwan diyAudio Member Join Date: Apr 2006 Location: Earth	Quad II - Can 6P3S-E/GU50 be used as KT66 direct replacement? Hi Two questions: I've got a pair of Quad II cloned OPT and interested in building Quad II (KT66). The KT66 is quite expensive, however, just wonder if the 6P3S-E can be used as KT66's direct replacement? ALso, beyond the heater requirement, can GU-50 can be used in this Quad II (KT66) schematic too? Thanks.

25th March 2010, 10:04 PM	#7
stevieg diyAudio Member Join Date: Nov 2009 Location: Gwynedd North Wales	It's going to be a quad II type amplifier, not a Quad II. NOS KT66 are expensive - modern retro are not, and they can sound very good. It's like replicating a speaker design but using different speakers and cabinet. __________________ steve if it ain't broke, I ain't fixed it

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25th March 2010, 06:46 PM	#2
Rod Coleman работник diyAudio Member Join Date: Jul 2004 Location: Warwickshire UK	ГУ50/GU50 sits in a different socket, and likes higher voltage than KT66. I wouldn't try that. 6П3С-Е/6P3S-E should be fine, so long as you can adjust the anode current.

25th March 2010, 07:17 PM	#4
Rod Coleman работник diyAudio Member Join Date: Jul 2004 Location: Warwickshire UK	65mA is allowed for the 6П3С-Е, but see that the anode voltage is low enough. At 20W disspation, the 6П3С-Е lasts forever. you can run it higher than this, but the life will go down. The 6L6GC Shuguang that I received a few weeks ago was made to the old 6П3С (not -E) design, meaning rated for lower voltages. The assembly looked very rough, and the valve compares badly to the 6П3С-Е.

25th March 2010, 09:32 PM	#6
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	6P3S-E is good but as said, don't go above 20w on its plate

26th March 2010, 07:40 AM	#8
405man diyAudio Member Join Date: Dec 2003 Location: Near Glasgow Scotland	Where did you get the output transformers Stuart

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