Help! Tube Rolling

davethomp · 1st February 2010, 04:29 AM

Hello everyone:
I have a Chinese valve amp and need some help to choose some better quality tubes/valves.
I need alternatives for: 6J4P. (An alternative could be 6SJ7 or RCA 5693 Red),
And:- 6N7P.
I can get original Chinese tubes...but an upgrade would be nice.
Any suggestions?
Thanks.
Dave

radiotron · 1st February 2010, 06:47 PM

A closer replacement for Chinese 6J4P is the 6AC7, should not be hard to find.
The 6J4P has much higher transconductance than 6SJ7, 9000 umhos vs 1650 umhos, 6SJ7 would still work but not optimal. Only warning about 6AC7, as they were designed as a wideband amplifier, not audio amp, some can be a bit microphonic, be prepared to try a few in order to get a good pair.

davethomp · 3rd February 2010, 04:29 AM

Thanks 'radiotron'. I'll certainly follow-up your recommendation. 6AC7 are indeed around and offer some options for improvements in sound. The 6N7P on the other hand has some options as an alternative is an ECC31. Whoa, there's a few options there...some are quite classic, and therefore expensive and worth more than the poor amp! A pair of globe type would be gorgeous! But we don't use valve amps for looks do we?
Thanks and Kind Regards:
Dave

1st February 2010, 04:29 AM	#1
davethomp diyAudio Member Join Date: May 2008	Help! Tube Rolling Hello everyone: I have a Chinese valve amp and need some help to choose some better quality tubes/valves. I need alternatives for: 6J4P. (An alternative could be 6SJ7 or RCA 5693 Red), And:- 6N7P. I can get original Chinese tubes...but an upgrade would be nice. Any suggestions? Thanks. Dave

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1st February 2010, 06:47 PM	#2
radiotron diyAudio Member Join Date: May 2007	A closer replacement for Chinese 6J4P is the 6AC7, should not be hard to find. The 6J4P has much higher transconductance than 6SJ7, 9000 umhos vs 1650 umhos, 6SJ7 would still work but not optimal. Only warning about 6AC7, as they were designed as a wideband amplifier, not audio amp, some can be a bit microphonic, be prepared to try a few in order to get a good pair.

3rd February 2010, 04:29 AM	#3
davethomp diyAudio Member Join Date: May 2008	Thanks 'radiotron'. I'll certainly follow-up your recommendation. 6AC7 are indeed around and offer some options for improvements in sound. The 6N7P on the other hand has some options as an alternative is an ECC31. Whoa, there's a few options there...some are quite classic, and therefore expensive and worth more than the poor amp! A pair of globe type would be gorgeous! But we don't use valve amps for looks do we? Thanks and Kind Regards: Dave

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