Best tube choice for 1st SET project?

roundel325 · 31st March 2004, 02:58 PM

This is my 1st post. I have been thinking of building a single ended amp for a while now. I have some tubes around and I am not sure which ones I should use in my design. I have a pair of 6v6GTA's, some el-84's, and a bunch of 12ax/u/t7's. I've also got a pair of telefunken OPT's with 5k primarys. So, I need to decide on the power tubes before I can buy a PT. Any suggestions? I am not limited to the tubes I have, I can buy more. But I'd prefer not to spend a bunch of money on 2A3's or 300B's. Any thoughts will be appreciated. Thanks!

-Jared

Roscoe Primrose · 31st March 2004, 03:35 PM

If you've got speakers that'll work on a watt or so, a simple 1/2 a 12AT7 into a triode wired EL84 ought to work fairly well, and it doesn't get much simpler than that...

Peace

SHiFTY · 1st April 2004, 04:29 AM

Both 6V6 and EL84 are nice tubes to use. I would go for single ended pentode (SEP) mode with a little negative feedback. In pentode mode they need very little drive, 1/2 a 12AX7 or 12AT7 would be ok.

You could get fancy and drive each one with 1/2 12AU7 in cathode follower (i.e 1/2 12AX7 -> 1/2 12AU7 cathode follower -> EL84) This would give you a 5W amp with decent bass and nice overload characteristics.

EL84 will give you more power which is a good reason to use them. Also they sound sweeter than a 6V6, IMHO. I like the bigger cathodes too. However, 6V6 are pretty decent if you have a pair of them...

SE triode mode is another option, but power will be down to 1 or 2 watts and you will need a better driver stage. Still listenable, but unless your transformers are super, IMO not worth it.

Doing a search on the forums you would see this thread about the same thing.

31st March 2004, 02:58 PM	#1
roundel325 diyAudio Member Join Date: Mar 2004 Location: Ohio	Best tube choice for 1st SET project? This is my 1st post. I have been thinking of building a single ended amp for a while now. I have some tubes around and I am not sure which ones I should use in my design. I have a pair of 6v6GTA's, some el-84's, and a bunch of 12ax/u/t7's. I've also got a pair of telefunken OPT's with 5k primarys. So, I need to decide on the power tubes before I can buy a PT. Any suggestions? I am not limited to the tubes I have, I can buy more. But I'd prefer not to spend a bunch of money on 2A3's or 300B's. Any thoughts will be appreciated. Thanks! -Jared

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31st March 2004, 03:35 PM	#2
Roscoe Primrose diyAudio Member Join Date: Jan 2004 Location: Virginia, USA	If you've got speakers that'll work on a watt or so, a simple 1/2 a 12AT7 into a triode wired EL84 ought to work fairly well, and it doesn't get much simpler than that... Peace

1st April 2004, 04:29 AM	#3
SHiFTY diyAudio Member Join Date: Jul 2002 Location: New Zealand	Both 6V6 and EL84 are nice tubes to use. I would go for single ended pentode (SEP) mode with a little negative feedback. In pentode mode they need very little drive, 1/2 a 12AX7 or 12AT7 would be ok. You could get fancy and drive each one with 1/2 12AU7 in cathode follower (i.e 1/2 12AX7 -> 1/2 12AU7 cathode follower -> EL84) This would give you a 5W amp with decent bass and nice overload characteristics. EL84 will give you more power which is a good reason to use them. Also they sound sweeter than a 6V6, IMHO. I like the bigger cathodes too. However, 6V6 are pretty decent if you have a pair of them... SE triode mode is another option, but power will be down to 1 or 2 watts and you will need a better driver stage. Still listenable, but unless your transformers are super, IMO not worth it. Doing a search on the forums you would see this thread about the same thing.