Tube suggestion for 10 or so watt, push pull

[Ed_Chambley]

I am going to build my first small watt non-Princeton type amp.  What I really want to make is a power section which will yield about 10 watts output and stay fairly clean.

I am looking for suggestions for power tubes since I know absolutely nothing about little power tubes.  I am dreaming, but I am going to attempt to tweak 10 watts to sound like a Blackface twin which means LTPI.

Let me know experiences with smaller output tubes.  Right now I have tried EL84's, but not quite right.  Anyone used a 6BM8, if so what type of tone?  Anything info shared would be much appreciated.

[sluckey]

6AQ5 would be a candidate. It's kinda like a 6V6 in a small 7-pin heptal tube.

[printer2]

6AQ5 is the obvious standard non-standard tube. You bias it up like a 6V6 but it does not like to have more than 275-300V on it, seven pin tube. 6K6 are a 8 pin lower power 6V6, more or less. The 12AB5 is a 6V6 in a 12 pin tube that runs off of 12V. Then you have EL84's, no reason to run them at maximum, at a lower voltage and power they will probably last you 10 years. Going a little different you have the 6W6GT, a pair might just make 10W. Its other equivalents is the 6GD6GT, and then they have their 12V brother 12L6 and 25V and 50V siblings. They are low plate voltage tubes, maybe 200-250V on the plate, high heater current though. NOS tubes are cheap though.

[Ed_Chambley]

Thanks for the replies.  I like it.  Let me know if something else comes to mind.

I got me some 6Aq5's already

Keep 'em coming.  Thanks Sluckey and Printer 2.

drgonzonm, I will look at the possibility of the KT33C.  I like me some GEC toobs.

[DummyLoad]

6AQ5 is down-rated 6V6 and probably what i'd use like the rest of ya...  ;-)

other candidates:

run 6V6 lower-volt for 10W output.

6V6 in a 9pin bottle - 6CM6 also good for 10W @ 250V B+.

http://tubedata.milbert.com/sheets/137/6/6CM6.pdf

6F6 is another.

http://tubedata.milbert.com/sheets/127/6/6F6.pdf

if you're considering a lower-volt plate plan 6Y6 is another choice.

http://tubedata.milbert.com/sheets/093/6/6Y6GT.pdf

if you want to dip down into the 4-5 territory with very low-volt plate plan use 6EH5

http://tubedata.milbert.com/sheets/127/6/6EH5.pdf

6CW5/EL86 - 180V to plates and screens into a 5Ka-a load should hit the 10W mark in class A. you could use a step-up isolation x-former for this plan. 

http://tubedata.milbert.com/sheets/093/6/6CW5.pdf

6CZ5 - with 250V B+ into 10K load makes about 10W - class A

http://tubedata.milbert.com/sheets/106/6/6CZ5.pdf

--pete

[tubenit]

Anyone used a 6BM8, if so what type of tone?

Heck yeah!  Geezer's Little Wing Bassman sounded FANTASTIC to me!!   Beautiful tone and reasonable clean tone for such a small wattage amp.  Amp schematic and layout are here:

http://www.el34world.com/Forum/index.php?topic=562.0

The sound clip used to be here and it was wonderful, IMO.  Maybe Geezer still has a copy that he could email you?

http://www.el34world.com/Forum/index.php?topic=737.0

With respect, Tubenit

[loogie]

The RCA datasheet shows a 6V6 at 250v and 10k running at 10W.

[printer2]

6CW5/EL86 - 180V to plates and screens into a 5Ka-a load should hit the 10W mark in class A. you could use a step-up isolation x-former for this plan.  [/url]

I am using a 15CW5 (15V heater) in a SE Champ type of amp at 175V and the thing kicks butt. I think a pair will do more than 10W as a single tube is said to hit 5.6W. One day I will do a P-P amp out of these, said to put out about 25W at 250V. Similar to a EL84 in sound. 

[PRR]

> The RCA datasheet shows a 6V6 at 250v and 10k running at 10W.

+1.

6V6 is THE go-to for 10 Watts. 14W is possible, though hot. Yes yes, Fender cranked them well past 20W... you don't have to beat your mule with a stick. Copy the 10W condition and a pair will last decades.

6AQ5 is nearly the same thing, smaller (so NOT the same), less popular, which means if you push past the 10W condition they will die someday, and you won't find 6AQ5 in the nearest Banjo World (they got 6V6). OTOH there are no new 6AQ5, so they are all golden-age; OTOH they are popular enuff that what you get today may have been picked-over, the cream skimmed off.

If you must build too small (two octals usually does NOT define your total amp size), then 6BQ5/EL84 is at least readily available on a rainy night in a far town.

Hel, two 6550 at 275V and 10K load gives your 10 Watts, and if they ever die you KNOW it wasn't from abuse.