# question about tube power section



## vandorp (Nov 13, 2011)

Hi!
In the last 2 week i had built my first tube amp based on the ax84 p1 6l6 version and when i had finish i was surprised about the power and guts he delivered..

My question is if i use only 1 6l6 and having big power with, why big companies like fender or marhall peavy dont build little amp with 1 6l6 or 1 el34?


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## J S Moore (Feb 18, 2006)

The Marshall class 5 is a single ended EL84 amp. Fender makes a class A amp as well. Most of them I've seen use EL84 or 6V6. If you hunt around you can find class A amps with almost any tube.


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## washburned (Oct 13, 2006)

One issue might be cost. In order to handle the higher voltages involved, they would have to use bigger, more expensive xformers etc. to produce the same output that an AB class amp with two 6V6 or similar would produce. The single ended 6L6 was a popular high end audiophile design.


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## keeperofthegood (Apr 30, 2008)

I am NOT an expert!! But, I have read a fair bit.

When you have 1 tube as your power out tube that is called Single Ended. There are many single ended amps out there (like say the Epiphone Valve Jr.) however they are not as common as Push Pull amps.

There are pro's and con's to either kind. For instance; if a tube has 10 watts MAX power handling on its own in a Single Ended in a Push Pull you can get at least 20 watts from two tubes and often 50% more than that because the tube does not work all the time, so say 30 watts out of two 10 watt tubes.


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## vandorp (Nov 13, 2011)

ok thank i understand but if i had compare 1 6l6 and 4 el84 for about 25-30 is just question asking for myself.

and yes i had see a lot of schematic in hifi systeme with one s.e. 6l6 
I had chosen this schematic because i own a dual rectifier and some old 6l6 may be good for a personal project and i think is awesome and intriguing !

thank for all who had respond me


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## blam (Feb 18, 2011)

vandorp said:


> Hi!
> In the last 2 week i had built my first tube amp based on the ax84 p1 6l6 version and when i had finish i was surprised about the power and guts he delivered..
> 
> My question is if i use only 1 6l6 and having big power with, why big companies like fender or marhall peavy dont build little amp with 1 6l6 or 1 el34?


Marshall has the class 5. single el84
Vox has the AC4, also a single el84
Fender has the champ 600 as well as the Champ reissue which are both single 6V6
Mesa has the 5:25, 5:50 and mini rectifier that all have a 5 watt mode that uses a single el84 or 6l6 depending on the amp.


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## vandorp (Nov 13, 2011)

yes i know that a lot of little amp using one el84 but one single el34 is rare like the 6l6 ,i never seen but if mesa make one, is this recent or an vintage amp ?


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## blam (Feb 18, 2011)

It's the 5:50 express of I'm not mistaken. It might be the 5:25 though 

I'm 5 watt mode it uses a single 6l6


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## bcmatt (Aug 25, 2007)

I had a single ended amp that I had converted from a Ceriatone Vibro-champ into the "Class Act" by Allen Amplification. Since the Ceriatone came with a quite over-rated OT, it was safe to do so. THe Class Act was set up to use a 6V6, EL34, or 6L6. It was a neat little amp and each power tube brought its own neat flavor.
I gave it to a friend though and he converted it back to a Vibro-champ with a tweed switch. 
I think that when most people want a single-ended amp, they are thinking they want something with good saturation at lower volumes, and so the smaller, less powerful, tubes are more marketable (and cheaper).


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## Furtz (Nov 27, 2010)

Single ended power amps *have to operate in class A* and are really inefficient compared to a push-pull operated in class A/B. 
The most you can squeeze out of a single-ended 6L6 or EL34 is about 10 or 12 watts, whereas typically a two tube 6L6/EL34 push-pull in A/B will give you 50 to 60 watts.
As an aside, all preamp tubes operate in class A.


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