EL84 DC 10Y Project

[korneluk]

Folks,

I'm looking for a summer project. What do you think of a DC coupled EL84 to 10Y output, similar to the one in the link below?

An externally hosted image should be here but it was not working when we last tested it.

http://www.tubemaster.de/e-diy-EL842A3.html

Alternatively, I am also contemplating a Yamamoto style 717A cap-coupled to a 10Y output - even though I am not yet convinced about the sonics of this combination - I think it may sound kind of thin...

The EL84 is a very musical tube and I think it would pair u well with the 10Y's extended highs. What do you think?

TIA,

-- josé k.

 

[alexg]

I have been looking at this particular schematic and has been in contact with the person who did this amp.

My only worry is that the EL84 will not be able to drive the 2a3 to full power.

Any comments on this?

 

[Sheldon]

I'm looking for a summer project. What do you think of a DC coupled EL84 to 10Y output, similar to the one in the link below?.

If you are going direct coupled, here's a thread that might be interesting: http://www.diyaudio.com/forums/showthread.php?s=&threadid=123211

Save you some iron.

Sheldon

 

[astouffer]

My only worry is that the EL84 will not be able to drive the 2a3 to full power.

Not much of a worry when the 2A3 will give 2.5 watts and a EL84 pentode is over 5.

 

[DougL]

Not much of a worry when the 2A3 will give 2.5 watts and a EL84 pentode is over 5.

astouffer, since the EL84 is being used as a voltage amplifier, its "wattage" is beside the point.

I ran the circuit through tube CAD. I got an Av of 11.5 with the values listed. Multiplying that by 2 Vrms output "standard", it results in 23 Vrms to the grid of the 2A3.

Plugging 70V peak into SE CAD with a 2A3 Fixed Bias with 250V on the plate shows signs of clipping, and 3.75 watts RMS

So it appears that the gain is just enough for full output.

HTH

Doug

 

[alexg]

Not much of a worry when the 2A3 will give 2.5 watts and a EL84 pentode is over 5.

I fully understand that in pentode mode the EL84 has higher power than 2a3, but EL84 as a driver fed with at the max of 2V from a CD player, would it develop enough voltage swing to drive the 2a3 to full power?