Power amplifier EL 34

[miguelnoda]

amplifier need it have more input gain like putting a 6s7l or changing the circuit 6SN7
Can somebody help me

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

 

[JonSnell Electronic]

Use a triode pentode as a driver? Like ECL82 or an International Octal version, if you can find one.

 

[petertub]

Add a stage before the existing tubes.

 

[miguelnoda]

power amplifier el34

Might help me design it
is valid parallel design of the 6SN7 or could be done otherwise considering having interstage transformer
has little input sensivilidad for me preamplifier Audio Research SP16

 

[Koonw]

http://www.diyaudio.com/forums/tubes-valves/279312-mu-follower-analysis-4.html#post4442892

The above is posted by MrCurwen, it is a CCS PP transformer coupled 6sn7 output stage which can be used to drive your output stage with a suitable IT. I think it's very nice, more gain, less distortion, probably more driving power. Can be adapted for balanced input too.

 

[michaelsamra]

You answered your question..You need a high mu voltage amp like a 6SL7 before the 6SN7..You have an IT is taking the place of coupling caps from the phase splitter but if you use the Tri/pent like a 6U8,6BL8.or7199,you will have to lose the innerstage. I would just add a 6SL7 or a 12AT7 in front of the 6SN7 and you will be good to go.

 

[miguelnoda]

power amplifier el34

Can you help me change my scheme putting 6SL7

 

[michaelsamra]

Yes,how about this schematic?

Then if you want to use the IT,just put it in place of the coupling caps.

THE DIRECT INPUT EL34 AMPLIFIER

 

[michaelsamra]

Mieguel
Just add the 6sL7 the way it is done in this schematic which is basically DC coupling the upper triode to the phase splitter and the NFB is fed to the lower triode.I have heard this circuit running KT66s and it's fantastic.

 

[lexx21]

Why not just build the amp as is and build a separate preamp if you need one. If you do end up needing a preamp you can swap them out if you want to try something different.

Make sense?

 

[Koonw]

It will need about 1.3V-p drive level to full output (if I got the IT LL1660 inductance correct). See similar simulation here. So do you still need more gain or sensitivity?

 

[miguelnoda]

power amplifier el34

I've put a better 6SL7 and will need to know if I have to change the resistance of the cathode has more gain and I have to go up less volume
the concept is good or parallel would have to change
on the other hand I put resistors in the cathodes of independent EL34 12w 820ohn

 

[Koonw]

I've put a better 6SL7 and will need to know if I have to change the resistance of the cathode has more gain and I have to go up less volume
the concept is good or parallel would have to change
on the other hand I put resistors in the cathodes of independent EL34 12w 820ohn

You'll get better bottom end response if you series the 2 primary windings and driven by a single 6sn7, using the other as gain stage. The give you 0.3V-p drive to full power.

 

[michaelsamra]

Why not just build the amp as is and build a separate preamp if you need one. If you do end up needing a preamp you can swap them out if you want to try something different.


Now that I think of it,you are probably right because this is using IT coupling and EL34 are relatively easy to drive and then he can just implement an extra stage later if he feels he needs more gain in the early stage.

 

[miguelnoda]

power amplifier el34

I feel very good the circuit I will make and tell you my experience
Thank you very much for the help

 

[michaelsamra]

I feel very good the circuit I will make and tell you my experience
Thank you very much for the help

Excellent..Since the innerstage trafo is handling the phase splitter duties and the 6SN7 is paralleled, it may be just enough for this circuit not to mention the innerstage could be stepping up the voltage gain as well.

 

[miguelnoda]

power amplifier el34

I have already tried the new scheme and sounds great but it has too much gain
I would like to take him down to change parameters makes me much noise
I have spent the filaments AC to DC so there is less