I look for a correct driver stage

[nonos]

Hello,

I built my own designed tube amplifer. You can see this below.

I think the driver stage not to good for the KT66. I don't know what kind of stage do I use in this. Parallel triode , SRPP, mu follower? Which is the best choice?

Can you suggest the correct driver stage schematic?

I thougth that I try the cathode follower between the first stage and the KT66. What do you think this is good idea?

Thanks,

Nonos

Sorry that you can something but my english is not to good. :-(

 

[Frank Berry]

KT66/6L6 is easy to drive but you'll need some gain in the driver stage.
You may want to look at the schematic in the following link.

http://www.bonavolta.ch/hobby/en/audio/6l6_1.htm

 

[nonos]

Look for a cathode follower schematic for KT66

Hi

I know this schematic. It was the first version of my amp, but I had some problem with this.

If you use 6L6 in this setting , the dissipation will be to big for 6L6. You need to use 6l6GC but it was very expensive for me.

The sound of this driver stage is very hard so I didn't like it.

I would like to heard soft but determined sound. Therefore I know the cathode follower stage.

Thanks

 

[Jax]

The KT66 needs some 18-19V RMS for full output. A triode with a mu around 20 will have a voltage gain of around 14 rendering an input sensitivity around 1.5V RMS for full output.

Say one triode in an ECC82 with 100k plate and 2.2k on the cathode with a cathode bypass and with Vb = 400V would do the trick if you have no feedback.

If you do not want a cathode bypass you will need a triode with higher gain (and harder sound in my opinion). I'm not a friend of ECC83 with output voltages over a few volts.

Another option would be a mu-follower using a couple of ECC82-type triodes.

BTW, the Linde schematic uses an ECC81 in an SRPP, in my opinion a very bad choice.

 

[Zen Mod]

cheap solution-ECC88 single or paralleled
better solution-say any gutsy triode (or trioded pentode) with lotsa gain and adequate IST

 

[nonos]

mu follower

What do you think about this driver stage?

I would like to try it in my amp, but I have to change the setting of the ECC83. The power supply for this tube is about 400V and I would like that the power supply will be same in bouth triode in the driver stage.

What is the correct current for this setting? Where does it sound in the best?

Thanks,

 

[SHiFTY]

Well I really liked a 6SL7 cathode follower driver stage on my SET. It increased the bass, made the music more alive and made it sound like a proper amplifier!

One thing I would suggest is putting 200 ohm grid stopper resistors in front of each ECC83 grid, this stops parasitic oscillation.

I don't know the best operating values, suggest what is used in your schematic.