Here is a quick test I did today that the 6e6p-dr is a promising valve as a driver. I’ve used 6e5p and made several tests with these fantastic valves. Anyway, looking at a single sample from my stock:
The 6e6p-dr can do well and provide a nice 0.17% @ 200Vpp. Not many valves can do this in triode-mode.
Now, let’s look at the harmonic composition:
Edit (28th July 2014): The harmonics should be read: K1=H2, K2=H3, K3=H4 and so on.
Harmonic level is very low and dominated by H2 with raising H4 above 120-130Vpp. An interesting dip takes place in H3 closer to maximum swing level. This may be due to CCS FET load interaction and harmonic cancellation I guess. Beyond 205Vpp my CCS is limited by its HT supply. It can be boosted, but for a quick test, here is were it ends 🙂
This will be another valve to try as a driver in my next 300B project.