I’m still in the process of testing valves, here is how the ranking is coming up so far. This is a mix of driver and output valves. All tested at Vo=+22.22dBu:
Looking at the chart above a couple of interesting points to highlight:
- 4P1L is the most linear valve I’ve found so far.
- 6e5P and 6C45 are expected to be on the top five anyway.
- 12P17L despite of having similar characteristics as 4P1L is not that linear
- 6N6P and 6N6P-I disappointed me. I thought the would be more linear..
- 46 and 47 in triode mode are superb drivers
Have so many other ones to test, but limited time….
Expect this chart to be updated in the future, so stay tuned 🙂
Supply voltage ?
Load impedance ?
Bias ?
etc.
CCS loaded and fixed bias. Both Vak and Vgk optimised to find lowest THD point
Should give you an idea of valve linearity.
Etc? Is not enough? Can you type more than three lines? 🙂
Hi Ale,
Have you tested a more known tubes as 6N1P, ECC99 or 6N30?
Hi Luis, no am afraid. Cheers
Happy to see your site is up.
I’m curious to understand whether these THD tests were done on one sample for each, or are these results an average of several? Thank you for your works.
Hi Jeffrey
Thank you. I cannot recall how many samples were taken to produce but varied depending availability on my stash. Needless to say, average is indicative and should taken as such as variance exist from valve to valve.
Cheers
Ale
Hi Ale, what do you think about using those nice EF184s as drivers for 45 triodes?
Cheers, Diego
Hi Diego
Sure. This is an old testing I made with probably not as big sample set as I’d have wanted to. Yet, is a good indication of which valves are more linear than others.
Having said that, the EF184 is a very good valve. A real sleeper in my opinion. Have a look at this: RL12P35 SE Amp – part I. It can definitely perform really well as driver!
Good luck
Ale