Any info on Tube EQ tone matches?


I’m mainly running my Synergy through a Seymour Duncan PowerStage (solid state) power amp. Although I am really blown away by this simple setup, I was wondering about how tube amps color the sound. I’m thinking that it’s a simple task of using an EQ to add that color to the PowerStage setup.

I’m thinking about doing an EQ Tone match, and find the EQ curve that way. Record a track with the PowerStage. Then a tube head. But, I only have a borrowed 5150 head, with EL34s. I know that 6L6s have less mids, etc. Does anyone know if there is any info on this anywhere?


I found an article over on the Fractal forums regarding frequency response curves of power tubes.

The conclusion, if I understood it correctly, was that the power tubes themselves don’t have a “sound”.

Perceived sonic differences might be more attributible to variance in impedence and output transformer specs.

I’ll try to find that article again and post a link if you want.



Just yesterday I ran a test between the PowerStage and EL34s in a 5150 II head. The results was pretty shocking to me. They sounded pretty damn close, but I recorded a track of each and compared them in Ozone

Here was the comparison: EL34s in White, PowerStage in Yellow.

I’m starting to think it doesn’t have much difference at all. Minimal at best. I set the Ozone bands to the same frequencies on my MXR 10 Band EQ. I then matched the EQ and it was pretty much dead on to the EL34s.

This is by no means scientific, but it makes me realize that the “tubes or nothing” crowd might not be sitting on as solid ground as they think.


Thanks for the link to the Fractal forum post. It was an interesting read, and it backs up my finding, which I have shown here. The EQ comparison shows there is VERY LITTLE difference from the Seymour Duncan PowerStage (Solid State) and the 5150 head with EL34 tubes.

I matched each of the frequency points with the slider on my MXR EQ. Made the adjustments and asked my son if he can hear a difference. He couldn’t, and neither can I.


Also, by all means, you can post my findings on the Fractal forum. Might make for an interesting comparison demo