Rolling Tubes in a high gain amp environment....

Springfield Scooter

Well-Known Member
Apr 13, 2017
Reaction score
Yeah I have found subtle differences with higher gain, my TSL was quite shrill and some Mullard, RFT and GE settled that down. Past that minor differences in gain.
Even with a clean amp it ain't night n day difference to these ears.

Interesting....Do you think you would know in a blind test, at decent gain levels?


Well-Known Member
Sep 8, 2008
Reaction score
Lakeland, TN
I find some preamp tubes are more open sounding like I61's vs I63's. But usually, the best sounding tube is the one that tests the highest.

Matthews Guitars

Well-Known Member
Aug 17, 2019
Reaction score
The biggest tonal change regarding a tube change I've ever personally encountered was with my own 2203 I currently own. It's my second 2203.

The first one was an outright monster. The Angus Young AC/DC classic tone was built right in, and that was at a low drive setting. At higher drive and tone settings it sounded like the REST of classic rock.

But this second amp has always been somewhat lackluster. Even replacing its Hammond OT with a correct, period correct OT that's right for the type, helped but didn't fix it.

It had EL34s in it. And so one day I decided to check the bias. Found out it was all wrong, very cold, with crossover distortion. Then I saw it: Non-standard bias circuit resistor values. At that moment I decided to try 6550s in the amp. And would you know it...that was it. It was a USA market 2203 made to run 6550s and when some prior owner retubed it, he put in EL34s and never changed the bias circuit to bias it correctly. A quick adjustment to bring the bias to 70 percent for 6550s and the tone was found to be greatly improved. Now it sounds as good as my first 2203. Rich, warm, with plenty of drive and harmonics.

What I was really surprised at is how much more overdrive it has now than when it was totally out of bias range with the wrong tubes. I would have expected that to be all a matter of the cold clipper stage which should not have changed at all with an output stage change, but apparently there's more interaction going on there than I would have guessed. It made a HUGE difference.

If you have a 6550 equipped amp, just try swapping in a set of EL34s and don't touch the bias. Play it and see for yourself how much things have changed. I think you'll be amazed. And you'll put those 6550s right back in.


Well-Known Member
Jan 24, 2008
Reaction score
Mifflintown, Pa.

Years ago, I acquired a small amount of vintage 12AX7 tubes.
I also purchased 5 or 6 different brand new 12AX7 tubes .
They all passed the test on my simple Orange VT1000 tube tester.

I then proceeded to roll tubes in my vintage 2204, with the preamp volume turned up high.
After spending an entire afternoon, testing sound quality between different tubes, I remember walking away scratching my head....

No matter what tube I installed, there was no significant difference to my ears!
In other words, there was not 1 tube, that I thought sounded superior to my ears.
I remember thinking at the time, that if I did a "blind" test, I would not be able to pick out any 1 tube that was superior.

So fast forward to today....
I added a few more brand new tubes to my small collection.
So I now have maybe 15 different 12AX7 tubes, both old and new.
Again, I pull out the my tube tester, and they all pass the simple Orange test.

So today, I sit down with a decent amount of different 12AX7 tubes, both old and new production ...
This time however, I use a different amp, thinking that simplicity would prevail.
So today, I choose a 5 watt Epiphone Valve Junior, which only utilizes 1 preamp 12AX7 tube.
Think poor mans Fender Champ. Similar but different.

My thinking was that by using the Epiphone Valve Junior amp that utilizes only 1 preamp tube, the differences between different preamp tubes would be much more pronounced.
Again, I spent several hours rolling tubes in the little Epiphone, with the volume up 3/4 to 100%, which is exactly where I like.
And once again, despite having many different tubes at my disposal, I walk away with basically the same result...

There was not 1 tube that was clearly better to my ears, than any of the others.
Again, I feel like I would not be able to identify any of the tubes, in a blind test.

Am I alone ?
Do I need to get my hearing checked? LOL!
I was expecting a much different result to be honest.

Im wondering if that because I play and prefer a distorted sound, that the effects of different tubes, has a much less noticeable effect, as opposed to a very clean tone.
Im now considering re-doing the test, utilizing the same 2 amps, but using a much less distorted and more clean setting.
But my thought is that if I seldom play with a clean tone, what would be the point.

Old tubes included several old Bugle Boys, RCA, Zenith, International and Mullard.
New tubes included Mullard, Tungsol, EH, 7025 prefered, Shuguang, Mesa, Marshall red labeled,Marshall white labeled and JJ.
Some have long plates, and some have short.
Dates range from the 1960's used tubes, to modern tubes purchased only a few weeks ago.

I should also add, that both amps are in great order...
No bad power tubes.
And that all tubes sounded great....Just not THAT different

The good news, is that this test re-confirms my own personal lack of needing more tubes!


Im wondering what other MFR's thoughts are, on tube rolling with a high gain, distorted sound ?

Do you feel like more distortion and a higher gain setting, has a lesser effect tube rolling has?

Are you able to identify your favorite tube, in a blind test, at reasonably distorted / high gain levels?

Your thoughts please...

View attachment 103608

View attachment 103610
I have done similar testing with my DSL40, 40CR & DSL1C & recall doing the same with my Studio 15 many years ago. I came to the same conclusion, I cannot hear any difference. I have had CP tubes that I did not like, but they most likely faulty tubes. I am considering selling off my old tubes to fund a new guitar if anyone ever gets a decent selection in stock again.


Well-Known Member
Dec 29, 2011
Reaction score
Though I don't use my tube amps anymore, I quit rolling tubes long before that...I found, the more gain stages, the less of an effect different tubes make.

Simple circuits yield more noticeable differences.


Well-Known Member
Nov 8, 2021
Reaction score
I have many RFT ECC83. Those
always have the biggest impact in v1 of
a classic MV Marshall. Instant Ratt. The Squish. The bite. I hate it.

Everything else, the inbetween differences are way more subtle.