Which tubes in my system are most critical to sound quality?
Apr 2, 2004 at 11:20 PM Post #16 of 18


Why is there a chaplain standing over his wallet?
Aug 12, 2001
The frustrating thing about tuberolling is that you really don't know just what you've done until at least a week or two after you've done it, unless the tubes have been freshly broken in already. It can take up to a month for a tube in regular use to take on its final sound. Fast impressions can guide you, but you do run a risk of missing something good.

A general rule of thumb is that tubes that provide a lot of gain affect the sound the most. That's usually an input tube, or driver. After all, they're magnifying the signal, which can make their effect disproportionate. An output tube is increasing current, but may not be affecting gain all that much. This dimishes the effect on the sound to a certain degree.

Ultimately, certain input tubes will sound their best with certain output tubes. An input tube that you think sounds bad with one tube in the output position may sound perfect with a different output tube. Finding the right combinations is not a job for the impatient.
Apr 2, 2004 at 11:26 PM Post #17 of 18


Founder of the Head-Fi Pay-to-Post Program.
Sep 1, 2002
I cede the floor to my esteemed colleague Hirsch. No single item in the chain stands alone, therefore, tuberolling one tube in the chain may not have as big an effect as we think. Synergy plays a bigger part than we generally put attention to, and it is to our system's detriment.

I'm looking forward to seeing how the tuberolling in the CDP affects the sound coming out the Weebl. Who knows, what is normally not the best sounding tube could be a real winner in this combo.

Thanks Hirsch. You're always a fountain of wisdom and practical knowledge.
Sep 8, 2011 at 8:49 PM Post #18 of 18


New Head-Fier
Sep 2, 2011


Originally posted by ServinginEcuador
Take one set of the input tubes and swap them on the preamp first, then remove then and try them in the amp. Lastly, try using a swap of the input tubes on both amps to see how it sounds...

sounds good. i just haven't had the patience. what i've noticed is that 12au7s on my preamp change the sound the most. i'm not really sure about whether the 12ax7s or 12au7s in the power amp have more effect though. i usually swap those around at the same time. if i get a chance i'll try seperately and report back.

I wonder if you did find any significant effect tube rolling of the 12ax7 or 12au7 of the power amp had on the sound, with a preamp.

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