Re: [Harp-L] Switching tubes for easier breakup...

[G <gigs@xxxxxxxxxxxxxxx>]

Date: Thu, 1 Sep 2005 18:38:31 -0700 (PDT)
From: Mojo Red <harplicks@xxxxxxxxx>
Subject: Re: [Harp-L] Switching tubes for easier breakup...
To: stiv whiskywine <thepinkcrickets@xxxxxxxxx>, harp-l@xxxxxxxxxx

>Hey Steven,
>I'm no expert, so don't take this as gospel truth.
>Hopefully others with a better grasp of this stuff
>will help straighten you out. 
8<
>When I talk about swapping tubes, it generally is
>with the goal of avoiding feedback and creating a
>little more "head room" rather than specifically to
>make for easier breakup. 
8<
>If you can crank up a your amp a little higher
>before you reach the feedback threshold the tubes
>get a chance to work a little more and express
>their coolest characteristics and you have more
>play in your settings before hitting the feedback
>threshold. 
8<
>Harpin' in Colorado,
>--Ken M.

After doing tube swaps of this type, players will find they can turn the
volume knob a lot higher than they previously could.  There is a
misunderstanding that this means the amp is playing at the same volumes as
a stock amp of this type dialed the same way - this isn't the case.  

An amp with a replacement 12AU7 preamp tube with the volume dialed to 7,
does not produce as much volume the same amp with a stock 12AX7 tube with
the volume dialed to 7.

  Depending on the amp and the tubes you swap in, and which ones you're
replacing, the extra volume you can squeeze out isn't that much more than
you were getting before. But doing this gives you a lot more control to
nudge up to that upper limit while avoiding feedback, and depending on the
setup, more distortion at lower levels.

I hope this helps.
-- G.