Members bass_n_drums Posted September 14, 2012 Members Share Posted September 14, 2012 yeah I will definitely buy more NOS tubes for the other positions. I have NOS tube GAS now Welcome to the NOS tube club finally! Took a while but you're there now!..lol I would check out ebay for NOS tubes. It's alot a cheaper and if you find a seller with good feedback. It's a good chance you'll get a good deals on NOS tubes. I haven't bought from online tube sellers for quite sometime now, because they are just too pricey. Link to comment Share on other sites More sharing options...
Members ENdtime Posted September 14, 2012 Members Share Posted September 14, 2012 it's a different effect from turning down the gain, the gain stays the same at the preamp input stage, but the output to the power amp is lower so the signal going into the power amp is cleaner. Yeah, I know its not the same, but I still think if you are looking for slightly cleaner gainit can still be accomplished with the amp alone.. And just for arguments sake, if what you are saying is the only reason the sound is different, i.e its sending a cleaner lower output signal to the power amp, then what would be the difference of putting a volume pedal into the fx loop and lower the gain with that.? Its lowering the signal before the power amp... I don't believe that, I think the tube itself alters the tone because its a different tube than the amp was designed for... Personally the Jan Phillips 5751 was the only lower gain tube that I thought didn't alter the tone in a bad way.. It seems to keep the tone in tact, but adding a slightly cleaner sound that still had a the highs and overall sound, but just a little different.. Link to comment Share on other sites More sharing options...
Members knucklefux Posted September 14, 2012 Members Share Posted September 14, 2012 it's a different effect from turning down the gain, the gain stays the same at the preamp input stage, but the output to the power amp is lower so the signal going into the power amp is cleaner. that's actually not the case. an AT in the PI yields a slightly larger peak to peak voltage swing than an AX. go here: http://www.ampbooks.com/home/amplifier-calculators/long-tailed-pair/ put in 10K for the tail resistor and look at the voltage gains (inverted and non-inverted), then change the tube type to 12AT7 and see what happens. how a tube behaves is very dependent on the circuit it's in Link to comment Share on other sites More sharing options...
Members peavey_impact Posted September 14, 2012 Members Share Posted September 14, 2012 I found a pile of vintage tubes the other day - couple of GE 12ax7's but mostly USA made 7025's and 12au7's. Would the 7025 or 12au7's be useful as a phase inverter? Link to comment Share on other sites More sharing options...
Members knucklefux Posted September 14, 2012 Members Share Posted September 14, 2012 7025 specs about the same as a 12AX7. 12AU7 isn't so good for PI, it's best used as a driver or buffer. Link to comment Share on other sites More sharing options...
Members Jack Tone Posted September 14, 2012 Members Share Posted September 14, 2012 Forumite Vbshredder posted this tip a few weeks ago about doing it to a Carvin MTS3200. I tried putting a 12ay7 in the PI. It took the life out of the amp. Then tried a 12at7, much better. Now it goes from growl to more growl. That could be perfect for some. I kind of like the original no name 12ax7 growl to scream. Might go back to that. Link to comment Share on other sites More sharing options...
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