gah, ok, preamp tubes

[drew_half_empty]

ok, i know 12ax7's are the highest gain tubes, and 12at7's are like a lower gain tube for the PI, but apparently i'm confused about 12ay7's and 12au7's

see, i thought both of those were just even lower gain phase inverter tubes, but the groove tube site says 12ay7's in the preamp will clean up the tone, and a 12au7 is either a low gain preamp tube or a "high current" PI tube, which i guess means more gain than a 12ax7? I know ampeg svt's use both 12au7's and 12ax7's, but i guess i assumed the 12au7 was in the PI

so basically, if you had 2 preamp tubes & one PI tube, what would be the absolute cleanest setup you could run without compromising any volume?

 

[Pierre]

Re: gah, ok, preamp tubes

I don't know about current. But usually running a pre tube (gain stage) at a higher VOLTAGE at the plate means more headroom, i.e a cleaner sound in a way.

 

[joelap]

Re: gah, ok, preamp tubes

I always thought that AU7 and AY7 had lower gain than a 12AT7. But don't quote me. This thread reminded me I needed to PM you, drew.

 

[Lake Placid Blues]

Re: gah, ok, preamp tubes

Regardless of numbers, in practice, a 12AY7 behaves much like a cleaner 12AX7. The 12AT7 really is best used as a PI and reverb driver, and not as a tone shaper early in the signal path.

 

[the guy who invented fire]

Re: gah, ok, preamp tubes

Drew,

Your PM has been replied to!

 

[Scott_F]

Re: gah, ok, preamp tubes

Go to www.kcanostubes.com and select Resources. Then look for preamp tube gain chart.