Double Bass preamp tubes

[Mr Ralph]

This question is for the electronics gurus. I am fooling with My ART Pro Channel preamp. I want to use it into a power amp and drive my Acme Low B 2. I have been experimenting with mics rather than pickups on my Kay DB. My question is this, if I swap out the 12AX7 for a CV4004 which has a lower gain would that help not overdrive the preamp and result in more volume before feed back. Would just setting the gain at a lower level and increasing the master result in the same thing. The ART is a little noisy and I think it might be time to swap out some tubes so I thought I might try to put something in that might be more friendly towards micing a DB. I have two amps to choose from. Crown DC300A 600 watts bridged in mono or a Peavey Tour 700 500 watts into 8 ohms.
Thanks

 

[drurb]

If you are overdriving the front end, then, yes, the best course of action is to reduce the level at the input. If you want to fiddle with gain (µ)-- which I don't recommend-- then you could swap among the 12A*7 family. Highest gain is the 12AX7 followed, in turn, by the 12AT7, 12AY7, 12AV7, and 12AU7. The gain factors are 100 (40 dB), 60 (36 dB), 45 (33 dB), 41 (32 dB), and 19 (26 dB), respectively. Again, if you're overdriving your 12AX7, reducing gain is not the way to go.

 

[Mr Ralph]

I guess a better way to ask the question would be, would a lower gain tube give more volume before feedback or help prevent any feedback. I always look for the cleanest sound so I it would not be my intention to overdrive the preamp tube. The Cv4004 is a 12AX7 with only 85% gain I believe.

 

[drurb]

In a word, no.

 

[Mr Ralph]

drurb, Thank you for the easy answer.