Integrated Tube Amp- Tube Types and Positions vs. Impact on Sound

[avanti1960]

Hi,
I just got a new tube integrated amplifier and have some questions about the types of tubes in the various positions on the amplifier-
2X 12AT7 (phase inverter)
2X 12AT7 (preamp stage)
2X 12AU7 (first stage power amp)
4X 6L6GC (power tubes)

If I wanted to tube roll, which positions would have the least and most impact on the sound?

Are any of the positions better suited to specific tube flavors- example put a bright tube in the phase inverter spot but put a warm tube in the preamp stage- in other words are there rules to mix and match?
Really enjoying the sound so far- much better than my old solid state amp. Just thought it would be fun to experiment but want a basic recipe if possible.

Thanks!

 

[nerdorama]

Seems to me that tubes in the higher gain locations would have the most impact on sound, i.e., the first power amp stage or a preamp stage, even though they all have an effect and especially if the stage is underdesigned.

 

[kward]

You'll have to try different manufactures of frontend tubes to see what sounds best to you. Try some old stock tubes if you can. Rolling power tubes will have a slight impact but not nearly as much as the small signal tubes.

 

[gadget73]

The inverter stage also generally will not have a huge effect on things, provided you have tubes that produce reasonable balance. Mostly its stuff upstream of the amplifier section that changes the most.