princeton reverb preamp tubes??

i'm thinking of swapping out some preamp tubes in my princeton reverb.
I don't know what the first 12ax7 runs, the one next to the output tubes.
I just want to know what each preamp tube actually does?
i've had a good look round the internet to find out which preamp tubes go in which sockets but had no luck.
when I find out which is the most/least critical for tone, then I can mess around a bit with my bog standard tubes and spend more on the one/ones that matter most.
thanks,
mal.

The one closest to your output tubes will actually be V4. Half of this runs the tremolo oscillator and the other half runs your phase inverter. The tube on the far end from the power tubes will be V1, which is your input tube. Usually you will notice the most pronounced change by changing V1, although the others will of course contribute as well.

V1-A: input and tone stack driver
V1-B: tone stack recovery
V2-A/B: these are paralleled and drive the reverb tank
V3-A: reverb recovery
V3-B: pre-inverter gain stage
V4-A: tremolo oscillator
V4-B: unity-gain (almost) phase inverter
V5, V6: output tubes
V7: rectifier

The one closest to your output tubes will actually be V4. Half of this runs the tremolo oscillator and the other half runs your phase inverter. The tube on the far end from the power tubes will be V1, which is your input tube. Usually you will notice the most pronounced change by changing V1, although the others will of course contribute as well.

V1-A: input and tone stack driver
V1-B: tone stack recovery
V2-A/B: these are paralleled and drive the reverb tank
V3-A: reverb recovery
V3-B: pre-inverter gain stage
V4-A: tremolo oscillator
V4-B: unity-gain (almost) phase inverter
V5, V6: output tubes
V7: rectifier

thanks, any ideas what tubes to try first?

I put JJ`s in the power section and Tung Sols in the pre amp section. Sounds great for inexpensive easy to find tubes.

To quote myself from my post earlier, "Usually you will notice the most pronounced change by changing V1..."

So I suggest changing V1.

In my homemade Princeton Reverb, I put the new Tung-Sol 12AX7's in the preamp (V1, V3, and V4) and a JAN Philips 12AT7 in V2. Power tubes are Svetlana 6L6GC's. (Oh, I should mention that my amp has 6L6 output tubes. The power and output transformers are sized for the higher power tubes and the bias is changed accordingly.)

Also, a 5751 sounds terrific in the V1 spot as well.

To quote myself from my post earlier, "Usually you will notice the most pronounced change by changing V1..."

So I suggest changing V1.

In my homemade Princeton Reverb, I put the new Tung-Sol 12AX7's in the preamp (V1, V3, and V4) and a JAN Philips 12AT7 in V2. Power tubes are Svetlana 6L6GC's. (Oh, I should mention that my amp has 6L6 output tubes. The power and output transformers are sized for the higher power tubes and the bias is changed accordingly.)

Also, a 5751 sounds terrific in the V1 spot as well.

thanks for the info,
much appreciated,
mal.