GPDI / IR -- Advice on tube replacement

Stage & Studio Valvulator GPDI/IR
1

Everyone, Happy New Year !

I few days ago I got the Valvulator GPDI / IR – my first tube amp, and I really, really like it :slight_smile:
I have been using AxeFX III for a few years now, but wanted to experience playing through a real tube amp. I am only playing at home through headphones, so the GPDI felt like perfect match for that.
Now I would like to try replacing the tubes with the ones suggested in the manual and have few questions. I hope someone can help me :slight_smile:

I am planning to order below tubes:
V1 – Tung-Sol 12AX7

V4 – Electro-Harmonix 12DW7-EH

– I am not sure if the BIAS or something else will need to be readjusted in the Amp or it is a straight tube replacement?

– Any other suggestions for 12AX7 and 12DW7 you have tried and liked?

I may order a few different models (manufacturers) of each and see which one / combination I like. I am aiming for smoot, edge of brake-up sound when roll back the volume to more saturated / compressed sound when bring it up. Important for me is the touch sensitivity even on low gain and the compressor in front of the GPDI really helps with that.
I am using low to mid output humbucker pickups. Single coils - Yamaha Pacifica Professional and Yamaha Revstart RSS02T (original pups replaced with lower output P90s)

My signal chain is:
StroboStompHD → Empress Compressor MKII → Empress ParaEQ MKII Deluxe → GPDI (IR out) – line input AxeFX III (using the AxeFX III for ambient effects only (Chorus, Delay, Reverb, no AMP and CAB blocks).

What about below two tubes (not sure what the real difference is tbh)? Are both compatible?

Mullard CV4004 / 12AX7

Mullard 12AX7 / ECC83

– Any other suggestions for V4 position?

– What about V2 and V3 tubes? I would like to get some spare.

– Do I need to request the tubes to be balanced?

Thanks in advance for any help! Happy to be part of Fryette community :slight_smile:

Edit: additional info and questions

2

Hi @Etomcat

Honestly it just comes down to taste, if you prefer different tubes in different places that’s fine. All of the ones you picked will work. I had a lot of fun playing around with real Mullard’s from the 1960.

Fryette recommends both JJ (for less gain) and TungSol

3

Thank you @dan
Will any adjustments need to be made to the amp when replacing the tubes?

4

Hi ,

I should have said, no need to by matched pairs, all the tubes operate as individual triode sections. And no adjustments needed, all the biasing is done internally by the circuit.