Lite Audio GA-31a phono preamp, is it a clone?

I can tell you that the driver tubes will be the most important for low noise then the output tubes second but i would listen with the stock tubes if you hear any noises or tube rush go for old stock tubes it will be much more quiet and the sound will improve.

@tablejockey ok, thank you very much!.

I'm not qualified to interpret that schematic, perhaps noromance  or someone else will chime in. 

If anything it's going to be just a pair(L/R), not all 4 that will make a noticeable SQ  difference? You can always just experiment when you get it. You'll be out just two pricey tubes instead of 4.

@tablejockey  looking at the project diagram, could you tell me which are the most important slots?

Hello noromance,
I had already noticed this hybrid setup. I hope it is a wit to improve the project, not a defect.
About the 47uF electrolytic cap on the single-ended input, what do you recommend to do? Remove it? Replace it?
Tenx!

I would give the stock tubes a chance, before putting costly NOS tubes. Also, there may be just one slot where rolling tubes makes a noticeable difference.

It's an unusual circuit in that the tubes are used in what looks like a cascode configuration with transistors doing the amplification. Are the tubes there to add gain or flavor only? There's also a 47uF electrolytic cap on the single-ended input which is not good.

Hello tablejockey,
I bought it in Italy. It is used but assembled with great care and at a low price. I'll get it next week. Currently it mounts 4 6922 Electra Harmonix tubes but I intend to replace them with 4 Philips 6922 nos valves or with 4 Amperex 6DJ8 orange logo.

Did you get it from here?
https://www.hifi-amplifiers.com/en/lite-audio-dac-phono-stage-mmmc-c-89/lite-ga31a-tube-mmmcmoving-c...

If so, seems like a nice price. I'd say that's a win if it's reasonably quiet and performs as intended.