tube suggestions/ brand new to tubes

There is quite a difference in sound between brands and models of 12AX7/ECC83 and 12AU7/5751 and 12AT7, etc. tubes.  As a very general observation, Mullards tend toward the warmer/richer side and Telefunkens are leaner/more detailed/dynamic sounding.  Somewhere in the middle are Amperex tubes and I recommend Amperex Bugle Boys as a tube that will please most listeners (safe choice).  In my own phono stage, I run genuine Telefunken ECC803 (12AX7 equivalent) which are very dynamic sounding).  I get away with running a leaner tube because the entire rest of my electronic chain is very warm (Western Electric 310a, 310b, 348, 349).

op

i agree with those saying don’t tube roll until you have at least 50-100 hrs time to burn in your new piece and the tubes

5751 are lower gain 12ax7 -- you can also step down to 12au7 (even lower gain)... how it affects the sound of your aric can only be learned by trying, no shortcuts available... leaving aside a different volume control setting which would likely result

fyi - I have many many of these small signal tubes pairs that have been accumulated over the years, happy to assist if/when you are ready to roll some (it is a lot fun, but as some have mentioned, it is its own rabbit hole of sorts)

among best of breed old stock 12v signal tubes, in my experience, you should look to at sylvania/amperexes among the usa made tubes, and telefunken/siemens/philips/tungsram among euro made ones

I rolled a lot with my Aric amp and Aric pre amp. I used Vintage Tube Supply for nos tubes. Andy is very helpful and his selection is excellent. Be prepared to wait for your order for several months, but worth the wait. If you are buying new tubes, not sure it really matters where you buy them from. I’m currently using JJ 12at7 and find them very nice. 
As far as which tubes to use, that’s trial and error, and the fun part! Just read reviews, listen to the tubes and purchase a different pair based on the reviews and what you hear in your system. You will find what sounds best to you over time. It’s a slow but fun process. There’s no what’s best. There’s only what you like best. 

@whart , I feel your pain regarding the 6H30, my preamp takes 8. Any opinion on the EH Vs the Sovtek is appreciated. I’ve read the Upscale Audio comments, but that’s all I know. My pre came used with fairly fresh Sovtek’s that have Upscale labeled boxes. BTW your rig is light years beyond anything I hope to have. It must sound amazing. Regards, Mike B.

 You have been given quite a variety of suggestions from NOS to JJ to Apos , that’s pretty extreme. It comes down to what you like in your system with your speakers in your room. I have a modest amp that takes a single input tube and a similar rectifier tube. I tried about a dozen input tubes and about a half dozen rectifier tubes all nos. I preferred Telefunken for the input and a nos Tung Sol rectifier. I would give your pre more time to settle in before you roll tubes. It’s unfortunate that Brent Jesse closed as they offered primo stuff that was Amplitrex tested. I’d definitely contact Aric and verify EXACTLY what tubes you have and EXACTLY what rectifier tubes you can use. As mentioned above regarding Terry London, read the actual review and contact him for suggestions listing your gear. I emailed him twice and he responded both times with excellent suggestions. I’d also like to share that I swapped so many tubes in my little amp I caused loose tube sockets so don’t get too carried away and maybe ask Aric about socket wear. Enjoy your adventure and maybe we’ll meet at a Tube Addicts Anonymous meeting, Mike B.