Tubes


I have recently come upon a tube amp a yaqin mc 13-s. I have been reading up a bit on tubes and different things to get better sound. I have asked some questions about speakers on here and received great feedback and its all very much appreciated, you guys who gave me your best input thank you. 

I paired my yaqin with a pro-ject tube box s2. Prior to purchasing the pro-ject preamp I came across a shiit lyr 2 and used it for a short period, unfortunately I'm not into headphones and it didn't pair well in my system the volume just want there because it's not really a preamp it's a headphone amp. Long story short it had ecc88 orange globe amperex tubes and that thing sounded smooooootthhh. 

So I have a few questions?
1. Should I change all the tubes in my main amp to matching tubes? It uses qty 4 (6ca7's or el34b's), qty 2 (12ax7's) and qty 2 (12au7's) for example if I were to use tungsol 12au7's should I use tungsol for the 12ax7's and 6ca7's or could I use gold lions for the 6ca7's? Does it really matter?

2. How big of a difference does it really make changing preamp tubes? like I said earlier the schiit really sounded great and I could only attribute it to those tubes but correct me if I'm wrong? I didn't have any other tubes to try.

Thoughts and opinions are all welcome and appreciated. Once again thank you all for the advice.
gguy767
Nos tubes matched from long standing a Vintage tube services,land Brent Jesse recordings especially for the smaller tubes ,the nos vintage tubes were built 
night and day better  with far more rigorous inspections. For the larger tubes
upscale audio buys the higher selected bunch then cryo treats them ,which for sure makes a improvement in several ways , NASA started this , now all racing teams, gunsmiths anything precision for it brings all its molecules much tighter 
and they permanently stay thst way they sound better and lsdt linger solder joints 
it helps balance the most ,these tubes are then mstched and runin for 3 days  before you buy them ,for $10 more per tube we’ll worth it , to replace the el34 
the Gold lion kt77 is a noticable upgrade myself and 3 friends have been very happy with this choice ,and the small tubes with nos tubes you can Taylor the sound , Brent Jesse recordings gives a rundown of each brands sonic character 

@zkidd - Great post. Thank you. what have you found to be the best new production tubes? I agree on your comments on the small signal tubes. I have been fooling around with 12AX7's in the V1 in my phono preamp and my fav so far is the RCA Command 5751.
Hello @gguy767
I've had the same amp and it was very nice for the price.
I even heard a Primaluna EL34 based tube integrated (about 5 times more expensive) and I believe it wasnt better. 
As it has 2x35W it can drive many speakers, but if you like rock o similar music, I would suggest 93 Db or more efficient speakers with a tube-friendly impedance curve. 
The tubes I liked the most on it were 12AX7 Psvane TII and new production 12AU7 Tungsol. 
@plga 

Yeah I have heard many people like this amp. Prior to coming upon it I had been searching for vintage amp's but didn't really find anything worth buying, so I started doing my research and found this model in high regard. I honestly didn't think I'd find one in my price range because even used ebay they are more than I wanted to pay. Some how some way I got really lucky with some guy on craigslist who had a brand new one. He said he bought a crate of random stuff on an auction and it was in there. He didn't know what it was but I got him down to about 350$ for it and it works perfect, it's flawless the only thing wrong was a crack in one of the cheap plastic tube protectors.

I still have some things I need to do to optimize my sound but otherwise it's the best sounding system I've ever heard or owned but then I'm still a newbie. Everyone says that I'll get addicted and want better this and that but I think I'm a tad more of a music lover than an audiophile. I know the sound I want and I know I can attain it with this setup minus my speakers the speakers are okay but I want better ones. I plane on doing speakers, tubes and stylus. I've heard a major deal more clarity from better styluses so that's a must I think mine is a flat sounding and could be brighter. Tubes is a whole new world for me so it will be my first time experimenting with tube rolling. I am convinced I can improve the sound because I had another preamp with some tubes that many people rave about and it sounded really good, I attribute it to the tubes so i want to start with my preamp tubes and move slowly from there. I'll follow @zkidd s advice and get myself some new tubes he makes a good point. I was thinking the tungsol would be my first try, I found a place that has them nearby so I'll probably pick up a pair to try out in the preamp first. Then in my power amp second I wanna experiment with it a bit.
To dmk_calgary

Ah, tubes. An area as dangerous as cables. I see from reading some of the replies that at least person believes that I prefer new production over NOS. Not always the case. What I am stating is that there is almost a prejudice that new production can in no way compare to NOS. I have been most pleased with the Gold Lion re-production of the small signal tubes. And before people jump all over me I also know that the original Genelex company did not always make small signal tubes in some of the sizes currently offered. That said, where I am most satisfied with the Gold Lion re-issues is that they are quiet, and to my ears, give me at least 90% of what several NOS tubes do. For instance, the Gold Lion  re-issue 6922 tubes give me the same sonic qualities that I have heard with some older (70's) Amperex 6922 tubes. The Gold Lions are not inexpensive though one can shop and find decent prices. Many reputable sellers offer warranties on the tubes as well.  I have also had some good luck with the TungSol re-issues and though I hate to use the name TungSol as I know it is just a Russian tube with the TungSol name, I again find the tubes to be pleasing to listen to, quiet, and pretty darn reliable. I have dropped some serious money on NOS tubes only to hear tube rush, microphonics and other issues. Some reputable sellers like Brent Jesse and Vintage Tube Services do their very best to try and eliminate those issues, but the fact remains that many NOS tubes are from the 1940's. I have read numerous times about the Sylvania 6SN7WGT metal base tube as one of the best 6SN7 out there. I did find a pair from a man who I have dealt with in the past. He sells good tubes and he actually loaned me a pair before purchase. Thank God he did that for the tubes were horribly microphonic and frankly, un-listenable. I think how horrible it would have been to drop the $300 (cheap at the time) for the pair.
So, like so many things in audio, it is synergy, opinion, and what works for you. My main point again is this: if one does not have a perspective on tubes and tube performance, just don't jump on the NOS bandwagon because a tube is NOS. Try new production, see what you think, and then perhaps try a pair of NOS tubes. One just might be surprised...