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
I myself buy and use vintage tube gear - and tubes! Old ARC, Dynaco, Heath, Harmon Kardon, Scott, Sherwood ... New tube gear doesn't turn me on! And I choose to use vintage speakers also: Altec, JBL, Klipsch ... the Big Three of the high-sensitivy group!
Your amplifier uses a similar tube complement as mine other than the AU7s. As for having all your tubes by the same manufacturer, no, it's not necessary, or even recommended. My 4 EL34's are Holland dual D getter dated 1957, 1960(2) and 1961. The small signal tubes I now use are 80's vintage Tesla ECC803S for the 12AX7 slots and 60's vintage Telefunken ECC801S for the 12AT7 slots. I've tried several others but this arrangement is my favorite so far.
Great reply zkidd.  I have 25 tubes in my system and none are NOS and for the same reason as zkidd,  performance vs. cost, they are way over priced these day, well at least for me. I also replace tubes as needed.
12 tubes total in my system; about $2100 in the lot. All of them are at least forty years old and have been in operation in their current service since 2012; replaced one EL34 in that time and it was over fifty years old. 
gguy767,
I find it surprising and interesting that your Yaqin is a pure class A bias circuit as opposed to the more common class AB (particularly in this price range). If this amplifier is well designed and built it should provide very good sound quality. I understand your strong preference for tube amplifoption. There are unquestionably excellent solid state amplifiers yet good quality tube equipment just consistently seems to be more natural and emotionally involving, So I get where you are coming from.

Good advice you’ve been given from zkidd in regard to NOS tubes. They can be quite exceptional but not all of them are and it is certainly circumstances specific. There are without doubt very good sounding and high quality current production tubes available. NOS tubes are "always" superior to current production tubes is not true. Many variables to factor in.
I believe that you will do fine in your tube endeavors and derive much music listening enjoyment. . IMHO there's  an unmistakable realism that can be heard/felt  with good tube components in the audio signal chain.
Charles