12AX7 What is Mu?

[Leo_Gnardo]

I was very unimpressed by the Sovtek 5751's available 15-20 years ago and stuck with used old stock and the GT5751M's.

from gear page (where I hardly ever look) 6 Aug 2012, Timbre Wolf wrote:

'I've found that the best sound to come from Sovtek's 5751 was a satisfying pop-crunch that it emitted when I stepped on it.'

I've found much the same with EH's 12AY7.

Your deal on 4 GE 5751's sounds terrific Steve! Good find, happy listening.

[dumbassbob]

Both V-1 and V-2 have had there day in my 63 Bandmaster,Funny I put them on my little tester and they both read 31/30 on my control dial...So being one over means No good...But you would think they are NIB tubes They read "better than New" 101% NOT!!....So I put a NOS RCA in V-1 and a ARS made in China in V-2 It came back to life...

[km6xz]

From a repair and music production perspective, NOS or OS are a waste of time and never ever means better music. I find that the importance placed on tube magic and super pixie dust fill capacitors is an inverse relationship between tweekiness and song quality.
The rare people who have writing chops and create listenable songs are not the tone chasers. Coming from the top end of pro recording end of things, I never remembered any players who were really good and had great material who was chasing tone the way amateurs who have no good material or playing chops obsess over. I never ran into the tube rollers or tweekers until opening a large repair shop/warranty station and started dealing with amateurs. I tend to ignore then and their obsessions. If they really want to sound more appealing to an audience, I can certainly help but they usually make equipment tweaking the core of their connection to a music hobby. I don't have time for that.

[Alf]

You may be partly right in saying that there are some musicians who think this way and are merely tonechasers but mho is that every guitarplayer likes his guitarsound to be as good as it can be and that involves using good quality tubes in your tubeamp(s).
I personally started playing the guitar in 1964 and have seen the quality of tubes deteriorate over the years.
Back then you bought Mullards , Rca, Philips etc for fair prices but over the years these have become very hard to find at resonable prices because stocks dwindle and so I started to buy new production tubes and have never been entirely satisfied with their quality and especially lifespan.
So I've spent quite some money on buying old production tubes and still get a smile on my face when I put e.g an RCA black plate tube in the V1 position. What a difference they make!

So km6xz, I have a different opinion.