NAD - Orange Bass Terror

[Obrienp]

OK folks. This process is amazingly straightforward, as long as your supplier has sent you the correct valves. My JJ ECC81 is fine (12AT7): sounds good but the Mullards I was sent are ECC84, that is not a 12AX7 equivalent. It should have been ECC83. Doh! The job is only half done but at least it won’t take too long when the JJ ECC83 arrives from Watford Valves. 
 

The original valves are branded Ruby. I did a quick Google search on them and it seems they are a low cost Chinese brand. Opinions in various forums range from they are crap to there’s nothing wrong with them. Apparently they have been used in various Marshall models as well. I guess manufacturers have to keep costs down and are bound to source components locally for their Chinese made products. I wonder if they put Ruby in the UK made amps. But hey, JJ are made in the Slovak Republic and loads of other makes are actually made in Russia. I doubt there are any still made in the USA or UK.
 

One thing I noticed while I had the cover off but with mains, speakers and bass connected, and powered up, you have to look really hard to see any glow from the valves,me specially with the protective housings in place. Don’t take lack of glow to mean the valves are dud. Try it all connected before deciding you’ve put a dud in. Probably obvious to all you knowledgeable people but one YouTube video said to look for the valves glowing as an indicator of success. I am sure that applies to output valves in an all valve amp but doesn’t seem to hold for the Terror’s preamp valves. 

[Obrienp]

Just a little addendum to the valve change saga. If you like clean headroom, I would recommend the MG version of the JJ ECC3. It seems JJ have various versions of the ECC83 but the MG is designed to give more clean headroom and a linear response. It certainly seems to do that, while providing nice creamy overdrive when you crank the gain. It definitely delivers more clean headroom than the original Ruby 12AX7 and the driven sound is more controllable.