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VAC Signature MK2a pre "phono tube questions"

Hi there I have a VAC pre with MC/MM, upon opening noticed there are two roles of 3 12AX7 tubes in each totaling 6.

Question;

1. Anyone have any experience tube rolling these and if so with what?

2. Are they three matched pairs or all matched?

3. They are a Chinese tube that came standard with the pre., anything special about them?
I have found on other gear which came with Chinese 12AX7 tubes they were nothing special and by substituting I found the sound was transformed, sounding allot better using other tubes.

4. Can you mix and match, say the first role Bugle Boys, second Tel for examaple or best to stay with one brand through out.

I have allot of really nice matched pairs but only that.

Any assistance would be appreciated.
dev
jafox
1,470 posts
 
Dev, I am surprised that you would ask such a question. From all your reports here, you have a wealth of knowledge and experience.

There never is any "right" way of doing things and this includes the tube set that we ultimately run with in any given link in our system. When it comes to tubes to try in a product, a good starting point is the manufacturer's suggested tubes. But very quickly I find tubes from my stash that far exceeds the performance.

When I owned Aesthetix Io and Callisto components, I mixed and matched tube types in each. The Callisto used 4 6922 tubes. I found the ideal match as one pair of Tele 6DJ8 and a pair of Amperex 7308. With the Io, which used 14 12ax7 tubes, I found 10-12 Tele's worked well with the rest as Brimar 12ax7. I have played the same game with ARC products, LS5 and MCP33, that used multiple pairs of Tele, Valvo and Amperex 6922 with great success.

Just try out all your tubes and see if you find a set of 6 that take the VAC to a new performance level.
inna
7,880 posts
 
Sorry about going sideline a little, but why would such an excellent company as VAC use "nothing special" tubes instead of the best new not NOS there is? This doesn't inspire my confidence in any way. I would want them to find overall best tubes for me instead of me chasing this all over the world. And again I am not talking about NOS. Or maybe I am wrong and they did put the best current production tubes, that just happen to be nothing but average. Do others like LAMM, VTL, Atmasphere, ARC do the same?
pcosta
241 posts
 
Inna

Most manufacturers do not use because of cost and availability. Most manufactures buy new tubes by the case and sort them out from there usually from China or Russia.
I am sure most would love to supply nice NOS, but have you tried buying a nice matched pair of Telefunken 12AX7 lately, you will likely pay around $200 and up depending on vintage and type.

Also when you use the Chinese or Russian tubes you have a standard to work with, meaning customers will be able to find the same tubes now and not have to hunt for expensive NOS. So the sound is consistant with what the manufacuter has sold you.

All that being said nice NOS tubes are very good compared to most of what is available new today.
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