Your valve /tube amp will sound best when the key valves in your amp are closely matched in performance to each other.
What needs matched?
There are two key areas to use matched valves. This is what is called the “phase splitter” which drives the output valves. This is usually an ECC81 ( 12AT7) or an ECC82 ( 12AU7) or an ECC83 ( 12AX7).
This valve needs the performance of the two triodes inside matched to each other.
The output valves need to be matched too. When there are two or more output valves in an amp they need to selected to be as closely matched as possible. It is ok ot replace one valve in an emergency but you should replace all the output valves at the same time. Many manufacturers only match the output valve anode current, however, this is only half matching in our view. We match the anode current AND the gain of the valve so that they are totally matched. We also supply a test certificate for the output valves showing the test conditions and the tester used. In the real world it is impossible to get a prefect match, however, as long as the anode current difference is about 1mA and the gain are then matched as close as practical then you will have Supermatch output valve set. Once valves are matched they tend to age very evenly over their lifetime and so your amp will sound good not just when the valves are new but when they are many months old.
Some of the smaller practice amps like a Fender Champ only have one output valve so don’t need any matching of valves.
We match the anode current and the gain of each valve. In a pre-amp valve we match the anode current and the gain of each of the two triodes. It i worth noting that many of the valve/tube manufacturers do not factory match the pre-mp valves so we have to go though all the stock e receive from the factory and tet to find the matched ones.
For an output valve set we also match the anode current and the gain. We do this test by hand on our orginal restored testers as used in the UK when valves were in every home electronic device. We carefully select fo rbest match. While the current can be matched many ” factory” matched valves do not have the gain matched.
For many of the most popular output valves we pay to have the factory valves matched into sets and then we test and mix and match to get the bet overall match. It is like trying to get the planets to align to get a perfect match. It does occasionally happen ! We match the current and work to get as good a match as we can on the gain. Current matching is within 4% of each other which is equivalent to 2mA with a 50mA anode current.
The objective is to give you the best match possible.
What is in a Supermatch Kit ?
So in your ” Supermatch” kit for your amp there will be one valve that is supermatched and that is for the phase splitter position in the amp ( usually it is right next to the big output valves). itself. When output valves are in the kit ( more than one) they will be supermatched to each other if the Supermatch option “Yes” is selected where ordering.
Where Do Put the Pre-amp Supermatch Valve in my Amp?
The Supermatched pre-amp ( the EEC81,or ECC82 or ECC83) usually is the small valve that is next to the output valves. So no circuit knowledge is needed. Just plug it in that position