Valves. Brimar Mazda ECC83 grey ladders plates NOS 1962-1972

concrete ??

I know that Brimar did make valves with the Mazda name. Typically, Brimar is slighty less warm than Mullard but have more extended highs and low-end. Highs and mids are very smooth. Both made in UK.

The best choice is the Mullard Longplate square getter, but very expensive. Mullard boxplate is also excellent and more affordable.
Brimars are great, just a different sound.

The Brimar cv4004 is a boxplate which is a military spec valve. It has a very different internal structure than a grey plate and will sound different. I have the boxplates and they have sweet mids with smooth extended highs.

There are different versions of the Mullard ECC83; short grey plate, longplate with square getter, longplate with O getter. They all have warm sonics, with the longplates having a better soundstage and deeper bass. 1950’s would be the best.

If the Mazda has grey ladder plates it will sound very different than a CV valve.