Power up noise: brimar valve in Eden head

[Ashwood1985]

Hi guys,

So first of all I would like to simply say WOW! The WT550 I picked up simply sounds beautiful! :-D tone and punch for days!

Anyway - I thought I'd try vintage british mullard and brimar 83s in place of the stock JJ/tesla valve. The difference is very notable. The mullard's tops are a lo more back footed and the low mids are very warm. The brimar is less warm but has a tightness that the mullard lacks that really shows on quicker lines and he tops a crisper. So my current tastes have made me close the head up with the brimar in the driving seat.

But - one weird thing.... After a few seconds from turning the head on, once the signal appears, there is a very loud hiss that gradually reduces over a period of around 20 seconds. Once it settles, I would say that it's louder than the stock tesla but this isn't the end of the world.

I can live with this but I am a bit baffled as to whether this is something to do with the valve's design, the combination with the amp, the age of the tube (it's physically in mint shape btw), a fault creeping in?

I'm new to the world of tubes so any wisdom shared on this would be appreciated as I'd like to understand what's happening to our my mind at rest.

Cheers,

Ash

[Mr. Foxen]

Have a look at the internals of the mullard and Brimar. If they look the same, then the sounding different is because one of them is going a bit wrong. They are the same valve with different labelling, unless they were made far enough apart in time to have design changes (or possibly some of the foreign marked Brimars, I don't see that many of those).

[franzbassist]

Is this the Brimar you just picked up from me Ash? If so, it worked fine when I tried it, and I bought it from Mr.Foxen originally btw.

Do you want to try the other Brimar I have, also from Oli, just to compare?

[Ashwood1985]

That's a very kind offer Gareth thanks! [size=4]I'll drop you a text soon.[/size]

Regarding tonality - I definitely hear more note to note clarity in the Brimar but I also understand they are of the same era so a little confused. I may take a snap shot of the two for the more experienced eyes on here

[Mr. Foxen]

I vaguely recall discussion about 'foreign' marked valves when I was selling some on BC, which may well have been those.

[Ashwood1985]

No it's marked 'made in england'

(I probably should have mentioned that by now!) [size=4] [/size]

Edited February 22, 2013 by Ashwood1985