GBE600 - Changing Valve from 12AX7

[MuddBass]

Hi,

Has anyone changed their 12AX7 valve in a Genz Benz GBE600 to a valve with slightyl less gain (ie 12AT7)?

If you have, what valve did you try?

Greg

[franzbassist]

[url="http://www.thetubestore.com/Resources/Guitar-Amp-Info/Gain-Factor"]This[/url] is always a good read when talking about gain factors.

[MuddBass]

Thanks for this - yes I have looked at this site before (from a post of yours I think!). Just wondering what other valves people actually recommend / have tried.

[franzbassist]

What are you hoping to achieve by using a lower gain valve?

[MuddBass]

A slightly higher sweetspot before the valve distorts

[franzbassist]

If I were you, first thing I'd do is buy a modern 5751 and a 12AT7 and just try them. If you like what they do then you can try different brands, and maybe even venture into new old stock. Diffrent brands can have different characters too, so well worth reading up on such things.

[MuddBass]

Thanks for your advice - much appreciated

[franzbassist]

[quote name='five-string.co.uk' timestamp='1395180007' post='2399595']
Thanks for your advice - much appreciated
[/quote]

My pleasure. There are plenty of GE JAN 5751s on eBay that are bullet proof and sound great, and not very expensive for NOS compared to Mullard, Telefunken etc...

[Sharkfinger]

If it's any help, I use an electro-harmonix 5751 gold in place of a 12AX7 in my trace head and it has that lovely gentle valve break up. I'm able to blend solid state and valve preamps and have the valve at about 2 thirds.

Fair amount of clean headroom and a good all-rounder IMO.

[Handwired]

I've got a GT 5751m in V1 of my Streamliner and it takes the edge off nicely but still allows plenty of room to push.