Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

Best Valve for a bass pre-amp

  • 19-01-2009 11:20am
    #1
    novarock
    Registered Users, Registered Users 2 Posts: 1,132 ✭✭✭


    help me out - I think the valve on my Eden WT-300 is a bit knackered (high pitched whistle, and when its being played for a couple of hours, it slowly loses its top end) tell me if im wrong, or if it is something else.. but what is the best replacement valve to put in.. The eden site recommends a 12ax7 or a 7025. No idea what brand or type to go with after that... Little help?


Comments

  • #2
    gotBass
    Registered Users, Registered Users 2 Posts: 108 ✭✭gotBass


    novarock wrote: »
    help me out - I think the valve on my Eden WT-300 is a bit knackered (high pitched whistle, and when its being played for a couple of hours, it slowly loses its top end) tell me if im wrong, or if it is something else.. but what is the best replacement valve to put in.. The eden site recommends a 12ax7 or a 7025. No idea what brand or type to go with after that... Little help?

    if it's a 12ax7 in there I replaced mine with a groove tubes one, cost me about a tenner from thomann. Has been going solid. On my ashdown the socket is keyed so you cannot put it in backwards or anything I can't comment for eden.

    for a tenner it's worth a go. I reckon, but if unsure get someone technically capable onto it.


  • #3
    novarock
    Registered Users, Registered Users 2 Posts: 1,132 ✭✭✭novarock


    I can do it alright - just wondering what valves people liked in bass amps - also is there any kind of variance in 12ax7's? I mean in terms of endurance or differences in guitar and bass preamps?


  • #4
    Paolo_M
    Registered Users, Registered Users 2 Posts: 880 ✭✭✭Paolo_M


    Couldn't really say on bass amps but there is one guitar amps. This is mainly in the way different brands, or even samples from the same brand, distort and produce harmonics. Even with clean tones on a guitar amp they some can have darker tonal quality than others so maybe that applies to bass also?

    As far are dureability is concerned I've used JJ, Electro Harmonix, Sylvania, Tung Sol, Mullard NOS, Pinnacle NOS, Mazda NOS (yes Mazda!!), and SovTek. Maybe I've just been lucky but I've never had a problem with any of these. I've read that many people have problems with Chinese production valves but I've no personal experience of them.
    Preamp valves are run well below their max power dissipation so it's rare enough for them to fail.

    What you've described does sound like valve microphonics and this, as it's name describes, is when a valve picks up the movement of air and vibrations around it and amplifies it. All valves are microphonic to some degree but when a valve is damaged (usually by getting dopped, knocked etc.) the elements move a lot more than normal causing a squeeling.


Advertisement