Marshall Amp Forum - View Single Post - Preamp Tubes?

joshuaaewallen · 03-24-2009, 05:30 PM

5:00PM

Ok... First experiment. I replaced the Westinghouse 12AX7A that was in V1 with the Raytheon 12BZ7. It worked alright in the clean channel. I think I may even catagorize it as a bit more "snappy". But... Not so hot on the crunch and lead channels. Distortion/Gain-wise I think it may have been good, but it was tough to tell because there was a constant tone coming from amp even w/ all my strings muted. The tone just about matched up to the note you'd find by fretting the D string at the 9th fret. First I'm going to pull out that tube and throw the Westinghouse back in V1, and if the noise goes away I'll try the GE in V2 and see what happens.

In case you are interested here are the tubes I have to work with (the ones that came with the amp when I bought it, and the ones I got from Marty... The Tube Corral

6:00PM

That GE 12AX7 really has a nice rich warm quality to it. That is a likely candidate to remain in the V2 Spot... But I am thinking I may pull it and try the Raytheon 12BZ7 there and see if that howling noise comes back. If it does I'd have to conclude that the BZ7 just ain't gonna jive with this amp. Any thoughts on this?

03-24-2009, 05:30 PM	#33 (permalink)
joshuaaewallen Senior Member Join Date: Jan 2009 Location: Minnesota Posts: 372	Re: Preamp Tubes? - Who, What, When, Where, Why, and How? 5:00PM Ok... First experiment. I replaced the Westinghouse 12AX7A that was in V1 with the Raytheon 12BZ7. It worked alright in the clean channel. I think I may even catagorize it as a bit more "snappy". But... Not so hot on the crunch and lead channels. Distortion/Gain-wise I think it may have been good, but it was tough to tell because there was a constant tone coming from amp even w/ all my strings muted. The tone just about matched up to the note you'd find by fretting the D string at the 9th fret. First I'm going to pull out that tube and throw the Westinghouse back in V1, and if the noise goes away I'll try the GE in V2 and see what happens. In case you are interested here are the tubes I have to work with (the ones that came with the amp when I bought it, and the ones I got from Marty... The Tube Corral 6:00PM That GE 12AX7 really has a nice rich warm quality to it. That is a likely candidate to remain in the V2 Spot... But I am thinking I may pull it and try the Raytheon 12BZ7 there and see if that howling noise comes back. If it does I'd have to conclude that the BZ7 just ain't gonna jive with this amp. Any thoughts on this? __________________ Josh 2004 PRS Custom 24 10 Top 1999 Marshall JCM 2000 TSL 122 - Power Tubes: JJ EL34L's - Assorted New & Vintage pre-amp tubes... I like to roll... HardWire DL-8 Delay/Looper http://irkinempire.spaces.live.com/ http://irkinempireoutpost1977.blogspot.com/ "... When you do things right, people won't be sure you've done anything at all." - Futurama Last edited by joshuaaewallen; 03-24-2009 at 06:14 PM. Reason: Update To Post