Egnater M4 preamp tubes anyone replace those rear ones?

stevekroeker

New member
M4 seems to sound kinda flat compared to some other preamp sections I have, wondering if it might be those tubes at that back. Anyone ever replace those? Did it change/improve your sound much? If so, what did you put in there? :confused:
 
I had mine blow (don't know which one) at a gig - and I didn't have any spares with me! :doh: Anyway, since then I've put a Tung-Sol in the bottom socket (labeled "12AX7"), and a Mullard 12AT7WA / CV4024 in the top socket (labeled "12AT7"). But I didn't like the tone as much - made it sound too thin I thought (I think the Mullard was the main culprit there, not the Tung-Sol). But when I put a pair of Groove Tube 12AX7-Rs that I bought at Guitar Center (what can I say - it was a Sunday), they actually sounded really good. Right now though I have a pair of Egnater labeled Sovtek 12AX7WAs, which also sound just as good to me.

Note that Bruce has stated on this forum that the socket labeled "12AT7" no longer requires a 12AT7 and that a 12AX7 (or equivilant) is fine.
 
guitarslinger":2lxdgck5 said:
I used a pair of NOS GE's, and it made the preamp come to life.

They DO make a difference.
OK Gene - you've piqued my curiosity :yes: . . . which NOS GE's are you using specifically?
 
HughJasol":16fviobo said:
guitarslinger":16fviobo said:
I used a pair of NOS GE's, and it made the preamp come to life.

They DO make a difference.
OK Gene - you've piqued my curiosity :yes: . . . which NOS GE's are you using specifically?

whichever ones came in that shoebox from the electronics graveyard that has since closed :(

I'm using a 12AT7 in the 12AT7 position. (actually, now that I think about it, this might be an RCA.

The GE is just a 12AX7A with long gray plates.

that's all I know. It's loud, clear, smooth, etc. It's just RIGHT. :rock: :rock:
 
You guys happen to know the function of these tubes and what kind of characteristics make an ideal tube for these spots?
 
I did at one time, but I don't remember any more . . . :confused: Bruce could tell us, but I know he's really busy lately . . .
 
The top one is the input tube that is common to all the channels. The equivalent of V1 in a "normal" amp. The other tube is the output buffer that is also common to all channels but does not provide any gain.
 
I replaced the 12ax7 and 12at7 with groove tubes 12ax7 and 12at7.

When my amp is working I notice they rig drives a little more with them in.

I am not sure if that is because they are new or just different.

I had to buy them local in an emergency, I plan to order the Egnater OEM tubes ASAP and use the groove tubes as spares.

I loved what I had and see no reason to change it. If I get bored I'll just buy another module. :)
 
Back
Top