#1
Hey,

About to put a fisher branded telefunken 12ax7 in a 1969 sunn Solarus.

Just want to make sure there's no issues with heater voltage, I can't find the voltages for the amp or the tube. Should I be worrying at all?

Right now there's a Raytheon 7025 in v1

Also, one of the power tube sockets is very loose in the chassis (tube is tight in the socket though)
#2
It should be just fine. First, Telefunkens were incredibly stout and durable tubes, and many lasted for over a decade. They're legendary for their longevity. Second, I think few guitar amps put enough heater voltage through their preamp tubes to cause any trouble. I'm pretty sure the 7025 is an industrial military version of a 12ax7, so you should be good to go. Now, for someone with a lot more knowledge on the subject, I'd talk to Cathbard. He'd probably be able to give you more definite information than I can.

Telefunkens are incredible tubes. I have two in my Splawn, and more left for spares. You made a good choice to get a hold of one!
Ibanez UV777 - Carvin TL60 & 727 - Jackson KE3
Splawn QuickRod - Mesa Stiletto & RoadKing - Peavey Ultra+ - Peavey Bandit
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7 String Legion
#3
A 7025 is just a low noise 12AX7. They are a direct replacement for each other. Nothing to worry about whatsoever.

The tube socket is probably held in place by two screws/bolts. They'll just need nipping up. If it was a newer amp with PCB mounted sockets it might be a concern but not in something like that. Just locate the screws and tighten them. Now if you have to get into the chassis to tighten them (like to hold a nut maybe) be very careful because there are deadly voltages in there even when turned off and unplugged. You need to discharge the caps. If you don't know what I am talking about or how to go about it take it to somebody that does.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#4
Thanks guys and cath, after opening it up, it's actually the pins that are loose in the socket, not the tube socket/chassis connection. Would a bit of hot glue be an appropriate fix? And thanks for the warning, I have worked in tube amps before (replaced the power cable and removed the death cap in this one not too long ago)

Cheers!
#5
No, definitely not. The words hot glue and amp should not appear in the same sentence without a big DON'T in between them.
It is possible to re-tension some sockets but it's best to replace the entire socket.
Gilchrist custom
Yamaha SBG500
Telecasters
Randall RM100 & RM20
Marshall JTM45 clone
Marshall JCM900 4102 (modded)
Marshall 18W clone
Fender 5F1 Champ clone
Atomic Amplifire
Marshall 1960A
Boss GT-100


Cathbard Amplification
My band
#6
I was afraid of that. Thanks again popped the telefunken in, will reassemble soon to see how it sounds

EDIT: fired it up and it sounds amazing as expected! The tube totally killed the muddiness present with the raytheon, added a nice shot of clarity. Quite pleased. (other tubes are british mullards and a raytheon 7199 in the PI btw).
Last edited by SGRocker400 at Feb 27, 2012,