#1
Ok, I've tried searching to find the answer, but no threads specifically answer my question. I have a '74 Fender Princeton amp that has reverb on it. Here lately, I have been hearing constant fluctuating between low and high volume levels when I play. I have come to the conclusion that my tubes need changed so, my question is, what tubes should I get?

It might help if I give you some info from the back of the amp. It says:

0.7 amp
8 ohms

117 volts
12 watts R M S

60 cycles
#3
See, the problem is, there are no shops for about 45 miles away, and its kinda hard to get there without a driver's license.
#4
Quote by bassdrum
See, the problem is, there are no shops for about 45 miles away, and its kinda hard to get there without a driver's license.


oh jeez. k lemme think here...

your amp has a fixed bias. meaning you have to buy the exact tubes. heres what you have in it now:

Preamp:
7025, ½ 12AX7

Power:
2 x 6V6GT

Rectifier:
GZ34 (early) or 5U4GB (70s)

Phase Inverter:
½ 12AX7 (split load)

Other:

Reverb Driver: 12AT7
Reverb Recovery: ½ 12AX7
Tremolo: ½ 12AX7 (bias vary)

so if you just want to swap tubes. these would be the ones.
#6
Quote by bassdrum
Wow....thanks a lot man.


yup.

oh yeah. forgot...the only ones you should be concerned about are the Preamp tubes and/or the Power tubes.
#7
nice amp...my dad has the same one...early 70s anyway..not sure the exact year...
Quote by Jack Off Jill
Because when I was younger I would wrap dollar bills around my wang while masturbating to get that extra dirty feeling.

Even though I quit doing it, it still turns me on when I see money.



Http://magnumman.dmusic.com
#8
Quote by GuitarJunkie
nice amp...my dad has the same one...early 70s anyway..not sure the exact year...


yeah. its a classic.
#9
.7 A is current draw (how much electricity amp uses), 117V is supply voltage (ac outlet you plug into wall), 60 cycles is American electrical cycles (Europe uses 50 cycles per second), 8 ohms is the resistance needed via the speaker( don't use a 16ohm speaker), 12 watts RMS I would say is the wattage of the amp output maybe(is it a 15w amp?), or perhaps the wattage used by the amp to create those killer tones. (Forgot my electrical conversion formulas). 45 miles round trip is worth having someone with knowledge to work on that vintage amp. Volume pot(knob) might be going out, be sure and try different guitars and cords to be sure problem is with the amp. Good luck
#10
Quote by havocrus
.7 A is current draw (how much electricity amp uses), 117V is supply voltage (ac outlet you plug into wall), 60 cycles is American electrical cycles (Europe uses 50 cycles per second), 8 ohms is the resistance needed via the speaker( don't use a 16ohm speaker), 12 watts RMS I would say is the wattage of the amp output maybe(is it a 15w amp?), or perhaps the wattage used by the amp to create those killer tones. (Forgot my electrical conversion formulas). 45 miles round trip is worth having someone with knowledge to work on that vintage amp. Volume pot(knob) might be going out, be sure and try different guitars and cords to be sure problem is with the amp. Good luck


I'm pretty sure its the amp. About 6 months ago, I used a Peavey guitar with other cables (the cables have long since been broken) and the volume would go down for about 30 secinds at a time, but not as much. Now, I use a fender strat with new cables and it fluctuates even more drastically very frequently.

You mentioned a broken volume pot. Is there a way to fix that without taking it to a guitar store and/or spending a great deal of money?

By the way, thatnks for all of the info onthe amp!
#11
Pot's are pretty easy to replace, if you know how to open your amp and you know how to solder.

Could be dangerous if you touch a cap or something, so. . .

We're not responsible.
#13
Quote by Mascot
We're not responsible.


i told someone to open his amp up and pry around in there. and the kid actually did, i didnt think he was gunna...got the piss shocked out of him. quite funny to watch though.