#1
Hello all, a few months ago I made a thread stating that I received a Vox AD60VT combo for free second-hand. Up until now I haven't had a single issue with the amp. The other day I went to my friend's house and plugged in. Upon switching on the amp there was no audible noise coming from the amplifier. I then dimed the volume knobs and even then the guitar was barely able to be heard. We went out for awhile and when I came back I had said "Man why isn't this working?" Then bumped the cabinet with my fist, BOOM sound back to normal.

I brought the amplifier to my guitar teacher and he said he thinks the single pre-amp tube might be dying out or that some foreign object fell into the vents and is bumping around inside the amp. He then gave me the name of a reputable shop in my area, but recommended I take the back panel off myself and look inside to see if anything is loose. Since I'd rather not electrocute myself and die I just decided to drop it off at that shop today.

Whether a part has worn loose and/or the tube is going. I'm going to replace the tube either way. Hopefully on my own, These particular models were produced around the early 2000's so I have to assume the amp is around 10 years old. The previous owner most likely didn't take the best care of it otherwise there'd be no issue with it.

So I ask you guy's what do you think is the best 12AX7 tube and why? After some random google searches I have my eyes on a Genalex Gold Lion. My teacher suggested a JJ. Will the choice of pre-amp tube make a notable difference to the gain structure of this amp?
Last edited by anthonymarisc at Aug 23, 2016,
#2
It won't change the gain structure at all, the tube is in the power amp. Just throw a JJ in there.
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
#3
Quote by Cathbard
It won't change the gain structure at all, the tube is in the power amp. Just throw a JJ in there.


Fair enough, I'm still an amateur in regards to understanding how guitar electronics work so forgive my ignorance. Nothing like a Genalex or Tung-Sol will make even a slight difference to the sound?
#4
Little to no difference in that amp. I like JJ power tubes but had a 12ax7 fail rather quickly after I installed it. No need to get some exotic tube in there though. A $10 off the shelf tube should be fine.
"Your sound is in your hands as much as anything. It's the way you pick, and the way you hold the guitar, more than it is the amp or the guitar you use." -- Stevie Ray Vaughan

"Anybody can play. The note is only 20 percent. The attitude of the motherfucker who plays it is 80 percent." -- Miles Davis

Guthrie on tone: https://www.youtube.com/watch?v=zmohdG9lLqY
#5
Quote by Cajundaddy
Little to no difference in that amp. I like JJ power tubes but had a 12ax7 fail rather quickly after I installed it. No need to get some exotic tube in there though. A $10 off the shelf tube should be fine.


Any ideas on how to get the tube out in the first place haha, I've heard this tube is a PITA to try and remove. I guess I'll have to remove that back panel anyway to possibly access it once I get it back from the tech.
#6
You have to pull out the chassis. So, back panel off > disconnect the speaker > undo the screws on the side > slide out the chassis > change tube.
Reverse process.
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
#7
Quote by Cathbard
You have to pull out the chassis. So, back panel off > disconnect the speaker > undo the screws on the side > slide out the chassis > change tube.
Reverse process.


On a scale of 1-10 how difficult would you say that is? Lmao I started to take out the screws to the panel before I dropped it off but stopped after being scared of electrocuting myself lol.
#8
1
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
#9
Quote by Cathbard
1


Cool I'll go for it once I get it back, I think I'll stick to the Genalex. Probably won't make a difference as you guys are saying but I want a good quality tube in there since I plan on having the amp for a long time. I do plan on upgrading to an OR15 after I save the cash though or maybe some pedals to refine the sound of the AD60VT. Particularly a good EQ pedal, the Valvetronix forum users state that a good EQ pedal makes a world of difference to the dirty channels on this amp.
#10
I dont think you can really electrocute yourself with a solid state amp.
Joža je kul. On ma sirove z dodatki pa hambije.
#11
Quote by gorkyporky
I dont think you can really electrocute yourself with a solid state amp.
SS amps often hold charges less often than fully-tube amps, but let us not presume so in case anthonymarisc never reports back...

Just have that shop replace the tube for you. I don't really think it's worth learning about to mess with on your own. Good score though (considering it was free).