Ampeg V2 with issues

[myker]

Hey guys, anyone have any experience with these amps? I have one on my bench that is troubling me. Here is the lowdown...
the customer says that the amp would crackle and give him trouble when he was playing and he would wiggle and jiggle the power tubes and it would play as normal, however he hasnt played the amplifier in years.
When i get the amp, it doesn't have much volume and cracks and distorts when i hit the strings hard, The tubes are glowing blue. When I am messing with the tubes i get no change in quality and i hear a pop and all the silver stuff on top of the 7027 tube is gone. I changed the tubes to some good 5881's i had laying around that test at 95% and the amp has a pretty low output, its about as loud as my deluxe reverb. i figure that it should be putting out at least 40 watts.
any suggestions??

[6string]

Run!!
They're really cool and great sounding amps when they're right. The early ones that is... It's getting them there that's the trick, and I don't have the answers. I have one that I had Todd Sharp go though for me. He's the man for these amps. Very complex circuit and a pain to work on.

[electricskychurch]

did you check the voltages and tried with new tubes (power and pre) ?
what about the speaker(s) ?
no connection problem ?

if all that is ok (verify also if the filter caps look ok if it's an old amp as i suppose) , maybe a coupling cap or resistor has gone bad.

[myker]

yeah, i pulled all the tubes and tested them all 85-95%, all magnavox branded great britain tubes. all speaker connections are 100%. it is an over-complex circuit in my opinion, for a very clean circuit without much personality. cant wait to get it off of my desk to be honest.

[6string]

it is an over-complex circuit in my opinion, for a very clean circuit without much personality.

It is a very complex circuit, but I have to disagree and say it has an abundance of personality when it is operating right. The midrange especially has a ton of character and is extremely versatile.

Check out this clip of a VT-40, which is the same amp except it is a 4x10 combo as opposed to the V-2 head version.

http://www.soundclick.com/bands/default ... dID=744038" onclick="window.open(this.href);return false;

[myker]

It is a very complex circuit, but I have to disagree and say it has an abundance of personality when it is operating right. The midrange especially has a ton of character and is extremely versatile.

i would say that the tone controls in this amp amp are friggin' cool, for sure! tons of options, and what appears to be an inductor based eq like an old recording console. no sparkle though, no punch, a sort of sterile tone. that clip sounds better than the one i got, but not a whole lot better imo. to me clean tones are all about running open loop, cathode bias, through a low wattage amp and speaker. something with color. this thing sounds like a P.A. amp. maybe if i could get some output on these tubes i could experience it for myself!

george? got any experience with these things? dan? flames? where are my old metro-forum buddies? i havent posted since 2005.
mike

[myker]

It is a very complex circuit, but I have to disagree and say it has an abundance of personality when it is operating right. The midrange especially has a ton of character and is extremely versatile

man, 6string you were right! this amp does have some sparkle, and the overdrive is very cool too, in a 70's punk kind of way. I swapped out the tubes i had replaced the old tubes with with yet another set of tubes. 5881's. And the old ampeg came to life! i guess my old tube tester cant be trusted.
-mike

[6string]

Glad to hear you you got it goin'. The early Rolling Stones stuff (Mick Taylor era) was done with these amps. Hopefully you have an early one. The later ones that have the distortion circuit and the plastic rocker power/standby switches are not so great.

[myker]

no, i got the plastic switch one. its funny how with these older amps a few years can make quite a difference in tone.
-mike

[myker]

New problem, cant get the bias steady. using the 1 ohm resistor to ground method i measure no voltage with hum balance circuit bypassed. however i can play the amp. i replaced the bias resistor with a 500k pot and have tried to switch on the standby and adjust the bias pot while playing. the sound goes from the notes having a distorted ghost note type of thing going on to a great sound then immediate red-plating. I realize that some of this is due to the pot being so large but i cant really just leave the pot in one position because it will begin to red-plate. The components seem to be drifting quite far. another thing i have noticed is that if i turn the volume up about mid way that the harder i strum the tubes seem to be glowing inside to my playing, much like an amplifier with a tube rectifier would. I also should note that the original tubes were 7027a's and i am trying to run 6ca7's in their place. Another thing worthy of mention is that the plates run at 583v, which is HUGE!

any suggestions would be helpful.
thanks in advance
mike

[myker]

not to be a pain in the ass, but i have now replaced the coupling caps and all components in the bias supply to no avail. the tube that red-plates the most glows blue when i turn it on.
thanks
mike

[yladrd61]

Get some 7027A tubes