ampeg v4b help

jerkass9879 · #1 07-19-2010, 04:36 PM

i just bought an Ampeg V4B. it sounded fine in the store. but of course I didn't turn it up as loud as i would for band practice. I got it home played it for about 10 minutes and the noticed a static, white noise that would randomly appear and get louder and louder till there was a faint pop and it would disappear until it happened again. Also the amp seems to break up a lot faster and with a lot of excess static. can anyone help please

will33 · #2 07-19-2010, 04:38 PM

Eliminate the obvious bad cable, whatever, otherwise take it back. Also whenever you're trying out anything, new or used, turn every knob/slider/switch, every one, all the way up and all the way down, make sure they do what they're supposed to do.

JimmyM · #3 07-19-2010, 04:56 PM

maybe a tube went bad, maybe a cap needs replaced, maybe a loose solder somewhere...i agree you should take it back and see what they think.

but bear in mind that it's a 100w amp and will break up at some point so don't expect miracles just because it's a beastly fantastic tube amp

KramerBassFan · #4 07-19-2010, 05:14 PM

Its possible you have a dirty connection, or a bad pre amp tube.

jerkass9879 · #5 07-19-2010, 05:26 PM

I understand it's only a 100watts but it breaks up at when the knob is around 7 or 8 o clock. And it doesn't sound like the v4b distortion I'm used too. I just played for 30 minutes and didn't notice any popping just early distortion

gricko · #6 07-19-2010, 05:55 PM

wait a minute - 7 o'clock is volume off.

jerkass9879 · #7 07-19-2010, 06:00 PM

Now I feel dumb I meant around 9 or 10

JimmyM · #8 07-19-2010, 06:03 PM

well your volume setting depends on the output of your bass, but i've found most ampeg tubers start breaking up around 11:00-noon with your average fender.

jastacey · #9 07-19-2010, 06:28 PM

My V4-B starts to break-up at about 10:30/11:00 ... I believe what your experiencing is some what normal for a V4-B ...IMHO

Jefenator · #10 07-19-2010, 06:47 PM

10:30 - 11:00 - that's about where mine maxxes out with a passive J-bass.

40-year old amp with unknown service history? Take it to a tech, for crying out loud! Those amps are things of beauty that deserve to be maintained, IMHO.

If the other channel works better, you might be looking at just a preamp tube.

coreyfyfe · #11 07-19-2010, 07:02 PM

I always had one channel that stayed cleaner on mine, I was never sure why. Anyways, given the pop and the hiss, it may be in need of a cap job. Mine was making similar sounds before I had it done. Could also be a tube or loose connection, but either way it definitely seems like it should have a once over by a tech. If you just picked it up, bring it back to the shop and show them it's got issues, maybe you can get a partial refund to cover the cost of repairs.

johnk_10 · #12 07-19-2010, 07:09 PM

IMO, others have already given good advice.
it could be anything from a dirty preamp tube socket, a faulty tube, a bad ground, or a cold solder connection.

another thing regarding the low volume..... when you played it in the store, were you running it thru the same cab that you are now? different (efficiency) cabs can have a pretty large effect on how loud a V4B sounds.

jastacey · #13 07-20-2010, 08:22 AM

Here's another thing I would do before you take the amp in .... if you have a few 12AX7 laying around, swap out the tubes in V1 & V2 positions, one at a time and see if the problems disappear, you also can use a 12AX7 in place of the last tube (12DW7, I believe ) before the power tubes, the other tubes will need exact replacements .... if that doesn't clear up the problem, then a trip to the repair shop is in order

Tim Skaggs · #14 07-20-2010, 09:04 AM

Follow all suggestions you've received so far. As for power / loudness, 100 watts is 100 watts, enen if it is being provided by tubes. Tube amps generally sound good, but there is no magic in them (contrary to what you hear about "magic" smoke that sometimes escapes from tube amps).

metron · #15 07-20-2010, 09:19 AM

With an old amp like that you almost should expect to need to take it to a "good" tech to get checked out. Once you do it should be good to go for some time. Tip: not all techs are good.

My guess would be a capacitor, loose solder joint, or even a lifting trace on the pcb. A tube problem is less likely. Could be a combination of things. V4s get really hot inside the chassis and can be more susceptible to heat deterioration. A tech will likely replace the caps and clean up the solder connections.

You might not want to ride it too hard until you get it checked out. Old Ampegs can run even with problems and that can lead to bigger issues later. Or just take it back and be done with it.

And yes breaking up around 11 on the dial is normal.