Ampeg SVT 4 Issue

xBrBaileyx · #1 05-13-2010, 08:55 AM

I have an ampeg svt 4 pro that i bought about a year ago used. Until the other day i've never had any problems with it other than the mono brige distroting which is not a problem seeing as in run it stereo anyways. But the other day at practice we were running through a song and I lost most of my volume. The amp had almost no volume and was feeding back and any string i hit gave me these very brittle scraping sounds. I opened the top of the amp and theirs nothing visibly blown or fried out. Reading up on it i found ppl having this problem and it was their tubes. My tubes were very old so i replaced them. That gave me some volume back but the amp is very muddy, lacking ton. Has and is cutting out and just dosnt have the power that the svt 4 sure. It was a great head before this and i'd hate to have to buy a new head. Anyone have an idea of what that problem may be?

rbonner · #2 05-13-2010, 09:19 AM

I thnk there's more than one issue here. Lets go right to the first thing you stated. The MONO-BRIDGE distorting. It should not be doing that.

You need to be running a specially wired MONO-BRIDGE cable in that mode and the small push button switch to select between Stereo, Dual Mono and Mono-Bridged needs to be pushed in. If you don't select the switch, it will sound all distorted.

Try plugging your bass and guitar cord into your guitarist's amp and make sure everything is OK with the Bass.

What does Channel B sound like?

But at this point, I suspect there's some damage done to the amp.

BOB

xBrBaileyx · #3 05-13-2010, 09:31 AM

channel B is the same.

I checked the bass and everything seems to be fine with it, no problems.

After changing the tubes i pluged the bass back in, and even though the amp had very little power it was pushing the speakers very hard. I could see them moving much to far in and out. I letf that part out.

But at this point im guessing im going to need to send it in to be fixed?

Jerrold Tiers · #4 05-13-2010, 09:20 PM

Sudden drops in volume etc are often due to connections that go bad, typically from years of vibration. Very possibly a solder joint, of course might be a tube...

Totally agree about the mono connection.... It should not be distorted...... If it is, there is some problem, either with the connection, or with not pushing the mono button, etc...... it should sound exactly the same in mono, except a little more volume, and a good deal more "impact" and headroom.