SVT-4 Pro problem! Help me!!

Guish · #1 06-02-2011, 03:23 PM

I'm new to the SVT 4 Pro and I am not a gear pro so! I just bought a used SVT 4 pro! And I have no power with it! I tried it in a Genz Benz 410 xb2 cab (8ohm), and it was only distorting! I tried it in a gallien krueger 1x15 and I had no gain, no power! The sound was poor! Even with the master and gain very high, I don't get the power I need at all... Anyone knows what this could mean?..

**Thor** · #2 06-02-2011, 04:01 PM

Try it with another cab first. And another bass. If the problem is still there try another instrument cable and another speaker cable. Get rid of all external effects in the signal chain. Basically, you are isolating which component is the issue.

If you identify its a cable, good. If it remains the cab, then I think you have to see a qualified amp tech and have him go over it.

I may have the schematic for the SVT4 -pro if needed. Don't work on it yourself if you have no amp repair experience.

There is a thread in the amps section on qualified Amp Techs by region.

Good Luck.

Jerrold Tiers · #3 06-02-2011, 09:48 PM

Did it sound OK when you tested it before buying?

Presumably so, since you bought it, so check your cables, etc. the problem is likely in somethng used with the amp.

Possible that something happened between your testing prior to purchase, and the checks you made now...... but........

There are a lot of controls and settings, do you need a manual? I can send you a PDF, and have the service data also. PM me an email address if you need manual etc.

**T. B. Player** · #4 06-02-2011, 10:02 PM

Didn't Ampeg USED to make the best amps out there?

Save yourself the hassle - take it to a tech.

I had a Polytone die on me - kept blowing fuses. Turned out to be a diode. It's over 30 years old and it's the best little amp in the world.

Z

scotch · #5 06-02-2011, 10:50 PM

Have you tried both power amp sides (A and B)? The '4 Pro's have been known to blow out one side at a time. There was a similar thread either yesterday or the day before...

here it is: SVT 4 Pro issues

Hope you figure it out! Reading the manual is a good place to start- this model is a bit of a bear to really figure out!

pukeorama · #6 06-02-2011, 11:18 PM

the GB 410T-XB2 has 700 W at 4-8 omh and should take it just fine. But probably take it to a tech, sounds like something's burnt on the inside.

JimmyM · #7 06-03-2011, 12:26 AM

there are a couple things you can do before taking it to a tech...first, you can clean the effect loop jacks. If you have contact cleaner, spray some into the jacks and run your cord plug in and out a few times in rapid succession. Sometimes they get corroded if you don't use them for a while, and it's been known to cause this problem.

Also, if you have any spare 12ax7 tubes around, you could try swapping out the tubes one by one and see if any of them are causing the problem. That's pretty easy to do...pop the lid, pull the old tube out, pop a new one in. And unplug it first

Might not be the problem, but it's the first likely suspect. Good idea to have a couple spares anyway, so if you don't have any, I'd pick up one or two.

After that, you should take it to a tech if it still doesn't work.

Plstrns · #8 06-03-2011, 02:23 AM

If you have a battery in your bass, check it.

allexcosta · #9 06-03-2011, 05:23 AM

Sell it.

Jerrold Tiers · #10 06-03-2011, 07:06 AM

Jimmy:

If one side of unit works, and the other does not, the preamp, or most of it, is probably OK..... or BOTH sides would be bad...... the pre goes to both, except for some stuff in the crossover etc which is split.

You can try patching the A pre out to the B power amp in and vice versa, to see if the problem stays with the power amp or is in the pre out.

I'd double check all the settings, and, yes, clean all the "loop" jacks, because they do indeed sometimes cause trouble if they have not been used for a few years. Contact cleaner and plugging a cord in a few times usually does it.

JimmyM · #11 06-03-2011, 07:41 AM

Quote:

Originally Posted by Jerrold Tiers

Jimmy:

If one side of unit works, and the other does not, the preamp, or most of it, is probably OK..... or BOTH sides would be bad...... the pre goes to both, except for some stuff in the crossover etc which is split.

Good point, Jerrold. Well you're the man when it comes to those amps, so Guish, do what he says and you'll be cool

agedhorse · #12 06-03-2011, 12:53 PM

If bridging, be sure your cable's amp end is configured correctly. IIRC, it should be 1+/2+ at the amp end and 1+/1- at the speaker end. Double-check the documentation.

Fair Warning · #13 06-03-2011, 01:21 PM

With the SVT4-Pro, with all of the optional setups and capability, it is easy to have a button in the wrong position. I am surprised that noboby here mentioned the A or B or Bridged plugs and the proper botton position.

If you do not have, or have not read the owners manual, you would probably have missed it.

If you speaker wire is plugged into either Amp A or B, your button in the back needs to be in stereo position.

If you are speaker wire using a speakon, plugged into the bridged output plug, the little button needs to be in the bridged position. Also, the wire connector for this bridged position needs to be speacially wired as directed in the owners manual.

I have accidently had my button in the wrong position before and have had similar output problems.

Buster Brown · #14 06-03-2011, 03:00 PM

Quote:

Originally Posted by Fair Warning

With the SVT4-Pro, with all of the optional setups and capability, it is easy to have a button in the wrong position. I am surprised that noboby here mentioned the A or B or Bridged plugs and the proper botton position.

If you do not have, or have not read the owners manual, you would probably have missed it.

If you speaker wire is plugged into either Amp A or B, your button in the back needs to be in stereo position.

If you are speaker wire using a speakon, plugged into the bridged output plug, the little button needs to be in the bridged position. Also, the wire connector for this bridged position needs to be speacially wired as directed in the owners manual.

I have accidently had my button in the wrong position before and have had similar output problems.

+1

My first thought also....might be an easy fix....push a little button..

RickenBoogie · #15 06-03-2011, 05:35 PM

The 4Pro is a fairly complicated amp, especially if you have little experience with big amps. +1 to the 2 posts above, and to EVERYTHING Jerrold said- first off, get a manual, read it, and learn *how* to use the amp, then you can trouble shoot if it's still not functioning.

Guish · #16 06-03-2011, 07:51 PM

Alright... a little button did all this and made me panik as hell! Thanx guys!! Now all I have to do is get a really good cab to go with the SVT 4!! Any suggestions? I was thinking of an ampeg SVT 410 HLF with a 15" cab! I want it to be loud and massive! =)

ButtUglyJeff · #17 06-03-2011, 08:06 PM

Quote:

Originally Posted by Guish

Alright... a little button did all this and made me panik as hell! Thanx guys!! Now all I have to do is get a really good cab to go with the SVT 4!! Any suggestions? I was thinking of an ampeg SVT 410 HLF with a 15" cab! I want it to be loud and massive! =)

Ick, not a 15" It won't keep up with a 410HLF. You're better off with a second 410HLF and bi-amp them. That's why you get the 4PRO...

Or better yet, get a fridge...

Buster Brown · #18 06-03-2011, 08:38 PM

Quote:

Originally Posted by Guish

Alright... a little button did all this and made me panik as hell! Thanx guys!! Now all I have to do is get a really good cab to go with the SVT 4!! Any suggestions? I was thinking of an ampeg SVT 410 HLF with a 15" cab! I want it to be loud and massive! =)

NO NO NO......

You have a big boy amp....go for the big boy cabinet. The 8X10!!!

Glad you found the "little button"....hell, I've been playing mine for years and I have done the same thing once or twice.

Cheers!!

Guish · #19 06-03-2011, 09:38 PM

Haha! I'll make a man of myself and try the 810 then!!

Thanx! I'll also try the 610 HLF! Just to hear the difference!!

JimmyM · #20 06-04-2011, 12:38 AM

Quote:

Originally Posted by Guish

Haha! I'll make a man of myself and try the 810 then!!

Thanx! I'll also try the 610 HLF! Just to hear the difference!!

Both great cabs IMHO. The 610 goes a bit lower than the 810e, and the 410hlf goes way lower than them and just about any other cab, but the 810e is the classic Ampeg sound so it's my favorite. I recommend the 810av or Heritage 810e, though...cooler looking grill cloths. The black grillcloth is cool but the Heritage and AV grillcloths rule.