Ampeg SVT pro 4 lost its juice??

[Thasher4001]

Hey all!
Maybe I could get a little input from owners or previous owners of this amp. I recently picked up a 97' svt 4 for a nice price and something a little less sterile sounding than my Mesa m6 carbine. I wanted the most juice out of it through my 8x10 so I put it through its mono bridge mode with the tiny switch pressed in. Now to my ears it sounds exactly like when it's just on one power amp section. I thought it was suppose to have much more power with both power amps together in mono bridge mode. Any ideas??

 

[lakedmb]

[DEL]I think there are two buttons that you have to press for bridge mode[/DEL]...I may be wrong though, it's been a few years since I sold mine.

Nevermind, must be going crazy.

 

[JimmyM]

Much more power doesn't necessarily mean "much louder." More wattage manifests itself in headroom, really, and the volume gains from doubling your power are slight. Takes 10x the wattage to get twice as loud.

 

[Ale the Snail]

Are you using the proper mono bridge cable?
If not, you are only using half the amp, regardless of mono bridging it.
You need a cable wired in a specific way.
Hopefully this can be of some help.

 

[lakedmb]

Yeah, it's surprising how much of a difference that cable makes. Mine came with a specific one that I passed along when I sold it, since it seemed important for bridged mode. It was a speakon to quarter inch.

 

[Thasher4001]

Wow! This seems to be the gold nugget of information I was needing!! Thanks so much, I just have one more question; the second I power it up the peak light flashes once quickly and there's a slight sound before you can hear the bass. Is this normal?

 

[JimmyM]

Yep. That sounds to me like the relay that keeps the amp off until the tubes are warmed up. Always makes a little noise before it kicks on.

 

[Thasher4001]

Thanks jimmy that's good to hear! I am still a little puzzled on the speakon connection. I was using what I consider a standard speakon cord into my cabinet, but the one needed for the 4 pro's mono bridge is different? Does it have to have a 1/4 inch end?

 

[MetroBass]

I went through the same learning curve - the speakon needs to wired +1 / +2 and not the normal +1 /-1 configuration. With this configuration your getting the hot output from both amps - otherwise it's just the standard 500W. They're pretty easy to disassemble and assemble since the wire leads locks into place with screws. Or you can buy a NL4-F for about 6-7 dollars from most music sites.

 

[Gearhead17]

Thanks jimmy that's good to hear! I am still a little puzzled on the speakon connection. I was using what I consider a standard speakon cord into my cabinet, but the one needed for the 4 pro's mono bridge is different? Does it have to have a 1/4 inch end?

It does not need to be the 1/4" end. Both sides can be a Speakon connector. It's VERY simple to rewire one of those.

 

[Ale the Snail]

Just make sure to mark witch ever end you wire to +1/+2, That will be the end witch goes into the amp.