SVT4-Pro Power/wiring/output

OK well... the way you currently are using the amp places the two cabs in parallel at 4 OHMS and you are driving the the cabs with only 1 channel. You are able to supply 490 Watts to the setup.

If you were to move one of the 1/4" jacks over to the B channel and make sure the Stereo / Dual Mono or Mono Bridged switch is OUT. This puts it in Dual Mono and at 8 ohms per channel you would be able to provide 300 watts to each of the cabs in the setup.

If you were to daisy chain the cabs from amp to one and from that cab to the next, would also put them in parallel and if you used the BRIDGED - MONO cable into the speakon and then out to the first cab, you would have 1200 Watts available to the 4 OHMS. Mono Bridged switch IN

HOWEVER, lets start at the way you are running this amp.

running the gain at 12 O clock isn't high enough. Turn the bass all the way up, plug into the main input and crank up the gain until the LED flashes REALLY GOOD and solid with each note. Mine ends up at 3 O clock....

Then crank the MAster up to where it needs to go. I would never turn it over 3 O Clock.

I personally would use 4 ohms cabs myself. But see if these things help a little.

BOB

 

I gigged with the 4 pro for about 9 years and yes You do have to crank up the gain and not worry about the red led/clipping. To honest with you though even in the mono bridge mode, which is how I always ran it, it should be loud enough, but not nearly as loud as the advertised power compared to some other manufacturers amps with lower power ratings.

Also if running in mono bridge make sure you use the right properly configured speak on cable ( see ampeg web site for pin outs if you don't have the Ampeg supplied cable)

If your not getting sound out of one channel you could have fried some fet's. Mine had a channel go out once and the other channel continued to operate fine. Didn't even blow a fuse.

 

The mono-bridge cable needs to be wired by yourself. It's not hard at all and I ended up doing it myself in very little time at all. Make sure you buy a speakon connector that you can open up and you will be fine.

You most likely are creating a phasing issue when running the 15 and 410 at the same time. Each cab puts out the same tone differently and the resulting tone could be terrible. Try running each cab alone and don't touch the ultra low. Also, don't boost the lows crazily. The 4 PRO with all knobs at the flat setting puts out a crap load of bass.

 

Read post #3. He doesn't get power out of one of the channels. One channel could be fried which = service tech time. Also the mono bridge speakon cable for the 4 pro
comes with the amp, although I think he may have bought it used, not sure,so maybe he doesn't have it.

 

You shouldn't expect a lot from this amp. The only Ampegs that get really loud are the all-tube ones.

 

Here ya go.This is how i run my 5 pro.with either 2- 410 cabs or 1-15 ,1-410.

 

OK, well lets see whats all happening here.

The first problem is not getting power out of the second channel. You will want to make sure the that other channel is actually working. You will need a small pointy object to stick in the hole and make sure the Stereo / Bridge switch is in the out position.

The four jacks are two for channel A and two for channel B...

I would highly recommend buying three cables. 5' - 10' should be fine. All three should be four conductor speakon males on each end.

You can use two conductor speakons for the individual channels, but I do not recommend wasting money on 2 conductor speakons as 4 conductor ones don't cost squat additional. Make sure you at least have 14 ga wire in them. I use 12 ga, just because mine are longer.

Then take your 1/4" phone jack cables and stick them somewhere... Where you wont use them.

Then hook one cab to each cable and each of the outer channel connectors on the amp.

Crank it up. You should have sound coming out of both cabs.

IF not you will have to trouble shoot the thing. Could be effects loop contacts dirty or something else more diabolical.

Lets hope not I'm leaving on vacation for a week on Sunday.

If the amp checks out OK with these better cables then we can move on. If it doesn't make sound from both channels we will need to FIX this before moving to BRIDGED.

If it works, then take your third cable and pop apart one end. You will find the cable wired usually +1 and -1, you take your -1 wire and a small screwdriver and move it to +2, reassemble the connector and BEFORE IT LEAVES YOUR HAND wrap a couple bands of electrical tape around the cable. I use colored tape from Home Depot of equivalent.

This will tell you this cable is a BRIDGED cable and what end is wired differently.

You disco the other two cables from the Channel A and B and connect the bridged end into the center speakon on the amp. Before turning it on, use the pointy object and push the selector switch in.

Hook the other end of your cable to the 410 cab and then use one of the stock cables from the 410 to the 15 cab.

I like to inspect premade cables and make sure they are wired correctly. I have had a couple not wired right.

Anyway. Give her another try.

BUT ONLY DO THIS STEP IF SHE WORKED IN STEREO. DO NOT TRY IT OTHERWISE as you could potentially do additional damage.

Hopefully with good speakon cables she will function.

you can call me if you need to my phone number is on my website... I will be loading bikes and readying my RV for vacation departure but if you get stuck we can do what we can.

BOB