Please help me with my Amp problem

[floridagatorfan]

I've got an Ampeg Svt Pro 4 hooked to an Ampeg Svt HLF cab, A couple nights ago i was practicing and all of a sudden i heard the head click a couple of times, and when it did my sound went out for a couple of seconds, and then it came back on as fast as it went out. I turned my gain and Master down significantly (they are both less than halfway now) and it still does it. I felt it and it doesnt seem to be running hot, i keep a clip on fan blowing on it at all times when playing. It does it when being monobridged as well as non bridged, if plugged into the power amp A or Power amp B, side, does anyone know what my problem could be, Iam about to start giging rugularly with my new band and i dont have a backup, Thanks in advance for your help and time

[floridagatorfan]

Bump

[floridagatorfan]

no one has any advice?

[rust_preacher]

Sounds like the protection circuit is turning on, for any one of a variety of reasons.

[JimmyM]

ya, not really sure, but something in there's triggering the protection system. is it in a tight rack, by any chance? try pulling it out if it is, and see if it still does it. maybe you're not getting adequate ventilation, even with the fan.

[craig.p]

Make sure the fan you're using is moving air in the same direction the internal fan is. If you've got the two fans working against each other, then you're creating what's known as a hot box. (A hot box is an environment in which air flow is stalled.)

Does the internal fan even work?

[floridagatorfan]

i pulled it out of the rack and it still does it, the internal fan moves air from sided to side i have my fan in the back point foward, i have noticed that when it does it the fan does seem to speed up, and when it finally comes back on the fan sounds normal again, i bought this amp used and a couple of times i noticed that the fan sounded funny and would get a little loud at times but would go back to normal after a while, but the clicking and cutting out just recently started, think it could be a problem with the fan?

[BassmanPaul]

Two words I'm afraid: Tech time. Get the amp checked out.

[Jerrold Tiers]

The click would be the relays disconnecting the speakers.

The few seconds off is very typical for overheating, it is off just long enough to cool down somewhat below the cutoff temperature.

Could be caused by poor ventilation, a slow fan that is not working right, a buildup of *spooge* on fan, vents, heatsinks , etc, a really hot environment, or a real electronic problem.

The "real electronic problem" might be a defective fan drive (it is supposed to speed up as the amp gets hotter), a defective heat sensor that triggers the shutdown too early, another problem that causes excessive heating.

Look for dirt, see if the fan speeds up, see if the amp seems smokin hot when it shuts down.

[Koog]

I briefly had this problem with an SVT Classic a few years ago. There are two inputs on this amp head....can't recall for sure how they are labeled, but, basically one is a regular input and and the other is -db. The problem occurred when playing a bass with active electronics through the regular input. The amp overheated and the circuits shut down.

Fortunately, this happened the first time I used the amp in a show setting at the end of the first set. I let the amp cool during the break and plugged into the -db input and had no more problems that night. I subsequently had a tech check it out to make sure I hadn't damaged anything and all checked out OK. The tech also confirmed the overheating and subsequent shut down was from the active electronics.

During those days (2004 - 2007) I often switched between an active G&L ASAT and my passive vintage P. When using the SVT I plugged the ASAT into the
-db input and plugged the P into the regular input. I never had any more problems.

If the SVT4 has similar inputs, the method described above may solve your challenge.

Good luck.

Koog.

[floridagatorfan]

thanks guys, yuo have been a big help, Iam taking the amp to a local tech tomorow to have everything checked out.hope whatever it is isnt a real expensive fix