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SVT 4pro getting too hot?

KLEIN

KLEIN

Apr 4, 2009
103
3
Lakewood CA
Disclosures
Endorsing: Schecter Basses
#1
I was at rehersal using my ampeg svt 4pro and after about 45 minutes it just shut off. After letting it sit for about a minute or two I tried turnig back on and then it was working fine. It would do this very so often. This is a rack mounted head. My question is if its getting too hot and because of insuficiant are flow due to the fan being mounted on the side rather than the back. Has anybody had this problem before? I use this with an 810 cab with a fender precision with EMG pj pickups.
 
#2
Take it out of the rack or modify the rack for airflow more suited for the 4 PRO. Stupid design on Ampeg's part to do side ventilation when NEARLY ALL rack cases out there are without side vent holes. Ampeg did make cases with side vent holes - good luck trying to find one except on EBAY.

The amp should be fine out of the rack. It's pretty strong on it's own without a rack case.
 
#3
Hi.

If the thermal protection shuts the head off, it's most definately getting too hot.
If the thermal sensor is workin correctly of course.

There's quite a few reasons why this might happen and rack-mounting is only one of them.

If there's plenty of room on the sides for the air to circulate, that shouldn't pose a problem. If the airflow is restricted (SKB), You'll have problems.

The most likely reason is dust build-up in the heat sinks. If You're handy with electrical appliances and know the safety concerns, open up the head and clean the insides. If You're using compressed air, make sure that you don't just jam the dust into corners, but blow it all off.

It's also possible that the FETs need their periodical rebiasing done, and while You can find the instructions how to do it yourself, that's something best left to a tech to do.

Regards
Sam
 
#4
i happen to have the same rig as you. i how ever do not keep it rack mounted only because the way the fan pulls the air into the head. you could try taking it out of the rack and play with it. if you take it out of the rack you could also try putting a fan on the outside (have it so if your looking at the nobs the fan blows in the right side) that is if you get really desperate but dont take the top of and blow air in because that could do more damage. this is because the amp head its self was made to canal air into it and push it out (kind of like a vacuum) so if you take the top off you would ruins the air flow and it could get hotter. i could be wrong as i have never had this problem but i think that would work.

i hope its nothing to serious as they are terribly expensive.
 
#5
T-Bird said:
The most likely reason is dust build-up in the heat sinks. If You're handy with electrical appliances and know the safety concerns, open up the head and clean the insides. If You're using compressed air, make sure that you don't just jam the dust into corners, but blow it all off.
Click to expand...

make sure if you get the dust out that you do it like out side or somewhere where it doesn't run because if you get all the dust out and you turn it on all you will do is suck the dust you just got out back into it. also if you try to get the dust out make sure you are properly grounded so touch the outside of the case that way there is no way you can shock the main board or anything else. be sure to do that any time you are working in the case
 
#6
I love this head and the way it sounds. It is capable of all the highs, mids and lows that I need. But for the love of god, what a stupid place to put a fan! When I bought it new, I never had a rack for it, and it never gave me problems. Well Im glad you guys can help me with my questions.
 
#7
KLEIN said:
I was at rehersal using my ampeg svt 4pro and after about 45 minutes it just shut off. After letting it sit for about a minute or two I tried turnig back on and then it was working fine. It would do this very so often. This is a rack mounted head. My question is if its getting too hot and because of insuficiant are flow due to the fan being mounted on the side rather than the back. Has anybody had this problem before? I use this with an 810 cab with a fender precision with EMG pj pickups.
Click to expand...

Hi KLEIN.

From your description it sounds like your Ampeg is overheating and occasionally going into thermal protection.

If you're using a tight-fitting rack, does your amp have an empty rack space above and below it to aid in convection cooling?

Have you considered venting the rack near your amp's cooling fan by drilling a pattern of small holes in it?

All fan-cooled gear eventually gets clogged with airborne dust & dirt. This can have the effect of thermally insulating electronic components causing them to overheat.

Have you inspected the interior of your amp for this? If dust & dirt is present inside your amp, you can blow it out with a can of compressed air.

Please note: when pressurized air (or any gas I believe) is released, it exits at a very cold temperature which can freeze components which are too close to the can's nozzle. Fire the compressed air into your amp in short bursts to further prevent the possibility of freezing your amp's innards.

Oh yeah, and do this outdoors while wearing old clothes. Blowing a dust buildup out of electronic gear can get messy.
 
#8
Ok I was already thinking of drilling some holes in the rack case unless there is a special rack made for this head. Also I have never changed the tubes in this thing. Could this also be a problem with overheating?
 
#9
KLEIN said:
Ok I was already thinking of drilling some holes in the rack case unless there is a special rack made for this head. Also I have never changed the tubes in this thing. Could this also be a problem with overheating?
Click to expand...

Mmm... I'd doubt that the three pre-amp tubes in your SVT-4Pro would cause overheating.

If your amp sounds fine then those 12AX7 tubes are OK and don't need to be replaced.
 
#10
I had the 4 pro for a little while. I had it in an SKB rack also. I just used a small hole saw to make holes in the side of the rack that lined up with the vents in the amp. I bought 1", rubber plugs for those holes at Home Depot for bad weather conditions. Not sure what the plug's real use are but I found them in the electrical department. I then went online to ProCool Rack Fans and ordered a custom fan unit to mount in the spaces above the rack in the amp for more air flow. The pro cool unit is awesome and they look killer!!! I think the website is: www.rackfans.com. There ended up being a few more things wrong with that amp and the replacement for that amp and I no longer have a 4 pro but I can say over-heating was not one of the problems.
 
#15
BassmanPaul said:
The gentleman seems to have done a search for every thread dealing with the SVT4 to post the same thing. One of them is ten years old!

it would have been much better if he had started a thread with a title like “A cooling solution for SVT4 owners.” :)
Click to expand...

Very true. If I am not searching for a solution, I am usually just entertaining myself with these posts. Always some humor here.
 
#17
BassmanPaul said:
The gentleman seems to have done a search for every thread dealing with the SVT4 to post the same thing. One of them is ten years old!

it would have been much better if he had started a thread with a title like “A cooling solution for SVT4 owners.” :)
Click to expand...
Here is the problem with starting a new thread. "Jerks" always try to refer back to older threads that talk about the same subject. I cut out the middle man. The fact that you chimed in says you checked it out.
 
#18
I tend to read anything and everything that comes up on page one. It’s irritating to be reading away and formulating replies only to see names of members who I know are no longer active on the site. Zombie threads are somewhat looked down upon.

If you start a new thread people will read it who have a connection to the said amplifier. I get that you were trying to be helpful and applaud it. It’s just the way you went about it dragging up years old threads that the owners might well have sold that particular amplifier a long time ago. :)

If a “jerk” comes along and gives you a problem ignore or report it. For most of the members here “Jerk” doesn’t apply in any way.

Good luck to you sir!. :D
 
#20
charlie monroe said:
Rod has a point. Sometimes you can't win.

I see as many "Do a search" posts as I do "Zombie alert..."
Click to expand...
I have to agree with Charlie. People on here often look for ways to be irritating. However, I think one zombie post is sufficient. 8 or 9 is unnecessary, especially when there was a new thread on the topic posted just last week. But in the grand scheme of things, it's small potatoes either way.
 

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