HOGFAN Posted September 7, 2011 Share Posted September 7, 2011 Tis the season for football and tailgating. Last season, I started bringing a few stereo components to our tailgate and noticed that at higher volumes, my amp would shut down.....like in a protection mode. I can turn it back on and it works great, but I have to keep it under a certain volume (about 11 o'clock). My amp is an older Sansui AU-717 (listed at 85W/ch), tied to Quartet's. The amp is being powered with a Honda generator (2K watt)....a small portable one. Is there something wrong with my amp.....or is it just doing what it is supposed to do....reaching the protection mode? I don't think there is an issue with the generator's power. If I could get more out of another amp, what should I be looking for (used, as it will be used mainly for tailgating and outdoor purposes).....say under $500, if possible. Any suggestions would be appreciated. Thanks, Hogfan Quote Link to comment Share on other sites More sharing options...
Guest " " Posted September 7, 2011 Share Posted September 7, 2011 check your line voltage with a Digital voltmeter. make sure your speaker impedance matches the amps rating. make sure you are using a copper ground rod for the generator. Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 7, 2011 Author Share Posted September 7, 2011 When you say check the line voltage, do you mean from the electrical outlet on the generator? I actually use an extension cord between amp and generator (heavy gauge). I guess I could check it at the end of extension cord where amp plugs in for power. I have not been using a ground with generator.....will make sure to do so going forward. So, the above two items would cause the amp to automatically shut down at higher volumes? It shuts down at exactly the same volume level.....anything under this level and it works great. Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted September 7, 2011 Share Posted September 7, 2011 I would check the frequency of the AC coming out of the generator. If the generator is a non-inverter type, it's possible that the frequency is lower than the required 60 Hz. The lower the frequency, the less voltage headroom the amp's power transformer can provide (in addition to raising its operating temperature). So, if you're only getting say 55 Hz AC from the generator, you may not be getting enough voltage to allow the amp to deliver its full output. Pushing the amp into clipping is likely to engage the protective circuitry to prevent damage to the output transistors. Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 7, 2011 Author Share Posted September 7, 2011 I would check the frequency of the AC coming out of the generator. If the generator is a non-inverter type, it's possible that the frequency is lower than the required 60 Hz. The lower the frequency, the less voltage headroom the amp's power transformer can provide (in addition to raising its operating temperature). So, if you're only getting say 55 Hz AC from the generator, you may not be getting enough voltage to allow the amp to deliver its full output. Pushing the amp into clipping is likely to engage the protective circuitry to prevent damage to the output transistors. How would I go about checking this? Please be specific, as I am not very tech savy. Thanks, Hogfan Quote Link to comment Share on other sites More sharing options...
russ69 Posted September 7, 2011 Share Posted September 7, 2011 It's entirely possible the amp is working as designed. Play the system at home and see if you have the same issue. That will eliminate the power supply issues. Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted September 7, 2011 Share Posted September 7, 2011 What else do you have plugged into the generator....? It isn't a frequency problem and you do not need the ground rod...(Would be kinda hard to drive one through the parking lot asphalt anyway) If you have additional load plugged into the generator the 2K honda might very well be having a hard time keeping up. You may be experiencing some type of voltage drop condition. What size is your extension cord and length? There are all kinds of possibilities. Most electronics don't like square wave generators. Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 7, 2011 Author Share Posted September 7, 2011 I have no problem with the amp at home....it performs great, but I am not pushing it (not sure I could stand it) quite as hard. The generator has the amp, cd player, tv and portable dish plugged into it. I borrowed a friends 3K watt honda generator late last season, and the amp shut down just the same as it did on the 2K watt generator. The extension cord is a 15' contractor grade.....thick and heavy. Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted September 7, 2011 Share Posted September 7, 2011 Your amp is very sensitive to voltage fluctuations (you did say it was an older model). One of the newer SS amps would likely be more tollerant (sp) to the voltage supplied. The generators are supplying square wave voltage and not a pure sign wave so some of the older electronics aren't really compatible. If you could get your hands on a pure sign wave inverter 2KW you would be in business but that is an expensive alternative. I would suggest investing in a newer amp and you should be fine. Your TV, CD and Dish don't seem to be experiencing the same problem, so it is kinda pointing to the amp. Your amp does have a two prong power cord, correct? Quote Link to comment Share on other sites More sharing options...
tube fanatic Posted September 7, 2011 Share Posted September 7, 2011 It's entirely possible the amp is working as designed. Play the system at home and see if you have the same issue. That will eliminate the power supply issues. I'm tending to agree with Russ. Given that it shuts down the same with the other generator, yours probably isn't the problem (it would be weird if both were way below 60 Hz). Why not grab some hearing protectors (get everyone out of the house!), connect the speakers at home, and see if it does the same thing. That will answer the question. Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 7, 2011 Author Share Posted September 7, 2011 Correct, not experiencing any issues with anything else plugged into generator. The Sansui does have a very thin power cord with 2 prongs at end. Any recommendation for better/more tolerant amp? Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 7, 2011 Author Share Posted September 7, 2011 It's entirely possible the amp is working as designed. Play the system at home and see if you have the same issue. That will eliminate the power supply issues. I'm tending to agree with Russ. Given that it shuts down the same with the other generator, yours probably isn't the problem (it would be weird if both were way below 60 Hz). Why not grab some hearing protectors (get everyone out of the house!), connect the speakers at home, and see if it does the same thing. That will answer the question. Good idea....will give it a try (with ear plugs). Thanks, Hogfan Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted September 7, 2011 Share Posted September 7, 2011 HogFan, You could probably get by with any cheap solid state amp check out amps at parts Express. You can pick up any numbers for a 100 bucks or less, check the Bay. I certainly do not understand the BLOW OUT test you are planning at home. All you will achieve is possibly blowing your speakers. What is the point of that? It is pretty obvious that your old Sansui amp is not very tollerant of the generator vltage pushing it or your speakers beyond their limit or clipping it serves no purpose. JMO Quote Link to comment Share on other sites More sharing options...
Panacea Engineering Posted September 7, 2011 Share Posted September 7, 2011 Sorry Double Post Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 7, 2011 Author Share Posted September 7, 2011 HogFan, You could probably get by with any cheap solid state amp check out amps at parts Express. You can pick up any numbers for a 100 bucks or less, check the Bay. I certainly do not understand the BLOW OUT test you are planning at home. All you will achieve is possibly blowing your speakers. What is the point of that? It is pretty obvious that your old Sansui amp is not very tollerant of the generator vltage pushing it or your speakers beyond their limit or clipping it serves no purpose. JMO I think the purpose of the home test is to see if I can push the amp to the same level where it shuts down when using the generator. If it doesn't shut down, then it would point to a power issue with generator setup. If it does, then it would indicate it is certainly an amp issue (with protection mode). Thanks, Hogfan Quote Link to comment Share on other sites More sharing options...
MikeFord Posted September 7, 2011 Share Posted September 7, 2011 For about $20 you can pick up a power meter like the Killawatt P4400. Your amp or whatever plugs into the meter, and meter plugs into the power source, and you can push a button to monitor the voltage, power, whatever. Home Depot, Sears, etc carry them. If the power isn't up to snuff, most generators have some kind of adjustment to correct it. If power isn't an issue, look on craigslist for a cheap DJ amp. Think about some efficient speakers like a set of Heresy's. Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 8, 2011 Author Share Posted September 8, 2011 Ok, for what it is worth, I pushed the amp past the usual shutdown point inside my home, attached to the Quartet's......the amp stayed strong. So, does this tell me my problem is in the power supply (generator, or type of power it produces)? I went past the normal shut-off point a few clicks. That said, it looks like I either need to adjust the generator (if possible) or find another amp tolerable to my generator. Y'all agree? Anything else I should look at? Thanks, Hogfan Quote Link to comment Share on other sites More sharing options...
mungkiman Posted September 8, 2011 Share Posted September 8, 2011 Have you tried plugging the amp directly into the generator? That would help eliminate the extension cord as the culprit, which I think is an easy, cheap, and worthwhile test. Even if the cord is big, and contractor grade, it could still be 14 or even 16 gauge wire. Quote Link to comment Share on other sites More sharing options...
russ69 Posted September 8, 2011 Share Posted September 8, 2011 Ok, for what it is worth, I pushed the amp past the usual shutdown point inside my home, attached to the Quartet's......the amp stayed strong. So, does this tell me my problem is in the power supply (generator, or type of power it produces)? I went past the normal shut-off point a few clicks. That said, it looks like I either need to adjust the generator (if possible) or find another amp tolerable to my generator. Y'all agree? Anything else I should look at? Thanks, Hogfan If you ran it for a couple of hours than yes, it could be bad power. I still think you are just driving it to hard for too long but if you gave it a good test than you have your answer. Seriously if you are running outdoor systems, you should get a pro amp that is made for that kind of duty. Here's one: http://www.amazon.com/Pyle-PTA1400-Professional-Power-Amplifier/dp/B0010KCP98/ref=sr_1_2?ie=UTF8&qid=1315462512&sr=8-2 Quote Link to comment Share on other sites More sharing options...
HOGFAN Posted September 11, 2011 Author Share Posted September 11, 2011 I ended up picking up a QSC GX3 amp, hooking it to the Sansui au-717 and I no longer have an issue with my system shutting down when powered with a generator. In addition, I find the QSC amp provides so much more headroom.....very satisfied with the new addition. It even sounds great at lower volume. Thanks for all your feedback! Hog fan Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.