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Silver Member Username: Shane24Post Number: 151 Registered: Mar-07 | I have a vintage sansui au-d55x integrated amplifier coming on to 25yrs now with a pair of jbl L86 bookshelf made way back in the 80's, I do have a newer setup offcourse, but now and then I listen to music with the sansui setup I own... The problem I am facing for quite some time actually is that when I peak my volume a bit over the edge it starts to trip, comes back on after about 5-10seconds and it keeps happening, every time I turn it up, so I try not to turn it up that much.. I have given it for service many a times, but of no good as the same problem keeps occuring.. Now, the sevice guy, says he is not very sure as to what the prime problem is but its a combination of factors that my amp trips.. 1.Over-heating 2.No proper ventilation through the amp drill 3.Its expected, being an old amp There is nothin placed on top of my amp, as of which there is proper ventilation.. So, as a result I don't turn the volume way up for it not to trip.... Amp rated at 80wattsx 8ohms(4channels), spks rated at 150wattsx8ohms bookshelf.. Opinions much appreciated........ thxs........... |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 10369 Registered: May-04 | . Not what you want to hear but I can't imagine a repair that would be worth the money for this amplifier. You've had twenty five good (?) years together. Try that with a dog, even harder to say goodbye. But, goodbye would be the best answer at this time. |
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New member Username: Mr3dzpopWoodstock, Georgia USA Post Number: 3 Registered: May-07 | Shane... What you are probably experiencing is over-current shutdown. There can be several factors that influence this. Typically, in any receiver, amp, or integrated amp architecture is an "I" (current) safety feature. In layman's terms this means "if you exceed the current limitations of any channel in the amplifier section of this piece of equipment, then I'm going to cut you off". There is also the possibility that your amp is shutting down due to what it perceives to be a DC problem with one (or more) of the amplifier channels. Audio signals reproduced and amplified to drive any audible sound reproducing device (i.e. speakers) are by their very nature pulsing DC. This means they are positive and negative swinging voltages that drive a coil (in the speaker) and produce magnetic fields of opposing polarities. Protection circuits are built in to virtually all amplification systems to protect both the amp and the speakers attached to it. If you exceed the parameters of this protection system, then the amp, integrated amp, receiver; will shut down due to the over-current sensing in the particular system. Now, that being said, there is also a filtering network built into these protection circuits so that the amp in question does not react to every peak voltage of the above mentioned DC swings. If the capacitors in that filtering system dry out then the amp will shut down prematurely since it thinks you have a problem when in fact, you don't. Now the key questions are... how old is your integrated amp, how long had it been working fine until you noticed this aberrant behavior and what if any changes have you made to your system recently? Now, all things considered, are you capable and do you have the where-with-all to do the trouble-shooting and repairs that might be necessary to rectify this problem? Jan may very well be right, this may be simply put, not worth repairing. I am new to this forum as you can see from the number of posts that I have contributed. This is fun for me since I know I have a wealth of knowledge in the audio repair field that can be of assistance to those out there with audio problems and no one willing to assist them without some form of monetary return for their input or insights. Pass the word on, I am willing and eager to share my 40 years of experience to those out there who would seek it. |
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Platinum Member Username: Jan_b_vigneDallas, TX Post Number: 10427 Registered: May-04 | . MB - Welcome to the forum, I'm sure your experience will come in handy here. First, let me say that while your answer is quite thorough, the problem might not exist at all. Shane has not developed a reputation for honesty on this forum; https://www.ecoustics.com/electronics/forum/home-audio/354574.html So, answers directed to Shane are often short and, ... well, short. For discussion between you and I at least and assuming this is a real problem ... When problems arise in 25 year old amplifiers, I first suspect capacitors. However, in this case, while that is still my first guess, I would be somewhat surprised a qualified technician wouldn't check for dried or leaking caps and DC offset right off the bat. (Actually, only moderately surprised as I've seen the quality of techs coming out of the schools nowdays who only know digital circuits and have problems with anything older than the milk in the fridge. And, getting paid on a per repair/hour schedule, most techs today won't spend much time on this sort of problem in a "vintage" amplifier wishing not to get tied down to a dog.) So, the question is; do you take on items like this for repair and at what rate? Not discounting your diagonsis, but if someone carries an amplifier into a repair shop, the chance of the tech hearing that the problem might be in over current shutdown are slim to none. . |