>> I think my speakers are killing my amps.<<
I wonder if Al Sharpton's available. |
For record Aragon was obviously older amp, my other concern is if amp may be repaired and potential cost. I know its a stab in dark. Thanks |
Hi Chad,
I may be mistaken, memory isn't what it used to be, but if the 4004 is anything like my 3002, I seem to remember there were two internal fuses, one for each channel. Try lifting the lid, and check for them. Like I said, I may be mistaken, but it's worth a try.
Good luck, and regards,
Dan |
Thanks but yes it has 5 total fuses and all are fine. Nothing stands out as bad upon visual inspection. It knocked loudly then right channel was gone. Cheers |
Sounds like a protection relay. It may be that a device overheated and failed- thus the protection relay kicked in to prevent the amp from destroying the speaker.
Either way it sounds like service is indicated. I would weigh the cost of repair against how the amplifier served your needs; if a replacement amp is costing over just a few hundred dollars then its likely the amp is very well worth repair, assuming service info is available. |
you know, planar speakers (electro-static or true ribbon or quasi ribbon) could be a very capacitative load to the power amp. This means that, due to this highly capacitative load, the power amp could break out into ultrasonic oscillations. As a side note: Very recently I contributed to a thread that discussed ultrasonic oscillations - the OP had posted that his Odyssey Audio gear was frying his Green Mtn Audio speakers time & again - you might want to read that thread as well if there is any info worthwhile for you.
The ultrasonic oscillations could have sufficient amplitude thus generate sufficient heat energy to kill your power amp over time.
There's a good reason that InnerSound/Sanders Sound Systems makes their own power amp for their speakers. Not all power amps, no matter how bulky they look, can effectively drive a planar loudspeaker.
Maybe this is not the issue but it's something to keep in mind..... |
Hmmm, great info and food for thought. THANKS!
I am going to send the planar line array to VMPS for inspection, I talked to Brian yesterday. My largest concern is it always seams to be right channel thus a inspection of the series/parellel or reverse (I get them confused) is a culprit. 6drivers per side are wired in pairs then those three sets are joined. After that is looked into I will look at my best bet for the amp repair or to replace. Again thanks |
The VMPS is not particularly capacitive. Ribbons in general tend to have a fairly resistive quality so other than impedance they tend to be easy loads. |
It possible a capacitor may have arced. I have seen situations where the speaker was damaged by high frequency oscillation before the amp failed. Given its age, it sounds like the amp needs some tlc. |
Did you measure the fuses with an ohmmeter or did you just visually inspect them? Had several fuses over the years that appeared to have intact elements but were wide open electrically. |
Mcintech makes an excellent point! Check your fuses with a DVM. |
Will do, thanks for info. Though the click clack sound the amp made (not through speakers it was mechanical) tells me its more than fuse. |
How does the amp behave if there is no speaker load? |
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He means without the speakers hooked up
or try another pair. |
He means do you hear the click clack sound without a speaker load on the amp. Disconnect only the speakers and try it. My guess is you are hearing some kind of arcing since I do not believe that amp has any kind of relay or protection circuit. If a cap has started to leak it can cause this type of arcing when voltage is applied to it. |
If these speakers are primarily resistive, put a DVM across them and measure the impedance. If they are mis-wired and you get something very low (like 3 ohms or lower), maybe your amp just cannot drive that low of an impedance at the higher SPLs.
This is a simple test and will give you some idea of the issue. Also, compare left with right channels and see how they compare.
If both channels are the same and above 4 ohms, you may have a deffective amp.
However, a simple DVM resistance measurement still will not tell you if you have a capacitive load issue.
The previous poster was correct in that too high of a capacitance load will cause some amplifiers to become unstable and oscillate.
One quick test you can try is to get a large 50-100 Watt 5 ohm power resistor and connect it in series with the output of your amp. If the amp functions OK with this resistor connected (the volume will be 6 dB lower but will still let you perform the test, and the sound quality may not be great but who cares, it's just a test), then you may have a capacitance issue. This test may also give you an indication of whether the speaker loads are too low for your amp. |
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