Crispy
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Post by Crispy on Apr 16, 2016 19:53:25 GMT
those are the correct transistors. As the amp works on +/- 80V (160V) a 200V rating would already have been enough. So 300V is more than O.K. PNP is rated for -300V and NPN for +300V Transistors are always spec'd for DC ratings but mostly just voltages are given. Thanks Frans, the transistors arrived today and I had some spare time so I measured the new ones and the old ones using the same method. Most of them measured almost the same. I broke T2 & T4 getting them out and T8 measured completely different so I binned those three. I soldered in all the new transistors and the old T6 & T5 which measured the closest to the new ones: I also replaced the blown resistors. I am now waiting on the output transistors before I can hopefully finish the job? Do I need to make any checks before the output transistors are added? Cheers Chris
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Crispy
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Post by Crispy on Apr 26, 2016 7:47:04 GMT
The output transistors arrived the other day and I found time yesterday to solder them in, so hopefully the board is ready to be put back into the amp?
So Frans, do I need to make any measurements before I re-assemble or am I OK to go ahead?
Cheers
Chris
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solderdude
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Post by solderdude on Apr 26, 2016 16:40:49 GMT
I would test the amp without the output devices soldered in yet. You have done the procedure without output devices before.
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Crispy
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Post by Crispy on Apr 27, 2016 19:12:04 GMT
I would test the amp without the output devices soldered in yet. You have done the procedure without output devices before. Oooops too late Frans, I have already soldered the output devices into position and I really don't fancy taking them out again I honestly thought that putting brand new parts in would not really require measurements (Wrong) so where do I go from here? Sorry for my eagerness in just wanting to get it back together and hopefully concentrate on the ESL's.
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solderdude
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Post by solderdude on Apr 27, 2016 20:24:37 GMT
If all those parts have been replaced I guess it should fire up O.K. Would just have been a precautionary way of testing.
Just make sure all of the power transistors have enough cooling.
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Crispy
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Post by Crispy on Apr 28, 2016 18:49:45 GMT
If all those parts have been replaced I guess it should fire up O.K. Would just have been a precautionary way of testing. Just make sure all of the power transistors have enough cooling. Thanks Frans, I think it has got two chances in that it will work fine or it will blow again Not sure what you mean by making sure the power transistors have enough cooling? or did you mean the output transistors being firmly attached to the heatsinks?
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Crispy
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Post by Crispy on May 3, 2016 18:27:19 GMT
If all those parts have been replaced I guess it should fire up O.K. Would just have been a precautionary way of testing. Just make sure all of the power transistors have enough cooling. Thanks Frans, I think it has got two chances in that it will work fine or it will blow again Not sure what you mean by making sure the power transistors have enough cooling? or did you mean the output transistors being firmly attached to the heatsinks? Well some good news and some bad news Frans, I put the amp back together and plugged it in without any signal and nothing blew (PHEW) I left it like that for an hour and everything was OK I then plucked up the courage to try it in the system and speakers. It was very faint and crackly and I thought OH NO!! After a little think, I thought could the speaker have blown as well as the amp? So I substituted my AE1 speaker for a cheap and nasty one and low and behold sweet music came from it with plenty of volume. So it seems that the amp is finally mended again (MANY THANKS FOR YOUR TIME AND EXPERTISE). I now have taken my speaker off its stand and I will see if I can see anything obvious either in the crossover or the cones that needs sorting? Any pointers on what may have blown? Thank you so much Chris
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solderdude
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Post by solderdude on May 3, 2016 19:57:08 GMT
Most likely the woofer is blown. The crossover hardly ever dies and most speakers are not protected by a fuse. A large amount of DC may have passed through it which is fatal with the amount of power this amp can deliver.
I hope you can still find a replacement woofer for sensible money. They are large swing woofers, I would only recommend the original woofers.
Would take the woofer out and measure it with a multimeter after it has been taken out.
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Crispy
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Post by Crispy on May 4, 2016 20:17:26 GMT
Most likely the woofer is blown. The crossover hardly ever dies and most speakers are not protected by a fuse. A large amount of DC may have passed through it which is fatal with the amount of power this amp can deliver. I hope you can still find a replacement woofer for sensible money. They are large swing woofers, I would only recommend the original woofers. Would take the woofer out and measure it with a multimeter after it has been taken out. Your damn right again Frans. I took out the tweeter, woofer and the crossover. I could not see anything wrong with the crossover and the 2 power resistors both measured OK. The tweeter was Ok with continuity and the resistance on the 200 ohm setting measured 0.63 so I guess that is OK too? The woofer did not register on the continuity setting and also no reading on the same resistance setting. Pushing the cone in and out was also very stiff and noisy - so I guess you are absolutely correct in thinking the woofer is as dead as a Dodo The problem now is finding a replacement which I don't hold out too many hopes apart from Acoustic Energy themselves which going on last time they cost silly money Are there any companies out there that can re-furbish the old one? What is the score on speaker protection, I think it is high time I had some - are there kits to make them or can I make my own? Can they be fitted outside the amp / speaker in a separate box? Or is it a simple case of fitting a fuse somewhere in the crossover like you said. Cheers Chris
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solderdude
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Post by solderdude on May 4, 2016 21:03:55 GMT
Most shops that refurbish speakers will only replace the foam rings. Don't know any shops that also replace whole woofer cones (tweeter domes can often be replaced). I am afraid you will have to shop for new speakers or find the exact replacement woofer from AE.
Speaker protection would have to be an external and powered box if they need to prtect against DC. There are handy PCB's on fleabay that provide this functionality. All they need is a box, a power supply and connections.
A fuse may be too slow and won't work when there is a few volt of DC, yet a few volt of DC can already fry a woofer.
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Post by drumdrym on May 4, 2016 22:01:49 GMT
For what it's worth Chris here is a great vid of a speaker re-cone, would probably depend on the make of your speaker certainly doable if there is a kit out there.
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Post by drumdrym on May 4, 2016 22:26:46 GMT
Thought this one was worth posting.
How to Use Smartphone or iPad to Center Speaker Voice Coil - Easy
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Crispy
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Post by Crispy on May 6, 2016 12:48:43 GMT
Most shops that refurbish speakers will only replace the foam rings. Don't know any shops that also replace whole woofer cones (tweeter domes can often be replaced). I am afraid you will have to shop for new speakers or find the exact replacement woofer from AE. Speaker protection would have to be an external and powered box if they need to prtect against DC. There are handy PCB's on fleabay that provide this functionality. All they need is a box, a power supply and connections. A fuse may be too slow and won't work when there is a few volt of DC, yet a few volt of DC can already fry a woofer. Thanks Frans, I have been in touch with AE and they have been very helpful and can refurbish the woofer for £102 all in which is less then I was expecting You cannot find anything even close to the unit they use from the normal channels so I guess they are custom made in house? I had a quick look at speaker protection and it seems most of them use UPC1237 - whatever that is? Is there any you recommend or will any do?
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Crispy
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Post by Crispy on May 6, 2016 12:57:40 GMT
For what it's worth Chris here is a great vid of a speaker re-cone, would probably depend on the make of your speaker certainly doable if there is a kit out there. Thanks for that Alan, but as you will have already read I cannot find anything anywhere near the AE1 cones and think they must be made special in house? Check this link out? www.atombeers.com/I am teaching a woman who lives just around the corner from me and she works next door to this little micro brewery which is only about a mile away from where I live. Next time I drop her off at work I am going to see if they will sell me a couple of bottles of the Brown Ale and stout?
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solderdude
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Post by solderdude on May 6, 2016 19:25:17 GMT
Most shops that refurbish speakers will only replace the foam rings. Don't know any shops that also replace whole woofer cones (tweeter domes can often be replaced). I am afraid you will have to shop for new speakers or find the exact replacement woofer from AE. Speaker protection would have to be an external and powered box if they need to prtect against DC. There are handy PCB's on fleabay that provide this functionality. All they need is a box, a power supply and connections. A fuse may be too slow and won't work when there is a few volt of DC, yet a few volt of DC can already fry a woofer. Thanks Frans, I have been in touch with AE and they have been very helpful and can refurbish the woofer for £102 all in which is less then I was expecting You cannot find anything even close to the unit they use from the normal channels so I guess they are custom made in house? I had a quick look at speaker protection and it seems most of them use UPC1237 - whatever that is? Is there any you recommend or will any do? something like THISThe exact same one but cheaper from China or THIS one as long as they sport 'DC protection' it'll work. They just need a power supply and enclosure.
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