| Non-motoring > Fuming Amp | Miscellaneous |
| Thread Author: Ambo | Replies: 20 |
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New Fri 5 Sep 14 09:32
Fuming Amp - Ambo
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I had noticed a faint chemical smell in my “audio room†for three of four days but put it down to cleaning fluid. This morning I was listening to Radio Three on my hi-fi when there was a very loud crack from the Audiolab 8000A amp. The sound was cut off then resumed, but with a noticeable background hum. There was another, less intense crack and I saw thin but heavy vapour lazily drifting from the top ventilation slots. The smell was stronger, took on more that of overheated electronic devices and clearly emanated from there. The casing was not unusually warm. Opening it up I found that the plastic cover of the toroidal magnet looks slightly burned, as does the corresponding part of the plastic circlet glued to the casing. At the opposite end there is a little pool of what resembled the oily fluid that can leak from batteries and traces of it on the casing, about 3†above it and maybe carried up by an explosion. The manual does not include a circuit diagram but the pool is around the feet of two vertical silver and black components like little cylinders. About half an inch away there are two little horizontally mounted black components of different sizes, one of which shows clear burn marks on the circuit board. The amp won't be re-connected due to fire risk and I imagine it is a write-off. I can stomach that, after 28 years and an estimated 30,000 hours of faultless service, but what could have caused the problem? |
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New Fri 5 Sep 14 10:09
Fuming Amp - Fenlander
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>>>what could have caused the problem? Some will just go pop out of the blue and its not always the most obviously damaged component that started the failure. I buy quite a lot of house clearance hi-fi around that age or a bit older and I always put stuff into a system then use it for a week or so before selling. About 10% of it seems to fail after a few hours use... either like yours or a more gradual fizzling to nothing. That Audiolab is still worth about £50 as spares on Ebay and unless you need the very slim shape £100-£150 used on Ebay will get you a good condition other make amp that will match or exceed its sound. I guess yours looks like this inside... 2.bp.blogspot.com/_72VgihSgEs0/TIyWgTmC1bI/AAAAAAAAAGA/UboVNhLnwcE/s1600/IMG_2610.JPG |
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New Fri 5 Sep 14 10:26
Fuming Amp - Slidingpillar
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At a guess, failure of electrolytic capacitors. Often the death of modern electronics as much of the rest of the components will last a very long time. I removed the PSU in a VHS-S recorder I have and a colleague replaced pretty well all of them to get it to work properly. Not a fly by night name either, a Panasonic which from a repair perspective at least, was/is a pretty good name. |
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New Fri 5 Sep 14 11:26
Fuming Amp - J Bonington Jagworth
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| Agree with SP - capacitors often fail after a few years (also in computers). You will probably find further evidence if you look at the 'cans' which usually have score marks on the top to encourage failure there when they blow up. Replacing is usually straightforward (plentiful on Ebay, as long as you specify the right voltage) but it sounds as though yours has done some more damage. It's probably taken out a few diodes, too.. :-( |
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New Fri 5 Sep 14 13:04
Fuming Amp - Fenlander
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>>>Agree with SP - capacitors often fail after a few years Yes that seems to be the most common reason for failures I see. Sometimes the caps will be seen to bulge or leak before they finally go. Sometimes when they are on their way you can get a background light rustling sound when the amp has got really hot and they go microphonic. Cheap to DIY repair if you can but unless an amp is worth over £150 or cherished for some reason often not economic with repair shop costs. Last edited by: Fenlander on Fri 5 Sep 14 at 13:05
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New Fri 5 Sep 14 13:19
Fuming Amp - RattleandSmoke
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I tend to open up my older HIFI stuff every year and check the condition of the caps. Most of it is quite new although my Marantz CD6000 OSE LE is a good 12 years old now and my Rotel pre amp must be at least 20 or more years old. Slightly OT but I was looking to to upgrade my CD player but I was staggered at how expensive decent ones are second hand and I can't find anything new worth buying for less than £500. |
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New Fri 5 Sep 14 14:14
Fuming Amp - Stuartli
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>>Rotel pre amp must be at least 20 or more years old>> Marantz (then part of Philips) and Rotel were excellent products. My NAD 7300 30w per channel tuner/amp was acquired in 1979 at a cost of £179 - still going strong...:-) Will drive most speakers and capable of up to 60w bursts without clipping; even better is that it's a Japanese built model from the New Acoustic Dimension centre in contrast to later variations. Quite similar in appearance to: classicreceivers.com/nad-model-160 but tuning meters are on the left of the tuning scale and the tuning knob on the right is incorporated in the scale itself. |
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New Fri 5 Sep 14 14:18
Fuming Amp - Fenlander
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Good to see you're still about Rattle. Likewise I always open up old kit for a quick look to see if there are any obviously overheating components... and to vac out 20-50yrs of dust. I've just bought one of these Goodmans Maxamps from the 60s back to life... www.audiofriends.nl/forum/Goodmans%20Maxim/Goodmans%20Maxamp%2030.jpg It had been dropped enough to break the case but that's repaired invisibly now... quick vac out and twiddle the pots dozens of times to polish the crackles off the tracks and it's been performing perfectly for a couple of months now. By chance today I'm playing through a few excellent condition Joy Divison LPs bought as part of a collection... seem to remember you like the Manc bands. BTW not sure why you'd want to upgrade that Marantz CD. It would probably still sound good feeding £2000+ of amp/speakers. Last edited by: Fenlander on Fri 5 Sep 14 at 14:20
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New Fri 5 Sep 14 14:23
Fuming Amp - TheManWithNoName
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On the subject of amps, what causes the crackle when adjusting the volume rotary knob or tweaking the bass and treble controls? Is it dust and can they be cleaned? I've got a Technics SU-Z1 amp |
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New Fri 5 Sep 14 14:27
Fuming Amp - Zero
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>> On the subject of amps, what causes the crackle when adjusting the volume rotary knob >> or tweaking the bass and treble controls? Is it dust and can they be cleaned? >> I've got a Technics SU-Z1 amp Its dirty tracks on the variable resistors. Cant really be cleaned but spinning the knobs backwards and forwards a few times usually helps |
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New Fri 5 Sep 14 14:32
Fuming Amp - Fenlander
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>>> what causes the crackle when adjusting the volume rotary knob or tweaking the bass and treble controls? Is it dust and can they be cleaned? Weird... the SUZ1 was my first amp back in the early 80s. With the amp off rotate the affected knobs to and fro through their full arc dozens of times. If this doesn't have any effect I accept usually defeat but it is possible to get inside and squirt switch cleaner into the switch body before more twiddling. However I've also known this to completely ruin an otherwise just slightly crackly pot. In worthwhile cases I have taken the pots apart to clean but this has been on band gear rather than hi-fi so it's all a bit larger scale. Last edited by: Fenlander on Fri 5 Sep 14 at 14:33
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New Fri 5 Sep 14 14:24
Fuming Amp - BiggerBadderDave
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"Good to see you're still about Rattle." Me too. And I'm going through a New Order phase today. |
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New Fri 5 Sep 14 14:24
Fuming Amp - Ambo
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>> >> Slightly OT but I was looking to to upgrade my CD player but I was >> staggered at how expensive decent ones are second hand and I can't find anything new >> worth buying for less than £500. >> I don't know if my Marantz CD-67 is any better but it is going for a fair price, on collection only. If of interest let me have an alternative means of communication. |
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New Fri 5 Sep 14 15:53
Fuming Amp - RattleandSmoke
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Thanks, Nothing much wrong with my CDP other than dry joints at the analogue outputs which means I often have to give it a bit of a kick. Paid £150 for it in 2002 as it was an ex demo, is a very good bit of kit. I am not confident to solider it myself if I can get main board out I am sure my laptop DC jack man can do it very cheaply however I would want to use better quality solder in the audio path. I think the CD67 would be a bit of a sideways move, unless it is a Ki version. My main musical love is post punk and new wave, but I have everything from John Denver to Ramnstien in my collection. Listening to the Cure at the moment via my Senheisier HD25s, Rotel RC87BX pre amp and M Audiophile sound card. New Order sounds brilliant with that combo too, I think the HD25, RC870 and 80's electronic music go so perfectly together I don't think I could get a better sound even if I spent £2000 with this combination, for other genres the sound state is a bit lacking. Last edited by: RattleandSmoke on Fri 5 Sep 14 at 15:58
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New Fri 5 Sep 14 17:10
Fuming Amp - Ted
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>> My main musical love is post punk and new wave, Don't encourage him, you guys........we might be able to hear him over on the posh side of the village ! Although John D would be very acceptable :-) |
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New Fri 5 Sep 14 14:09
Fuming Amp - Ambo
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>>I guess yours looks like this inside... >>2.bp.blogspot.com/_72VgihSgEs0/TIyWgTmC1bI/AAAAAAAAAGA/UboVNhLnwcE/s 1600/IMG_2610.JPG Pretty much but I don't have the broad white tape shown. The fluid is around the two "cans" which are about 40% from the top. The burnt out component is about 45 degrees high right of the right-hand "can" of these two, but is now black. |
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New Fri 5 Sep 14 20:55
Fuming Amp - Armel Coussine
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Through an association with a guy whose father had worked in Nigeria as a doctor, and who was therefore an honorary Nigerian, I once involved myself in a medial exhibition held in the ballroom of a posh Lagos hotel. Although I knew socially some of the doctors involved, my role was that of a humble gofer expected to double as a techie. Boy was that a sweaty job. The electricity, PA and so on all arrived in bright blue highly decorated small lorries from Ibadan, whose wordless, very black crews (did I say my friend was an honorary Nigerian = knew what he was doing in local terms and wasn't going to waste money going upmarket?) swiftly assembled a spitting, sparking sort of network that ran all round the ballroom behind heavy, undoubtedly inflammble drapes and curtains. I spent a lot of time dodging behind those curtains and feeling the big cables to check how hot they were getting. The things one does for one's buddies... tsk. |
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New Sat 6 Sep 14 13:53
Fuming Amp - DP
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I dug my old Pioneer A-400 out of hibernation earlier this year. It had been sitting in my in-laws attic in its box for 15 years, and I was half expecting a cap or two to have dried out, and that lovely ammonia-esque smell when I turned it on. However, it powered on fine, and has had probably a hundred hours use since with no issues. Now in daily use partnered with a pair of second-hand Acoustic Energy AE109s I found on Gumtree for £80, and an old stable platter Pioneer CD player that's even older than the amp, and still works as well as the day I bought it. To be honest, I'd have to spend well into four figures to significantly improve on the sound of this collection of fairly budget 15-20 year old kit. Visitors can't believe how old the system is, and that the whole lot probably has a second hand value of £250. Love old hi-fi kit. |
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New Sat 6 Sep 14 21:15
Fuming Amp - Fenlander
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>>> partnered with a pair of second-hand Acoustic Energy AE109s They are cracking speakers for the around £100 they usually fetch.... as a cheesy hi-fi writer would say they punch well above their weight. Very good bass for such a slim tower... so much so I sold the last pair as they suffered a bass resonance in the tiny room I was using at the time... even with socks in the ports. |
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New Sat 6 Sep 14 16:39
Fuming Amp - Armel Coussine
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>> I spent a lot of time dodging behind those curtains and feeling the big cables to check how hot they were getting. To bang on a bit, I've just remembered the reason for the very heavy power demand (the main hotel fuse even tripped once or twice to everyone's consternation, and feeling the cables I got a couple of non-traumatic electric shocks). The numerous company stalls which had been set up using 6'6" high partitions, each with its own lighting, video and audio, also had - necessarily - air-conditioners to keep customers from dissolving. The company reps were a very variable bunch, but quite a lot were hard-bitten globetrotting tough guys I found pretty unpleasant. The mercantile atmosphere, like a flashback to my market research days, was very dispiriting. Indeed I more or less lost it and made a twit of myself in a way I wouldn't dream of specifying, sorry. It wasn't all bad though, when I didn't have to be in that damn ballroom but could go out and about a little. Last edited by: Armel Coussine on Sat 6 Sep 14 at 16:42
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New Sat 6 Sep 14 16:51
Fuming Amp - Mapmaker
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| AC, your posts like this put me in mind of Waugh's Remote People. Must dig it out and re-read it; I wonder where my copy is. |
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