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problem with cambridge amp



 
 
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  #1 (permalink)  
Old November 20th 06, 05:58 PM posted to uk.rec.audio
darwengray
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Posts: 1
Default problem with cambridge amp

Hi hoping someome might be able to help .
Wired up my speakers to the amp on a temporary basis while i was doing
some work in the room where stereo was connected speakers up with just
one set of wires and didn`t notice that the detached set were touching
each other.
Next minute hot smell from amp and now no sound.
Question is have i caused irrepairable damage to amp or can it be
repaired?
Could it just be a fuse inside unit.
Thank in advance

Graham H

  #2 (permalink)  
Old November 20th 06, 07:05 PM posted to uk.rec.audio
Trevor Wilson
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Posts: 801
Default problem with cambridge amp


"darwengray" wrote in message
ups.com...
Hi hoping someome might be able to help .
Wired up my speakers to the amp on a temporary basis while i was doing
some work in the room where stereo was connected speakers up with just
one set of wires and didn`t notice that the detached set were touching
each other.
Next minute hot smell from amp and now no sound.
Question is have i caused irrepairable damage to amp or can it be
repaired?


**Everything can be repaired. It just depends on how much you are willing to
spend. Unfortunately, most Cambridge amps use a rather unusual type of
output device, which can only be obtained from the Cambridge.

Could it just be a fuse inside unit.


**Not a snowball's chance in Hell. Fuses don't smell when they blow. You've
buggered the output devices and probably some other stuff as well.

Thank in advance


**My pleasure.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

  #3 (permalink)  
Old November 20th 06, 07:24 PM posted to uk.rec.audio
Anton Gijsen
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Posts: 5
Default problem with cambridge amp

Trevor Wilson wrote:

**Everything can be repaired. It just depends on how much you are willing to
spend. Unfortunately, most Cambridge amps use a rather unusual type of
output device, which can only be obtained from the Cambridge.


I fixed a Cambridge amp which had a power amp IC with a crater in it
courtesy of the previous owner. £10 for a Philips TDA1514A off eBay. The
hard and tedious bit is getting the power amp board out of the casing
and getting the heatsink off the ICs.
  #4 (permalink)  
Old November 21st 06, 08:21 AM posted to uk.rec.audio
Jim Lesurf
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Posts: 3,051
Default problem with cambridge amp

In article , Trevor Wilson
wrote:

"darwengray" wrote in message
ups.com...
Hi hoping someome might be able to help . Wired up my speakers to the
amp on a temporary basis while i was doing some work in the room where
stereo was connected speakers up with just one set of wires and didn`t
notice that the detached set were touching each other. Next minute
hot smell from amp and now no sound. Question is have i caused
irrepairable damage to amp or can it be repaired?


**Everything can be repaired. It just depends on how much you are
willing to spend. Unfortunately, most Cambridge amps use a rather
unusual type of output device, which can only be obtained from the
Cambridge.


Could it just be a fuse inside unit.


**Not a snowball's chance in Hell. Fuses don't smell when they blow.
You've buggered the output devices and probably some other stuff as
well.


Don't know the design, but if lucky it may be something like o/p emitter
resistors releasing magic smoke before the actual transistors died. In my
experience, resistors make more smell than transistors when failing. :-)

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html
  #5 (permalink)  
Old November 21st 06, 08:53 AM posted to uk.rec.audio
Terry
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Posts: 1
Default problem with cambridge amp


"Trevor Wilson" wrote in message
.. .

"darwengray" wrote in message
ups.com...
Hi hoping someome might be able to help .
Wired up my speakers to the amp on a temporary basis while i was doing
some work in the room where stereo was connected speakers up with just
one set of wires and didn`t notice that the detached set were touching
each other.
Next minute hot smell from amp and now no sound.
Question is have i caused irrepairable damage to amp or can it be
repaired?


**Everything can be repaired. It just depends on how much you are willing
to spend. Unfortunately, most Cambridge amps use a rather unusual type of
output device, which can only be obtained from the Cambridge.

Could it just be a fuse inside unit.


**Not a snowball's chance in Hell. Fuses don't smell when they blow.
You've buggered the output devices and probably some other stuff as well.

Thank in advance


**My pleasure.


--
Trevor Wilson


Amplifiers really should be protected against speaker shorts.

Regards


  #6 (permalink)  
Old November 21st 06, 11:37 AM posted to uk.rec.audio
[email protected]
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Posts: 3
Default problem with cambridge amp


Terry wrote:

Amplifiers really should be protected against speaker shorts.


I doubt this was a speaker short, but rather a short between the two
"hot" outputs (R&L). So, as Trevor so nicely suggested, it is likely
that the output devices blew, and possibly the drivers as well.

As to speaker shorts, most decent amps have fused speaker outputs, the
problem is whether the end-user is prepared to install the correct
fuses.

Back to my corner.

Peter Wieck
Wyncote, PA

  #7 (permalink)  
Old November 21st 06, 02:22 PM posted to uk.rec.audio
Don Pearce
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Posts: 1,822
Default problem with cambridge amp

On Tue, 21 Nov 2006 09:21:42 +0000 (GMT), Jim Lesurf
wrote:

Don't know the design, but if lucky it may be something like o/p emitter
resistors releasing magic smoke before the actual transistors died. In my
experience, resistors make more smell than transistors when failing. :-)

Slainte,

Jim


But neither is in the same league as a Selenium rectifier. One of
those going up will empty a room.

d

--
Pearce Consulting
http://www.pearce.uk.com
  #8 (permalink)  
Old November 21st 06, 04:13 PM posted to uk.rec.audio
[email protected]
external usenet poster
 
Posts: 3
Default problem with cambridge amp


Jim Lesurf wrote:

Don't know the design, but if lucky it may be something like o/p emitter
resistors releasing magic smoke before the actual transistors died. In my
experience, resistors make more smell than transistors when failing. :-)


Sadly, the resistors usually fail because the transistors are done. Not
the other way around. And also part of my comment on fused speaker
outputs. A typical fuse that will protect the amp will blow often if
the amp is driven at/near capacity for any more than a very few
seconds. A fuse that *may* protect the speakers will generally not
protect the amp.

You who are not in the US have (to us) a strange way of
describing/naming fuses. We use Dual-Element fuses for these
applications, something that will handle a brief peak (read
"clipping"), yet blow quickly if that peak is sustained for any length
of time. Last time I mentioned D/E fuse, I got ranted at as to how they
are illegal, immoral and/or fattening other than around here. But for
all that, they are might useful beasts. By no means perfect in speaker
applications, and there are some losses due to the fuse being in the
circuit (or so the massive-cost speaker-wire advocates maintain), but
again they are very useful.

For example, I use a 1A dual-element fuse from my 375WPC/RMS SS amp
into AR3a speakers. I *can* blow that fuse at ear-splitting volume with
some source material, but I will damage neither the amp nor the
speakers in the process. A 2A fast-blow fuse will fail far more often,
and I would not risk a standard-design slow-blow fuse at any rating.

Peter Wieck
Wyncote, PA

 




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