cambridge audio 640A - cut out point

fizzgog

Well-known Member
hi folks, i have a cambridge audio 640a amplifier and if i turn the volume up to just before half (12o clock) the amplifer cuts itself off after about 30mins. i think that it is overheating as i get two flashing lights. it is housed on an atacama equinox hifi stand so there is plenty of room around it. does this sound normal or is there are problem?
thanx
pete
 

Abyssandrew

Active Member
Going past the halfway mark on the 640 is pretty high. My 640A V2 tends to turn itself off after a while. What speakers are you trying to power?
 

fizzgog

Well-known Member
hi andrew, thanx for the reply.
my speakers are mordaunt short ms914s.
cheers
...pete
 

Abyssandrew

Active Member
No problem

Well by co-incidence I have the same speakers as you, so it would appear all is normal. Out of interest, how are you finding the setup, and what sort of cabling are you using?


One question I have, have you by any chance tried bi-wiring your speakers using speaker outputs A and B. I have been having problems doing so (as per my thread http://www.avforums.com/forums/showthread.php?t=313928.)


Cheers, Andrew.
 

fizzgog

Well-known Member
my amp is connected to my cd player using a van den hul interconnect.
my speakers are bi-wired using the speaker cable i got free with them, i think that it is gale. i have 4 banana plugs going into the speakers and bare wire into the back of the amp. i have had none of the problems you mention when starting up.

i have bought some belden speaker cable and intend to biwire the speakers using banana plugs in a 4:2 combination and see if that makes a difference. i originally tried using banana plugs into the back of the amp but they never fitted - it turns out that there is a piece of plastic that needs removing from the connections first, doh.

hope this helps
pete
 

Abyssandrew

Active Member
Do you use both output A and B on the back of the amp for bi-wiring?

Yeh there is a bit of plastic that needs removing. Its pretty hard to get them out, best bet is a really small (e.g. glasses) screw driver, to prise it out.

I'm using Van Damme blue speaker cable, and the "shoe string" interconnect detailed on the TNT audio website.
 

fizzgog

Well-known Member
Abyssandrew said:
Do you use both output A and B on the back of the amp for bi-wiring?

im not sure that i know what you mean. as far as i can remember, there was only one set of pos/neg connections for each of the left & right speakers.
maybe that is one of the differences on version 2 of the amp??
...pete
 

fizzgog

Well-known Member
ive just checked on the cambridge audio site and it shows that version one only has one set of speaker connects and version two has two sets.
...pete
 

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