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What might happen.

D

David Patterson

pfm Member
I have been using 821 boards in my 72 and have just changed to the Audiophile type. i decided to sort out the powering of the boards in that i have changed from one board powered from motherboard track and the other from the other rail that fed the 729s by a jumper lead ,to a dedicated line from din to each board.At the same time i have removed the relay switch on board.
Now i know that the PS must be switched on before amps , but what happens if you have a power cut and everything comes on at once, is there a chance of damaging the speakers.

Thanks
David
 
NO everything should be fine , Ive accidently turned everything on from the wall socket , having forgotten that I hadnt powered down the amps the night before , you just get a nasty thump.
 
The only time you have to take more care is with an active system, though I still many a time get it wrong and create a thump. I do usually try to turn off power amps first, which depending on caps can take a while, once off all the rest cant ge to your speakers of course.
 
teddy_pardo said:
It depends which type of tweeters you have, some may forgive you, others may not like it...
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And under no circumstances be tempted to try limited excursion drivers like the Lowthers. Slamming them into the end stops is not recommended.
 
David, have you determined that using the relays impairs sound in any way or are you just contemplating their removal on theoretical grounds?
 
Robert said:
David, have you determined that using the relays impairs sound in any way or are you just contemplating their removal on theoretical grounds?
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Robert, i removed the relay as i had the links available to try. This along with the 821s being powered straight from the din via wire has given me a more detailed, greater presence sound, although it could border on being a tad bright, but the sound may mellow with burn in if it exists.

I will remove the relay and compare, i sometimes feel you get a more unbiased view when you backgrade.

David.

PS the 821As are brill
 
my gutted and stripped to the bone 32.5 , when turned on with the power amps running just goes "phump" , from memory its less noisey than the relayed 32.5 , cos I think it causes more problems , ie when it gets a bit old it starts to arc a bit and the noise it produces get spitchy , ie its not a clean phump , more like Schhhcchump , if you understand ????
 
David Patterson said:
Robert, i removed the relay as i had the links available to try. This along with the 821s being powered straight from the din via wire has given me a more detailed, greater presence sound, although it could border on being a tad bright, but the sound may mellow with burn in if it exists.

I will remove the relay and compare, i sometimes feel you get a more unbiased view when you backgrade.

David.

PS the 821As are brill
Click to expand...

I meant replace the relay.....
 
Strangely when I start up my kit in sequence I often trip a circuit breaker but after a power cut everything comes back on all together and is just fine. ???
 
Thats because after a power cut the board ar usually very careful to restart the grid at the zero volt point in the cycle, hence limiting the initial current surge. When you switch your amps on the cycle could be at any point, and if its at the top or bottom (+-300V) then you effectively momentarily short a high voltage (consequently drawing an enormous current) as your amps' caps charge.
 
Tim, I've had similar experiences [although not like my present one] and It is good the have some clarity. Thanks colasblue.
 
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