Loud Snapping when turning amp ON and OFF

I hooked up a new (used) Eagle 2 amp into my system last night, turned off all the sources and turned down the volume on the preamp. When I switched on the amp there was a loud (evil and dangerous sounding) SNAP! then metallic sounding ZITTTT! noise through both speakers. I shut off the amp and heard the same noise, more evident this time through the right channel, followed by a noise sort of like ssssffffttt!

So I checked all the grounds, and changed out the preamp to a reference Line passive. Same noise happened again, so I left it one and played some tunes through the system.

Amp sounds killer, very authoritative bass, but the ON/OFF noise is downright scary as if the next time one of the Celestion SL 600 speakers could turn to toast.

Thoughts? Speculations? Thanks in advance. Kolledog
Could you please describe the sounds again? (Only joking)

How old is the amp? It sounds like it may need to have some capacitors replaced.

#1Turn your amp before preamp on
#2 provided the amp is solid state, I would leave it on
Some do not have a Soft on off function especially if that old', I believe many newer amps use a relay to kick on after the power supply and caps come up to speed, you might just be hearing the nast power surging the board when powering up, and no relay in front to block it, unless a part is worn out, might need repair.
No Bi0drain,

Power amplifier is always "Last to turn on" and "first to turn off". Reason because of the power amp having the most electricity current.

Chime in if you agree or disagree.

I have 2 old Eagle 2 amps, as well as 2 Eagle 4's and a newly minted Eagle 2C. One of them I bought recently was an early s/n and "well used". It did the same thing when I powered it on. Here's what I suggest first: 1) Open it up and clean out th einside thoroughly. You may want to install a new power switch (you can get them from EKSC) or clean the existing onw with switch cleaner/lub from Ratshack or other similar product. 2) Check that the fuse is proper (7 amp slo-blo). 3) Power it back on and leave it on - 24x7 for at least a week. Play it during this time as long as it's operating properly. See if the noise returns after this time.

If it does - see the following from the EKSC Website:
If you own an older Eagle product, more than 10 years old, we STRONGLY recommend having all the electrolytic capacitors replaced. For Eagle 2 series amplifiers, we have a flat fee service with two year warranty. Please contact Eagle concerning other products. This is true no matter what brand of amplifier is involved. Failure to replace worn out electrolytic capacitors in any amplifier can result in catastrophic failure, possibly damaging the amplifier and loud speakers.

You may want to have the amp recapped and/or modded. Thet aren't cheap, but it's worth it. The Eagle 2C is a really nice amp even factoring the cost of the upgrade.

hope this helps.
Yea, echoing many of the above, many amps have a time-delayed muting switch that kills the feed during powering on / off in order to avoid this issue. Some don't, however, and you get to listen to the nasty bits as they ramp up or down.

Bryston, for example, had a batch of amps that went out with a muting switch which failed after a number of years. Once it went, you knew it. Particularly at powering down. Kinda sounded like they were trying to tear the speakers in half as the stored power bled through the feeds as you powered down. It was a known issue, however, and was fixed for free (ah, Bryston service really is second to none) with no fuss nor muss.

Definitely sounds like what you're hearing, though. I'd check with the manufacturer. If it's something the amps do, then nothing to worry about. If, however, they're designed with a muting switch which isn't doing it's job -- then it may be time to think about having that looked at.

And I definitely agree with Joe, as a general rule of thumb, the amp is the first off and the last on in order to avoid passing such artifacts to the speakers in the event other items in the chain pull similar shenanigains. Best of luck.