2. amps-preamps
  3. 127980-84541

Preamp popping!

Salutations! 

I have a problem and was hoping to use our collective experience to solve it..

My preamp (dared mc-7p) produces a VERY loud pop through the speakers approximately 10-30 seconds after I power it up. I'm now concerned about blowing a tweeter. I can even see the 12" woofers move.

Obviously I can just turn the dared on first, then turn the amp on after a minute or so. But that's just hiding the problem. I'd like to solve it..

Ideas? I've tried nothing yet. My first inking is to try replacing tubes.. Good idea? If so, shall I start with the power or signal tubes? Again, my inkling is to start with power.

Assuming that doesn't work.. What else could it be? Some kind of capacitor gone bad?
128x128toddverrone
minorl
1,015 posts
 
The advice to turn the pre on first is sound. However, many new pre amps like Audio Research have an auto mute feature. It allows the ore to stabilize first. It also forces the owner to physically inmate the pre before using it. 

Its is funny to to see that the initially responded ignored the OP's concerns regarding if a real problem exist.

amps on last. But, if a real problem exist with the pre, it may still have D.C. On the output when you turn the amp on. So in general if all things are working correctly amp on last, pre on first is sound, but if the pre is faulty, it would not have mattered. 
toddverrone's avatar
toddverrone OP
840 posts
 
@minorl right? I knew something was wrong because it didn’t pop like that normally and everyone is telling me I’m turning things on in the wrong order... I'm glad you caught that. I was wondering if I’d lost my ability to communicate

paul79
173 posts
 
10-30 seconds was the kicker.... That and no tube preamp I have ever owned popped at start up.
escritorjuan's avatar
escritorjuan
120 posts
 

rodman99999
2,875 posts
01-19-2017 2:23pm
@escritorjuan - Don’t know who gave you that advice(amp on first/off last), BUT- Don’t ever take any advice from them again!

---------

I was borrowing my mentors mobile DJ rig and talking on the phone with him as I powered up his amp (the mixer/preamp and dual CD player were already on). A loud POP burst over the speakers. Needless to say, he was not happy! That’s when he gave me his advice.

Now, this was a powerful pro Crown amp. With that gear (and my DJ gear, with its 550 watt Crown PB-3 amp), this was the correct approach.




kalali's avatar
kalali
1,977 posts
 
Its funny. I used to think the amp was before the preamp in the power up sequence during the entire 25+ years I owned my Adcom separates and never heard a pop or had any issues, not even a blown fuse. The first time I heard about the "correct" power up sequence was from reading it in this forum.
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