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
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.
toddverrone's avatar
toddverrone OP
840 posts
 
@atmasphere thanks for the tip! Both tubes that went were new electro harmonix
atmasphere's avatar
atmasphere
11,646 posts
 
@toddverrone Thanks for confirming my suspicion! If I recall rightly the RCAs are the 6V6s to be looking for.
escritorjuan's avatar
escritorjuan
120 posts
 
In my case, the advise to turn on the amp on first and off last came from a mobile DJ in regards to his pro audio gear.  I was working for him at the time and had turned on his Crown amp last, creating a big "POP"!  He was not happy. 

With my LampizatOr Lite 7 DAC (which acts like a preamp in my system, as I use a passive preamp), I was advised to turn it on first, and then the amp, etc.  

Cheers,



Juan 
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