Amp biasing question


I don’t have a problem (that I know about), but from what I have read here is that:

1) if the amp is on, the preamp should be connected and powered up

2) biasing should be done with no input from the preamp.

Am I misunderstanding something?

 

immatthewj

I believe what you meant to say is that amp tube biasing should be done with the speakers connected.  It doesn’t matter is the preamp is on or off as long as it is not passing a signal. 

@whart  and @testpilot 

I understand what you are saying.  My question was due to reading separate threads that: if I was understanding them correctly, were stating that prior to turning an amp on, not only should it be connected to speakers, but the preamp should be turned on first (and shutting the system down should be done in the same order--amp off first and then preamp)

AND

that (again, if I was understanding correctly) that biasing should be done with the preamp turned off.  Perhaps that was what I misunderstood and what was meant was that no signal should be being sent from pre when biasing. 

Yeah, the turn on/off sequence is mainly to avoid a nasty "pop" noise from preamp turn on or off going through the system. You got it, @immatthewj 

Separate issue from biasing in my book. 

@whart  , yes, I agree that is separate from biasing.  And I may have misunderstood the postings I have been referring to.  I just was getting the impression that before turning the amp on, the pre should always be on.  If I had that right, one would have to have his or her preamp on while adjusting the bias.

 

 

The point of sequencing is in case your preamp causes a thump when turned on.
This way I f the amp is off, the thump does not go through to the speakers. If your equipment doesn’t do it, then not something to worry about.

My preamp or up stream equipment does not produce any noise, so it doesn’t mater. I don’t think I owned a piece of electronics that thumped for decades.

All of my equipment is tube and has a delayed soft on. So, no racket regardless of the sequence.