Wonks wrote:Howdy Doody Time wrote:The valves came in a pack of three, plus a single in a different package. So no hope of matching them. Nevertheless I am not hearing hum, so whether I was lucky, or Laney (since they don't mention matching) must have designed the circuitry somehow to account fora mismatch.
As I said in one of my posts, Laney do state in the manual that the power valves should be replaced as a matched quad set. It's not made that obvious (nothing in bold type or in any warning section), but it's there. Almost on the last page of the English section of the manual, rightbefore the signal flow diagram.
Just mentioning it for correctness.
Great news that it's working!
Yeah, Manufacturers put a lot of A saving stuff in manuals! Some will state that you MUST use exactly the right impedance speaker when there is no such thing and it is not THAT critical anyway. Some say use of a power soak will wear out the OP valves. True but no faster than playing 7 nights a week at full chat in a club.
Some warnings are I understand required by law? Electrical safety is paramount of course but I always smile about the SPL charts? The punter has bought a 50W combo with two V30s in it..What's he gonna do?
As far as valve matching goes, a very big unbalance will lead to hum and some reduction in clean power but where balance really matters it has to be much better implimented. Not only DC balalnce of the OP valves but LF and HF balance of the drive from the PI.