It was in fact changed. They were idling really high, and it was brought down quite a bit. 5 years ago I cannot remember the figures for this particular amplifier, but I remember the idling current being ridiculous, and way too high.
I have Messenger 2Kw serial Number 1. I also have the 2 boards that where pulled OUT of mine (with 16XMRF454s) and replaced with the 2879s. I ALSO have a black Messenger 2Kw (the original Messenger was GOLD anodized).
Justin is RIGHT. The bias scheme in them, the early M4Vs, and basically EVERY Messenger amplifier was skewed, skrewed and caused them to BLEW!
BOTH the M2Kws I have will do 2400 PEP EASILY.
Justin: They ALSO had 1.4 volts STOCK at 13.8 on the base of each transistor. I didn't actually look at the bias current, but did rework my bias supplies (yes, I use a single supply for each board)..... I use a regulator driving an active circuit to each side... TO-3 devices on the heat sink (I use the 'end caps', rather than the big sinks so as not to have as much thermal drift.
Going to this route enables (after capacitor replacement) to up the collector volts to 16-17.... Enabling 3Kw + output WITH fully regulated bias.
If you do NOT want to go to the extent on the bias that I and others have, find the bias resistors (they are BIG wirewounds on EACH board). Pull one side. Go get another, and put it in series. They only need ABOUT .7 to .75 volts on the base. ONE of the reason Messengers kicked so much ass back in the day, so to speak, was this high bias current.... It made a REALLY clean amplifier in comparison to Pal / Palomar / Texas Star / etc.
I do NOT have the internal drivers hooked up. Running a driver in the same cabinet, ESPECIALLY with the power gain of this brick, is just asking for trouble.
I've ALSO run my M2Kws with grounded base. Yes, they produce slightly more power, but at the expense of cleanliness.
Cool job on the vids.
--Toll_Free
