Low output on ZX450 after repair

[gfunk_nz]

After spending a lot on having a ZX450 sorted out, I finally got round to installing it, I had intended to use it to run my fronts actively, however after removing the ZX250 and installing the 450 the output was way lower, infact when I measured the output just with music, obviously not ideal it was the last 1/16 of a turn of the gain that made the voltage jump up about 3 volts, but even then only to about 9v as opposed to 27v in a similar measurement setup on the 250.
One of the things that was done was all the output fets replaced then the bias was reset, could the bias adjustment have caused such a huge difference in output level?

[Eric D]

The bias adjustment does not affect output level. How does the amp sound? If the sound of it is at all off, then there is probably something else wrong with that channel or channels.

[gfunk_nz]

it sounds pretty normal, not distorted at all. So may it just be coincidence that there is something else wrong there possibly in the pre amp department then?

[davidtemple]

it sounds pretty normal, not distorted at all. So may it just be coincidence that there is something else wrong there possibly in the pre amp department then?

Sounds like something else is wrong with the amp it should have more headroom than the ZX250

[Eric D]

I am pretty sure the ZX250 would be the same, or if anything the ZX250 would have more headroom actually.

[valeks1]

Sounds like you have a problem with Current Limiting circuit. Can you heck rails without loads and with loads at maximum output? If rails down by more than 25% at maximum output you have a problem with current limiting circuit.