Ampeg BR4 low output

[nosaj]

There is no ground of any type on your load?

Not that I can see. I've got a bunch of 2 ohm 120watt resistors wired up in an array that equals 8 ohms wired to a switchcraft jack mounted on a wooded board. I believe that is floating. If it were on a chassis with a ground point that would be non-floating I believe.

Thanks,
Jason

[g1]

In case you missed it see post #30.
Also, as far as the load, even as stated, if any other grounded test equip. is connected to it, it would no longer be floating. That was my main concern.

[nosaj]

In case you missed it see post #30.
Also, as far as the load, even as stated, if any other grounded test equip. is connected to it, it would no longer be floating. That was my main concern.

Signal Gennerator is only other connection but it is also floatin I believe. It is part of my oscilloscope with the ground not connected. I will check with a meter then scope the switch,
Thanks so much,
nosaj

[nosaj]

A dirty mono switch could be the issue.
If you scope the 2 channels as if testing stereo, but engage the switch, (using only ch.A input), the 2 channels should be out of phase. Are they?

They are out of phase, but I believe this bass amp has only one input. Now this amp has been messed with before me. So now I'm not sure the Binding posts may be hooked up correctly it doesn't look likes it stock. I still have to pull the board out to replace r168
Thanks,
nosaj

[nosaj]

They are out of phase, but I believe this bass amp has only one input. Now this amp has been messed with before me. So now I'm not sure the Binding posts may be hooked up correctly it doesn't look likes it stock. I still have to pull the board out to replace r168
Thanks,
nosaj[ATTACH=CONFIG]49623[/ATTACH]

Turns out board was too burnt in that section and a 3.3 was attached on the bottom of the board.
Cables are hooked up correctly. When I disabled the Limiter I get a big Volume boost
Still not real sure the bridge function is being measure right or that I'm getting full power out of it.

nosaj

[nevetslab]

In the Bridge Mono mode, you're correct in measuring between the Ch A and Ch B RED binding posts. You should be reading 68VAC....twice that of the dual channel mode, where you were reading 34VAC on each output. A quick reality check would be to drop the level real low, connect a speaker in dual channel mode and adjust the signal to a 'sensible' acoustic level. Then, change to Dual Mono mode, and re-connect your speaker accordingly. The Output across the RED binding posts should sound louder (6dB voltage increase). In that mode you can also unplug the speaker and go back to one of the channels, going RED to BLK binding posts, just to be sure. That at least confirms your amp IS working in Bridge Mode.

Does your meter have a problem measuring higher AC voltages? I'm assuming the meter is a battery powered DMM, and not a wall-powered unbalanced input meter, where the low side is grounded. There, you can't measure differentially, but can add the two voltages together for the correct answer.