Before there are a bunch of wild theories about failures, I would like to share with you some troubleshooting techniques that can help determine if the problem is within the unit or form an external or semi-related cause that is not specific to the unit but more of a general issue that might affect all manufacturers regardless of the topology of the amp. Here's a brief refersher course:
1. If you experience a loss of audio, slow down and verify a few simple things (like cables, connectors, power, battery, wireless) BEFORE moving onto the more unlikely and speculative things. I can't tell you the number of "amplifier problems" I have troubleshot only to spend additional time with the customer to determine that it was something completely unrelated to the amp. It's no problem, sometimes things get overlooked in the panic of the moment, but just a few days ago I was deep into talking somebody "off the ledge" and discovered that the power circuit the amp was plugged into was off. Sh*t happens, simple fix.
2. Eliminate all external signal paths, for example devices in the effects loop, in-line tuner, pedal board etc. Rule out these things before assuming it's the amp, bass or speaker cabinet. I remember a problem where the player was complaining of excessive distortion and was sure the amp was the culprit. Seemed reasonable, I spent a couple hourse testing and retesting the amp, couldn't find anything wrong. Sent it back and he had the same problem. Turns out the muting circuit on his in-line tuner had failed and was partially shorting the signal line on his active bass. The audio clips really did sound like a bad amp but in fact had nothing to do with the amp.
3. Verify that the 3 basic components are working correctly. The bass works and has clean output (I can't tell you the number of "amp problems" that were due to a player forgetting that there was a battery in the bass for active pickups), the speaker operates correctly (speak-on wiring problems are not uncommon, things like somebody uses a bridging cable (1+/2+) with a standard amp (1+/1-) or a 2+/2- specialty cable) and then that the amp works with a known good bass and cabinet.
4. If the amp has a serial or series effects loop, verify that the loop is not intermittent and passes signal by plugging a short shielded cable from the effects send to return. This is an issue ALL manufacturer's experience to some degree, including pro audio consoles that use TRS insert points. For some reason, spiders like those little holes and effects return jacks contain a normalling switch that routes the signal back into the amp when the loop is not used. The spider web silk is a good insulator and it seems to get everywhere.
5. Contact the manufacturer for support. Many manufacurers are quite good at helping troubleshoot and diagnose these problems. We try hard to insure that the real problem is resolved, I normally handle support for the touring world (25 years in pro audio) so my approach may be a litttle more sophisticated and "experienced" than others, but at least give them a chance to support you.
6. Verify that the power is indeed good. The new amps contain much more sophisticated protection circuitry that will protect the amp against most (reasonable) power like RFI, transient spikes and undervoltage. Voltage under 95-ish volts is considered a fault that could possible damage the power supply or amp section and the power supply will shut down to isolate the amp from this fault. Technically, the excessive ripple and artifacts can causes problems with the voltage doubler circuit and may exceed the limits of some of the SMPS components. It's better to protect than let the amp possibly fail. My best guess is that this is the problem with biobasses unit pending further information.
Frankly, I haven't seen an actual failure of the 9.0 unit yet so this is why I want to handle this unit personally as I am "the guy" responsible for failure analysis. The high reliability of the class D product is a double-edged sward... they have proven to be so reliable that we just don't get all that much opportunity or experience analyzing faults. Because of this, I don't know what might have happened. Let's see this through and determine the real cause and resolve.
We'll get Dr Funk up and running in no time.
Hope this info. helps.
