agedhorse

Your dealer or the service agent of record for your region can order a replacement diaphragm, there is no reason to replace the entire driver unless you prefer to spend additional, unnecessary money.

As Bill mentioned, low frequency extension is generally one tradeoff, another is power handling. As power handling increases, sensitivity generally decreases. The idea is that the SPL gain from increased power handling exceeds the SPL loss due to higher power handling (which it usually does up until a point). For instance, you may lose a dB in sensitivity to double the power handling. Regarding sensitivity specs, I typically use the average sensitivity from 50Hz to 5kHz for bass guitar because this seems to reasonably represent the bandwidth that most players perceive as "volume". Unfortunately, there are plenty of examples of sensitivity that are simply impossible to achieve using such metrics. Also, it's important to distinguish sensitivity at 1W/1M from 2.83V/1M because 2.83V/1M with a 4 ohm cabinet will result in numbers 3dB higher due to it now being the equivalent of 2W/1M rather than 1W/1M.

Your dealer would need to contact the distributor for your country. I do not know what the policy is for this kind of accessory

Correct, I should have been clearer in my explanation. The footswitch operation on the M6 is different, individual contact closures for each voice (1, 2, 4, 5) with 3 being default. Sorry for the confusion. The original concept of the switching on the M6 came from the guitar amp side of things where MIDI switchers and contact closures were commonplace. When a program change is sent via MIDI, it triggers the appropriate contact closure to enable that voice. With the M9, this was simplified and it kind of works in reverse, you set the voice you want to switch to on the voice knob, then the footswitch toggles between no voice and the selected voice. This is the tip contact, the ring contact is for mute. Hope this helps.

Just be sure you get the latching type.

Correct, applies to the M-6 only. [edited for accuracy]

This switching scheme was designed to be used with a variety of switcher boxes that are more common in the guitar side of the industry. There were a bunch of semi-custom products, but some stock ones too. https://mesahollywood.com/products/voodoo-lab-control-switcher Here's another, uses 2 x TRS that have to be broken out at the amp's end into 2 x TS: Here's another, I believe this breaks out to 4 x TS: Here's an example of the kind of product that would be used at the amp end, and a programmable MIDI footswitch would go on the floor with a single MIDI cable between the two. The box would provide the contact closures upon command by the MIDI signal. The guitar world is full of such devices, we had some too, but things have changed considerably over the years and they are in fact fading away: https://six4pix.net/product/midiswitcher/ We also made a 4 footswitch pedal with 4 outputs that could be connected through a single 4 pair snake terminated in 1/4"-TS plugs, I don't know much about the accessories, but customer service would know. Hope this helps

Because the gain structure is very similar between the two, and with the channel volume on the Shuttle 6.0 control set to ~1:00, the gain structure is the same. The results are virtually identical in the pre position and overall within a few dB in the post position. The DI circuitry is in fact identical. In case you don't realize it, I designed both of these amps. What the OP is experiencing is consistent with either the DI output level switch being set differently or the sound guy being unaware of the gain structure of his console's input channel strips.

The different preamps make no difference to the OP's situation.

With all 4 MOSFETs, it was capable of greater power into both 8 ohm and 4 ohm loads. There were many versions of these amps that used a similar output section, but it depends on the power transformer (thus the rail voltage) also. If the rail voltage gets too high (to achieve greater power into 8 ohms), then 4 output transistors may not be enough for the resulting higher power into 4 ohms. There were also different MOSFETS used throughout the production history, including special "double-die" parts. Over the years, there were some output stage applications that weren't all that reliable, and sometimes incorrect transformers were fitted in order to ship amps. Many of these unrelaiblities could be traced back to the liberal build philosophy rather than the circuits themselves.

The AH-100 links are for manufacturing to use this PCB assy. with a different model. This amp, from the photo, uses a single pair of output MOSFETS. Depending on the power supply (rail) voltages, it may very well be rated for 8 ohms minimum load only. Especially because it has a single speaker jack in what was a combo, and because Celestion confirmed that it was an 8 ohm driver.

You are going to need to do more testing and troubleshooting. There may be a small difference in DI level between the two different amp models, but not a huge difference.

The later BLX-80's were rated for 4 ohm use and had a larger heatsink. There is no output transformer in the amp, so that part can't be part of any discussion. There were earlier versions of this amp, and there was indeed a version that was 8 ohms only, I believe it can be identified by having only 2 output transistors rather than 4, but my documentation is not entirely clear on this. It was not uncommon for Trace to have several versions of any model, making is more of a challenge to support. This appears to be part of the company culture, as I have had 2 supposedly identical models side by side on the bench and they were entirely different internally.

The ground lift switch can't change the level. By any chance could the mic/line switch be set to the line position on the louder amp?

Note that virtually all of the Chinese IcePower 125ASX2 modules being sold on eBay are counterfeits. The original manufacturer of your amp should be able to supply the part, though many will only supply them to authorized service facilities.