agedhorse

The preamps of the pedal and the amp are almost identical.

Also, verify that you are using genuine Neutrik parts. I have seen an awful lot of intermittent problems (exactly as you describe) from sub-standard Asian knock-off parts, and cables improperly assembled by tinning the wire before assembly. About 1/2 of the intermittent speaker issues have traced back to defective SpeakOn connectors (generally the cable mount type).

The critical information being left out of the statement above is that "underpowering" is not what causes the damage, but the clipping which causes damage primarily to the high frequency drivers. Otherwise, how would all of the overdriven tones work... they are various forms of clipping. This information is from a pro audio perspective, one that generally avoids high level clipping, and also generally has better (more effective) processing to prevent mechanical damage form too much power. Speakers have both thermal and mechanical failure modes. Clipping is generally a thermal failure mode in the high frequency driver, which is why players who use overdriven and distorted tones generally play cabinets without tweeters also. Not only do tweeters disproportionally reproduce the harmonics generated by clipping, but they don't last long doing so at higher power levels. In bass guitar, the most common form of speaker damage is mechanical, and this always occurs from too much power. This is either from an amp that is too large for the speakers, or a misunderstanding of how the amp and the speaker are rated (ie. RMS, program and peak descriptors). When a speaker is rated at say 1000 watts, without any descriptor, the FIRST question to ask is HOW that rating is made.

Explain to me how it's possible for an amp to be so popular and well talked about (bragged about even) in Europe, yet have the reliability and support issues that are being discussed here?

There has been quite a bit of player discussion on the combinations of cabinets over at TalkBass. This may be a more helpful resource.

Your impression is exactly correct, all models within the Subway line are designed with similar phase response, sensitivity and power bandwidth to work well together. The engineering and math have been done, listening tests agree with the predictions, and it's not influenced by the marketing department. Note that this is not true mixing the Subway cabinets with other manufacturer's cabinets, nor mixing cabinet models from Mesa outside of the Subway models (for example, PH and Scout cabinets may not mix well with Subway cabinets). The most common combination is the 115 with the 210, but the 115 with 112 is not far behind.

I just suggest that you have some real experience. I see a fair amount of unrepairable damage caused by attempted repairs.

I did suggest a factory authorized service center as they will have the necessary access to resources and parts. I would have expected them to be fully supported and serviceable for much less then the cost of buying a new one. It's not an inexpensive amp is it? (I don't have a good grasp of European/UK prices of course)

Why not have your amp repaired. I would expect that a qualified MarkBass authorized service center would be able to get this taken care of for you.

I have not seen anything that specifically states that the + and - signals are fully isolated from pin This is an essential requirement for use with ANY amp that contains bridged topology.

Yes. The direction is screen printed on the PCB. Use all safety precautions, the PCB does not need to be removed. It’s a double sided board with plated holes so be be gentle.

There is no difference as the Streamliner's speaker outputs are parallel wired from a single output. I suggest a single cable, simpler and just as effective.

Thanks Al, tried to grab the correct page from my phone but obviously didn't get it quite right. Cheers.

Thanks.

I have addressed some of this to the best of my ability in a TalkBass thread. Rather than rehash this here, please take a look at the thread: https://www.talkbass.com/threads/official-mesa-boogie-subway-series-club.1181245/page-1144#post-24825163