agedhorse

Don’t go poking around creating new problems. Surrey Amps is fully qualified to service your amp correctly, I can work with them directly to solve the problem. If you create new problems, the cost is sure to go up,

Both of these are possibilities, not terribly common but possible.

Solid state amps don’t have to sound nasty beyond 1% THD, those that do haven’t designed around this parameter. Some tube amps clip very similarly to some solid state amps. Some us different than all.

Is the amp quiet without the pedalboard, bass straight into the amp? Where are you located? What is your power source? there is also a possibility that there is a ground loop between the amp and pedalboard, or even a single pedal on the board.

You just might be misunderstanding how power amps are rated and specified however, therefore your generalization inaccuracy.

If the amp is quiet with nothing plugged into the input, this means that the interference signal is entering from the bass or wiring. Now, when it's quiet using humbuckers but noisy using single coil (or split coil), this confirms that the noise is environmental and is entering the bass through the pickups. In humbucking mode, this cancels common mode environmental noise, which is working as it should. The same thing applies to the Nordstrand pickups, which allow you to sweep between single coil and hum bucking, and the noise nulls out when fully humbucking. Also, the noise profile is mostly 50 (or 60Hz) with very little second or third harmonics which also indicates that the noise is radiated from the power source and is unrelated to the amp's power supply. I bet the noise changes with your position in the room, or just turning it around a bit? Things that cause this include an amp with a noisy line frequency (lead sled) transformer that has a loose radiated electro-magentic field, large motors, some lighting, and some old school fans. There is a slight possibility that the noise is due to circulating currents in your power ground/earthing system, but unlikely since the amp would usually have some noise with nothing plugged into it.

Except that this is not true for well designed amps, class D or otherwise.

IEM rigs work great for some players, doesn’t work at all for many players. It depends very much on the particular application and situation. I don’t like it where a player denigrates another player’s choices based on only their particular choice, even if that choice may not reflect the other player’s needs or situation.

Other ware some models that used the same module operated at 8 ohms with lower rated power. Much of the emulation/simulation involves significant dynamics processing which limits the power into their respective rated loads. Otherwise those poor speakers would fail at an unacceptable rate. It’s a combination of both approaches depending on the specific product. Active power management while maintaining musicality is a game changer. I remember when such adaptive algorithms (including dynamic HPF’s, adaptive multi-band compressors/limiters, dynamic crossover points, HF lift circuits (came into existence in the pro audio world in products like Meyer, Renkus Heinz, Appogee, etc), they are now ubiquitous in today’s pro audio products at all levels. That’s one reason why reliability has dramatically improved.

A quality power amp designed for 2 ohm operation should have no problem driving 2 ohm loads with no reliability issues, I have been doing so for >30 years.

Often this is done intentionally, to give the impression that the amp “gets louder” more quickly as the control is turned up. This comes at the penalty of usability and control. It’s more common in lower quality, lower priced amps, but not always.

There are a couple of reasons for using a 200 watt module… the first being that the amp is not operated at 4 ohms, therefore the rated power is only 100 watts. The second reason is for duty cycle management combined with the modeling algorithms, specifically relaxing the compression and limiting attack time versus how hard the amp is driven. There’s a ton of stuff going on under the hood.

I've heard the name but never run into him, or any of his amps. I was indeed fortunate to have grown up in the right era, learned from the right folks and took every opportunity that I possibly could. For example, my supervising engineer while I was working for one of Fender's companies was Bill Hughes (lead engineer behind the SVT and some of Fender's big bass amps like the Fender/Sunn 1200S, Bassman 300 Pro, along with the PassPort PA series). He was pretty old school, talking with him was always a learning experience. In the pro audio side of things it was even more interesting because many of the concepts that we take for granted today were just being discovered and I got to experience it first hand. It was smaller companies and more personal interactions, much more enjoyable (IMO) than with today's very large business entities.

Mike’s still here, doing mostly legacy repairs and touring support of legacy products. There are lots of things being done with solid state that can address most of the feel issues, your example of the MOSValve amps is one approach that was originally designed by BK Butler, we acquired the brand after it fell on very hard times (we built cabinets for TubeWorks for a while, before they shut down) and developed some new products, but the brand reputation was just too damaged to overcome the legacy issues. The work on solid state power amps for guitar continues on under the radar, Pat Quilter’s efforts are probably some of the most successful but then there’s also the Tonemaster series that’s gaining ground and popularity. It’s a very complicated balancing exercise to develop new technology that convincingly emulates both the tone/voicing and the feel of the older technology. Of course you already know this with your products, specially the SansAmp.

If he's a truly qualified service tech, he should know this already,and have the tools to figure it out.