tubes or transformer?

[baxter_x]

Transistors CAN be defective microphonically, but it's pretty rate because of how they are constructed and encapsulated.

If I understand correctly, that means a transistor is more reliable than a tube?

 

[Al Kraft]

I assumed that microphonics issues would have been one of the significant benefits of moving away from tubes and would not have guessed it could be a an issue with a transistor.

 

[Al Kraft]

If I understand correctly, that means a transistor is more reliable than a tube?

I would say it depends who manufactured the part and to what specification (including QA), how highly stressed the part is in the circuit where it's used, and the operating environmental conditions (including vibration, temperature extremes, etc.). In general I would go with solid state for consistency and reliability, but I've seen some tube powered gear that lasted decades and was retired from service before it ever failed.

 

[Wasnex]

I would say it depends who manufactured the part and to what specification (including QA), how highly stressed the part is in the circuit where it's used, and the operating environmental conditions (including vibration, temperature extremes, etc.). In general I would go with solid state for consistency and reliability, but I've seen some tube powered gear that lasted decades and was retired from service before it ever failed.

Overall I think solid state devices are intended to last for the service life of an amp. If they fail, the amp is considered damaged. To fix it requires removing and replacing parts that were never expected to fail.

Tubes are a bit different. They are generally not expected to last the life of the amp. When they fail, the amp may or may not be damaged. I think of tubes as consumable/extendible service items like tires, spark plugs, brake pads, or fluids in a car. The expectation is these items will be used up over time or mileage and require replacement. Ideally you replace the bad tubes and set the bias if necessary, and the amp is good as new. IMHO, replacing bad tubes is better described as servicing the amp, rather than repairing the amp.

Solid state amps require some level of service. For example, it may be necessary to periodically clean the pots or cooling system.

 

[agedhorse]

In general, well designed solid state amps are more reliable.

 

[Old Garage-Bander]

Not sure what 'galvanic isolation' might be but it is my understanding that power transformers do make a difference. A power transformer the size of a marshmallow in an SVT would not get the job done.

Here's the Wiki if you are interested.
But in short it's keeping your peanut butter off my chocolate.
Galvanic isolation - Wikipedia

 

[Old Garage-Bander]

If I understand correctly, that means a transistor is more reliable than a tube?

Yes they are.
Mechanical: You can drop a transistor and it has a much better chance of still working just fine.
Leakage: Transistors don't required a sealed envelop to maintain a vacuum.
Thermal: Transistors don't require a source of heat to allow electron flow.

 

[crazyBassClown]

Another factor that I think many people overlook is the mechanical resonance of the electrodes in tubes; microphonics is an extreme example. In lower amounts though, it can add a reverb like effect that some listeners may find pleasing.

Quoted for emphasis. I suspect many of the differences people hear or think they hear when tube rolling is the variations in how microphonic the tubes are and in what sounds they actually pick up.
Doing home recordings on guitar many many moons ago I set up a sepearate iso room for a guitar cab and put the head near me and was dissapointed that the amp had lost it's magic. Turns out that the tubes in the amp on top of the cab picking up vibrations was at least some of the magic that I heard in that tube amp.

 

[agedhorse]

Quoted for emphasis. I suspect many of the differences people hear or think they hear when tube rolling is the variations in how microphonic the tubes are and in what sounds they actually pick up.
Doing home recordings on guitar many many moons ago I set up a sepearate iso room for a guitar cab and put the head near me and was dissapointed that the amp had lost it's magic. Turns out that the tubes in the amp on top of the cab picking up vibrations was at least some of the magic that I heard in that tube amp.

There is indeed some merit to this, but like everything else... too much of a good thing quickly becomes problematic.

 

[Al Kraft]

I'm frequently amazed at what quirk, artifact, or nuance in a design, sometimes even a latent quality/capability unplanned by the designer and unknown (i.e. not included in the marketing pitch) to the user, is what actually makes something "special or legendary".

 

[byacey]

Yes they are.
Mechanical: You can drop a transistor and it has a much better chance of still working just fine.
Leakage: Transistors don't required a sealed envelop to maintain a vacuum.
Thermal: Transistors don't require a source of heat to allow electron flow.

I was taught that electromagnetic pulse doesn't agree with transistors, but I haven't personally experienced that.

 

[agedhorse]

I was taught that electromagnetic pulse doesn't agree with transistors, but I haven't personally experienced that.

They don't agree with a lot of things, including human health...

 

[byacey]

They don't agree with a lot of things, including human health...

I guess the tone of a bass amp isn't high on the list of priorities after such an event...

 

[Al Kraft]

I was taught that electromagnetic pulse doesn't agree with transistors, but I haven't personally experienced that.

In aircraft carrier flight deck compatibility testing over the years I've seen all manner of crazy things happen to systems that were not properly hardened (e.g. adequate shielding, shield termination on backshells, EMI/RFI gasketing, etc.) to handle high RF energy environments. My first class on designing for EMP hardening (Naval Postgraduate School course on nuclear weapons effects) was back in the 70's and as I recall tubes were significantly inherently more survivable/resilient to an EMP...solid state stuff needed a lot of attention to design to even come close.

 

[ardgedee]

I guess the tone of a bass amp isn't high on the list of priorities after such an event...

After you've heard the ultimate boom, any bass amp is going to seem inadequate.

 

[Al Kraft]

After you've heard the ultimate boom, any bass amp is going to seem inadequate.

...and no light show will ever compare, especially since the power grid will likely by down for years.

 

[byacey]

In aircraft carrier flight deck compatibility testing over the years I've seen all manner of crazy things happen to systems that were not properly hardened (e.g. adequate shielding, shield termination on backshells, EMI/RFI gasketing, etc.) to handle high RF energy environments. My first class on designing for EMP hardening (Naval Postgraduate School course on nuclear weapons effects) was back in the 70's and as I recall tubes were significantly inherently more survivable/resilient to an EMP...solid state stuff needed a lot of attention to design to even come close.

That's what I was taught as well. Missile guidance, military Navcom, etc all had tube based redundancy at the time.
I still keep my HQ 180 ready for such an event.

 

[Al Kraft]

That's what I was taught as well. Missile guidance, military Navcom, etc all had tube based redundancy at the time.

While many made fun of the Soviet era tube based systems, many of those systems were class leading and inherently more EMP survivable than our SS technologies would have been in the event of a significant nuclear exchange. IIRC at that time most people still thought more about nuclear weapons as a major explosive event with fall-out (i.e. dropping a bomb). There were fewer folks who recognized that other delivery techniques for nuclear effects could have much more wide-spread debilitating impacts and would permit troops to operate more freely after the event.

I would argue that our military and civilian infrastructure today is in many ways more fragile than it used to be. IME denial of service/capability in specific regions can be accomplished with a high degree of precision without even resorting to something like a nuclear airburst. That said, a strategic nuclear event with a significant EMP could transform our smartphone, networked society into a stone age existence in a nanosecond. Almost every device we use on a daily basis has susceptible components...even when they don't actually need to.

 

[Michedelic]

I was not a big tube user back in da day.
Dad's B-15, I had a Sunn Model T for a bit.
Didn't like the under powered B-15 for playing rock with half stacks and the Model T was so loud that I didn't get it into any tube grit, it was ran clean all the time.

That little WD box is da kine

I can get a vibe that reminds me of the sound I liked at low volume of the B-15 but with some power behind it without breaking up but if I want that, that power tube emulation gives me that sound with more consistency, and 800 watts to draw from.

Wait a minute, I’m confused…a 150 watt tube amp was too loud, but now you have a 800 watt(well, 400 into 8 ohms) transistor amp?

 

[agedhorse]

In aircraft carrier flight deck compatibility testing over the years I've seen all manner of crazy things happen to systems that were not properly hardened (e.g. adequate shielding, shield termination on backshells, EMI/RFI gasketing, etc.) to handle high RF energy environments. My first class on designing for EMP hardening (Naval Postgraduate School course on nuclear weapons effects) was back in the 70's and as I recall tubes were significantly inherently more survivable/resilient to an EMP...solid state stuff needed a lot of attention to design to even come close.

Agreed, but it’s a fine line between necessary functionality and survivability under such conditions.

A trebuchet, for example is 100% immune to EMP, but not very effective under modern warfare scenarios.