Why do Tube Amps sound more romantic v SS amps

"Why do Tube Amps sound more innacurate v SS amps"

Fixed it for ya.

@atmasphere agree with you on tubes could match better than PMOS/NMOS or N/P BJTs. Please try to measure distortion of tube amp while adjusting bias/balance of the output tubes, and you’ll see how sensitive it is. Then please repeat the same after 50+ hrs. If you are luky, and your AB tubes are aging the same pace, then distortions will not increase much. There is a lso big issue with output transformers in the tube amp, depending on core magnetics, resistance of coils, symmetry etc you will get variety of imbalance/distortion/FR problems, which does not exist in SS> 

"You may not get 100,000 hours on the equipment before corrosion has had a chance to damage the semiconductors"

-good point on corrosion! In my experience corrosion hits tube amp sooner than SS! Just look at the power transformer, capacitors, output transformer inside the 20yr old tube amp.

Please try to measure distortion of tube amp while adjusting bias/balance of the output tubes, and you’ll see how sensitive it is. Then please repeat the same after 50+ hrs. If you are luky, and your AB tubes are aging the same pace, then distortions will not increase much. There is a lso big issue with output transformers in the tube amp, depending on core magnetics, resistance of coils, symmetry etc you will get variety of imbalance/distortion/FR problems, which does not exist in SS

@westcoastaudiophile 

We've done that plenty of times. No measurable difference. You can avoid a lot of the imbalance issues in output transformers by using a Circlotron, since the issues in the transformer are usually related to DC components, which are minimized in a Circlotron. This is so successful that Circlotron amps made in the 1950s were class B and had no crossover distortion at all. However such amps are rare.

IME tube amps suffer less from corrosion than solid state. I've serviced literally thousands of amplifiers over the last 50 years. You can have a well preserved solid state amp that shows no signs of corrosion but its semiconductors are failing on that account. If a tube amp is given the same treatment its likely the only service it will need (in time) is filter capacitors.

About the only place I see your age argument holding any water has to do with filter capacitors. Because tube amps run warmer, the filter caps have a shorter life than in solid state amps. So 30 years instead of 35, unless the designer placed the filter caps in such a way that they really ran too warm.

This is a great read.  I really appreciate people, Engineers, Manufacturers, etc. contributing to a well thought out and discussed topic like this one.

I have to say, that I have repaired, serviced, designed, built tube and solid state amplifiers over my ehem..... 45 or more years as an Engineer and I have to say that many people that compare solid state to tube are not comparing apples to apples in terms of specifications on the amps.

Also, most I have encountered do not level match before comparing anything.  Then they attribute differences in volume to mean better or worst.

But, I have found that the specifications of transistors do indeed change over the years and usage.  Although the amp may work, those transistors are not like new.

Take a 15-20 year old (or older) amp and remove the output transistors. measure the characteristics, then get brand new (if you can find them) same transistors and measure them.  Won't be close.  Better yet, if you knew or documented the specs of transistors before you put them in the amp, then 20 years later removed them and measured them.... not close to original.

Anyone trying to tell you that transistors don't degrade is no accurate.

But, I have done A/B comparisons of tube vs solid state amps.  level matched and similar specs.  in the same systems.  let me tell you, for excellent tube or solid state amps.  I'll take either.  They both sound excellent.

And great designers have solved the major distortion problems with solid state amps years ago.  

There is some great stuff out there people.

Look at class D now.  @athmosphere (Ralph) is right.  I can't wait to hear his new Class D amp.  He knows people are going to A/B his class D amp with his tube amp to determine if they can decide which is best.  For him to market a Class D amp when he spent decades (still do) designing and marketing tube amps, well, it must be worth hearing.

enjoy