Tube amps - what 3 things…

I see recommendations for autobias.  I much prefer manual bias. I Like to be able to calculate my preferred bias and adjust it.  For example sometimes i run tubes that have a max voltage near my b+, so I'll lower the current a bit and run at a slightly lower plate dissipation power.  Additionally manual bias will tell you if one is biasing much differently than the others, meaning a degraded tube.  

If all this seems like work to you, then go with auto bias.

Jerry

Tube amps tend to be more noisy than solid state

Not if they are properly designed and installed.

 

The world of tube sound is vast and very variable--much more so than the sound of good solid state.

Not true. Tube amplifiers are current devices. Many hook up tube amps to roller coaster, Mt Everest peaky impedance speakers. Not the best match. Solid state is  just as variable. A lot of it comes off a production line and is improperly set up. 

Tube gear has a magic that solid state doesn't. If you're a bottlehead, you're hooked for life.

Tube rolling is a fools errand. Tubes are not identical, not even matched sets. Rolling various tubes in and out without any idea of the tube condition and how far it varies from design center is silly. VERY few tube rollers measure and balance different sets and what they hear are level and distortion changes. See ieLogical Rolling

Autobias is nice and generally works very well. However a catastrophic tube failure can take out the AB unless there is other monitoring to shut down the amp. Today, I wouldn't have an amp without it. Most AB circuits allow you to select a preferred bias. It requires a trimmer and a voltmeter and a healthy appreciation for sticking your hands in and around several hundred volts DC. MESSING ABOUT IN A TUBE CAN KILL YOU IF YOU ARE CARELESS.

Nobody has mentioned the driver stage. Some amps have CCS for phase splitter AC balance. Others have fixed resistors that are calculated with an ideal tube, but are seldom exact. Others have a pot for adjusting AC balance. This is the most flexible BUT requires test gear for optimum - read lowest distortion - results.

Hello mpoll1. Not to be a downer - have you considered the cost of replacing tubes? They do wear out in time and die a natural death. One day the amp is working fine and the next day it isn't. A matched pair of output tubes can set you back over $1,000. Are you ready for that? Put $1500 in a savings account and wait. I just had to replace a set of tubes myself. Ouch!  Plan well, listen happily!

@mulveling, man your type of clear and concise information is this is why I read this forum. Very direct an super informative empirical data. Peace ✌️

1. (Big, read 1940s- 1950s NOS) Choke filtered power supply

2. Fixed (manually adjustable) output tube bias

3. 2 times maximum duty rated transformers (power and output)

Bonus round: Point-to-point wiring