What contributes most to a change in how an amplifier sounds?

I had a 300b integrated SET amplifier from 2005.

I tweaked a lot of different things:

1. Interstage capacitors.

2. Tubes working points.

3. Cathode and load resistors.

4. Power supply capacitors. Including increased value of capacitors from 100uf up to 3500uf per each tube b+.

5. Cathode capacitors. Including increased value of capacitors from 100uf up to 100000uf.

6. Added interstage transformer for driver and input tube.

7. Added a separate power transformer for drives and input tubes.

8. Build a new 300B SET with external power supply.

9. Changed driving tube from 6f6 to 6v6 and 6L6.

10. Changed output transformers.

I didn’t try to do:

fixed bias, voltage stabilization, SRPP, choke load (LC coupling), direct coupling and many other things.

Hardly any mention of AC cable.  It makes a difference, and it's something users can often change, unlike most of the other components.

@knotscott

You certainly know your way around the inner workings of the mystery boxes in an audio system and how cool to have you as a neighbor. So much knowledge between your ears.

Seems like the power supply and transformers, no surprise, dominate how an amplifier sounds. I’ve always wondered why amplifiers don’t have a second Power chassis but this clearly would be impractical. Capacitors certainly influence the rebustness of amplifier dynamics and I would guess these wear down overtime.

I, like you, pursued biamping, and I use a MC 901 pair from McIntosh. a more safe approach for me by ensuring added amplifiers Will get along and avoids additional interconnects. I upgraded all the small tubes with NOS telefunken but have continued with the same power tubes I'm not sure how much these will influence sound but quite a price tag to replace them all.  

You have a nice size room and a lovely space. My amplifier does quite well in a 20 x 16 room but is deserving of a much larger space.

@alexberger 

You need to have a play date with.  @knotscott 

I saw your YouTube channel wondered how it might be you could do a narrative of the types of work you do with your system.  Inspiring to see people with all this knowledge and putting it to good use.  Very very technical stuff.

Hi @emergingsoul ,

This is a good question.I thought about it, to make stuff about tweaks on youtube. But my English is not good enough to do it. English is my 4th language. I am also not a good speaker in general. For me it is much easier to write.