Question About Capacitor Upgrade in Tube Amp

Engineers with ears pick caps where the evaluation circuit and signal allow them to be fully formed… in many cases those big monster caps never get fully formed… or stay formed…especially at reasonable listening levels…

Applaud the OP for diving in and trying….and learning…

Enjoy the music and the journey

Hello calieng!  Nice photography!  That cap looks pretty good. It's purpose is to keep high frequency noise from riding out on the B+ line. I would add a .01 capacitor in parallel as well. Keep the leads as short as possible. I'd use the fanciest Mundorfs (gold foil etc) with a voltage rating at least 100v higher than your B+ supply. I have lots of experience with power supplies and the noise that can show up on them. I used to live near a Navy base and discovered 2 volts of HF & VHF garbage on unused, unconnected phone lines in a rental house. How it got there, I don't know. I used to run a computer lab that had 51 PCs driven mad when someone plugged an extension cord through an open window and fired up a hedge trimmer outside! It took two days to get the lab back to normal. There is so much electronic stuff around these days that it is good to be as careful as possible. Please forgive those respondents with negative comments. This may be their only outlet for their hostility and it keeps them out of the bug house. Happy Listening.

@boomerbillone 

Hey thanks for the reply.

The 300B tubes are around 300-350v with max plate voltage of 400V.

I see most of the caps being used in these type of amps at 600VDC and up. I ordered the 1000VDC Mundorfs just to be safe. The power in our house is pretty clean and all the amps are dead quiet. So I think primarily the coupling capacitors on the preamp tubes with show the most improvement in clarity but i will do the filter cap bypass as well.

@tomic601 

Interesting point on some caps being too big for the application.

But in this case I think the Mundorf Supreme SGO are in a similar size range to those being used - just better quality.

On the Muzishare X7 model I suspect the Muzishare silver label on the coupling caps is covering a Mundorf EVO silver cap. They refer to the cap as Germany in origin and has the same 1200VDC rating. I may have to try to peel the silver label off to see what is underneath. Maybe someone on here knows which caps Muzishare is rebranding?

The Muzishare X9 and X10 are using Mundorf labeled caps - EVO Supreme Oil.

The elephant in the room that no one notices is Power Supply Impedance and Phase. It is perhaps the most important and neglected aspect of HiFi design.

Capacitors have two frequency dependent properties, ESR and ESL, often ignored by engineers and almost certainly by Joe Audiophool.

The amplifier circuit, if perfect, does nothing more than regulate the power supply. If the power supply has poor phase and impedance, it passed on to the next component. Sequential components alter the preceding and this is why a really great component may get so-so response in one reviewer's system and sterling accolades in another.

Sequential components & cables all add their sonic signature.

Hence, when Walter Wannabe audiophool swaps out ReallyGoodMatch for  BigFatSilver caps, he is altering his entire system and any perceived change, improvement or not is only valid for his system.

Add in the $$$$ and time incentive, and of course it's better.