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Question About Capacitor Upgrade in Tube Amp

Hi,

I am preparing to do a coupling capacitor upgrade on a recently purchased tube integrated amp. The two 0.22uF on the preamp tubes are fairly straight forward. But I noticed another similar model 0.33uF cap on the large filter capacitor for the B+ supply that is installed across the hot lead to ground.

Does this cap on the B+ just block high frequency noise from the power supply or does it have any effect on the amp tone? Is there any reason to "upgrade" this cap?

I know it may be hard to tell exactly what is going on without a schematic.

Also any recommendations on a good cap to use in the upgrade of the coupling caps? I was looking at Mundorf SilverGoldOil for the quality at not too crazy a price. The amp already sounds good but lacks a little clarity that I think a coupling cap swap will help with. It is SET 300B amp.

Thank you!

 

calieng
calieng OP
144 posts
 
gregl3a
1 posts
 

If your looking to upgrade coupling caps you can also play with the value of the

caps because they play a critical role in output impedance. For example,  I purchased a tube preamp which sounded terrible, no dynamics, no amplification.

Turns out there was an impedance mismatch between my amp(LSA class D) and the newly purchased preamp. After some research, I purchased a slightly upgraded cap with an increased value and surprisingly, it worked and am extremely happy with the outcome. Wanted to give my 2 cents cause coupling caps play a critical role, whether you're upgrading or changing the value, dismissing it's importance is  just anti-audiophile.

sns
3,003 posts
 

I've used most of the caps mentioned here and have found the Duelund Cast, in my case tinned copper version relegates every other cap to  a distant second place, really special cap, future plans for going into my speaker crossovers as well. I also like bypass film cap on electrolytic power supply caps if one doesn't have room for all film caps.

 

Charles is correct, SET circuits low parts count, so every single part change has bearing on sound. Resistor upgrades also worth investing into.

calieng OP
144 posts
 

Once I get this one done I will take a look at the Muzishare X9 next. It is also a SET 300B and better built than the Willsenton. It also has the clarity of solid state with the warmth of tubes. But it is lacking in bass. It may improve with more run in but I suspect a few capacitor value changes will help. Although I am not knowledgeable enough about electronics to really follow what is happening in the circuit.

It certainly is a fun hobby and I appreciate all your expertise.

charles1dad's avatar
charles1dad
10,236 posts
 

@calieng

You certainly have quite the amplifier stash. I wrote earlier that the Bottlehead tube products were although inexpensive they are well thought out engineered components. A price point is targeted and so the best quality parts can not be utilized.

Well, it seems that this principle is applicable to the Muzishare and Willsenton amplifiers. Good solid design with decent but not the best quality parts due to cost restraints. So very good candidates for upgrading part quality to achieve better sound. I believe that your project will turn out fine.

Charles

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