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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
 

From my understanding the existing non-polarized caps are silver film. I do not think they are junk but for a reasonable cost certainly am willing to upgrade them.

So no love for the Mundorf Supreme SGO 1000VDC caps here? I had originally been thinking of those.

And thanks for the advice to replace all three of them.

The electrolytics are Nichicon so I will leave those be.

 

perkri
907 posts
 

The small film caps that are put across the electrolytics, are bypass capacitors.

A small high quality bypass cap can greatly improve the SQ from the bigger electrolytic.

I recently recapped a tube amp and I put Myflex capacitors with great success.

Also recapped a Marantz 7T and because of space restrictions, used Audionote electrolytics with Myflex bypass capacitors on each one. Also sounds fantastic.

Deoending on how long you plan on keeping the amp, buy the best capacitors you can justify putting into it. They will make a difference. Humblehifi’s capacitor list has served me well in the past when deciding on what caps to use.

 

And ignore the comments about your amp not being worth the effort. It’ll be worth the effort. Anyone who has done a recap, either themselves or by a tech will tell you it’s worth it. 

perkri
907 posts
 

Paul from PS audio on caps…

 

He discusses caps/bypass caps.

 

 

calieng OP
144 posts
 

Thanks! I will take a look. I have watched a few of his other videos before. Seems like a nice guy in addition to all his knowledge.

charles1dad's avatar
charles1dad
10,250 posts
 

@perkri 

Depending on how long you plan on keeping the amp, buy the best capacitors you can justify putting into it. They will make a difference.

Yes! 👍

Charles 

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