Upgrade capacitors in tube amplifier?

@chinook9, There are 7 film caps in there. The two on either side of the chassis appear to be the coupling caps. The two towards the front of the chassis appear to be doing additional filtering for the input tubes, they are tied to what appears to be a ground buss bar across the front of the amp.
The 7th cap appears to be on the power supply. The biggest improvement will be on the 4 coupling caps. Next would be the two caps acting as filters for the input tubes. Also agree with bigkidz though. If you add really good caps, they are likely to be 30-60 bucks each, and will quickly approach a significant portion of the amp cost. The amp appears to be made by same factory that makes the RFTLYS amp. good build quality; only a small notch down from the factory that builds the Primaluna and Cayin amps.

Have you tried any different output tubes? give the shuguang Nature sound series black glass a try. they sound quite good.

Both tube rolling and cap and resistor upgrades will improve sound quality. Only question is cost effectiveness. I'd say go for it, while you may spend as much or more than amp originally cost, its a learning experience. Better to start learning on cheaper equipment.

I started learning about parts substitution on cheaper equipment, such that I now trust myself with more expensive equipment.

I recently changed out caps, resistors and all tubes on PrimaLuna Dialogue Four. Miflex, Mundorf caps, Takman resistors, NOS miniature tubes, SED and Svetlana EL34. Sound quality improved to the extent I now consider this amp a real contender to totally stock Coincident Turbo 845. Prior to mods, sound quality just ok.

Thank you all for your input. 

I will do as recommended by many of you: roll tubes first and then consider the caps.  I took the bottom off the amp and found that the caps mentioned by most are two large 0.33UFD 5% 630VDC and four 0.022UF 5% 630VDC.  I realize you can't tell much by looks but they did look pretty good.  They are oval.

I have some ECC82 (Tung-Sol black glass) and 5751 (GE black plate) on the way and now I'm trying to decide on the EL34/6CA7.

Thanks again.

For your coupling capacitors (particularly the 0.33mfd), and importantly, if you physically have the room, consider either Jupiter Copper Foil Paper & Wax or Miflex KPCU-01. The Jupiters are a bit more expensive but you won’t go wrong with either.

I’ll second (or third) the suggestion for Takman REX Carbon Film resistors. Very musical.

While you’re at it, consider the output transformers. Look into Lundahl.

And look at the power supply rectifiers. I don’t see a tube, so it must be silicon. If it has Schottky rectifiers, you could consider replacing with (third generation) silicon carbide (SiC) rectifiers.

And has been pointed out above, once you start down this road, you’ll probably end up spending as much on component upgrades as the initial cost of the amplifier. Be sure your comfortable with that.

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