When it comes to Capacitors i like using the SOLEN I have used the Mundorf film caps and compared it to the Solen i did not hear a difference.
Output Capacitor Options:
I was just now writing this for Paladin79, but this may be useful to others looking to upgrade. Humble Hifi's cap comparisons really are a lot to take in. Here is a sifted list of the common, and some not so common, 100uF caps, many of which other Crack builders have tried. So, based on all my research before starting my own build, this is how I'd break down 100uF output cap options (in bold are my picks within each tier):
Tier 1 (Sensible):
-
Audyn Q4 400V $24 (Pretty big, mine are only 68uF...)
- MKP-kondensotor 250V $27 (They seem cheap, but hey they're an option.)
- Dayton MKP 250V $32
- Jantzen Crosscap 400V $32
Seeing as the general consensus is that
any MKP cap would be sufficient,--since the effect of film over electrolytics is subtle here--it's hard for me to justify not choosing the German-made, crazy-inexpensive Audyn. But life has so much to offer lol...
Tier 2 (I wonder how much nicer these are exactly...):
-
Obbligato Film Oil 630V $36 (68uF is the highest capacitance for these, so make sure you won't be using lower-impedance cans...which you shouldn't be anyway. Also, they're big and require a larger wood base, or some creative mounting, to fit. I'm curious how the oil will affect things.)
- Ansar 100uf 450V $40
- Solen 400V $41
- Mundorf MKP 250V $41 (For the pair, you'd be spending $34 more than you would for their German brother Audyns. I'd like to do a double-blind test!)
Tier 3 (Splurging):
- ClarityCap PX 250V $51 (Big, requires a larger wood base.)
- Mundorf EVO 350V $60
- Mundorf EVO aluminum + oil 350V $68 (If I built an ultimate Crackatwoa, I'd be curious to try the Obbligatos or these just to see what, as Audyn calls it, the "fairy-like oils" are all about hahahaha.)
-
ClarityCap ESA/CSA 250V $90! (Also very big. I have a suspicion that all the previous MKP, non-oils, are indiscernibly similar. But these ones stem from a very rigorous two-year research program "on the audible effects of improved control over mechanical resonance [microphonics] in a metalized film capacitor," and "employs a non-standard polypropylene film." So, I'd like to do another double-blind test with these haha.)
Tier 4 (The land of irrationality!):
- Mundorf EVO silver/gold + oil 350V $360 ($720 for a pair lol...)
To sum up:
I picked the Audyns because of price and reason. Furthermore, having a matching third as the last PS cap was decided after I read, designer at Bottlehead, Paul Joppa's post on the BH forum:
"The output audio current flows through the power supply, mostly the last capacitor, as well as through the output coupling cap and the output triode. So the final power supply cap should, in theory, be as important as the output coupling cap with regard to the sound of the amp. This is a characteristic of cathode follower circuits, such as the Crack and the Foreplay."
"I post this with some frequency: 'I never met a power supply improvement that was not also a sonic improvement.'"
Continuing on, then bypassing the last Audyn in the PS was a nicety, sure, but the Jantzen Superior-Z is only about $15 ($12 for my 0.68uF version) so I could deal with that as a single upgrade. One day though I hope to get an Audyn True Copper 0.68uF ($45-ish) to replace the Jantzen--only because I've come to really admire Audyn as a company and it would be a nice kingly crown for my much-beloved build. Cheers!