However, Greg Johnson from TNT mentioned he liked it more than other caps he tested, also inexpensive. My customer and I decided to try it with these upgraded components.
https://www.tnt-audio.com/ampli/bottlehead_moreplay_e.html
While we are always appreciative of reviews, there is some information posted in there I don't really agree with.
The cathode bypass cap handles the signal current rather than the cathode bias resistor at all but very low frequencies. We provide a nice 1% Vishay CCF resistor there and I wouldn't recommend swapping that out, as something with a looser tolerance like a carbon film resistor may move the bias voltage around in undesirable ways. The Nichicon UKA and UKW are (for now) their two highest tier electrolytic caps for audio. For the purposes of being able to fill orders, we selected a cap that looked like it was generally available in large quantities, and with the discontinuation of many of the Nichicon audio grade caps, I'm glad we did.
Using a 250V rated film cap with a surge to around 300V isn't a problem, though I wouldn't be as happy about doing that to a 250V electrolytic. Looking at the datasheet for the typical cap we provide, it's rated to 375V for 1 minute, and typically (though not in this particular datasheet) there will be a specification that the cap needs to be run at or below its rated voltage for at least several minutes after being surged. You'll see lots of old Counterpoint preamps from the 90s running 250V film bypass caps that see 400V every time you turn the preamp on, and they are still going strong. When looking at the more expensive audio type film caps, the datasheets tend to be a little spare on application data, so YMMV.
