I recently picked up a VPI Classic Signature. It was set up by Mat at VPI and immediately after hooking it up to my system I noticed the dreaded pop when the motor was started and stopped. This is a well known issue with VPI turntables (had I really understood how big, I might not have purchased it...). I have it hooked to a Tavish Classic phono stage and a SpaceTechLab preamp. But the odd thing was that the popping—sometimes it was more of a clicking—always sounded like it was coming from my SE84UFO. This occurred even when I turned the volume to zero on the pre AND when I switched the input. The pre has two inputs, I use the RCA for the phono state, and the XLR are empty. So I would switch to the XLR, start/stop the turntable, and I would still sometimes still hear a pop/click.

Today I started up the system and the rectifier on the UFO flashed (Sophia Electric Aqua II 274B). The Sophia was still glowing so I tried it out, nothing, no sound. I swapped in my PSVane and.... nothing. No sound at all. So, wondering if I blew the fuse on the UFO, or something worse.

Before I open it up and have a look I thought I would post here and see if anyone else has a similar experience.

Also, I have called and emailed VPI several times this week asking for them to send me the more beefy capacitor, but they have not responded or answered the phones. To be honest, this is making me want to return the turntable and look for something else.

Unfortunately it seems like the Sophia Electric Aqua rectifiers have a pretty high mortality rate. I think what happened is when you turned the amp on and the rectifier flashed it blew one or both the the low value fuses under the rectifier. If the tubes glow the main fuse with the power cable is still fine. The fuses are either 0.5 or 0.25 amps, I forget which.

FYI/FWIW there are two circuits in a tube amp. A high current low voltage circuit that makes the tubes glow and a high voltage low current circuit for the actual music. It is the high voltage circuit that goes through the rectifier and blew the fuses so your tubes still glow but you get no music.

To answer my own question, I found this post by Steve. I will give it a shot.

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1655403160/1

Looks like i might need two 200mA fuses and maybe (but unlikely) one 5A fuse. Does anyone have any recommendations for good fuses? Fuse swapping was a rabbit hole I was looking to avoid....

I agree with James, it's highly unlikely the turntable caused this failure.

Replacing the fuse(s) is easy enough. Having the right values on hand is something I've learned to maintain.

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Oh boy. "Audiophile fuse" like e.g. "Audiophile power cables" and "Audiophile ethernet" is a whole world onto itself. There are plenty of threads here about specific fuses and fuse replacements, as well as probably every other audio site. My usual recommendation is to start with ceramic fuses which only cost a little more than basic glass fuses and offer (for me, at least) a small but noticeable improvement.

If the 6 amp fuse is not blown you could leave it in place I believe, may not hurt however to replace it with a ceramic 5 Amp fuse.

I’m under the assumption that SE84UFOs used 3 amp fuses in the IEC spot. What does your sticker on bottom state for fuse rating?

I don’t believe I’ve read about upgrading the fuses under the hood, I could be wrong about that. As stated by others the IEC fuse is a rabbit hole. Personally, I’d jump the fuse rolling and go for a SDFB…then you just go down the sluggo rabbit hole!

Thanks for clarifying Lon, every day is a school day!

Just a quick update: I installed some new ceramic fuses and got everything back up and running. The PSVane rectifier is back in while I wait for a Mullard GZ33 to arrive. Unfortunately, I think my Sophia is just past it's 30 day warranty so I will eat it on that. So put me down as someone who have had problems with the Aqua II 274b.

VPI is also sending a new board and capacitor, so that should help the pop on the turntable.

Thanks everyone for your help and recommendations.

Good news! I have a Psvane rectifier that I prefer to a NOS British rectifiers etc. that I have. . . so at least you are up and running with a good rectifier in the meantime.

Sitting down to explain "soft starting" a tube amp has been harder than I expected. I guess the short answer is it means the rectifier tube warms up slowly, so the current and voltage are applied gradually to the to filter capacitors and to the tube plates after they have started conducting current.

But that probably raises more questions than it answers. The details of how that works and why it matters means a deeper dive into circuit theory and vacuum tube electronics than I expect you want to read or I feel like writing.

It is an imperfect analogy, but you can think of a light bulb: when they fail it is usually when you first turn it on and it is hit with full power when it is cold. Soft start would be like gradually turning up your light bulb.

Well, that is interesting. I had a total of three 274b Aqua II and two flared out in the 300B.  I put the third one in the UFO25, and it has been fine. My other tube for that amp is a Mullard GZ33, which performs and sounds excellent. I don't need another rectifier tube at the moment, but I would not go with another Aqua II if I did.

I contacted Sue at Sophia Electric about the blown tube and they offered to replace it although technically out of the warranty date. So that is great.

More importantly, she said they will be releasing the Aqua III within "the next day or two" and that should (ideally) alleviate many of the problems. I told her what amp I had and so it seems they have heard from a lot of customers about arcing tubes.

So, one question for all of you: I can get the new Aqua III OR I could get any other of their (non NOS) tubes. Are there any other Sophia tubes that people like? I was thinking of the KT88 and 6SN7 combo for my preamp. I generally have all NOS (aside from the Aqua) so this would be a change in tube strategy. Or maybe just go with the Aqua III and see how it holds up.

My 2 centavos is I'd try the Aqua III. I wouldn't trade NOS for new production Chinese in any event, and you like the Aqua II so I'd say stick with what you know you like, and you may have better luck with the new version. But that is JMO/FWIW/YMMV and all that.