New Variac for Joule Electra Amps

Hi Jea48,
Thanks for the input. The variac is the latter; manually 'dialed up' to operating voltage of approximately 166 volts. It's not a branded variac; it came with the amps, and am sure is designed for the amps. It's part of how the joule amps work. Even the latest Joule amps have a variac, but they are internal, one per amp, but mine is a single, outboard one. It's not an optional piece of kit - my amps won't function without it.

The reason I need a new (or rebuilt) one is because it's no longer working properly; the core has likely failed, because it's sparking a bit when I initially dial it up, and then glowing, with a slight burning smell when operating.

Thanks guys for the input. I'm not so mechanically inclined, but am ambitious enough to try.

The variac used to have the original (small) fuse holder scenario, and the fuse kept failing on me, so I sent it back to Joule and they replaced it with a massive essentially external (sticking out) fuse assembly which has since been bullet proof, so I don't think it's the fuse in this case. Just to be sure, I had swapped out a new fuse just to see if there was any change in operation and the sparking, glowing and burning symptoms were still there.

I'll see if I can investigate further

I managed to open the variac and I saw that the windings were blackened generally, there was little to any 'brush' to speak of and probably most worrying, there was a vertical segment of the winding that was essentially gone (the outer metal winding was likely smoke/carbon at this point, revealing an inner winding. I guess it's hard to describe but I have the photo.

I wish I could just buy a cheap new one or have this one fixed quickly, but am guessing there's no recourse there?

I guess I'll have to bite the bullet and ship it to the after-warranty service dept.

Hi Jea48,
Thanks for the great info. Yes, I'd feel far comfortable buying a new one, assuming it will work with the amps.

The 166volts recommended setting is likely because the momoblock amps are approximately 160 watts per channel into 8 ohms and the variac is driving both of them (Could that be it? - The setting recommendation is quite specific in the instruction manual). A friend of mine had the VZN-80 (which is essentially the stereo version, but half the power - like one monoblock with two sets of speaker outputs in inputs) and the voltage setting for his variac was essentially half mine.

My wall outlets are regular 15-amp.

I think a key reason an aftermarket variac may not work though is that the one that came with the Joule connects between each amp twice (an output power cable from the variac to the amp, and back from the amp to the variac, for each channel). Two of those connections are hard-wired from the variac and plug into the amp, and the other two connections are regular/removable power cords (plugging into the variac via male connection and into the amps via female connection, if that makes sense). I'm not sure why that 'feedback' loop is there...and I don't think other aftermarket variacs have that setup.

If it's useful I could send photos..

Thanks again for the great help. I certainly would feel more comfortable with a new variac, but would it work with the amps (especially given what I assume is some 'feedback cabling' that is employed with the Joule amps)?

Hi Swampwalker, yes, I've been very careful to follow Jud's guidance on dialing up the variac - per his actual words - a smooth, constant motion taking about 5 seconds in total.

The variac is actually very rickety though - my sense is that plenty of aftermarket variacs are bigger and have more tolerance that this one. The core itself is very small compared to some I've seen. I'd love to have one per amp - that would at least half the load, which may be part of the problem with using this little thing to drive both amps.

Hi Thaluza, I have explored that route (and that would definitely be my preferred route), but it was not an option. I'm working with Rich at Signature Sound in NY on a rebuild - I've been very happy with his speedy and thorough engagement so far though I understand that there are no guarantees on what may be possible but will see. It may involve retrofitting a new variac vs. fixing this existing one.

Swampwalker, yes, it's a pity that these units aren't more bullet-proof. It's hard to put a price on reliability - it's easy to take it for granted until something goes awry with one's equipment..

I wanted to post the fact that there was a happy conclusion to this issue. I sent the kaput variac to Richard Brkich at Signature Sound. Rich is pretty familiar with the Joule amps and uses a pair himself. He researched my variac, got a new one(higher spec/capacity) from a great source for a great price. He then did the custom work on ensure that it would work perfectly in my application. I got the variac back in a timely fashion and there was always excellent communication and attention to detail along the way.

Independent of Rich's help, I bought 16 new power tubes as it became clear that I had some runaway current on at least one tube.

I'm not back in business with a wonderful sounding pair of amps that are very stable and the variac is prefect again.

I could not have hoped to work with a better technician/expert than Rich - he was a joy to deal with and I cannot recommend him highly enough if you ever need any work done or if you are in the market for new equipment. His advice and recommendations were thorough and super helpful and he was very generous with his time.

I'm back to a lot of happy listening now (exploring my new Tidal subscription and exploring more vinyl with a new Thor phono-stage as well). Happy listening!!

Thanks Swampwalke.

I meant to say ..."I'm NOW back in business with a wonderful sounding pair of amps" and not 'I'm NOT back in business..." ;-)) Spelling is not my forte sometimes.

I believe that Jud is no longer handling day-to-day activities for the business, but Simon Thatcher seems to be involved in the business and managing communications in a timely manner when I reached out to the Joule email alias.

Spencer,
Am sorry to hear that sad news. My thoughts are with him and his family.

Best,
John