Welborne Labs: Moondog and Sovtek 2A3 Opinion by mobile homeless

If this is your first SET amp, then I am sure you will not be disappointed with the stock Moondog. That being said, I think upgrading the caps, resistors, and tubes will lead to better sound, although depending on the choices, some might disagree concerning which choices ARE better i.e. some really prefer the Jensen oils and some the Hovlands etc (I prefer the Jensen myself). The Black Gate in the PS will provide a nice upgrade but the Cerafine is a good choice since it's less expensive and still sound great (it IS, however, harder to find these days since they are not manufactured anymore). To answer your question, I actually believe the upgrades are worth the cost, but I think you will be ecstatic with your Moondog if you cant afford it right now. Personally, I would go for as much as you can. Sadly, the upgrade bug will be nagging at you down the line, and you will always be wondering exactly how much better the sound could be. This confusing enough?

On the tube front, the SOVTEK 2A3 is just about the best bargain you will find. It has a great midrange and offers a very rich sound that is also very well balanced. It was the first tube I tried with my Moondogs as well. It is actually my main workhorse 2A3 that I leave in for everyday listening. The highs are very natural and the bass is surprisingly robust and well defined. The tube appears to be constructed very well and mine have done great, and when in, are powered up all the time! One disappointing note about this tube is its lack of light ; the damn thing is very dark and one must practically turn out the lights to see the faint blue glow. 2A3s are generally not glowsticks but the SOVTEK is especially this way.

Weaknesses? Well, you cant get everything for $40 or so, although the SOVTEK 2A3 comes very close in many ways. Compared to a good NOS 2A3, the SOVTEK is missing some of the refinement and bloom exhibited in, say, a good RCA black plate. It's just ever-so-slightly more coarse than a top notch NOS. You wont notice this unless you have the other tubes around to compare it to, but it just doesn't quite offer the open, unfettered, musical quality and ease I find in the NOS RCA black plates. Others will disagree here but I have found it to really be true; that being said, those damn NOS 2A3 are getting very hard to find and are much more expensive now. Buying off eBay is a BIG risk and, more often than not, a losing one.

Sad you cant afford the KR2A3? Well, it is the most ruggedly built 2A3 I have put my hands on! The heft and weight is really impressive! As for the sound, there are many positives... It does, just as reported, seem to have a very defined and powerful low end, with more oommph than any 2A3 I have used. And the highs are VERY extended.... In addition, the KR2A3 appears to be a VERY quiet tube and it might just have a slightly blacker background. Unfortunately, I have found the midrange to be just not as rich as even the SOVTEK. Something just seems to be missing in the musicality factor and I believe the midrange might be slightly less warm. Others on here will disagree; many appear to be smitten with the KR in the Moondog. I want to also preface this by saying I am still auditioning this tube and have only really had it on hand for a few weeks; I plan on giving it a little more listening time. In addition, the KR 2A3 are designed to run at a higher voltage (removing the resistor at R13), so take this into consideration.

But as far as your choice with the SOVTEK, don't be upset at all. You will get some GREAT sound from your new Moondogs using this tube. Also, don't be afraid to experiment with better 6SN7 tubes; I got a significant upgrade in sound from inserting better NOS Sylvania 6SN7WGT into CBS 5692. This switch offered a surprising upgrade in the performance in my Moondogs. I have not gone back to the stock Philips tubes since.

Hope some of this helps; good luck with the soldering iron!