(This page was originally placed as an ad for the 2A3 Moondogs a few years ago. I have since taken them off the market)

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You are looking at one of the most highly acclaimed single-ended amplifiers in the World! This amp has come in tops in all 2A3 SET amp shootouts and has received nothing but glowing reviews both online and in print (copies available on request).

Each shot below opens to a full size graphic that is 1024-1280 pixels wide so best viewed via a 17" or larger monitor set at a minimum of 1024 x 768 (standard resolution for 17" screen). Obviously, the larger the monitor the better here, but will get detail and idea through any screen with a bit of scrolling.

I have not totally decided I am selling my Moondogs but am considering it as I have access to some top notch transformers and quality parts for a Single-Ended amp project I might delve into. I have not decided what tube to revolve it around but the transformers would support a wide variety of choices (NOTE:I have since decided NOT to sell these amps unless met with a very good offer so I could build from scratch).

As for this pair of Moondogs, they were built by an electronics engineer out of Atlanta with professional soldering skills. Based on comments from other Moondog owners, he did an excellent job with the wiring, on par with a factory built unit. The unit was wired with OFC copper and Silver Solder was used throughout. In addition, many upgrades were installed with this pair, such as far better resistors and caps. I will outline the differences below. The amps come with the Cardas binding posts and Tiffany input jacks, both top notch components. In addition, there is a power cord socket to experiment with different wire, if you so desire.

These amps were extremely well taken care of and are in EXCELLENT shape as seen in photos. The brass is perfect and still exudes a healthy shine. The name tags were installed to facilitate a full view of the tube compliment, rather than the normal end placement. The wood is also in excellent shape and responds well to a simple oil conditioning every month or so.

The shot above can be clicked for a more detailed view (as all can). This picture was taken on 3-15-01 and is the most recent view of my amps. The first shot above, was taken less than a month after I got them. You will notice a variety of tubes in and around the amps. The Moondogs, like any other piece of tube gear, responds very well to tube rolling. I find improvements can be made with different NOS 6SN7 drivers but the stock NOS Philips units are extremely clean sounding and very neutral. The top shot shows the amps with these drivers and my vintage RCA 2A3 Black Plates from 44. These are extremely musical tubes but I have to add that the Sovtek 2A3 monoplates are a GREAT deal and sound very close, perhaps providing a bit more extension in the bass if not quite the lush qualities of the vintage RCA 2A3. The Sovteks have relatively low hours coming in around 500 or so. They test near new on my Hickok 800. The Philips 6SN7WGTs also test VERY strong. In addition, the Mullard CV378 rectifier tubes have an extremely long life, some say up to 10 years or more.

To the right, you will see a shot of my Moondog interior wiring. I believe the ELNA Cerafine in the center is the larger 220uf model which is much heavier than stock; the ELNA Cerafine is considered one of the best PS caps made, alongside the Blackgate. Notice the larger value Solen caps in the three positions left of the small ELNA. The farthest left is a 630v as well. The resistors that are traditional in shape are the AudioNote Tantalums, which many consider as one of the finest resistors made. In addition. I think the Tantalums are a more musical resistor in comparison to the Caddock. I believe there is only one Caddock left in the amp ( I have all the caddocks for it - $$ Resistors). This unit also comes with Audio Note (Jensen) Paper in Oil Copper foil caps, which are also considered as tops for their smooth, musical nature while retaining the revealing quality of film caps. The two coupling caps are seen top center; these are between the first and second 6SN7 and from the second 6SN7 to the 2A3 output. I considered opting for a second set of Hovlands to hear the difference, I am happy with the Jensens. As above, you can click on the interior wiring graphic for a full-size, high resolution shot to see the wiring in close detail.

I am sure you know this already, but my Moondogs come with the great MagneQuest DS-025 output transformers which have received rave reviews; in addition, most of the reviews of the Moondogs are with THESE very transformers. These are the very same units in many of the Wavelength Audio amps. They changed to the Electraprints a few years back because of business differences. Make no mistake about it, the Moondogs have some great iron.

These amps are approximately three years old. They sound GREAT and are extremely transparent while retaining a great smoothness and ease. I do recommend you have speakers with at least an easy load, not dropping too much below 8 ohms. While it doesn't hurt to have super sensitive speakers over 95dB or so, I have found that the benign impedance is an even more important factor. I drove a pair of ProAc Mini Towers that were below 90db but provided an extremely easy load. These speakers were driven to satisfactory levels in my room, which is rather small. A 2A3 amp does not really open up and "sing" unless coupled to some higher sensitivity speakers in the 98dB range and above, however. Still, I was very amazed at the sound I did get from the ProAcs. I now have a pair of vintage 1977 Klipsch Cornwalls with Alnico drivers in the tweeter and midrange horns. These speakers have simply been a revelation and have brought my single-ended triode system to a new level. Quite frankly, there is nothing like SET and horns - they were made for each other.

These Moondogs are very dynamic and have an excellent bottom end. They do reward better recordings like most single-ended amps. If you have flaws in your source components, they will reveal them. Also, complex speaker wire is best avoided. I actually preferred two pairs of 18awg solid core copper twisted (from Radio Shack) over my $900 pair of Transparent Audio speaker wires. The Goertz wire also does well with a nod going to the simple copper variety althought others prefer the silver. I finally happened upon the DIYCable solution which utilizes a mixture of Jon Risch with Belden 89259/89248 as the primary conductors. Vampire Continuous Cast Copper is the basis of their top IC. These wires work VERY well with the Moondogs ProAcs and Cornwalls. Of course, doing their web work provided me with great access to their product which turned out to be the best wire combination I have used with these low watt amps (I count Purist Audio Design's Maximus to be another favorite with SET).

Take a look at the shots and let me know. As I said above, I have still not decided if I am selling these units but have been considering attempting to build my own amps for the experience. Below, if interested, I am including the schematic to the Moondog. These amps come with the full manual / paperwork as well as the Mullard GZ-37, Philips NOS 6SN7WGT, and Sovtek 2A3.

Kelly Holsten
kh@i-vol.com



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Welborne Labs 2A3 Moondogs!

 

* schematic for the Moondog via the .pdf file of Joe Roberts interesting and informative review entitled,
I never Met a 2A3 Amp That I Didn't Like.