Alan Eaton 300B Monoblocks

Here we have a wonderful pair of 300B monoblock amplifiers by builder Alan Eaton. Alan has been building tube amplifiers for many years now, and these days he specializes in monoblock single ended 45 amplifiers which he sells through eBay under the username eclectic_electrics. If you cruise single ended amps on eBay you’ve likely seen them. Like myself, Alan is a big fan of the Sony/Tamradio transformer set from the 1960’s TC-500a reel to reel machines, and his 45 amps make good use of this amazing antique iron. This amplifier, being a 300B, is a bit of a departure from those, but let me assure you this is the best performing 300B amp I have yet had the pleasure of owning.

300B amps have been an elusive beast for me, a White Whale of sorts. These days (2019) there are certainly plenty of examples of 300B amplifiers out in the wild, but in my experience I’ve had trouble finding one that made sense to own long term. I like the way many 300B amps excel in the midrange, and the tube has a certain glow which is very nice, but the amps tend to be expensive and the tube prices often seem to reflect some kind of wishful thinking more than actual performance. In comparison to the PX25, an equally expensive tube of roughly similar power output, the 300B seems outclassed in just about every respect. But in the end, I usually prefer the sound of the 45 to just about everything else, with single ended Pentodes like the EL84 and SV83 being a close second.

These monoblocks come closest to unseating the 45 of any 300B amp I’ve owned so far. Alan’s amplifiers make the 300B sound very good indeed; full and emotional, but still pretty fast and nimble. And as is often the case these features were apparent from the first moments of firing the amps up. These monoblocks present a sound field that I have not yet heard in 300B so far, with a dimensionality and presence more like the 45, all wrapped in the amazing glowing presence of that infamous and magical 300B mid-range. And while midrange is certainly the strength of any 300B platform, and these amps do not disappoint; these come with enough extension on both ends to hold their own with pretty much anything I’ve had so far (although as I age the top end is more elusive, so take that for what it is). With a good recording, voices float in the air, instruments and performers occupy their own clearly defined space and the sense of realism I’ve come to so appreciate is the best I’ve experienced with 300B. I'd love to hear my old BEZ monos back to back with these! The BEZ were the most emotionally engaging 300B I've had before Alan's creations.

From a build perspective, these amps hit the top marks in every way. Alan has done a great job of making a minimalist presentation on the top plate. The chassis themselves are made by the same craftsman who built the chassis used in my Tom McNally Darling amp, and this pair of super-chassis are quite robust and heavy duty; very thick and solid aluminum mounted into oak bases. The 15-or-so pound amps feel fantastic in-hand and there will be no sagging top plates here! The tube sockets are beautiful NOS James Millen ceramics, and are as good as it gets. The power and filament transformers are vintage Triad units, and the chokes are Stancor. The output transformers, so very important in any tube amp, are made by a newcomer to the market, a company from Brazil called Steel Labs. I was unfamiliar with Steel Labs, but Alan holds them in high esteem and I agree that they certainly sound excellent, and in-person are well potted nicely made transformers. These monoblocks each feature volume controls, something really important to me now, so in this case the level can be tailored to your room quite effectively. Hum pots are mounted on the back, but in my experience hum has not been an issue with these 300B amps. One unusual feature are the power receptacles; Alan likes the cords and power inputs that came with the Sony TC-500a and they are recycled here. All in all this is a very clean build that looks the business. Tubes are a classic 300b lineup; 300B driven by 6SN7 for about 6 wats. The rectifier is a 5R4.

Alan Eaton’s 300B amps deserve my highest recommendation. 300B is a tricky one to get right, and this one does it for me. If you think that you need that 6 watts, I can’t help but feel that anyone looking for the best of the 300B sound would be well served to contact Alan and see what he has on his schedule. I may have finally found my reference 300B amps!

Classic tube amp lines.

6SN7, 300B, 5R4.

Clean build. I wish the speaker jacks were better looking but these are adequate and do the job with no issue.

The classic 6SN7 input certainly has many flavors. Here as 1960's Toshiba.

These are modestly priced NOS early-2000's GuiGuang 300B tubes recommended by a friend. They have actually proven to be quite good sounding in my (also modestly priced) 300B comparisons.

A WW2 era 5R4 from GE.

These power recepticles are salvaged from Sony TC-500a reel to reel recorders, the same as Bob Dylan used for his earliest demos.

These are just great looking power amplifiers, and I really like the heavy duty chassis.

The vintage green pilot lights are a nice touch, if slightly bright. Overall these 300B monos are quite good performers. Highly recommended.