Oliver Sayes Western Electric 421a

Here is a sweet and compact little single ended amplifier by one of my favorite builders, Oliver Sayes. I’ve owned a number of Oliver’s creations now and am always impressed. This one is based around the double triode 421a tube with a 5691 (a higher spec industrial 6SL7) driver and a 5Y3 rectifier.

This amplifier is a real performer, and has a nice open sound that has everything in order; bass drive, a sweet golden midrange and highs that sparkle and shimmer just as anyone could want. With 3 or so watts per channel it does still require somewhat compliant speakers, but set up with the proper load this amp has a sound that puts a smile on your face and has a very definite triode profile.

Dating to 1948, the 421a tube is a double triode, meaning it is two triodes in one glass envelope. So, for a stereo amplifier, you only need one tube. What a revelation! Designed by Western Electric (although evidence points more to Tung Sol manufacture), and intended for use in series as a voltage regulator, this tube was “rediscovered” in the 1990s as a hifi power tube, and what a tube it is! This bottle had some chutzpah! This is a very good sounding triode, with a sound profile that I would classify as slightly dry but nicely detailed and with excellent imaging. More a 2A3 profile than a 45.

Driven by the 6SL7, and tube rectified with the 5Y3, the tube rolling possibilities are pretty wide here. 6SL7 has a lot of flavors, and the 5Y3 can be subbed easily enough with a type 80, and that opens up a variety of tubes to select from. So this amplifier is not limited and can be tweaked by the user to have a harder or softer sound as desired.

The 421a is also a 5998 and both sound very good to me in this amplifier. In fact I am hard pressed to find a difference in the sound between the Western Electric branded 421a and a Tung Sol/Chatham 5998. This is a tube that was never meant for audio, much less a high end amplifier like this. I wonder what the Western Electric techs from the 50’s would think of this creation? If they heard it they would likely be blown away by the fidelity.

This is an amplifier that delivers a big sound in a small package and has been a real treat to experience. Another flavor of triode, this sounds similar to some of the others but still has its own profile, and is a very good sounding amplifier. Both Oliver and the 421a are sure to please.

A mighty mini amplifier!

Classic Triad power transformer.

A nice and clean rear panel layout. I like the way Oliver sinks the RCA connectors, it's a classy touch and makes for a very clean and professional presentation that is a step above.

This amp is driven by the 5691 tube, an industrial version of the 6SL7. I’ve tried a number of 6SL7 and although I like the look of the traditional 6SL7 round plate tubes, the 5691 sounds just as good here.

This amplifier delivered from Oliver with a Chatham 5998 tube, but I sourced a genuine Western Electric 421a tube from Brent Jesse in order to have and experience the real deal. I mean, compared to the 300B the genuine WE 421a (in this case from mid 1952) is a steal! Truth be told, I cannot tell the difference between the Western Electric and the Chatham tube sound wise. It makes me wonder if these are not exactly the same tube with a different base.

Since this amp is built around the 5Y3 rectifier, I've placed one of my 80 globes on an adapter and, as always, it is an improvement. Micro dynamics and the overall sense of weight and space come to life with the globe 80. If your amp can take this tube type, I highly recommend trying one. I cant remember a single time that I did not prefer this tube over all of the other choices.

The dimpled plate 421a is certainly an interesting looking tube.

This little amp has a certain gravitas that is undeniable. Its compact in size but uncompromised in sound. Little big man. The 421a is certainly a tube that is worth a look and offers a level of performance that is top shelf, and a two-in-one proposition. Try one while the prices are still in the basement.