Oliver Sayes Single Ended Type 42 Amplifier

Now here is an unusual little single ended jewel! This is a Type 42 amplifier built by Oliver Sayes. Oliver often pushes the envelope a bit by working with some unusual tubes, his amazing Type 46 amplifier that I owned previously being a good example. Here we have a great little amp using a power tube that just isn’t really ever seen in the hifi world, and that fell out of favor pretty much everywhere just before World War 2. Resurrected here, its proven to be quite a sleeper. HiFi tube builders take note, the 42 is a tube that you want to start experimenting with!

The Type 42 is one of the very early Pentodes, dating back to 1932, and was used in quite a few early radios in the mid 1930’s through the early 1940s. Old enough to have been made in the S or Globe shape, the 42 evolved into the 6F6, and is sort of a predecessor to the 6V6. It turns out that the 42 is a wonderfully clear sounding tube with a drive and warmth that sort of brings the Type 10 to mind, but with about 4 ½ watts per channel its a bit more speaker friendly than many of the true Triodes. Driven here by the 6A6, the older brother to 6N7, this amplifier sounds extremely good on my Telefunken panels driving the little Coral Flat 5 drivers. Images are big and quite well defined, perceived spaces between players and instruments is right up there with the best I’ve heard, and voices float out into the room well defined, flesh and bone. It’s quite a treat!

The 6A6 driver tube used here is worth some explanation. A very early tube, this one is also not used much by anyone and is available at quite reasonable prices, often still sealed in their boxes from the 1930s and 40s. About the same size as an ST 45, this is a large and robust tube. A close look at the internals reveal the highly desired round plates, there are smoked glass versions as well as clear glass, and pretty much all of the manufacturers of the day made this tube so many varieties are available. If these were 6SN7s, the round plates would fetch quite a premium price now, but no one is buying these beautiful 6A6 and NOS boxed tubes currently (2020) sell for about $10 each.

This amplifier features a lot of good quality parts, including the Tamura/Tamradio iron I like so much. I really do think this is a big factor to the quality of sound in this amp and others, and I’m happy to see so many projects being built these days using these high quality 1960s Japanese transformers. Get them while they last!

Bottom line, this is a great sounding amp, and with its power output it could be at home in a lot of systems that might be out of reach for the 45. And I don't feel like I’m missing anything. In fact, the pace and dynamics from the 42 might even be better than the 45, depending on the circuit. Aural memory is hard to pin down, but I would be willing to bet that this little gem would compare very favorably with the big guns like the AD1 or the PX25. It wouldn't be a knockout, but it would be a hell of a contest. I hope to see more 42 projects out there in the future. Not only is it a bargain, but I think this is a tube that lots of people will really enjoy.

Another unusual tube here is the rectifier, in this case a 6BY5. Thomas Mayer has a page on this tube, and it turns out to be a fairly unique tube originally used in color tv sets.

Philco seems to be the only manufacture that made the 42 in the globe shape. At least they are the only that I've found so far.

The 42 Globe is a very cool looking tube. Maybe one of the best looking globes I've seen so far. And they sound sublime.

The round plate 6A6 is a great driver tube.

Here with 1940's Hytron 6A6 drivers. Hytron are always superior tubes. $10 folks... In 6SN7 these would be soooo much more expensive.

A selection of 1930’s 6A6 tubes. From left to right, a Wizard (great name!) smoked glass, a Philco and a Hytron. The Hytron has a twin flat plate construction while these others have twin round plates.

Four Type 42 tubes. The Philco globe is the earliest and sounds best to me (no surprise really). Philco seem to be the only globe shaped 42 I can find. All of them are nice tubes, and except for the globe they were all purchased new in their boxes for around $20 a pair!