Few tubes have as storied a history as the 6SN7GT originally announced in 1939 and officially registered by RCA and Sylvania in 1941; it went on to become one of the most used small amplifier tubes of the next 20 years. The 6SN7GT is a dual triode tube with an 8-pin octal base and medium gain (20) which made it suitable for signal amplification in radios, guitar amplifiers, and a range of other military and scientific electronics.
It was continually refined with a GTA version released in 1950 and a GTB version in 1954.
Hardened versions for military service were labeled as 6SN7A, 6SN7W and 6SN7WGT.
It is likely safe to say that the 6SN7 is the most commonly used tube in guitar amplifiers even today and this has put audiophiles in direct competition with those upgrading or repairing guitar amplifiers and those repairing old radios and other early electronics.
The result is that there are a lot of 6SN7 tubes out there, but there is also a lot of confusion, outright lies, and misinformation.
By about 1980, most western sources of the 6SN7 had ceased production so what had once been an easy tube to find suddenly became much more difficult. As a result, it is not uncommon to see Soviet made tubes of that era sporting “made in Holland” or “made in Great Britain” on them as unscrupulous vendors skirted import restrictions.
In some applications, gear could be rewired for 12AU7s or 6922s instead of the 6SN7 but neither had the cathode emission or plate dissipation of the 6SN7 which meant the later tubes were not good substitutes in many amplifier designs (both guitar and 2 channel gear).
It is for that reason that the 6SN7 is still sought after today and continues to be used in new designs. With import restrictions having eased (at least until the recent embargoes due to the Ukraine conflict) Eastern European, Russian, and Chinese made 6SN7 tubes have filled the void left by the closure of RCA, Sylvania, Brimar, and other western makers.
The upside is tubes have remained available. The downside is that many new tubes are not as good as some of their older counterparts and shopping the old stock market if fraught with its own perils. Often used tubes will be badly imbalanced with one triode near new and the other near failure.
Others will be rebranded to command a premium and even among the better old stock options, one must remember that some are approaching 80 years old and 70 years of wear and tear has taken its toll.
This is where the new Apos Ray 6SN7 tube enters the conversation. Apos is not a tube manufacturer but instead is a broker that is contracting with various factories to make tubes to their specifications and then testing the daylights out of them to be sure the resultant product meets their quality control requirements.
This allows Apos to choose the best factory for each tube type and then cherry pick the best 4-5% of that factories production to sell as Apos Ray tubes.
The Apos Ray 6SN7 uses a white base and coke bottle style glass rather than the short glass tube of the original giving it a distinctive look but be aware that is nearly double the height of a standard 6SN7 so while it won’t be an issue in gear with exposed tubes, it may present fitment issues in closed cases like guitar amps or the tight quarters sometimes found in old radios and 2 channel gear.
The coke bottle shape was originally used to help make tubes sturdier, but in recent years it is more cosmetic than functional so it is likely that the choice was made to create a more aesthetically pleasing tube but that choice may cost Apos sales to guitar players due to limited cabinet space.
Internally, there are 4 support rods held in alignment by the base at bottom and a mica spacer at top that is nearly hidden by the flashing. Plates are gray T-plates with plate size and geometry the same as standard 6NS7 short bottle tubes.
The getter is a bar style below the plates.
Much like the previous 12AU7 tubes I tested from Apos, I’m fairly certain I know the OEM behind their 6SN7 offering and it is a maker I consider to be the best of the current production 6SN7 options so I agree with their choice of vendor.
And much like my previous testing session with Apos tubes, the 6SN7 tests near perfect for all tests run with both triodes extremely tightly matched.
To put the Apos Ray 6SN7 through its paces I tried it in a modified Bottlehead Crack and the xDuoo TA-26 which in many ways parallels the Crack at a considerably lower price point.
I built the Crack years ago to original specs and thought it lacked a bit of detail and authenticity so being a tinkerer, I added the speedball mod and did a few other small modifications before deciding to scrap the 12AU7 and go to a 6SN7.
After some minor wiring updates and drilling out the smaller socket to accept the larger base, I installed an early Sylvania 6SN7 (not quite a bad boy, but close) and I’ve never heard a Crack sound better.
Today it wears a Tungsol Mouse-ear 6SN7 most of the time with a Bendix 6080 behind it. It’s a great amp with headphones like the Sennheiser HD650, the AKG 240 Sextett, and the Beyerdynamic 600Ω models.
OTL tube amps are not a good fit for the big planars so it is best to test these amplifiers using at least a 300Ω load in my experience.
I found the 6SN7 Ray to be well balanced with good soundstage dimensions and a solid level of detail; I think one of the reasons I find the 6SN7 sound a bit more authentic than other small signal tubes like the 12AU7 and 6922 is that the 6SN7 has better dynamics than either.
That realism I was looking for when I switched the Crack over to the 6SN7 originally is present when using the Ray. The Ray doesn’t bring a lot of warmth to the signature and is closer to the classic Tungsol Mouse Ear or black plate as it favors the top end slightly.
This is not to say they don’t have good bass presence, just that tubes like the RCA VT-231 bring a bit more low-end to the presentation than the Ray in my testing. I like a tight bass presentation and had gone to the Tungsol from the Sylvania to tighten up what I thought was a lack of control in the mid-bass so the Ray is a good fit for my listening preferences.
It’s nice to have a pre-vetted option in the market as the 6SN7 market has become increasingly difficult to navigate and when I had done my TA-26 tube rolling article, I found a lot of junk tubes on the market that would have made it a minefield for new buyers.
The xDuoo TA-26 offers new comers an inexpensive way to enjoy an OTL tube amp without having to build it themselves (Crack) or spend a fortune to see if tubes are their thing, but without quality tubes, it wouldn’t be a solid option.
I’m glad to see the Apos Ray 6SN7 enter the market as I can now recommend the TA-26S Amplifier ($319 at Amazon) with the Apos Ray 6SN7 and an RCA JAN 6AS7G (for those who want a little warmth) or a Chatham 6080.
These options keep tube costs reasonable while still offering a solid improvement over the stock tubes that ship with the amplifier.
With Apos now offering a year warranty on all Ray tubes and a money-back return policy for 45 days so if you don’t like the tonality or it won’t fit the cabinetry, the good news is the tube can be returned without a hassle.
With the 6SN7 retailing for $65, it isn’t as cheap as some of the other options, but ask those vendors what their return and warranty are before saving a few bucks.
With many vendors, once you install the tube in an amplifier, the warranty is over and if you don’t like the sound, you’re out of luck (and your cash).
Part of the reason Apos can offer the warranty is their packaging which puts the standard tube box to shame. Each tube is well packed in closed cell foam inside a book-fold box. I’m still trying to convince Apos to put the tube model on the end of the box as well as the lid so I can quit writing it on with a Sharpie, but that’s a small complaint.
Where to buy: $64.99 at Apos Audio
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September 25, 2024 at 7:15 pm
“Shallow Hal needs a Tube”…Yup. Looks matter and these Apos Ray 6SN7 have the LOOK.
Now all I need is an amp or pre-amp to put them in. I am beyond shallow. I am the “toddler pool” level they had at the Little Creek Naval Base. About a foot deep and 8 or so feet across. Shallow enough to be deemed safe for a teenager that couldn’t swim at all.
But then David Dunn couldn’t swim either. I bet he would like these tubes in his home setup.
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