Riverstone Audio - Tested/Matched Pair (2 Tubes) 7-Pin JAN 5654W Fully-Tested Vacuum Tubes - Upgrade for 6AK5 / 6J1 / 6J1P / EF95 - JAN 5654W Platinum Grade Pair

This alleged matched pair of 5654W vacuum tubes were my first tube purchase from Riverstone Audio. Very impressive packaging – safe, secure, and it looks like they take pride in their work. As I do not have access to a tube tester, I have to take Riverstone’s word on them being matched and on their measured performance specs. These tubes replaced the cheap Chinese crap tubes that came with my equally cheap Douk Audio T3 Plus phono/headphone preamp. The T3 Plus itself is underwhelming, but for the price that’s what I expected. However, for relatively little money, these 5654W tubes made a subtle but very noticeable improvement in sound quality in my T3 Plus. And that improvement was well worth the cost of these tubes, regardless of the following concern:HOWEVER – and I’m hoping Riverstone reads and responds to the following comment – I am a little concerned that these 5654W tubes may (or may not) have been counterfeit, or not completely advertised honestly as real GE NOS / New Old Stock tubes (actual NOS means they were manufactured many decades ago in tube’s “muscle car era” and have never been used since. Such NOS tubes command very high prices now, due to their reputation and scarcity). Here’s my concern: The green ink printed labels on the outside of each tube appear to be printed over, and on top of, other labels in light gray ink that appear to be on the inside of the tube - question mark ( ? ). Hmm. While this is unlikely to be an actual problem, our friend The Internet is full of counterfeit knock-off tubes that are “advertised” as NOS / New Old Stock but are actually modern tubes that are not manufactured to the same old-school tolerances and specifications. Similar to cheap Gucci and Louis Vitton handbags, etc. As these Riverstone 5654W’s have both green and gray printed labels, one on top of the other, it makes me doubt their true manufacturing / vintage. That said, they sound better than the tubes I replaced them with, and that’s all that really matters. In addition, a deep dive into research on GE 5654W tubes from other vendors also shows them as having the double green/gray printed labels, so at least these Riverstone’s are no worse than that competition.All that being said, for the asking price, these Riverstone 5654W’s are well worth the asking price – they simply sound better than the cheap factory installed tubes I replaced them with, and for less than the price of dinner out this evening. As this 5654W tube and its numerous compatible variants are not commonly used by tube amp/preamp manufacturers, it’s difficult to get trustworthy research on them no matter which vendor you consider. Even tube “Godfather” Brent Jessie’s website has scant info about this tube family, and Brent Jessie’s website is the most trustworthy for vacuum tube research.

As others have done with my Dayton Audio HTA-200 hybrid tube amp, I also decided to swap out the 6K4 tubes for these or "a" pair of 5654W tubes. To test the difference I uploaded a decibel meter to my iPhone. Maintaining a consistent or fixed mid-range volume, I auditioned about 15 seconds each from a particular starting point in four different songs (Low Spark of High-Heeled Boys/Traffic 5:33, Berlin/Fenne Lily, 1:24, You and Your Friend/Dire Straits 3:00, and Hurricane Party/James McMurtry 1:35). The difference was so jaw-droppingly apparent it rendered further comparison absolutely unnecessary. My 50W/ch@8-ohm amp's volume increased like it were now a 75W/ch@8-ohm amp, EASILY half again louder with seemingly unlimited headroom. Gee, I didn't KNOW it was legal to put PLUTONIUM into a pentode vacuum tube -- like catching lightening in a (Tube-Like) bottle! These tubes are worth e-v-e-r-y s-i-n-g-l-e p-e-n-n-y of the proportionately diminutive $24 upgrade.[Two things to note/mention: (1) I found a pair of 5654W tubes for $20 (i.e., $4 less) on Amazon as well, so asked the A1 chat service, Gemini, why it might be worth spending the extra $4 when this tube's description added the words, "fully tested." They related that it was unequivocally much better to get the set marked fully tested for perhaps a half-dozen quality control reasons which completely convinced me this was the wise way to go; and (2) 6K4 tubes are triode tubes noted for warmth and emotion. Conversely, 5654W tubes like this provide a higher gain and better stability for a more clean and detailed sound. That said, maybe don't throw away your 6K4s depending on how you may feel.]

Very well packaged and works fine. My 70 year old ears can not offer an opinion of sound quality.

Matched pair is great, on pre-amps too.

Quality tubes…all good…

Noobie to tubes but I noticed a better sound stage, more open, nice sound to vocals... When the Fosi T20 amplifier tubes were replaced with the Riverstone tubes

Bought these to replace a broken vacuum tube on a small Douk ST-01 Pro amplifier that broke. These work well. I only wish they were a bit taller because they sit exposed on top of the Douk amp and they are short compared to the originals which doesn't look quite as nice..

These tubes are very nice. They made a step up performance of sound quality in my phono pre-amp. I did, and always will fivevthem a warm up period of 15 minutes before use. Also, there is a lot of discussion on breaking in tubes before they achieve peak sound quality. I let mine burn in for about 50 hours of time, and they still sound as good as they did out of the box. The left and right channels on my pre-amp that feed directly into my active PreSonus 5BT speakers are very equal. The sound is very full and I recommend these for anyone with a similar setup.