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

Repond a mes attentes. Son mieux défini. Pas encore roder. Meme apres 4h d'écoute le son evolu encore. Son bcp plus stereophonique je redecouvre certain morceau avec l arriver de nouvel instrument

5 Stars for a Rs.3000/- upgrade. Changed the stock tubes on my Aiyima T2 preamp. The result is awesome. To my ears the improvements are 20% warmth, treble 25% and bass 30% comparing the stock tubes(6J-?). Little bit muddy on MID but on some files only.

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.

Using these in a Fosi X2. They sound a bit harsh at first, but very good after about 10 hours of play time, and continue to improve with use. Mine have 50 hours now and I couldn't be more impressed with them.

Best packaging ever and a great matched pair product!! I feel like im back in the 1980s spinning my vinyl.... Awesome highs and lows sound quality.