Perfect these worked great in my Hta-200 preamp section. more details, bass was tight and open up the soundstage.

I was very happy with a Douk st-01 Pro. Standard tubes were 188-05. After a couple of month I noticed some hum originating from the right tube. The music was still awesome but I decided to upgrade the tubes to 5654W’s. The sound is phenomenal. I’ve never heard such clarity before. Every voice and instrument is crystal clear. $20 for the matched pair at Riverstone Audio.

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

The Riverstone Audio - Tested/Matched Pair (2 Tubes) 7-Pin JAN 5654W Fully-Tested Vacuum Tubes are of very good quality. These tubes will give you balanced frequency bands. They do not have a lot of gain, so the sound should be smooth, and balanced. They do not add a lot of what you call warmth, or brightness. To me everything just comes out sounding very detailed, and balanced. Definitely not bright sounding, or muddy sounding. To me these are the best 7-pin tubes I have ever heard. I am currently using them on the upgraded AIYIMA T2 6K4 Tube Preamplifier. A stellar preamplifier using stellar Matched Pair 7-Pin JAN 5654W tubes. AWESOME!

Added these to my Xduoo MT-602 headphone amp. The difference over the stock ones is huge.Can't recommend these enough

Replaced my fosi 5654 year old tubes with these and they definitely sound better. The fosi tubes were a great improvement from the 6a2 tubes, and these are definitely better balanced then my fosi tubes, amazing quality would highly recommend. Lower price and better quality can’t go wrong with these.

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.

I have a Little Bear tube preamp. To be honest, I just wanted the bougie glowing tubes with my turntable set up. ...It was horrible. It was noisy and just flat. Didn't sound good. I did a Google look to see if there were modifications people were making to him to make him sound better. I read one person changed the tubes for a quality set of tubes... Claiming the Chinese manufactured tubes it came with the unit weren't good. So I ordered these and gave them a try.... The difference is stunning. They are quiet, accurate, and balanced. I haven't measured the tube specifications to see if they met the matched claims of less than 3%, but I have no doubt that they do. Awesome matched NOS product at a super reasonable price! They were well packaged and obviously intended to be sold together... 100%. I'll buy from these guys the next time I need tubes!

Made a noticeable improvement to the midrange, balance and tone of my Fosi Audio Box X2 Pre amp, that I ordered another set for my Douk Audio ST-01 Pro Amp. The difference is night and day. The sound is still that analog tone, however, it's not muddy like it was before.

I purchased this as a replacement for the factory-installed tubes on the XDUOO MT-602. Initially I was skeptical of purchasing these tubes, mainly because the clarity, soundstage, etc., was already very good on the factory installed tubes, with a minor caveat that there was a very faint "crackling" noise sound that was completely inaudible when music was playing and you had to really pay attention when there was no music playing to hear the sound. I found these Riverstone tubes and decided to give it a try. To my surprise, the sound quality was NIGHT AND DAY. Again, it already sounded amazing with the factory tubes but with these installed it was at a completely different level of clarity which I did not expect for a $99 USD amplifier at all. Zero noise, zero crackling, pitch dark when there's no music playing. Overall the music just sounds warmer, richer and with an extreme level of clarity. Great job Riverstone team!

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

¡¡Excelente compra!!Apenas llevo un par de días con estos tubos, sin embargo, desde el inicio se ha notado la diferencia en el sonido. Los compré para cambiar los tubos que vienen de fábrica con el Fosi Audio Tube-P1 y la diferencia es notable.Uso el equipo junto con un DAC para mis BOCINAS Logitech Z607 y Z625 y de verdad que ayudan a resaltar el sonido. Se escuchan más intensos y profundos los bajos y nítida la música en Tidal o YouTube o ver series en Amazon o Netflix.A mi gusto, ha valido la pena el cambio de los tubos de vacío, pues han mejorado sustancialmente la calidad de sonido (no el volumen, que es diferente). El sonido es más claro, profundo, potente, sin distorsión y nítido, manteniendo el nivel de volumen que uno desee.Cabe mencionar también, que se calienta menos el equipo con estos tubos de vacío.Incluso he pedido un segundo par para tenerlos de reserva por cualquier eventualidad, dado el excelente precio también y el cuidado en el embalaje.¡¡Valen 100% la pena!!... Espero que sigan funcionando bien mucho tiempo y mejorando "al irse asentando"....Actualización 10/03/2021:Hoy he estrenado mi segundo par, no porque hayan salido mal los primeros, sino porque me han gustado mucho. Este segundo par, lo he instalado para probarlo (en caso de defecto, devolverlos), y me he llevado la gran sorpresa de que tienen un sonido un poco más profundo que el primer juego y siento que viene "más asentado" (no sé cómo llamarlo). Habrá que seguir probando este par. Pero excelente sonido.

Riverside Audio is my go-to for these tubes. I remember when tube testing kiosks were in regular stores (Sears, mid-60’s). Makes sense to match them for two channel music applications, and Riverside does this; i can’t. They come well packaged (with an “if seal is broken” notice, an “extra mile”) with documentation of the testing. What this means to me, along with my listening experience, is confidence in the brand. I paid more for a pair of 1940s vintage tubes but it wasn’t long before one burned out, leaving me with an orphan. Better to go Riverside, all of mine still work, though I can’t estimate how much time I have in them, at least a couple years in one pair. These are worth it, especially at the current price, under $20 a pair in early ‘21. What they add is an improvement in the depth of perceptible soundstage, vs. a more 2-D experience. Less potential for listening fatigue with the treble. No serious sacrifice in the details. When I have them out of my signal chain I can still enjoy the music, but then a restlessness sets in (“Audio nervosa?”), as if something’s missing. Knowing what that is means in theory is that there’s a possibility of it being all in my head — but then that’s where my ears attach. Then back in they go, and it’s “ah ...”I use them in three of those inexpensive “Chi-Fi” preamp/tube buffers that Amazon sells, in three different stereo systems, all with class D amplifiers, after many years of the same A-B amps, for something different. My first impression of class D was skewed by having it drive brand new speakers, which (seriously) benefited from a good period of break-in (believe it or not). The sound signature of all the class D I’ve heard is, to me, detail-oriented, flat across the frequency range (so far as I can tell), neutral, possibly a tad dark, which I like, after years of relative warm & creamy. But in that first combination I was reminded of the difference between early remastered CDs of rock music I had on vinyl — the analog knocked it out of the park. CDs sounded more compressed, with “digititis” leading to listening fatigue. Not so anymore.I have Riverside tubes between one of those little TDA7498 amps (32v 5 amp power supply) driving early 90s Definitive Technology DR7 speakers. One between an ICEpower 125ASX 2SE amp and Dayton Audio MK442t speakers. Even in my work-in-progress endgame (if there is such a thing) system, my sources to a Schiit Saga + and a made in Ohio VTV Hypex NCore 252MP amp, as far up the class D chain as I’ve gone, driving sweet Q-Acoustics 3050i speakers (for me the balance between two channel simplicity and enough bass to preclude a subwoofer). An issue I had was wanting to push the volume higher on certain music when using my current budget streamer, a discontinued NEXUM TuneBox TB20. The Saga has little gain. My heretical solution was to put a tube buffer back in the chain, between the Saga and the amp. Two preamps, but “Ah ... just right.” System synergy. So especially if you’re new to class D, or need a little extra volume (I set the buffers to around 11 o’clock), for not much money I found they worked for me.