TubeCube | 7 Stereo Vacuum Tube Amplifier

DIY-TC7

The TubeCube | 7 Stereo Vacuum Tube Amplifier is a great sounding, sleek looking amp at an affordable price. Not really a kit, this envy-inducing machine boasts a power output of 3.5W+3.5W at 8 ohms which is perfect for a desktop audio amplifier with bookshelf speakers. The TubeCube | 7 comes fully assembled and ready to play your favorite tunes with a matched pair of Sino EL84s and one Sino 12AX7B. Tube upgrades are available.


This tube amplifier not only sounds great, but takes up very little space on your desk. Here is a soda can next to the TubeCube | 7 for reference.

TubeCube | 7 Stereo Vacuum Tube Amplifier


You can connect your CD player, computer, or even your mobile device to the TubeCube | 7, all you need is an RCA cable and you are ready to listen to great tube audio. For phono use, you'll also need a phono preamplifier.

TubeCube | 7 Stereo Vacuum Tube Amplifier

The TubeCube | 7 is powered with a standard IEC cable. This amplifier can be used in any country as it runs on 100V - 240V AC. You will need to purchase the IEC cable appropriate for your country. Banana plugs and power cable sold separately.

Check out the Ken Rockwell review of this product.

How to Hook Up Your TubeCube | 7 In 30 Seconds:

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    I had no idea how much I was going to like my TubeCube | 7. It's tiny, so it's a joy to move around and connect. It's so easy to use and sounds so good you'll want a few of them. It's stable and works great.



    reviewed by: Ken Rockwell

    Yes, this amplifier has the midrange magic that you expect from a single-ended design. Clean, natural and coherent sound that can make you think the singer is in the room with you. When coupled with good quality fullrange speakers and good quality recordings, you can experience spacious soundstage and good imaging rather than the thick and indistinct “Wall-of-Sound” that is common in mainstream equipment.



    reviewed by: Kent Smith

    I was gifted a TubeCube 7 and a variety of tubes for Christmas. This little amp drives a set of Klipsch RP150M bookshelf speakers loud enough to wake up children at night, make wives angry, and impresses friends who think 100W minimum per channel is the only way to go. Do not be scared off by the 3.5W rating of this amp!!!

Rolling, changing, swapping the 12AX7 preamp tube has a DRAMATIC IMPACT on sound! I am currently using the 1964 RCA 5751 (NOS) from TubeDepot instead of the Chinese 12AX7 preamp tube included. This is the best sounding NOS tube I’ve ever heard, and TubeDepot sent me an absolutely gorgeous specimen. I wish I had a 2nd as a backup; it’s just that good!!!

The Genalex Gold Lion EL84 reissues seem to pair perfectly, but the included Chinese EL84s sound just fine!

I should also mention that I have emailed two questions to TubeDepot and Dave responded promptly both times!

Thank you TubeDepot!



    reviewed by: Paul

    My TubeCube has arrived, in good condition, it sounds fantastic, with the Telefunken tubes, and the Telefunken ECC803s that i keep for this special project.....i have changed the caps, and the sound is getting better every day :).



    reviewed by: Jos

    I have been interested in SET amps for many many years... The high price per watt always scared me away... I have owned equipment from Crown, Krell, Mark Levinson, Marantz, Yamaha, Norman Labs, Infinity and many more... When I saw your site... I finally decided to pull the trigger and boy am I glad I did! I purchased my TubeCube 7 with some dreambox speakers... I tried the amp with these speakers at first and was somewhat impressed but I kept getting the itch to plug my Martin Logan Motion 20s into the amp....OMG it is the best amp I have ever had on these speakers... I am now using it as my primary amp along with a Marantz reference preamp, Project turntable and Martin Logan Dynamo subs... I believe I have finally found my audio Nirvana...

Thanks for a GREAT product with OUTSTANDING value!!!

I look forward to doing more business with you...

Also the shipping was AMAZINGLY FAST!!!



    reviewed by: Adam

    I have owned the TubeCube 7 for a few months now, and decided to write a review for those especially who are considering taking the plunge to experience tube amplified sound for the first time.

First let me say, at this price you aren't risking too much if you have understanding of system matching (amp to speakers), and on this alone I encourage anyone to go for it! I would simply recommend that you make sure your speakers are rated at 8 ohms or higher. There are 4 ohm taps, on the amp, however, I find the amp is happiest with speakers nominally rated as 8 ohm speakers.

I in fact got more drive and fullness from my 8 ohm speakers (Klipsch KB-15) using the 4 ohm taps. A simple explanation for this is that impedance swings exist in the majority of speakers, and many drop to 4 ohms at some point within their passband. I also tried my small Epos ELS-3 speakers which are rated at 4 ohms using the 4 ohm taps, and they just didn't come alive like I would have hoped. Now, keep in mind, not only are the Klipsch KB-15 rated as 8 ohms, but they also have a sensitivity of 94dB! The Epos are 87dB sensitive [that's 7 dB(!) quieter with 1 watt of power].

So then, this amplifier sounds plenty powerful when matched to an appropriate set of speakers. Since it is rated at 3.5 watts per channel, you have to temper your expectations regarding what it can drive. Think of this amplifier as the ideal computer room/bedroom stereo amp.

I was excited when the amp was delivered, and opening the box did not disappoint. The packaging was of very high quality polymer/foam (?) that was both sturdy and flexible to more than adequately protect your precious cargo. This little amp made me chuckle when I took it out of the box, in the way someone would upon seeing a cute puppy (sorry didn't know how else to describe it). It is in fact cute, yet solid and in that way no laughing matter. I felt like I got something for the money I spent.

I have heard other tube amplification previously, and fell in love with things that seem to be inherently reduced/missing through solid state gear such as: instrumental texture, a greater sense of instrumental timbre, sometimes a kind of juiciness that causes music to have more of a life-like ebb and flow, and sometimes warmth.

Since the TubeCube 7 is so affordable I wanted to know what it could do. It uses one 12ax7 preamp tube and two EL84 power amp tubes. The tubes are Sino brand, which I believe are manufactured by Shuguang, the well-known Chinese tube manufacturer.

Right out of the box the sound is quite good, if somewhat inhibited sounding. Once the amp warms up and gets to stretch it's legs a little, it opens up more.

The Sino tubes are inoffensive and you can pick up on subtleties in the music that solid-state doesn't typically deliver. You get a bit deeper peek into trailing sounds following a guitar pluck, cello and other stringed instruments. You also can pick up on echoes in a hall better, and there is a generally more organic characteristic to the sound. Electric guitar texture comes through better than via solid-state gear. This made Sweet Child Of Mine and Welcome to the Jungle by G'N'R very satisfying. Axel Rose's vocal raunchiness seemed very realistic, as well.

Harshness is completely missing, but not because of any veiling of the sound. On the contrary, this amp sounds very neutral, rather than leaning in a direction of hot or cold. It sounds well balanced across the audible spectrum, and is satisfying with all kinds of music. I can't comment on the perceived soundstage size due to the horn-loaded tweeter on my Klipsch speakers, which reduces room reflections. Happily, it never sounds slow-paced.

I later purchased Electro-Harmonix 12ax7 (1) and EL84 (2 matched) tubes to experiment with how the sound may change by tube swapping. I began just with the 12ax7 tube; right away there was an increase in gain and a general sense of "more of everything"! Whether this is better or worse will depend on listener preference. I actually wasn't instantly decided because I wanted to see if I could detect specific differences. Over time I concluded that I thought perhaps I lost a little bit of low-level information; being a fan of subtleties in music I didn't like that, but I did like the additional drive that music had, although there was a tinge of harshness (very small) introduced.

I kept the EH 12ax7 installed, because I wanted to see if it would synergize with the EH EL84's. It ultimately did match nicely with the EL84's but the first impressions remained sonically. Overall, despite the stated discrepancies, I still like these tubes and feel they are of high quality of manufacture. Since the general soundscape remained pretty much the same, I switched the preamp tube back to the Sino and left the EH EL84's as the power tubes.

Voila! Now we have a REALLY good synergy. Harshness disappeared, but additional drive and volume was retained, with all the positives of the original Sino tube combination intact.

FUN! That's what this amp is, and for anyone afraid to hand over serious dough to get their feet wet, this is the best way I know to get your tube fix on, with minimum financial risk.

Thanks TubeDepot!



    reviewed by: Justin

    I spent the last few weeks looking for a new tube amplifier (working with a small budget but hoping not having to give up a very good quality sound) and after reading all the great feedback here about the TubeCube 7 decided to give it a chance.

Now after almost two days of putting the TubeCube 7 through the ropes the first thing that comes to mind is wishing I still had my vinyl LP records and turntable from the 70's so I could really hear what this Miniature Marvel can do. Over the years my entire music library has become all digitally stored on my MacBook Pro and I've been trying to replace more and more of it with AIFF 16bit quality files especially now with using a tube amplifier for better and warmer listening. 

So far everything ranging from Joe Cocker, Melody Gardot, Joe Satriani to CC Coletti and more that has been flowing through the three pre-installed tubes that arrived with this tiny amplifier while connected to an inexpensive set of Polk Audio T15 Bookshelf Speakers (mounted on the wall and wired with Monster 16-gauge speaker wire) hasn't disappointed one bit because of it's surprising big sound.

I've already purchased a pair of Sovtek EL84's, Electro-Harmonix EL84 EH Power Vacuum Tubes and a Mullard CV4004 / 12AX7 Balanced Triode to see how they will sound compared to the matched pair of Sino EL84s and Sino 12AX7B that came with it, So after the new tubes arrive it may take some time to find just the right amount of warmth, bass and highs but in the meantime the flat digital world of music will slowly fade away to a better place inside my ears.

Thank You TubeDepot,



    reviewed by: David

    This is my first tube amp and I can't believe it. There is an openness and placement I'm just not used to; a depth and space I can't believe. It is like I'm perceiving another spacial dimension. When I close my eyes the music has a shape, even a color. For $175 !?
Granted I am putting them through some really high quality Vienna 6 ohm speakers but it's stunning how much better they sound than my $800 transistor amp.

Plenty of power for this room.

When I turned the TubeCube on there was no sound at all. No hum, not even a click. I thought, oh, no, something's broken. Then I noticed the light on the switch (good idea) and then the little tubes started to glow. I had hooked it up through an airport express and so I just hit airplay on my laptop and there was sound.

If these sound so good I wonder what the bigger more expensive amps could possibly do. I wonder what it would do with a high quality input.

Oh my. Thus starts my full migration to tubes.



    reviewed by: Michael

    I’m really impressed. I played it for a day using the stock Sino tubes, using both my iPod and turntable as sources. The sound was pretty surprising for such a small amp, full and rich, a with the warmth of tubes. Given the smallish power output, I used a pair of Klipsch RB51 bookshelf speakers which have a good efficiency rating. Overall, the amp did a great job considering the size and price. I was very happy with the output.
Next, I swapped out the stock tubes with a matched pair of Sovtek EL84M power tubes and a balanced triode Mullard CV4004 / 12AX7, both ordered from Tube Depot. After an hour or so of burn-in, the TubeCube 7 really sounded great. A bit more headroom, and both the bass and midranges were much improved.
This is a great little amp and at the price point of less than $200, it is perfect for your desk, bookcase or office. Pair it with a couple of efficient speakers and you’ll enjoy some pretty awesome tube sound without a needing a lot of space. Highly recommended.



    reviewed by: Dan

    It sounds great! Definitely a good way to add tube tone to your listening experience without paying a fortune.



    reviewed by: Dustin

    As always, you guys don't disappoint. Love this little cube, powerful but yet graceful, love doing business with you guys. The small amp is super quiet on idle and don't produce any hum like conventional valve amp. Thanks for this great product!



    reviewed by: Wessel

    Received the unit well packaged, and although no instructions are provided or needed, a spec sheet and warranty information if any, would have been welcome.
I provided my own power cord and soldered 4 banana plugs on some speaker wire and the amp was all set up.
This little amp sounds great after a few hours of burn-in. It really settles into its own after about 10 hours or so. After that its only about 20 seconds of warm-up time (from cold) and its ready to rock! Almost zero perceptible noise floor and no AC hum at all. At all normal listening levels I cannot believe the music quality!
I matched the TubeCube7 with a pair of vintage black Realistic Minimus 7's and the sound is fantastic! Yes, three products with '7' in the name and seperated by 30 years but they compliment each other beautifully, both visually and sonically. And, coincidentally, the tube design in the TC7 predates the Minimus 7 by at least another 30 years or more.
I am currently driving the amp with some standard definition mp3 audio from a large itunes music library with a high quality laptop and much of the older music sounds all new to me now. I'm hearing subtle sounds in some of the music I never noticed before when it was played on the typical transistor amplified loudspeakers that are sold for computer use. (It may be obvious that those systems are not audiophile quality, but that is the digital world we live in.)
Thanks for bringing the joy of tube audio at a great price. Please list a few tried and proven tube substitutions on your website to give us a starting point if/when a tube upgrade is desired.
I'm looking forward to years of use with the amp, and now I think I might even buy another as a gift....



    reviewed by: Brian

    I just want to write a quick note to tell you that I think the price of the Tube Cube 7 is the best money I have spent on audio in years. The sound of this amplifier with the original tubes reminded me of my grandfather's console radio, and with the set of Sovtek tubes --- balanced triode 12AX7A and 2 matched EL84M --- that I purchased later, the sound is so detailed and musical I could not believe it. I would play either set of tubes really , because after about 20 hours of play, either set was great sounding, just different. I am playing CD's through a TEAC PD-H300- MKIII , with Fostex FE127E full range speakers in double bass reflex enclosures. I don't think I have had the volume control more than 1/3-1/2 up from minimum and the volume is loud enough to be enjoyable with any style of music I have played. With good recordings the sound stage is three dimensional. Amazing! I have changed to a higher quality interconnect and better speaker cables for the Tube Cube 7, the sound this little amp produces is worth it.



    reviewed by: Eric

    Just a note to say thanks. The cube arrived very well packed and paired with the smallest Klipsch, the RB 41's, sounds just plain great. Fills the room prefect, very pleasant to listen to for long periods and I'm hearing things in familiar recordings that I haven't heard in years.



    reviewed by: Chris

    Hi, Guys
I wanted to comment upon the TubeCube 7 amplifier I purchased from TubeDepot recently as well as your offerings of NOS vacuum tubes. The TubeCube 7 is everything that you fellows and others say it is – it’s fun, it’s amazing and it sounds super fine. For the past several years I have been using a stereo tube power amp that produces 0.75Watts RMS per channel so the 3.5 Watts per channel that the TubeCube 7 brings to the party is just crazy powerful. It drives a pair of circa 1967 Tannoy 12” Monitor Golds to realistic levels and doesn’t crap out. Played within its limits (no hooking the TubeCube up to your Apogee Scintillas now) the TubeCube 7 delivers music with finesse, but on a solid foundation. A balance that satisfies IMO. For all the wonderful things that have been said about it, I can’t recall anyone mentioning the fact that this TubeCube 7 is a single ended amplifier –one power output tube (6BQ5) per channel.
If you have never heard a single ended amp, the TubeCube 7 is an inexpensive and rewarding opportunity to experience the single ended sound. If you’re reading this, and have been considering the purchase of a TubeCube 7 amp, my advice to you is … take the plunge. OK,that’s all for the moment, except to commend you fellows on the terrific job you’re doing regarding selecting and sourcing your NOS vacuum tube stock. Nice clean selection of vintage NOS tubes. Goodwork guys!



    reviewed by: Edward
  • Tube: Shuguang EL84 2pcs , 12AX7B 1pc
  • Power Output: 3.5W+3.5W @ 8 ohms
  • Frequency Response: 30-40Khz (+-1db)
  • Input Sensitivity: 500mV
  • Signal-to-Noise Ratio: -80dB / 3.5W
  • Residual Noise < 1mVac
  • Input AC Voltage: 100-250Vac
  • Power Consumption: 38W
  • Input Impedance: 50K ohms
  • Output Impedance: 8/6/4 ohms (Japan Z11-EI48*24 Output Transformers)
  • Dimensions: 130mm (w) x 130mm (d) x 130mm (h)
  • Weight: 2.6KG
  • Input: RCA Jacks
  • Output: Banana Jacks
  • AC: Standard IEC Jack with Fuse protection (2A Fuse)
  • Color: Black