Massdrop x Alex Cavalli Tube Hybrid Amp (CTH) - Dropping Monday
Aug 11, 2017 at 5:00 PM Thread Starter Post #1 of 1,441
DAC-less dedicated headphone amps aren't exactly at the height of their popularity these last several years, most of us now looking for single-chassis DAC/amp combos. Also, relative to the total market, plug-in-the-wall desktop-size headphone amps seem to me to have taken a back seat in popularity to more portable gear, like portable DAC/amp combos and premium digital audio players. Only a few companies seem able to successfully buck these trends, and next Monday we may have the emergence of another: Massdrop. Next Monday (August 14) Massdrop is going to "drop" a plug-in-the-wall desktop size, DAC-less headphone amp--a tube / solid state hybrid one--called the Massdrop x Alex Cavalli Tube Hybrid Amp (CTH). I've had a pre-production CTH for just a couple of days, and it's beautifully made, versatile, and, most importantly has gorgeous sound on tap--the CTH sounds every bit a Cavalli amp in very early listening.

Cavalli CTH-07649.jpg

What does a Cavalli amp sound like? In my experience, you don't buy a Cavalli amp for a sound that's ruthless, dry, or lean. In my experiences with amps Alex Cavalli has designed, I'd say you go for a Cavalli amp when you want tonal richness, perhaps a touch of warmth, but somehow without sacrificing the ability to resolve like a high-end amp should. Cavalli Audio's $4000 Liquid Gold, a fully-balanced flagship beast of an amp (which we did a Head-Fi TV episode about some years back) remains one of my reference amps for driving low- to mid-sensitivity headphones, especially top-notch planar magnetic headphones. If your tastes favor a leaner, drier sound, where a sense of incisiveness is one of the prevailing characteristics (which some do prefer, and there's nothing wrong with that), I would generalize that perhaps Cavalli's amps won't be for you.

If the "CTH" name sounds familiar, that's because the Massdrop x Alex Cavalli CTH is based on the legendary DIY tube hybrid amp designed by Alex Cavalli that was called the Compact Tube Hybrid (CTH). This new Massdrop x Alex Cavalli CTH is a revision of the original CTH circuit. For this latest version, Alex Cavalli drew from his years of product development experience at Cavalli Audio to refine and modify the original circuit. Also, as this latest version is a desktop-sized amp, it's not quite so "compact," so the "C" in CTH now stands for "Cavalli."

Cavalli CTH-07645.jpg
I'll have more to say about this amp after I've had more listening time and more headphones used with it. Again, the Massdrop x Alex Cavalli CTH just arrived a couple of days ago, so my time with it has been limited. So far, I have mostly used the Sennheiser HD800S with the CTH, and it drives the HD 800S beautifully, with a richness of tone through the bass and mids, and with treble clarity and smoothness well beyond what I'd expect at the price.

Oh, the price? $249.99 with free U.S. shipping. That kind of pricing coupled with sound like this, that's what bucks trends.

Again, I'll have more to say about it, but you can see the drop announcement for the Massdrop x Alex Cavalli CTH at the following link:

Also, I know a couple/few other Head-Fi'ers have spent a lot more time listening to the Massdrop x Alex Cavalli CTH than I have and will be posting their reviews, so watch this thread.




2017-08-11 18:37 EDT: By the way, when the Massdrop x Alex Cavalli CTH arrived, I happened to have another DAC/amp on the test bench doing measurements. So I quickly swapped the CTH in to get some quick measures on the Audio Precision APx555.

RMS Level.jpg
(Above) Frequency response from 20Hz to 20kHz. (I'll post one later that extends higher, as a later measurement showed it flat to >200kHz.) (dBrA = 2V)

Deviation (20.0000 Hz - 20.0000 kHz).jpg
(Above) Frequency response deviation from 20Hz to 20kHz. (Again, deviation was just as flat out to >200kHz.)

THD+N Ratio 3.jpg
(Above) THD+N (total harmonic distortion + noise) is very good, with slightly higher levels in the right channel.

THD Ratio.jpg
(Above) This THD ratio graph shows that there's just a touch more noise in the right channel (based on the previous THD+N graph).

Crosstalk.jpg
(Above) Crosstalk measurements are good, with slightly better performance with the left channel.

CCIF Ratio.jpg
(Above) Intermodulation distortion (IMD) - CCIF

Some quick notes on these preliminary measurements:
  • Our Massdrop x Alex Cavalli CTH unit is pre-production, and Massdrop expects production units to be even better (built to tighter tolerances), which would be a nice bonus as this unit already measures quite well for a tube hybrid in my opinion.
  • We used a 300Ω load. I believe Massdrop's specs use loads of 45Ω and 50Ω.
  • Massdrop's CTH specifications (unless otherwise specified) use a 1V output (with volume knob maxed out). These preliminary measurements were done with the CTH at maximum volume, but with the input set by the Audio Precision APx555 to generate 2V at the amp's output.


Our audio measurements in this post were made using:
 

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Aug 11, 2017 at 5:09 PM Post #3 of 1,441
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Confession time - Historically, I have not been a huge fan of Cavalli Audio products. Or rather, I should say the commercial products sporting Cavalli's name. The Liquid Lightning, Liquid Fire, and even the highly regarded Liquid Gold all seemed underwhelming for their respective asking prices. They had interesting aspects to the sound, but none would be anywhere near my first choice in their price brackets. To be fair - I know folks who absolutely love those amps, so I chalk it up to system differences and sonic preferences just not being a match in my case.

The Liquid Carbon was probably the most promising, especially at its original $599 price, but the DIY Cavalli stuff always stood out as being more interesting to me. I really enjoyed the Cavalli Stacker 2, the Bijou, the EHHA, and even the little CTH (Compact Tube Hybrid), as being more compelling offerings than the commercial models. I know, DIY and commercial, apples and oranges, but still.

When Massdrop told me they were bringing an updated CTH to market for a great price, I was intrigued. Define "updated", I thought to myself. And define "great price". As it turns out, both terms are used in the best possible way.

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After spending about a week with the CTH, I'm not sure "updated" even applies here. It's more like a complete reworking of the original design, with numerous improvements. This thing is now a true fire-breathing desktop component, rather than the mighty-mite design of the original. CTH now stands for Cavalli Tue Hybrid as the word Compact no longer applies. Massdrop even discussed future plans for this chassis - there are some great ideas on the table, but I'm probably not authorized to go into that yet. Suffice to say - the Massdrop crew knows what they are doing. Price? $249.

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Quick impressions: this thing punches way above its weight class. I'm hearing succulent midrange body, clean, non-fatiguing treble, and solid extension on the low end.... surprisingly so for a cap-coupled design in this class (and with this build quality). Something typically has to give to allow for such a reasonable price but in this case I'm having trouble identifying the compromise.

I'm already on the hunt for tubes to roll as the stock Elecro-Harmonix 6922 - while pretty darn great for a stock tube - can surely be improved upon. It doesn't make sense to go overboard but I'm thinking the Amperex 7308 is a prime candidate (which I've purchased in the past for reasonable prices).

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I'll have a more thorough review coming as I log some further hours on this thing. Just for perspective, I'm currently using it with a Zenion music server ($999) powered by a Keces P-8 linear power supply ($599), a Cayin iDAC-6 ($999), and the MrSpeakers Ether C headphones ($1499). At $249, the Massdrop CTH doesn't look or feel like a weak link at all. Impressive!

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More to come in the near future.
 
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Aug 11, 2017 at 5:13 PM Post #4 of 1,441
Wow! I just got the email from Massdrop...
I have no need for this amp, so I'll pass. But this is an exciting entry for Massdrop, and should get A LOT of attention. 2 years in, and I still love my first-gen Liquid Carbon. I have no doubt this will be equally exciting to own...
 
Aug 11, 2017 at 5:50 PM Post #7 of 1,441
Just a noob question. It seems doesn't have balanced analog input, but it has balanced headphone output. Does it make sense to do that?
It's a single-ended amplifier, but the 4-pin XLR output is included for convenience. Cavalli has done this on other SE amps as well. Personally, I appreciate it because that means I don't need to adapt to 1/4".
 
Aug 11, 2017 at 6:08 PM Post #9 of 1,441
More Cavalli the better!!! Glad a lot of new people are going to be able to check out their sound.
 
Aug 11, 2017 at 7:08 PM Post #11 of 1,441
Please be aware that this is not made by Cavalli. It's made by Massdrop by a China manufacturer with the Cavalli name being licensed, etc.
 
Aug 11, 2017 at 7:23 PM Post #12 of 1,441
Had a chance to spend some time with this new entry in the Cavalli lineup. TBH I'm pretty reluctant these days when it comes to evaluating new gear, as I've been on a bit of a hiatus from the world of audio evaluation, but Cavalli is one of those brands that have consistently impressed me in sound and the overall experience of ownership over the years---I still see my Liquid Gold as a go to for anything planar magnetic---so I was quite curious to hear their newest, much more affordable product.

I find myself quite satisfied with my current setup. Really, it takes something bowling me over for me to want to get on forums to talk about it nowadays. As you might've guessed, this little amp is one of those things for me.

Simply put, I haven't encountered anything else in this price range I'd rather own and listen to on a daily basis with my usual headphones of choice. For the dosh, there's some good competition from genuinely awesome manufacturers out there to be sure, but for me the CTH is ideal for several reasons:

-It has that "Cavalli magic" the larger amps do. Probably sounds corny to some, but there is a definite warmth and natural ease to Cavalli amps that, together with their ability to let headphones' great resolving capabilities shine through, makes for a really immersive and addictive listening experience. Perhaps I could find an amp that out resolves this amp for the same money, but thus far I haven't found anything else I'd rather use for listening to music.

-It has a beautifully robust design and build. This amp looks and feels significantly nicer than some amps I've used at twice the price. Operating it just feels nice: the volume pot is smooth, the ventilation holes look stylish and form a subtle nod to Massdrop with their arrangement.

-It matches quite well with the headphones I keep around: the Audio Zenith PMx2, modified Yamaha YH-1s, the Paradox and Code X, even the obscenely priced Susvara. Hungry stuff I'd normally use the considerably more expensive Liquid Glass and Liquid Gold amplifiers from Cavalli to drive. The CTH handles my favorites like a champ.

Do keep in mind I've only been evaluating the amp off and on for about a week now, so I'll probably have more specifics to add as I continue to listen.

Sources used so far for those curious:
Sonic Frontiers SFD-1 mk2 SE DAC
Onkyo DAC-1000
Orbit U-Turn turntable
AMW V12 Turbo turntable w/ Teatro cartridge
 
Aug 11, 2017 at 7:41 PM Post #13 of 1,441
Massdrop x Cavalli Tube Hybrid Amplifier Review

Massdrop has another very exciting, collaborative product they’ve just announced, the Massdrop x Cavalli Tube Hybrid headphone amplifier. You may recall the CTH used to be a DIY offering from Cavalli. What Massdrop is offering is a highly reworked version of the CTH, in a sleek chassis, ready to go out of the box (including the tube), all for $250.

Historically, it has never been easy to find pre-built, affordable tube amplifiers that sounded genuinely good and worked well with about any headphone, especially when bringing headphones like the HD650 to life. While Massdrop isn’t the first company to try to disrupt this particular barrier to entry in the hobby, the product they are offering is an incredibly welcome addition! (And with their HD6XX, Massdrop has been on a real roll lately making it easy to get high end gear and build a full rig at relatively affordable prices!)

Form and Function

The Massdrop x CTH, which I’ll simply call the MCTH from here on out, is a rather straightforward amplifier. It uses a 28V wall-wart power supply, has a single pair of RCA inputs, has single ended and balanced headphone outputs, and uses 6922 tubes or equivalent. It comes with an Electro Harmonix 6922 tube in the box.

The MCTH is a rather nice, clean, and simple looking amp, in my opinion. It looks sleek and modern without drawing much attention to itself. The chassis seems to be of high quality. It’s about the size of Schiit’s Jotunheim, though somewhat longer in the back and with a bit less height, if I had to go off memory.

Beyond that, there’s not much more to say. It’s a simple, hybrid tube amplifier. It’ll power almost anything without strain, though you may or may not notice some hiss on very sensitive headphones. It looks and feels like a more expensive amplifier. I also received some hints that this chassis style may be used in some upcoming products, which would make it easy to visually match your rig components if so.

Sound Stuff

The MCTH is a good sounding amp, to the point a more boutique company could sell this at a much higher price and get away with it in this industry. The same could be said about the Schiit Vali 2, which I’ll be using as my main comparison point for the MCTH. (NOTE: I did not know who else participated in the MCTH tests, did not know anyone’s thoughts on the amp, and all of this was written prior to this thread being posted.)

The MCTH is a slightly warm sounding amp, at least with the included EH 6922 tube. The Vali 2, in comparison, is a bit more neutral sounding. That’s not to say the differences are major, but if using the same tubes in each to get a sense of the amplifier’s own flavor, you may want the MCTH if you’re looking for a bit more of that tubey sort of tone.

I think both the MCTH and Vali 2 are surprisingly detailed, resolving, nuance sounding amps, and not just for the price (albeit most amps aren’t really worth discussing, so…). The MCTH, I think, may capture a bit more of those background nuances like reverb and decay, bringing out a bit more of that tube “magic.” The Vali 2 sounds a bit more restrained in comparison. If you want to boil down technicalities, the MCTH is the better amp, but not magnificently so. Enough to be worth the extra price.

Timbre is fairly good on the MCTH once you burn in the EH tube for a while (more on that in a bit). Yes, on better amps, you will get more liquidity and clarity. I dare say there may be the slightest hint of midrange grain in the MCTH’s sound, but it’s incredibly minor and not at all bothersome. The MCTH is easy to get along with but isn’t boring. The Valhalla 2, for example, is much drier sounding. Bass and treble are handled fairly well on the MCTH, timbre wise, particularly the treble. No real issues or nasties. Once again, though, a truly better amp will net you more bass slam and clarity as well as additional treble clarity. But for $250, or even ignoring the price, the MCTH is really great to listen to.

The MCTH is not what I would call a laid-back amp, but it’s not all that forward either. It strikes a nice balance between the two. The Vali 2 leans a little more towards the laid-back side with the MCTH going the opposite direction. For further comparison, an amp like the Jotunheim or Mjolnir 2 are much more forward than the MCTH.

Because of the nature of the MCTH, the stage sits a bit closer to you and has less width to it than the Vali 2. I think both are similar in terms of layering or depth, though this is tough to tell. The Vali 2 sounds a bit more solid state to me in how it presents the stage and elements within, whereas the MCTH has more of that tube sound despite it being more forward.

Dynamics and the like are good on the MCTH. Again, a truly better amp will get you some additional bass slam and macro-dynamics, as well as some greater nuance to micro-dynamics, but the MCTH makes the HD650 sound lively enough. If an amp can do that, you know it’s no slouch in keeping you engaged!

Tube Burn-In and Rolling

Now, I do recommend you burn in the MCTH and (especially) the EH tube for a good while, as I touched on earlier. The EH tube doesn’t sound quite right at first, to put it nicely. Just leave your amp on with some music going through it in the evenings for a couple weeks or so. Shoot for 50-100 hours before judging the MCTH + EH tube.

I say this, because stock, the MCTH + EH combo sounds a bit too mid-bassy and has a sort of fuzzy sound in the midrange. With time, the sound became more even, smoother, and with a blacker sounding background. I’m not saying these were absolutely massive, life altering changes, nor can I rule out placebo, but I have often had this experience with new production tubes.

Speaking of tube rolling, I found the MCTH to respond rather well to some tubes I picked up. In a sense, the MCTH does a fairly decent job getting out of the way of the tube, or so is how I hear it. The Vali 2 also responds fairly well to tubes, but I think it may impart just a hair more of its inherent character on the sound no matter what tube you use. But if you compare either to, say, the Valhalla 2, I found the Valhalla 2 to always impose a certain sound in a noticeable way regardless of what tubes you rolled.

Still, I do suggest you burn in the stock EH tube before you drop a ton of cash on questionable eBay tubes. It really does sound pretty good after plenty of burn-in.

If you are intent on tube rolling, I actually found I liked whatever Canadian 6BZ7 came with the Vali 2 I have on loan. It sounds pretty darn balanced in the MCTH. You can get those at a good price, matched and all, directly from Schiit. I also found a USA-made Sylvania that sounds fairly lively, a bit bassier, cleaner, and slightly brighter than the EH tube in the MCTH for less than $20 on eBay, NOS. I’m just not sure how to describe exactly which one it is.

Point being, I do NOT suggest you go crazy and dump tons of money on unobtainium tubes just for the MCTH, even if it does change a good amount depending on the tube you roll.

Conclusion

The MCTH is a really cool and exciting amp, and I know Massdrop (particularly CEE TEE, who put in a ton of awesome effort to bring this to the community!) is really proud of this one. It looks sleek and modern, sounds great, works well with about any headphone, was developed and refined by Massdrop, Alex Cavalli, and several testers, and lands at a very agreeable price of $250. The MCTH delivers the sort of performance that historically meant a lot more cash out of your pocket. If this at all sounds like an amp you might be interested in, I strongly encourage you to buy one!
 
Aug 11, 2017 at 7:46 PM Post #14 of 1,441
Introduction:

Some time ago- a PCB, wall wart, and an army of tubes found their way to my doorstep. What showed up at my house that day would eventually become the Massdrop x Cavalli Tube Hybrid, an entry-level tube hybrid designed by Alex Cavalli for Massdrop.

Throughout the past several months, I’ve tried various versions of the amp and have had many full-sized headphones and amplifiers that I’ve tried alongside amp prototypes earlier this year.

Timing for this review is a bit difficult for me since I’ve been downsizing in preparation for a move (plus traveling) but I still want to be a part of this launch after helping test the amp and provide feedback.
It’s really nice to see a well-established, top-of-the-line amp designer focus on high value and high performing entry level product while today’s market sometimes seems to be moving in the direction of making ever more costly products.
And, I like this amp. A lot.

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What Does It Sound Like?

Describing the sound of the amp right now is a little challenging because I am about to be up in the mountains. :)
I’ll describe some comparisons from memory while testing and comparing the amp plus impressions made with my current rig and the final version right before traveling.
(Tried with HD800, HD650, T-X0, HE500.) I’ll also try to add some more at the end of the month (August 2017) when I am able to do some direct amp comparisons again with the final version based on what people are interested in.

Tonal Balance: The CTH is comparatively neutral with a slightly lean aspect to the bass compared to something like the Jotunheim (solid state amp with good bass slam).
It makes up for any comparative leanness with solid transients and a slight euphonic decay in the bass. There’s nothing wonky going on with the frequency response that’s going to prevent you from using the CTH with an HD800.
In fact, the CTH is a great pairing with the HD800, but for me…the real winner is pairing it with an HD650.

Headstage: If you spend a lot of time in “Schiitland” you get used to an up-front or “closed-in” headstage. The CTH really shines with a far more natural headstage than most of the Schiit I’ve played with.
Even though it has a tube, you’re not going to get a massive headstage with the CTH like you may get with other tube amps. I use term natural here because it doesn’t jump out and grab your attention in one way or another, which I really prefer.

Macrodynamics: I usually fall short in being able to express impressions about macrodynamics, but I feel that this area might be the weaker link in the CTH. The CTH still outperforms most amps under $500.
Jotunheim beats CTH in slam or “macrodynamics” but the Jotunheim is a freak of nature in this respect.

Microdynamics: Again, similar to the headstage. Nothing grabs my attention in one way or the other here, which is a plus. I’ll update with A/B microdynamics comparisons at the end of this month with other amps in-house.

Clarity: This is where the CTH really shines. Clarity is one of the most important aspects in any audio products for me and I used to complain about older HD650 headphones all the time because they seemed veiled.
The clarity CTH brings out in HD650 is on par with the best amps I’ve heard under $1500. This I do want to grab me. There’s no haze, no veil, just awesomesauce.

Plankton: When you swap from the Laconic NBM to the CTH, you notice a significant improvement in “plankton” retrieval (low level detail, connectedness, etc). Swapping from the CTH to the Jotunheim, there is only a slight improvement in plankton.
I remember the standout during amp testing for me was swapping from the Laconic Night Blues Mini to the CTH while listening to The Bill Evans Trio’s Waltz for Debby album. There was a lot going on in album that I didn’t hear with the Laconic NBM.

Which Tube Should I Put in the CTH?
A new production EH 6922 comes with the amp, and I’d recommend sticking with it. Throughout my testing, I tried out probably every compatible new production tube that cost less than $50.
The EH 6922 was by far my favorite of the any of the tubes. It offers the best clarity and resolution without doing odd things to the FR or transients.
You’ll get a little more air with the tube than some of the other and maybe a little bit less warm. Even so, this tube was still my favorite with the HD800.

Okay… Which Fancy Tube Should I Put in the CTH?
The only super expensive tube I stuck in the amp was an Amperex 7308, which sounds great with other amps, but I wasn’t too thrilled with it on the CTH.
I don’t remember much more about it than that. I’m sure there’s something better out there than the EH 6922 that’s nice and old, but I’d put that money elsewhere.
Personally, I wouldn’t exceed 20% the cost of an amp for a single tube.

Balanced at $250!?
The CTH has balanced output connector, but it is singled-ended, not balanced. I really enjoy this since most headphones that seem to find their way to me have balanced connectors only.

What Don’t I Like About It:
I like to listen to music at lower volumes than most people I know. For me, about 90% of my listening is done between eight and nine o’clock on the pot.
This isn’t really an issue for me, but it would be nice to have more range. One way to do this if you have a “hot” DAC that outputs a strong signal is to reduce the digital volume a little as desired.
(Some argue this can decrease DAC resolution but you can try it for yourself and see if you hear any difference.)


UPDATED IMPRESSIONS: Post 193

Summary:
The CTH is currently my favorite headphone amp for under $500. I can’t think of a better match for the HD650 at this price point and is a solid choice for the HD800.
It can drive planars such as the TH-X00 and the HE-500 with ease, provided you’re not trying to use them as small speakers. :)

With the CTH, you get the best of both worlds from what a tube hybrid is supposed to be: You get the resolution and clarity of a solid state amp.
You also get nice transients up front, but get a slight bit euphoric decay that lets you know there is a tube is somewhere inside.

Reviewer’s Note:
I am camping/ backpacking through Mammoth and Yosemite starting on 8/12 and will be unable to post any replies to this thread until about 8/22.
I wrote this on this on 8/6 and am posting it right before I leave for the mountains!
 
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