Massdrop Cavalli Tube Hybrid Amp

This is rather interesting. Haven't done much DIY but have a reasonable grasp of basic electricals. However, I have no idea what kind of chassis could be used to enclose it.



https://www.galco.com/buy/International-Power/IHB28-1.0

 

You probably want at least the 2A version to make sure you have enough headroom.

https://www.galco.com/buy/International-Power/IHC28-2.0

This is probably not on par with the supply atomicbob mentioned. Those supplies run at around $300 iirc.

..dB

 

First off, for those not familiar with OEM power supplies, soldering, working with mains power without getting shocked, specifying an input fuse and building a suitable grounded metal or double insulated enclosure, please leave well enough alone or find someone with sufficient technical skills and time available to build.

Inrush current during power on appears to be less than 1.0 Amp, so a 1 Amp supply is likely to be sufficient. Run time current is approximately 0.35 to 0.40 A depending on tube heater current.

The Acopian A series for the specific model I listed has a maximum ripple of 0.25 mVrms which translates to 0.71 mVpk-pk.

The Acopian B series for the specific model I listed has a maximum ripple of 1.0 mVrms which translates to 2.83 mVpk-pk.

The IHB28-1.0 has a maximum ripple of 5 mVpk-pk.

Will these ripple values have an effect on the residual noise levels? If so, how much? If you aren't in a position to answer that yourself, then you probably should leave well enough alone until after successful completion of a structured DIY project such as the BottleHead Crack followed by some serious study of power supplies and their specifications. No offense meant to anyone but working with mains power can have a shocking and possibly deadly outcome. Random substitution of other power supplies has great potential to blow up your amp. Don't do this unless you understand how to read OEM power supply specifications and understand the differences, such as between regulated and unregulated, for example.

 

As put so eloquently by philosopher Harry Callahan, "A man's gotta know his limitations."

 

I appreciate this as a retired attorney and former history major who has zero experience or knowledge of electronics and has never held a soldering gun in his life. (I also sucked at grade school arts and crafts and was lucky not to have failed shop in high school.) When I've discussed tube amps on other forums, I've taken criticism for avoiding the BH Crack (which would only be an exercise in frustration for me even in the unlikely event that I finally got it working) or even Garage 1217 amps (available fully built, but various adjustments require you to play with jumpers and the manual, which was more of a guide to building the amp than a user guide, was gibberish to me). When I noted my lack of talent in this area, it was pooh poohed, sometimes nastily, and I was told how easy it was. I'm glad someone acknowledges that not everyone has the same skill sets. (FWIW, I started with a LD MK III and am now using a Valhalla 2.)

 

Measurements are in process, as time permits, including both SMPS and LPS.

 

MCTH measurements are now up:
Massdrop Cavalli Tube Hybrid amp technical measurements

 

Yeah, this thing is interesting. So one week later, comparison against black Jot (the thing for sale):

1. Jot has better bass. This is immediately apparent to me. More slam, cleaner, more weight, more "powah." Not up for debate, I think, since objective measurements also support this (thanks, @atomicbob!). MCTH is just slightly softer with its impact. But when I wear HD800, that softer bit makes all the difference.

2. MCTH to me sounds like it has better soundstage. At least deeper than Jot, and equally as wide. This is also not very subtle, especially with HD800. Jot sounds like a wall of sound in front (I think I have mentioned this multiple times now?) whereas MCTH sounds like it's properly spacing things out. Jot is a bit claustrophobic in comparison.

3. Despite Jot having a cleaner sound and more impact, MCTH to me sounds like it has more air for some reason. Simultaneously, MCTH has much smoother treble than Jot to me. There's a hard edge to lower treble with Jot that's slightly more apparent in direct comparison against MCTH. But please note that this is with HD800 (notorious for its treble peak). I don't notice Jot's peakiness otherwise. In fact, even with HD800, I probably wouldn't notice the peak if there was no MCTH.

4. MCTH is still the darker amp of the two overall. This is very apparent when it comes to cymbals. MCTH has a slightly smoothed over/muted sound there whereas Jot rings out properly, I think... even when it hurts my ears. My preference goes toward MCTH, but I think Jot is the more neutral amp.

5. Both are equally solid/warm/organic where midrange is concerned, I think. MCTH used to sound really bloomy, slightly grainy and cloudy at first, but after a week (I turned the amp off for only one or two days?), it's just like master @Hands said: it's smoother, more calm, and cleaner sounding. MCTH also sounds a bit more distant than Jot due to its bigger (read: deeper) soundstage, me thinks. The effect is especially good with HD800, but it only helps the claustrophobic soundstage of my HD580 and HE-4XX ever so slightly.

6. I think MCTH has just ever so slightly more compressed dynamics compared to Jot with its softer hitting bass and smoother, less "impactful" (bitey?) treble. But to me, it's the "calmer" of the two. I remember Liquid Crimson sounding more... aggressive than this. MCTH is more on the laid-back, musical side, I think, with just enough technicality so as to not make it sound like goo, and at the same time, it still has that tube liquidity(tm) magic thing going on. I'm not sure how to best explain it here, but overall, it sounds a bit less "hurried" (hyper?) than Jot, which sometimes sounds like it's straining the transducer to try and reproduce signals faster. MCTH flows more naturally with all of my transducers (HD800, HD580, HE-4XX, and T50RP and... whatever else I have lying around here).

7. Details-wise, I don't think I'm losing out on anything going from Jot to MCTH. In fact, I feel like MCTH sometimes pulls out certain things that Jot doesn't. Or else... maybe what I should say here is that MCTH makes details easier and more apparent, versus Jot's tendency to spotlight everything and throw everything in my face. There are better gradations of information coming at me with MCTH, I think... like sounds that are soft and distant sound properly soft and distant, whereas Jot tends to "increase contrast" by sometimes making it sound like it's hard-clipping things that are further at a fixed distance, and then things that are closer are just hard-clipped to my face. Maybe this is the whole soundstage thing again, but it's not quite like that.

8. I'm still writing about the comparison, and I think that's a good thing, because... I'm torn enough about the different qualities of these two devices that I'm nitpicking everything possible. So, on that note, I'm really torn between the two amps where sound quality is concerned. I like the macrodynamic, the boosted contrast, and the slam/impact that Jot offers, but at the same time, I like how MCTH is not forcing me to listen to the music.

9. What I'm really not torn about is the ergonomics of the amps. Jot is more solid, more industrial, and more substantial, probably because it's a densely-packed small package, versus MCTH is really just a big board with only half of it being populated with components, and then a lot of empty space inside. So MCTH is bigger but lighter, and Jot is smaller and seemingly denser/heavier. MCTH's volume knob is 10,000% better than Jot's volume knob. I think that's an objective fact. Schiit should take note and produce volume knobs that are light and smoother to adjust like that. Jot's volume knob feels heavier and sluggish in comparison. Last but not least, Jot's LED is annoying as eff, especially at night. MCTH's LED verges on being almost invisible at certain angles, and I can barely see it, which is good because the LED should not be a distraction! Build quality is about the same but ergo is just far better with MCTH.

Short summary: I slightly prefer MCTH's more laid-back sound to Jot's warm-neutral presentation. Jot is just not a good match with my taste in music in some specific cases (too aggressive-sounding?), despite it having clearly better technicality than MCTH. In fact, I don't even think I'll like it if I could get something that sounds like it's in between MCTH and Jot. I know for sure I'd still prefer MCTH. It's the "sweet spot" per se. But seriously, Jot is still an awesome amp. MCTH just fits me better.

Now, to see when Jot will sell so I can plonk down moneh for a LPS. Cleaner bass and more grunt while keeping everything else the same sounds good to me.

Trivial bits: sorry, forgot to mention these:

1. No difference that I can hear between XLR vs SE output. I'm guessing they're one and the same. I can hear a difference with Jot, though. (I prefer XLR on Jot)
2. Yeah, you can drive two headphones with both plugged into SE and XLR outputs at the same time. Can't push volume knob up to 11, though. The protection circuit will kick in and power-cycle the amp then.
3. Will tube-roll MCTH some time next week (or whenever I have time, really...)
4. MCTH doesn't get as hot as Jot. I can touch MCTH's tube while it's in use. Sometimes I wonder if the amp is on at all because from where I'm sitting, the LED light is so dim.
5. MCTH doesn't have any microphonic problem. In fact, I regularly drop stuffs on the table and I have tried tapping the casing of the amp, and no ringing. Must be Russian magic.

 

Thanks to atomicbob for all the info on the CTH. Massive amount of work you did.

On eBay I found both the 1A and 2A International Power LPS. I'm leaning toward the 2A because the ones on eBay are cheaper than new prices so might as well. Since the stock supply is rated at 1.25A, should a 1.25 fast blow fuse be used on the LPS?

 

Time to buy too. 20% off everything on eBay with the coupon on the ebay home page. Save up to $100

 

I received the CTH yesterday and have been comparing it with Liquid Glass using Code-X and a few other headphones. Unlike LG, I haven't tried any tube rolling with CTH although I do plan on testing a couple 6922 variant tubes I have lying around (Telefunken E88CC/E188CC, Siemens CCa, etc.) later.

This is a totally unfair comparison, but I was really surprised how the CTH managed to hold its own against its much bigger brother. I'm not sure how much this amp or the stock tube could improve with burn-in, but even without it the CTH proved to be quite a competitor. Here are my initial impressions.

1. The LG clearly wins in terms of soundstage width/depth. However, maybe it's because of this, but the LG sounds somewhat distant and diffuse whereas the CTH sounds more focused and upfront in comparison.

2. The CTH is more aggressive sounding than the LG. That is not to say it is an aggressive sounding amp, both amps are still relatively laid-back compared to my Mjolnir 2. I would agree that the CTH is a slightly smooth sounding amp, the LG more so.

3. The LG delivers more oomph and power to insensitive headphones like Code-X, and this is evident on recordings that were recorded at a low volume. This could be problematic for CTH which fails to drive Code-X to sufficient SPL, but such recordings comprise only about 10% of my entire music library. For most music including contemporary ones, the CTH has senough power for Code-X.

4. The CTH is quieter and has a blacker background than LG. I thought it was because of the tubes used in LG, but rolling 5 different sets of tubes on LG yielded the same result.

As you can see, it's been only a day and the CTH has already impressed me quite a bit. While the LG is the more versatile amp, the CTH doesn't fall far behind given its price and small footprint. The CTH actually betters the LG in certain aspects, especially its background noise (or more precisely the lack of it), and for certain tracks, I think I somewhat preferred the CTH's more focused and aggressive presentation despite the tradeoff in soundstage. Besides, soundstage doesn't make a huge difference when it comes to headphone listening, at least not in the same sense as that of 2-channel speakers.

 

I just got the CTH today and have been putting it through it's paces. Here are initial thoughts after a few hours.

1. I like the build quality. Materials, fit and finish make me happy. I would say that Schiit products are somewhat more "substantial and industrial" but I don't find anything wanting from the MD chassis. Nicely done!

2. The smooth action of the potentiometer is...slick. It moves effortlessly.

3. The 1/4 is a little rough when inserting and removing. This is slightly annoying.

4. Sounds impressions after an hour with stock replacement tube: this is a very good sounding amp. What jumps out at me is beautiful tone and better than average staging. Tone of female vocals is downright impressive. I've owned lot's of amp and many that cost considerably more than the CTH. The CTH produces vocal with subtle inflection that makes you take notice and draws you into the music. And this is not vocals done with an overly tubey sound. Details are coming through as well. Guttural sounds and raspy vocals are there in all their glory to be savored.

5. I wish that there were a contrasting white dot on the volume knob so much it easier to read the volume level. No worries, I'm sure that I can doctor it up with something.

Bass response might be a tad overdone, but this tube is new so I'll see how things sound after a few days.

 

I'm getting goose bumps listening with this amp. This is always a good sign for me. Just using 650 ATM and I'm almost afraid to plug in a planar. Usually when an amp sounds this good with high impedance dynamic drivers, it falls short with planars.

Fingers crossed....

 

Okay, here is a down and dirty Vali 2 vs CTH comparison while it's fresh on my mind.

1. Both amps are worth more than their asking price, easily. How refreshing to see companies taking this approach. Granted this is an expensive hobby and we certainly understand that going in. But how great is it to get gear that performs well above it's price point?

2. Although the CTH is $100 more expensive, it is certainly worth the extra cash IMO. Bottom line in terms of amp performance (with 650), is that I have gotten more "scale" with the CTH and my Senny's sound better than with the Vali 2.

3. Vali 2 requires tube rolling to get to it's potential. CTH does not require tube rolling and may well sound best with the included stock tube. This is preliminary and I need to roll some of my NOS 6922's to back this up. But if this is true, then that can be factored into the cost of ownership.

4. Vali 2 is somewhat miniscule where the CTH is more of a standard sized desktop amp. I don't mind the smaller size of the Vali 2 but it irritates me when the amp moves around when I plug/unplug headphones from it.

 

Just slotted a Sylvania into my MCTH. It came earlier than I expected. LPS to come next week (Acopian A28NT125 <- probably the "just right" version for this amp, I think).

I'd agree that MCTH doesn't seem to change much with tubes, but to my ears, the Sylvania tube sounds just a bit more exciting/sharper than the stock Russian tube. It's also a bit bassier at first blush, but I think what it does is just clearer bass. Impact is still about the same. Black Jot still hits just a bit harder, but at least MCTH doesn't have cloudy bass with this tube.

So I'd recommend Sylvania with stock HD650 (based on what I remember of it at least), but maybe not with KISS-modded... as the amp can be a bit too... lean-sounding then. Basically this is for warmer and more relaxed sounding headphones.

What's cool, though, is that despite being slightly brighter/cleaner/leaner, the Sylvania doesn't seem to cause any extra sibilance, even with HD800. And it doesn't even seem to have tipped sound balance, so I'll probably keep it in there for now. MCTH to me sounds like it just needs more clarity, and this tube seems to help with that.

 

Let us know how you hook it up? Bob mentioned an inline fuse is required on the AC side. Looks like outlet power cable live and neutral wires go into screw clamps, and same for output power which needs a Y-cable that terminates with 2.5mm barrel connector?

I bought the MCTH today, managed to snag an unopened box from a local guy at retail price. Feels good to get one without the wait time. I even have a sniff tester to tell me when the tube is burned in.

 

I don’t think anyone has mentioned this yet, but the MCTH runs really cool despite the owners manual claiming it gets hot. Not just cool compared to any Schiit amp I’ve owned, (tube or SS), but just plain cool, as in barely warm.

 

I agree. In part this is due to the design and chassis. Big chassis and good thermal design equals cooler running Temps.

 

The description makes a big deal of the convective cooling design. The internals are somewhat sparse for the large area. While it seems like you could easily make a more compact design, like Vali 2, the gains in thermal management seem worth it to me.