Massdrop Cavalli Tube Hybrid Amp

@atomicbob did say he was going to test some. Maybe he has an update?

 

Same price, +$35 shipping = $125

 

@Junki, if you think that noise is the only thing to consider when choosing a power supply you are sadly mistaken.

An amp can only be as good as it's power supply. It can make or break an amp. All of this amplification power has to come from this supply. Noise is just one of the things we can measure. Go back and compare Bob's measurements of THD between the two PS's.

The SMPS that comes with the MCTH is about the worst thing about it. It is aslo is really easy to upgrade because it is an external part and will not require any mods.

But any amp builder will tell you a good power supply is key, and I mean KEY, to a good sounding amp.

And if others want to spend more than the amp for a PS, that's their business.

 

Sure.

MCTH with SMPS into 30 ohm:

• Channel A THD: 0.00429%
• Channel B THD: 0.00409%

MCTH with LPS into 30 ohm:

• Channel A THD: 0.00424%
• Channel B THD: 0.00411%

 

Sorry, I meant THD+N

THD+N 30 ohm load, SMPS:


THD+N 30 ohm load, LPS:


I also said that noise is not the only measurement. Good grief. It's like you didn't read or consider everything I said.

Measurements aren't everything anyway. I'm not having this argument today.

 

Ok...to keep on subject.

I now understand this veil or lack of clarity. Did an A/B on my 650's between the MCTH and the Valhalla 2, and I get it. I will likely never get rid of my Valhalla 2.

Anyway, the details on my T20's and D2000's are great as if contributes to the engaging an enveloping sound. Instruments just sound like real instruments, unlike the Magi 3 that made them sound like a facsimile. Not to say this is the end on detail, but in the sub $500 rage, probably. Remember, the MCTH has more in common with Vali 2 than Lyr 3.

And secondly, I am also mistaken on the plastic case. It is a metal case that has an odd flat black rough texture powder coat.

 

The ebay LPS hasn't arrived yet. I posted data on 2 SMPS and 3 LPS in a technical measurements thread. When the ebay unit arrives it will receive the same measurements and the thread updated here.

 

The replacement EH 6922 I obtained appeared to cause my mcth to have a higher power on inrush current than the original tube which became noisy after a few tens of hours.. My lab supplies will briefly go into current mode limit at 1.25 A but not at 1.30 A during cold power on.

The AliExpress / ebay LPS will be tested soon. Possibly a low cost alternative.

 

Acopain A28MT300 ordered (off ebay).

 

See this post for some important notes here.

 

Okay, so that looks like what may be happening to my unit then. I'm guessing the stock SMPS is less susceptible to overcurrent than an LPS.

In any case, I feel like an LPS should be chosen with some amount of headroom if tube rolling is a consideration.

 

I tried my MCTH with the genalex gold lion tube. I agree with previous evaluations that it sounds inferior to the included EH tube. Specifically it sounds more congested with a smaller overall soundstage. There is also significantly less treble clarity and "sparkle". Bass is about the same, but the mids also sound a bit muted as well with the gold lion.

I guess this is all a good thing because the EH tube is cheaper.

 

The MCTH has a richness and slight warmth to it's tonality that I find similar to the BW2 and ZDS, though more the former as the ZDS's tone can change on tube preference. The BW2 is a tad smoother, and presents a much more open and enveloping stage. The MCTH sounds more forward, hits less hard, and sounds a touch compressed by comparison. The ZDS just has MOAR of the BW2's superior holographic stage and dynamics. Dynamic contrast is much more apparent on the ZDS, likely assisted by how open the sound is; while the MCTH does decently well, the volume shifts sound on a more narrow plane (confined) with granularity less delineated.

As for clarity, resolve, and plankton... they're close. The BW2's euphony and the ZDS's OTL-ness have a similar richness/sweetness that lend them to be a tad hazed compared to something like my Jot (early build). Yes, veiled or filtered or whatever you want to call it, but like the MCTH, there's a coloration that's shy from being completely transparent. Resolution and plankton are similar, with the EC amps edging out with their better dynamics and staging, lending to more nuanced details.

What's nuts is that this guy is 10X less expensive than a ZDS, and IMHO you probably get roughly 85% of the sound.

 

https://m.bonanza.com/listings/acop...y1p3eOpnlBoH6jgEEr4eR3O8zJsEL-kRoCZSUQAvD_BwE


LPS - no idea how good the vendor is

 

I offered $68 and seller accepted it! Thanks!

 

There are some good Acopian's on eBay. Just sayin'. Search the model numbers - A28MT210 or A28MT300.

 

Here follows some thoughts and impressions of the MCTH relative to the Schiit Vali 2. The playback chain was:

Schiit Gungnir Multibit (Gen 5 USB) → MCTH (EH tube) / Vali 2 (EH tube) → Sennheiser HD650 (stock with balanced cable, bought 2016)

Both amps were fed from Linux using bit perfect FLAC playback from DeaDBeeF and the phase invert trick. No equalization was used.

The MCTH and stock tube were thoroughly burnt in as per the instruction manual. Initially, when I first switched on the MCTH (prior to burn in) it sounded dull and a bit muddy but after a couple of hours it opened up and began to take on its normal character.

The MCTH was tested with its stock tube (Electro Harmonix). For the purpose of this comparison and for scientific fairness, I decided to use the same tube in the Vali 2. After much tube rolling in the Vali 2, the Philips SQ E88CC (Heerlen, Holland) had become my preferred tube and I considered performing the comparison with this tube – but in the end decided against it. The Philips tube is a forward tube in the mids and lessens the Vali 2's laid back nature to some extent. After trying the EH tube in the Vali 2, I found that it was significantly more forward than the Philips and is a very good match for this amp. Anyway, I digress.

For the comparison, I listened to a variety of music, including but not limited to Roxette (“Look Sharp!”), Chris Huelsbeck (“Turrican – Orchestral Selections”), Nick Molyneux (“The Beautiful Suchness of Things”), Various Artists (“Paula, Agnus, Denise”), Rage Against the Machine (“Rage Against the Machine”).

Now the difficult bit. I’m quite split over the MCTH. After becoming used to listening to the Vali 2, it is quite a shock to switch to a more capable amp. The most obvious differences that the MCTH has over the Vali 2 are significantly improved clarity and greater treble extension. The MCTH with EH tube has very obvious sparkle in the treble, high hats (for example) are much more apparent. The MCTH can pull out details in the music that are lost in the mud with the Vali 2. Sometimes, though, this can sound unnatural and less cohesive (but this could be down to the particular music track) – it is as if an instrument is suddenly sticking out on its own. Perhaps these instruments / sounds contain frequencies in the newly revealed treble region.

The Vali 2 is perhaps thicker in the mids and is definitely more forward than the MCTH – but both amps are laid back compared to something like the Jotunheim, which is in your face. The Vali 2 has more body but also more veil compared to the MCTH. I considered the Vali 2 to be a laid back amp until I heard the MCTH.

I am very sensitive to treble and I find the MCTH with EH to have prickly treble. It is quite insidious and can cause me ear fatigue in short order even at low volumes. Albums such as those aforementioned by Roxette and Rage Against the Machine are particularly good examples that show this characteristic.

In an attempt to alleviate the treble difficulties I am experiencing with the MCTH, I have rolled a couple of tubes that I have, a Philips E88CC SQ (Herleen, Holland) and a Valvo E88CC (also Herleen Holland). Both tubes smooth or roll-off the treble and make the MCTH much easier for me to listen to. The Valvo has recessed mids and is quite boring in the Vali 2, but I did notice that it has tight impactful bass when used with the MCTH. The Philips tube (my previous preferred tube in the Vali 2) has great mids in comparison to the Valvo tube, but less bass. Unfortunately, using these tubes in the MCTH causes it to lose clarity and push the soundstage back too far. When listening to orchestral music for example, such as Turrican Orchestral Selections, it sounds like I am sitting in the back row. Even with the EH tube the MCTH is not particularly enveloping, but with the other two tubes it definitely sounds like I am listening to a recording, detached from both the music and the experience. In my opinion, the MCTH (even more so than the Vali 2) needs a forward tube to make it shine.

It is seems apparent that this amp is tuned for a tube such as the EH. For me, it is a shame about the prickly treble, therefore I am searching for a tube that is forward and engaging like the EH tube but without its shortcomings. If I can fix the treble I may keep the MCTH, otherwise I will be hanging onto the Vali 2 for a while longer – I haven’t decided yet. There is something about the Vali 2 that is just more cohesive than the MCTH. The Vali 2 already has rolled off treble, therefore the unfavourable treble characteristics of the EH tube are less apparent than with MCTH – but they are definitely still present even on Vali 2.

The MCTH is undoubtedly a great amp for the price (even taking into account import taxes to the UK) and technically a noticeable step up from the Vali 2 (Although I prefer the Vali 2’s more forward presentation). However, it does exhibit some shortcomings. For example, it exhibits some lack of clarity compared to amps such as the Jotunheim (from memory) and some lack of involvement with the listener (due to being very laid back – but that could be just my preference). There is, however, the potential for improvement with an LPS, but investing in one would bring the cost closer to the Lyr 3 (yet to be released in the UK). Whether this is a worthwhile investment would be dependent on how far the amp can be elevated sonically and more importantly whether the amp’s characteristics are to one’s personal taste.

EDIT: I think the treble discomfort I experience is mostly down to the EH tube, but is exacerbated by the superior treble extension of the MCTH .

 

Hi @Bill-P . Is the Sylvania tube you describe in your post above the JAN military tube, like this one: https://www.ebay.co.uk/itm/6922-JAN-SYLVANIA-NOS-VALVE-TUBE/262740314143 ? I'm looking for a tube similar to the stock EH but without the prickly treble. I've also ordered an A-Frame Philips ECC88 (Herleen Holland), I'm hoping it is the same tube as the Orange Label Amperex.

Don't know yet if I'm going to invest in an LPS for the MCTH, depends on how the tube rolling goes. Also need to understand the floating ground requirement, which may be an issue in the UK with our grounded power plugs / leads.

 

The floating grind just means don't tie the negative DC output to ground. The AC input side of course use the ground.

 

Just hooked up the Acopian LPS to the CTH and starting a session for critical listening. This should be fun.