Massdrop Cavalli Tube Hybrid Amp

I have my MCTH running off Pre Outs from a Marantz SR7400 with Sound Direct on, and I’m quite happy with it so far.

I disable speaker sets A/B, set it to 0db, then control volume at the MCTH. Just be sure you lower the volume before you start the speakers up again!

learned that one the hard way...

Edit: oh, you mean the other way around... off to grab more coffee...

Since I made the post, is there any reasons to not have 2 sets plugged in at once? Last night I had the HD800S plugged in with the XLR, and TH-X00s via the 1/4 jack. There was a moderate volume difference, but it was handy to compare the two. The amp never clicked off from overcurrent or anything, but just want to be sure.

 

@Nathan (Darkmatter35) , @dBel84 is intimately familiar with the MCTH and is being commendably cautious, but my experience doing exactly the opposite of his recommendation jives with what the last two posters have said. Leaving the MCTH volume knob at 1 o'clock (unity gain according to measurement maestro @atomicbob farther back in this thread) and the volume knob of my integrated (which controls its variable pre-outs) at normal listening level for my speakers, there's no click through the speakers when I switch on the MCTH.

Re. sound quality with (my) pre-outs in the chain vs not, I didn't notice a difference but my initial comparison was a quick one and I'm far from being the best ears here. I posted suggesting an integrated with pre-outs in response to your question in the all-purpose advice thread just before seeing your post here. The Rogue looks interesting. You could also consider the Emotiva TA-100; I don't know that model, but the brand seems to be viewed favourably in terms of quality and value for money.

 

sorry - my screen had not updated newer posts - experience with trying this is what matters most.

..dB

 

Clarification: I wasn't meaning to dismiss your recommendation - just to say that (for me) doing it the opposite way hasn't led to disaster.

I see also that I misquoted @atomicbob : MCTH unity gain is 1:30, not 1:00 (see this post).

 

You guys are talking about putting the MCTH in front of the rest of your system, using it's headphone out as a source for the pre/integrated amp, right? Above discussion is confoosing

I don't hear any pop on power up, but a significant one on power down. I wouldn't want going out to a power amp and speakers and would power down or turn volume down accordingly.

If I've totally misunderstood, please ignore.

 

No sorry. We are talking about the MCTH at the end of the system, behind a preamp.

 

Since Massdrop seems unable to replace the EH tubes that break, I am looking at getting another online.

Is there a difference between the standard Electro Harmonix 6299 tube or the gold Electro Harmonix 6922 tube?

Should I just get the regular and be done with it? or would gold be slightly better?

 

Bill-P recommended Amperex A frame 6922 with orange print. My experience has confirmed that the Ameprex tubes are superior in many ways. Definitely worth a try, especially if you can find one under $20.

https://www.ebay.com/sch/i.html?_fr...+6922.TRS0&_nkw=Amperex+A+frame+6922&_sacat=0

 

My orange amperex a frame is my favorite, bugle boy was a close second followed by the stock EH and then a seimens (didn't like it at all in the MCTH).

 

Just go for the regular. No real advantage to gold plating.

 

Anyone plan to mod capacitors?

 

Wait until they explode before upgrading.

 

Funny you say that, got a knock on the door right after posting, an Amperex 'Bugle Boy' 6DJ8 came in. Running it through it's paces now. So far i'm a fan. Just as expansive as the RCA 6ES8 that I was using, but without the ridiculous noise floor and neutered bass. Probably a touch less treble extension but with the HD880S i'm ok with that. It's quite laid back and relaxing.

Might just stick with this, who knows.

 

Another LPS adventure, this time with a c. $70 open-frame industrial unit:

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

My ebay source still shows 5 available at $37.99:

https://www.ebay.com/itm/302559328492

Chateau Degraded hosts no pets or children, but to protect the sensitive electronics from the clumsy sausage-fingers of curious drunken houseguests (and vice-versa, I suppose), the unit was screwed to 3/4" wooden rails and dropped into a vented box to which a switched, fused socket and rubber feet were mounted:



The finished unit, c. 8" x 6" x 4", doesn't look too offensive in my equipment rack. The amount of venting is possibly overkill as it doesn't run particularly warm, but better more air than too little.

Sound (between Modi Multibit and stock HD6XX):

Given previous reports, I'm not sure what I can say that won't make this read like reinforcement syndrome/expectation bias. Regarding bass, I'd noticed an apparent decrease in level but improvement in tightness during tube burn-in. The LPS adds to the tightness and brings back the power, so that both amplitude and quality are improved (by quality I think I mean attack from bass guitar and slam from bass drums; hopefully not massacring the terminology).

I was surprised by the increase in microdetail (maybe also microdynamics), manifested mostly in the treble but also in the upper mids. This seems like it might result from the removal of noise - but noise which I don't notice is there when switching back to the SMPS. It's a bit like the removal of treble hash I hear when switching from the D-S DAC of my old CD player to CDT->Modi Multibit, but more subtle, and leads to the impression of better imaging and staging. There's also a reduction in sibilance in troublesome recordings.

Reading back in the thread I see others have described the effects as profound. Not sure I'd go that far, but I'm sure what's 'noticeable' to me would be more evident to many others. Anyway, definitely a worthwhile upgrade for the price.

A second unit will be released to @msommers as soon as he's signed the waiver

 

Just saw this thread... It appears @atomicbob states the Acopian Gold Infinity is the best of the acopian line if I caught that correctly. I had already purchased an A48MT120 w/over voltage protection for a Garage1217 Polaris. Some of the specs are https://www.acopian.com/inc/streamFile.asp?loc=info&id=AcopianCatGoldBoxLinear.pdf and https://www.acopian.com/store/9-(7).aspx?min=36&max=70 Is the Infinity a lot better than the Gold A series I already have? Or are they about the same? Thanks for your input!

 

Judging by the spec sheets, the Acopian Infinity series looks to be more configurable, and specs are only slightly better..

Regulation

• Infinity: +/- 3mV
• Gold Box A: +/- 14mV (based on 0.005% on 28V)

Ripple

• Infinity: +/- 0.25mV RMS
• Gold Box A: +/- 0.25 RMS

So maybe slightly better regulation, but as good as the Gold Box A, I would not think there would be a huge difference.

 

Looks like the Gold Box A doesn't have the wide output adjustment (voltage and current adjustment from zero to full rating), whereas that is available as an option on the Inifinity series. So the A48 will be good for your Polaris but not for example for the 28V MCTH.

 

Ok, at $46 shipped this is in "screw it, i'll give it a shot" territory. Now, how much modification is needed to actually use this thing? From the photos it seems you wired a socket and then just have the output running out of the box? Do you have some specifics on the wiring needed for the input socket and output plug (and what size that barrel plug is)?

I'm wondering if I can cram this into a smaller enclosure and make it look a bit more presentable.

Edit: Just found the schematics on the GALCO site, so do we need to add a resistor somewhere for this or was that specific to other LPS mentioned earlier in the thread?

 

The resistor was only for testing noise, not for operation.

It is suggested using an inline fuse with the hot side of the power (so you don't burn your house down). A 1.5 amp will do.

Check this thread for more info on LPS's and follow atomicbob's suggestions.

 

Went through the spec sheet again. Sure the infinity has slightly better specs. Not sure that I could here those differences, but my concern would be the built-in fan... Nonetheless, I created a power cord with a ceramic fuse, and wired up the 2.1mm x 5.5mm power connector. Then I adjusted the voltage on the unit so that it provided exactly 48.0V via my test equipment, and I gave it a shot. I was fully expecting to hear no difference. I know that I did some cable testing years ago with silver vs copper that were at least to my ears no difference that I could discern. Nonetheless, the difference is subtle but detectable. It just seems smoother with less noise. I'm not sure how to describe it exactly... Nonetheless, it was kind of a crazy experiment since after getting the power supply, cables, fuse, and plugs I'm probably out roughly $400 for a $250 amp. Oh well, it's a crazy hobby. Nonetheless, I highly recommend it, but I could see someone enjoying the amp as is depending on how particular you are or how good your hearing is.