[Zachik]

Not sure about your Cavalli, but the instructions I got with mine say,
"If you do employ break-in, we recommend about 100 hours playing in continuous music mode WITH NO HEADPHONES and the volume set to about 10 o'clock. ..After break-in period, the amp should only need 10 minutes to stabilize operation. After about 100 hours. it is not recommended to keep the amplifier on constantly. "
Of course, if you have new headphones that need to be broken in, why not just attach them and leave your music player on repeat.

I did have this note attached, too. Since the NO HEADPHONES made no sense - I just ignored it... figured no harm doing 2 burn-ins at the same time...
That was also based on feedback from others on OTHER tube amps, where doing so WITH headphones supposedly pose no danger / problem.

If the follow the instructions it will burn in quicker cause of the higher 10 o'clock volume will burn the inpurities in the tube faster. You could do either but the Headphone connected techically should be slower. I did both. I also did a hour at 2 o'clock with no headphone. 16 hours at 10 oclock. And few nights with headphone connected. I would recommend at least a few hours at higher operational output closer to 10 to 12 with no headphone and with music playing.

The 10 o'clock was not an issue - the headphones I burned in needed almost 11 o'clock before it started sounding too loud for me. So I figured if the only reason for NO HEADPHONES was volume-too-high, then it was a non-issue for MY headphones (HD600, BTW).

 

[franz12]

Odd. I have written earlier in this thread about my love of the volume pot on this amp, how smooth it is, and the lack of audible noise when changing volume. You have a peculiar problem indeed.

It turns out that this unit was faulty and it was idiosyncratic. Massdrop was very responsive and they immediately replaced my unit. Their customer service is top notch.
After comparing two units, it seems to me that this issue has gone. But to make sure, I will burn in it for hours.

 

[jeffrt]

I did have this note attached, too. Since the NO HEADPHONES made no sense - I just ignored it... figured no harm doing 2 burn-ins at the same time...
That was also based on feedback from others on OTHER tube amps, where doing so WITH headphones supposedly pose no danger / problem.


The 10 o'clock was not an issue - the headphones I burned in needed almost 11 o'clock before it started sounding too loud for me. So I figured if the only reason for NO HEADPHONES was volume-too-high, then it was a non-issue for MY headphones (HD600, BTW).

Unless the manufacturer's instructions prove to be wrong, I tend to follow them, as who should know better.

As for the volume, I'd assume there'd be little difference with 10 o'clock vs 11 o'clock IF headphones were attached. Since they recommend no headphones, wouldn't you think that 10 o'clock was the safest condition?

 

[UNOE]

Interesting experiment. Thank you.

Currently doing a "burn" of both amp and phones and new cable, all at the same time. Don't want to put the volume control higher than I can listen to safely, for fear of harming the headphone drivers. I prefer to let it go longer at safe levels, rather than suffer potential harm for the sake of lessened times.

I was saying high volume without headphone connected (like the instructions mention). I would never use anything that high with my low impedance cans, I have nothing over 30 ohms. (I imagine HD 650 are at 10 o' clock at normal listening with this amp). Most the break is with the tube. I higher temperature on the tube even for short time should be faster.

That sounds like some really good advice BTW did the

I listened to the first day with the amp after about 2 hours break in for about 4 hours. Then broke it in with 16 hours with no headphone overnight next day was quite a bit better. I was thinking I would have to sell it first day. I never heard any amp that changed that much. Jude review he mentions break in too.

I PM someone last week that had the amp listed for sale. The description mentioned 5 hours of use. On my PM I said why not let it break in before selling it. He wrote back to thank me he was so pleased of the difference.

 

[runeight]

Hey folks, I posted my experiences with burn quite a while back. I have serial #1, so same production piece as what you all have.

1. Sounds decent out of the box, but not spectacular.
2. Begins to lose its new amp sound about 25 hours.
3. Cleans up pretty well at 50-100 hours and takes on its real character.
4. Slowly changes between 100-200 hours, but not a lot, assuming you've left the same tube in all this time.

I don't think it's really necessary to do a prolonged burn in session. In my case I just let it run for a day and then let it burn in while I listened to music. It was an interesting process to hear the changes.

When I was making the bigger amps, nothing was shipped until at least 50 hours burn in at the assembly shop. For the electrostatic amps, we waited 100 hours.

 

[Stabby]

Another question for the HD650 owners: does the CTH completely get rid of the veil?

Hey folks, I posted my experiences with burn quite a while back. I have serial #1, so same production piece as what you all have.

1. Sounds decent out of the box, but not spectacular.
2. Begins to lose its new amp sound about 25 hours.
3. Cleans up pretty well at 50-100 hours and takes on its real character.
4. Slowly changes between 100-200 hours, but not a lot, assuming you've left the same tube in all this time.

I don't think it's really necessary to do a prolonged burn in session. In my case I just let it run for a day and then let it burn in while I listened to music. It was an interesting process to hear the changes.

When I was making the bigger amps, nothing was shipped until at least 50 hours burn in at the assembly shop. For the electrostatic amps, we waited 100 hours.

This makes me wonder how hard it must be to design if it takes 100 hours before you can judge the results.

I was using some Havi B3 pro's with the MCTH the other day, sounded good but they are 32ohm, was a bit of noise floor. I'll grab my wife's momentum's (over-ear) and give 'em a try. Let ya know how it goes!

Back: Sounds fantastic, haven't listened to the Momentum in a long while, the dynamics of this amp is simple eye-popping. The momentum's just sung!

Did you test the Momentum 2.0 over ears? Since you also have the HD650, would you mind if I ask how it compares to the Momentum in sound signature, both in general and on the CTH? Sorry if this is too off-topic, but I haven't been able to find out by asking in the relevant threads.

 

[Zachik]

Hey folks, I posted my experiences with burn quite a while back. I have serial #1, so same production piece as what you all have.

1. Sounds decent out of the box, but not spectacular.
2. Begins to lose its new amp sound about 25 hours.
3. Cleans up pretty well at 50-100 hours and takes on its real character.
4. Slowly changes between 100-200 hours, but not a lot, assuming you've left the same tube in all this time.

I don't think it's really necessary to do a prolonged burn in session. In my case I just let it run for a day and then let it burn in while I listened to music. It was an interesting process to hear the changes.

When I was making the bigger amps, nothing was shipped until at least 50 hours burn in at the assembly shop. For the electrostatic amps, we waited 100 hours.

Alex - can you please shed some light on burn-in with vs. without headphones connected?
I personally used HD600 burning in at the same time, volume at approx. 10 o'clock (as recommended)...

 

[Bazirker]

It turns out that this unit was faulty and it was idiosyncratic. Massdrop was very responsive and they immediately replaced my unit. Their customer service is top notch.
After comparing two units, it seems to me that this issue has gone. But to make sure, I will burn in it for hours.

Glad to hear you got it worked out. My volume pot continues to be squeaky clean.

Another question for the HD650 owners: does the CTH completely get rid of the veil?

This makes me wonder how hard it must be to design if it takes 100 hours before you can judge the results.

Some HD 650 owners don't believe there is a veil in the first place FWIW I don't hear a veil, but YMMV.

Also, interesting question about the design! I wonder how much of it has to do with the tube?

 

[ab_ba]

It's great to see this is dropping again. For $250, I can highly recommend it. It's a pretty no-frills device - they clearly put the effort into the sound quality. I found the sound to be clear, detailed, and smooth. There is good texture to sustained notes. Instrument separation is good. Background is very black - palpable silence between notes and tracks. Sound is what you might expect from a much more expensive amp. (I'm listening with Focal Utopias, and a Violectric V800 DAC.) Drawbacks? At very low volumes, the channel balance is poor. At high volumes, things lose control, and the sound gets a little shrieky. The looks and build quality are not stunning, but at this price-point, you're not looking for visual aesthetics. Overall, I'd say this is a teriffic second amp, like for work, or for somebody who wants a great budget-conscious rig.

Also, the CTH has made me a "believer" in burn-in. it really sounded bad straight out of the box, but after a week of playing continually (volume knob set to ten o'clock, no headphones connected) the sound became open, full, and natural.

 

[UNOE]

Hey folks, I posted my experiences with burn quite a while back. I have serial #1, so same production piece as what you all have.

1. Sounds decent out of the box, but not spectacular.
2. Begins to lose its new amp sound about 25 hours.
3. Cleans up pretty well at 50-100 hours and takes on its real character.
4. Slowly changes between 100-200 hours, but not a lot, assuming you've left the same tube in all this time.

I don't think it's really necessary to do a prolonged burn in session. In my case I just let it run for a day and then let it burn in while I listened to music. It was an interesting process to hear the changes.

When I was making the bigger amps, nothing was shipped until at least 50 hours burn in at the assembly shop. For the electrostatic amps, we waited 100 hours.

I was already sespecting part of the reason there so much difference in break in for this amp was it's not ran before it ships like alot of amps from other manufactures that run break in before shipping.

 

[Stabby]

ad to hear you got it worked out. My volume pot continues to be squeaky clean.
Some HD 650 owners don't believe there is a veil in the first place FWIW I don't hear a veil, but YMMV.

It's subtle. I mostly notice the veil in live recordings and classical. There's a little something missing to make me feel like I'm there.

 

[runeight]

Alex - can you please shed some light on burn-in with vs. without headphones connected?
I personally used HD600 burning in at the same time, volume at approx. 10 o'clock (as recommended)...

It has a lot to do with the particular topology of the amp. In this case a capacitor coupled tube hybrid with a tube front end and a solid state power buffer for the output.

When you are playing music though the amp, regardless of headphones or no headphones, the tube stage is exercised exactly the same because it is not connected to the output and is always looking at a very high impedance load. And the tube is what really needs the first 50 or so hours of burn in. Thus, either type of burn in does the job for the tube no matter how long you burn in so long as you are feeding signal into the amp.

So, music or not, the first 50 hours (or any number of hours) burn the tube in the same.

The SS buffer needs some burn in too and this happens better, MHO, when there is a load at the output because this causes the amp to actually deliver current from the output devices. My experiences are that there is less of an effect of SS burn in, but it is still easily noticeable, especially in a pure SS amp where the tube burn in does not swamp the SS burn in.

Because of the hybrid topology, there are two burn-ins taking place, one more noticeable than the other. This is why, I believe, you all are hearing lots of changes in the first 10-50 hours (the tube) and slower changes after that as both the tube and SS settle in further.

Beyond 100 hours, neither element of the amp changes a whole lot, but some, hence the more gradual change in the sound until it really doesn't change again (in a normal aging process) until the tube begins to fail.

In case of my larger amps, the Liquid Glass (capacitor coupled tube hybrid) and the Liquid Gold (pure SS) did indeed have different burn in characteristics though they both settled in somewhere between 100 and 200 hours (at least for me).

 

[Zachik]

It has a lot to do with the particular topology of the amp. In this case a capacitor coupled tube hybrid with a tube front end and a solid state power buffer for the output.

When you are playing music though the amp, regardless of headphones or no headphones, the tube stage is exercised exactly the same because it is not connected to the output and is always looking at a very high impedance load. And the tube is what really needs the first 50 or so hours of burn in. Thus, either type of burn in does the job for the tube no matter how long you burn in so long as you are feeding signal into the amp.

So, music or not, the first 50 hours (or any number of hours) burn the tube in the same.

The SS buffer needs some burn in too and this happens better, MHO, when there is a load at the output because this causes the amp to actually deliver current from the output devices. My experiences are that there is less of an effect of SS burn in, but it is still easily noticeable, especially in a pure SS amp where the tube burn in does not swamp the SS burn in.

Because of the hybrid topology, there are two burn-ins taking place, one more noticeable than the other. This is why, I believe, you all are hearing lots of changes in the first 10-50 hours (the tube) and slower changes after that as both the tube and SS settle in further.

Beyond 100 hours, neither element of the amp changes a whole lot, but some, hence the more gradual change in the sound until it really doesn't change again (in a normal aging process) until the tube begins to fail.

In case of my larger amps, the Liquid Glass (capacitor coupled tube hybrid) and the Liquid Gold (pure SS) did indeed have different burn in characteristics though they both settled in somewhere between 100 and 200 hours (at least for me).

Alex - thanks for the VERY elaborate and educational explanation!
So... when you write that burn in for the SS part works better when there is load at the output - does that happen WITH or WITHOUT headphones connected to the amp?
If the load is there WITH headphones - doesn't it contradict the recommendation (included in the box) to burn in without headphones?!

 

[runeight]

The headphones are the load. The SS burns in better with headphones, but.....

Since the SS burn in is not as significant as the tube, the SS will burn in naturally as you listen after the first 50 or so hours (and the SS will burn in before that too, the load just helps it along a bit). Hence, MHO, no real need to have headphones for a forced burn in.

I wrote that part of the manual and this assumes that you are not doing a marathon burn in session. I've mentioned before that I don't think this is necessary. The main thing is to clean up the tube and the rest will naturally follow. Plus, I kind of like to hear the burn in process so my preference is to get past the early stage and the listen in to hear what's happening.

 

[jrhill]

Perhaps Alex, you could design a better power supply (or a non-switch-mode unit) for this amp that Massdrop could issue as an aftermarket addition for the different world's mains power voltages- the 'wall-wart' unit that comes with the amp does work okay, sure, but a better supply brings out a far better performance that far exceeds the humble price, even with the issued AH 6922 tube

Congratulations on another very successful headamp design