[newworld666]

I would say XLR4, 4.4mm, 6.35mm should be the more secured and convenient for such a portable and rather heavy item...
I feel DJ44B 2.5mm/4.4mm adapters gets easily broken (I got 2, in less than 1year, of these items broken).
I use XLR4 as my favorite plug (to switch easily to my desktop amp THX 887), but I also sometimes use a 4.4mm to XLR4 .. it's working fine, though it's a bit too long to fit in the pocket.

So 3.5 and 4.4mm on the cool side and the 6.35 and XLR4 on the hot side...

If power could reach 2x3W at 32ohms, it should leave more room for demanding headphones.

I am not sure, but as I read the Cayin C9 thread and as far I can understand why they limit their recommendations to more than 100db and less than 300ohms headphones, it seems that peak voltage/instant power, compatible with batteries abilities, are maybe the most important factor to compete as much as possible with Desktop Amps.

The M8V2 seems to be already rather optimized concerning instant power delivery, though I feel there is still place for some improvements to drive at best HEDDphone, HD800S, or any 600ohms TOTL headphones to deliver faster low and ultra low impacts as a simple THX887 can do. I wonder if there is a tiny way with capacitors to avoid batteries limitations ( I am not competent in electronics at all and just trying to figure it out)

 

[haoyuan]

All, good, thank you! Have you seen a $25 massdrop adapter that you plug into the 4-pin XLR and it gives you a 2.5mm female plug on the other end? Is that any good? If so, then it's a case to ditch the 2.5mm. Pretty clear on the other stuff.

I have and use it on the v2. It’s very convenient.

 

[SDBiotek]

I would say XLR4, 4.4mm, 6.35mm should be the more secured and convenient for such a portable and rather heavy item...
I feel DJ44B 2.5mm/4.4mm adapters gets easily broken (I got 2, in less than 1year, of these items broken).
I use XLR4 as my favorite plug (to switch easily to my desktop amp THX 887), but I also sometimes use a 4.4mm to XLR4 .. it's working fine, though it's a bit too long to fit in the pocket.

So 3.5 and 4.4mm on the cool side and the 6.35 and XLR4 on the hot side...

If power could reach 2x3W at 32ohms, it should leave more room for demanding headphones.

I am not sure, but as I read the Cayin C9 thread and as far I can understand why they limit their recommendations to more than 100db and less than 300ohms headphones, it seems that peak voltage/instant power, compatible with batteries abilities, are maybe the most important factor to compete as much as possible with Desktop Amps.

The M8V2 seems to be already rather optimized concerning instant power delivery, though I feel there is still place for some improvements to drive at best HEDDphone, HD800S, or any 600ohms TOTL headphones to deliver faster low and ultra low impacts as a simple THX887 can do. I wonder if there is a tiny way with capacitors to avoid batteries limitations ( I am not competent in electronics at all and just trying to figure it out)

With any amp, portable or desktop, there's a bit of a trade-off between designing the amp more for delivering current, versus swinging a high voltage. High impedance dynamic driver headphones, such as the Sennheiser HD series, need the amp to be able to provide high voltage, but do not need tons of current. Planar headphones primarily need a lot of current. Iems don't usually need much of either, but it's hard to develop a high power amp circuit that handles all 3, while still having a low enough noise floor for sensitive iems.

There's no way that capacitors can be used in the place of batteries. Capacitors can temporarily store some energy, and you often see banks of them in non-portable amp power supplies, but they are mostly just there to help provide enough power when the speakers are pulling extra "juice" during dynamic peaks in a recording. The caps need a way to be recharged pretty quickly. They are not meant for slow steady power drain like batteries.

 

[newworld666]

With any amp, portable or desktop, there's a bit of a trade-off between designing the amp more for delivering current, versus swinging a high voltage. High impedance dynamic driver headphones, such as the Sennheiser HD series, need the amp to be able to provide high voltage, but do not need tons of current. Planar headphones primarily need a lot of current. Iems don't usually need much of either, but it's hard to develop a high power amp circuit that handles all 3, while still having a low enough noise floor for sensitive iems.

There's no way that capacitors can be used in the place of batteries. Capacitors can temporarily store some energy, and you often see banks of them in non-portable amp power supplies, but they are mostly just there to help provide enough power when the speakers are pulling extra "juice" during dynamic peaks in a recording. The caps need a way to be recharged pretty quickly. They are not meant for slow steady power drain like batteries.

Cayin for their C9 seems to be pointing out that actuek batteries have limited capabilities to deliver instantly a lot of current (depending on also a lot with existing battery internal protections or not).
So they already told me that my HEDDphone (42Ohms 87Db) won't be driven efficiently due to battery limitations by the C9. They include in those limitations even the rather efficient HD800S due to the 300 ohms. Both Headphones will be moved nicely or very nicely, but, we can't expect to reach the level that most of desktop amps will offer with those type of headphones.
I feel rather nice from Cayin dealer/sponsor to be clear before selling us such 2K item, though some bought it and really like the C9 + HD800s results.

 

[HeadphoneAddict]

All, good, thank you! Have you seen a $25 massdrop adapter that you plug into the 4-pin XLR and it gives you a 2.5mm female plug on the other end? Is that any good? If so, then it's a case to ditch the 2.5mm. Pretty clear on the other stuff.

I have that 4-pin to 2.5mm adapter and it works fine with my HD-6XX on the mass drop 2.5mm TRRS cable, with both the M8 V2 and the Cavalli Liquid Carbon. The $40 2.5mm drop cable is not bad either.

With the same cable the HD600 are better on the M8 V2 than the 6XX, more of an issue with headphone/device synergy. I often find the HD-650/6XX to have the upper bass bleed into the lower mids with many amps.

I have yet to try the adapter with any IEM though.

 

[HeadphoneAddict]

I would say XLR4, 4.4mm, 6.35mm should be the more secured and convenient for such a portable and rather heavy item...
I feel DJ44B 2.5mm/4.4mm adapters gets easily broken (I got 2, in less than 1year, of these items broken).
I use XLR4 as my favorite plug (to switch easily to my desktop amp THX 887), but I also sometimes use a 4.4mm to XLR4 .. it's working fine, though it's a bit too long to fit in the pocket.

So 3.5 and 4.4mm on the cool side and the 6.35 and XLR4 on the hot side...

If power could reach 2x3W at 32ohms, it should leave more room for demanding headphones.

I am not sure, but as I read the Cayin C9 thread and as far I can understand why they limit their recommendations to more than 100db and less than 300ohms headphones, it seems that peak voltage/instant power, compatible with batteries abilities, are maybe the most important factor to compete as much as possible with Desktop Amps.

The M8V2 seems to be already rather optimized concerning instant power delivery, though I feel there is still place for some improvements to drive at best HEDDphone, HD800S, or any 600ohms TOTL headphones to deliver faster low and ultra low impacts as a simple THX887 can do. I wonder if there is a tiny way with capacitors to avoid batteries limitations ( I am not competent in electronics at all and just trying to figure it out)

Your idea above is not bad. But I would not want the 4.4mm jack to be only tied to the cold side. Maybe it would be best do not have a hot side and cold side, and just have hi-lo gain settings with a quiet noise-free hot amp? So, maybe “stamina” mode would be shutting of some features and only having low-gain. Although with class A amps I guess you can’t draw less power by lowering the gain and this lowering the power output.

Some of the full-size headphones that I would use with 4.4 mm are those that need higher power with big voltage swing (or strong current), depending on the phones. I would not want to be limited to using those 4.4mm headphones on the cold side only (HD800/800s for example).

Also, many headphones with a 3.5 mm plug also need more power than an IEM, but of course they could be used on the hot side with a 6.5mm adapter.

The Palab M1 mini manages to use a high-power 4.4mm jack that is great with IEM AND rocks with HD-600/6XX, so there is no noise on the IEM (58 yr old ears with tinnitus) and it also has good voltage swing for full size headphones like HD-6XX and HD-600. What the Palab cannot do well is drive HD-800s with authority, nor the HE-6 at all, and it cannot be used with camera connection kit on external battery or via Bluetooth. If people will recall from my previous review, the M8 V2 drives my HD-800 S with the authority of a desktop amp.

PS: how did you break the ddHiFi adapters? I have yet to break one that goes from 2.5mm female to 4.4mm male plug. I only just got my 4.4mm female to 2.5mm plug, so not sure about that yet.

So for me, it’s not opposition to a 4.4 mm instead of 2.5 on the basis of needing an adapter, it’s on the basis of not wanting the 4.4 mm to be low-power cold-side.

 

[mgoodman]

...Maybe it would be best do not have a hot side and cold side, and just have hi-lo gain settings with a quiet noise-free hot amp?

Let's not get ahead of ourselves. Yet

 

[doctorjazz]

Since most iem balanced cables have used 2.5 mm connector, almost alli mine have that connector. But adaptors are acceptable...

 

[Snly84]

As for me..I pretty sure that 2.5 jack is the best for iem because of size and weight. So for the cold side balanced output it is still the most suitable...on pair with unbalanced 3.5.

But on the hot side 4.4 is maybe the better option instead of huge XLR.

So if we go this way the total unit dimensions could be reduced and it is really cool for portability, because it's important for everyday use and use on the go...as for me I take m8.2 with me when I go for a walk listening via BT.

 

[talan7]

Cayin for their C9 seems to be pointing out that actuek batteries have limited capabilities to deliver instantly a lot of current (depending on also a lot with existing battery internal protections or not).
So they already told me that my HEDDphone (42Ohms 87Db) won't be driven efficiently due to battery limitations by the C9. They include in those limitations even the rather efficient HD800S due to the 300 ohms. Both Headphones will be moved nicely or very nicely, but, we can't expect to reach the level that most of desktop amps will offer with those type of headphones.
I feel rather nice from Cayin dealer/sponsor to be clear before selling us such 2K item, though some bought it and really like the C9 + HD800s results.

My IFi signature drives my Heddphone very well. It has more power than most desktop amps

 

[newworld666]

My IFi signature drives my Heddphone very well. It has more power than most desktop amps

It seems to be two different matters .. I would think 2x1.4W is in the "comfortable" sustain power (more or less 10 to 12V) to give a lot of sound volume.
But, for fast clear and powerful "impacts" it seems instant power can largely exceed what any batteries can deliver compared to a desktop amp. And the HEDDphone can be impressive on this point with a proper amp.

The Ifi diablo is still a possibility, though it's a DAC with no BT connection available nor 4.4mm/xlr4 input => so, it doesn't make the Job as I expect it. But probably the most powerful portable amp available today.

 

[cleg]

My video about the reborn of the legend

 

[teleaxefan]

Have been using the new HI-FI M8 v2 now for about a week and super impressed with the improved sound quality, performance and greater soundstage it’s provided. I also own a HI-FI M8 v1 and a DACportable, wasn’t sure how much of an improvement the HI-FI M8 v2 would provide but early listening has shown a night and day difference so it’s been very well worth the upgrade.

The one big problem I seem to have run across is the battery life. It’s suppose to offer 6 hours of use after a full charge where the battery level indicator shows 3 lights, but after less than 3 hours, the battery indicator is down to 1 light. The Meter Brightness indicator is turned all the way down and both the Charge and Stamina switches are turned off so they should not be drawing on the battery. Am just using a set of Bose QC20 IEM’s so nothing too challenging for now. Now one thing, during the 2nd day of using the HI-FI M8 v2, it got quite hot to a point where it was uncomfortable to hold onto it. Since then, it hasn’t gotten as hot during use. Has anyone else experienced this and what battery life is everyone getting?

Also, Mophie has a portable battery unit that provides USB-C Output of 5V/3A.....wonder if it could be used to charge the HI-FI M8 v2....the unit is the one at http://cdn.cnetcontent.com/3f/a6/3fa6bd7b-83f2-45de-9644-907c2c53b650.pdf

 

[HeadphoneAddict]

Have been using the new HI-FI M8 v2 now for about a week and super impressed with the improved sound quality, performance and greater soundstage it’s provided. I also own a HI-FI M8 v1 and a DACportable, wasn’t sure how much of an improvement the HI-FI M8 v2 would provide but early listening has shown a night and day difference so it’s been very well worth the upgrade.

The one big problem I seem to have run across is the battery life. It’s suppose to offer 6 hours of use after a full charge where the battery level indicator shows 3 lights, but after less than 3 hours, the battery indicator is down to 1 light. The Meter Brightness indicator is turned all the way down and both the Charge and Stamina switches are turned off so they should not be drawing on the battery. Am just using a set of Bose QC20 IEM’s so nothing too challenging for now. Now one thing, during the 2nd day of using the HI-FI M8 v2, it got quite hot to a point where it was uncomfortable to hold onto it. Since then, it hasn’t gotten as hot during use. Has anyone else experienced this and what battery life is everyone getting?

Also, Mophie has a portable battery unit that provides USB-C Output of 5V/3A.....wonder if it could be used to charge the HI-FI M8 v2....the unit is the one at http://cdn.cnetcontent.com/3f/a6/3fa6bd7b-83f2-45de-9644-907c2c53b650.pdf

With your IEM you need to turn stamina mode ON, not off. Stamina mode ON makes it last longer, more stamina, by turning off the hot-side high-power amps (and also turns off the LED meters).

You should be able to keep the battery topped off by plugging in the battery pack to the USB charge port on the hot side. The hot side is the one with the four pin XLR and 1/4 inch jack.

By the way, the charge switch simply modifies the front USB data port function, so that it’s data-only, and it will not charge the M8 V2 via that port, which might drain the battery on the phone or device that is feeding data to the M8 V2.

if I recall, battery life should be 6 to 8 hours with stamina mode on, and four hours with stamina mode off, with the hot side amplifiers being turned on. Bluetooth DAC will draw much less power than using the USB DAC (like 30mw vs 120mw or so).

 

[teleaxefan]

With your IEM you need to turn stamina mode ON, not off. Stamina mode ON makes it last longer, more stamina, by turning off the hot-side high-power amps (and also turns off the LED meters).

You should be able to keep the battery topped off by plugging in the battery pack to the USB charge port on the hot side. The hot side is the one with the four pin XLR and 1/4 inch jack.

By the way, the charge switch simply modifies the front USB data port function, so that it’s data-only, and it will not charge the M8 V2 via that port, which might drain the battery on the phone or device that is feeding data to the M8 V2.

if I recall, battery life should be 6 to 8 hours with stamina mode on, and four hours with stamina mode off, with the hot side amplifiers being turned on. Bluetooth DAC will draw much less power than using the USB DAC (like 30mw vs 120mw or so).

Hi, thx for taking the time to respond......you’re absolutely correct on turning Stamina Mode ON so that it turns off the hot-side high-power amps and the LED meters...I’d misread that turning the Stamina Mode OFF would do this!....egads, my bad so thx much for that correction and hope this will provide the expected battery life!

.....and thx for the other info as well on the portable battery pack and Charge switch!