The Centrance HiFi M8 thread - Page 7

4pin for me

I would love to have 4pin too.
 

Hi Michael,

 

I have read this thread twice, as well as your development blog , sorry if my questions have already been asked/answered already ..

.....or if they are just newby.

 

1)   Is the M8 a fully balanced DAC/AMP ?  

 

Some manufacturers just add XLR connectors, even if the AMP is not balanced.

 

 

2)   Will the Dual XLR from the CEntrance HiFi M8 provide better sound than if I used a HP cable with 1/4 jack connection (or 4pin XLR) ?

 

With the above two questions I am trying to understand if there is sonic benefits above my existing DacMini CX.

My DacMini CX has only a 1/4 " jack.

My experience with my speaker HiFi when I moved from unbalanced RCA to balanced XLR connections was a significant improvement (noise floor dropped and sound staging significantly improved).

I am wondering if I would get a similar improvement by using balanced XLR headphone connections that are available with the HiFi M8.

 

 

3)   I currently run a DacMini CX with an external battery (Energizer XP18000, gives me about 18 hours on a single charge). As I already have a great CEntrance product running off a battery,   apart from the M8 being more portable, should I expect further sound improvements?   I know this is a bit of an open question.

 

 

4)   Hifi M8 power output ?  I believe my DacMini CX (and the Dacport I had before it), output 1.5 watts. Is the M8 same or better ?

 

 

5)   Will the HiFi M8 have any improvements to the Class A AMP section above those that are in my DacMini CX (or previous Dacport) ?

 

 

6)   Believe this is the first CEntrance product with asynchronous 24/192.  Does this still allow your Jitter guard technology to work ?

 

 

Also, you mentioned in your blog that an optical Toslink input is a possibility. I would like that as it eliminates any ground connections (plus a great glass  optical Toslink cable is inexpensive  .... compared to good USB or Digital Coax cables).

 

John

Please indicate your preference of connector type here: https://docs.google.com/spreadsheet/viewform?formkey=dEhTaWI4TzlCM0VEM2xveklCcFBCUGc6MQ

One question, what is a Lemo 4 pin? Are there any headphones or amps using this connector now?

Edited by mgoodman - 9/29/12 at 8:44pm

What would happen if I tried to connect my balanced studio monitors to the XLR outs? Explosion? 

Compatibility - yes, explosion - no. Sorry to disappoint :)

 

In fact, that's a great application. The only issue is that you would need special XLR cables (Male/Male XLRs). Typically XLR cables are Male on one side and Female on the other.

The other issue is that M8 might have a touch more output level than some monitors are comfortable with. In this case, you may need to dial down the output level on the HiFi-M8.

 Would it be possible to have a switch that would set the outputs at line level? I expect this probably isn't possible because of space limitations though.

Michael,

 

In the HiFi-M8 blog's "27 Sep" entry, the following statement can be found:

 

 

That's awesome!  I've been using both the Meier Corda Stepdance and the iBasso PB2 Pelican amps with a 5-cell LiPo Energizer XP8000 external battery pack, in combination with inline voltage regulator cables (the XPAL WI15 and WI16) so that I can maximize the audio performance of these amps (at their respective maximum supply voltages) while trying to remain "portable."  

 

The original Meier Stepdance was chastised for the short play time offered by its internal 9V battery, so Jan Meier answered the complaint by replacing the OPA1611 op-amps of the Stepdance with more battery-conserving OPA209 in its successor, the 2Stepdance.  (Datasheets reveal, however, that the OPA1611 offers lower THD+N and a faster slew rate than the OPA209).  People complained about battery life, so he gave them what they wanted, in addition to making the case flatter for stacking, as well as smaller, and offering an external gain-control switch - again responding to the market's wishes.  I've never compared the Stepdance to the 2Stepdance, but people say it sounds every bit as good as its OPA1611 predecessor. As always, YMMV depending on your choice of source and headphones, so I remain curious as to the impact of going to OPA209 in the 2Stepdance.  The punch line here is that, I would personally prefer a really beefy battery with better SQ to a really long-lasting battery with compromised SQ.

 

In hard-to-find comparisons of iBasso PB2 Pelican performance vs. Ray Samuel's SR-71B, it goes unnoticed and unmentioned that the SR-71B has a four-cell internal LiPo battery, delivering 16.8V on a full charge vs. the iBasso PB2's three-cell internal LiPo battery, which delivers only 12.6V on a full charge.  Just looking at the their internal batteries alone, it seems that a PB2 cannot compete with an SR-71B when self-powered (on the internal battery). 

 

The Triad Audio L3 uses two 9V batteries internally, but owners wanting to unleash its potential end up buying the Triad Audio LLP external battery pack, with switchable output of 24V or 30V - all to improve performance while remaining portable.  The L3 will actually accept external voltages as high as 32V, but piddles along at 18V or less when using the internal 9V batteries - with reduced dynamics and everything else that's lost with a reduction in Watts RMS out.

 

In recent e-mail exchanges with David McKrell (at CEntrance), he has confirmed that my recently purchased DACmini CX can accept any external voltage ranging from 9V to 19V, without concern for the supply voltage impacting sound quality.  Indeed, I am unable to hear any difference in dynamics or bass extension, for example, when powering the DACmini with 9V, 15V, 16V, or 19V external 3-amp power supplies.  For "portable" use, or at least, when using the DACmini CX without access to an AC outlet, I've settled on using it with the 5-cell Energizer XP8000 LiPo pack and a 15V inline voltage regulator cable.  I selected the XPAL WI15 cable because the 5-cell XP8000 pack will discharge to its minimum 3.0V per cell (from 4.2V when fully charged) at an output voltage that perfectly matches the 15V input requirement of the WI15 voltage regulator.  In other words, by choosing the XPAL WI15 regulator cable, I am deep-cycling the XP8000 battery pack instead of shallow-cycling it (as would be the case if I used the 19V regulator cable, instead) - obtaining the maximum possible play time from the XP8000 between charge cycles.   This would not be possible, but for the very sophisticated power supply design of the DACmini CX, that maintains a constant swing voltage at the rails, independent of supply voltage.

 

All that said, believe it or not, I have some very relevant questions regarding the HiFi-M8.  

 

1)  Will the HiFi-M8 incorporate technology similar to that of the DACmini CX to ensure a constant swing voltage at the rails, independent of internal battery state of charge or external PSU voltage?   

 

2)  What is the fully charged voltage and mAh rating of the HiFi-M8's internal battery pack?

 

Here's hoping that much of the HiFi-M8 case is filled with at least a five-cell LiPo battery or, better still, that the voltage at the rails does not decrease with battery state of charge - which would be a first in portable amps, to my knowledge.

 

The DACport, DACport LX, DACmini CX, and DACmini PX have already established CEntrance as the KING of sophisticated internal power management, so I'm expecting to hear great things about the HiFi-M8's capabilities in this regard.  Bring on the really beefy batteries and smart power management!   I want the HiFi-M8 to deliver its maximum performance all the time, with all power sources, internal or external battery, or plugged into an AC outlet - just like my DACmini CX!

 

Thanks!

 

Mike 

Edited by zilch0md - 9/30/12 at 6:56pm

Q1:  Will the HiFi-M8 incorporate technology similar to that of the DACmini CX to ensure a constant swing voltage at the rails, independent of internal battery state of charge or external PSU voltage?

A: Yes, that's exactly what we are doing. We will regulate and ramp the battery up to proper voltages for the analog circuitry. The voltages at the analog circuitry will remain high until the battery runs down and shuts off. As the battery discharges, there will be no degradation of SQ. Your smartphone behaves the same way. The battery voltage doesn't affect phone's performance, until the battery is so low that the phone decides it's time to shut off -- but it performs the same way all the way up until shut off.

 

Q2:  What is the fully charged voltage and mAh rating of the HiFi-M8's internal battery pack?

Based on the explanation above, I would have a slight concern with comparing products on the basis of battery voltages. Saying: "Product A has a 19V battery, while Product B has a 4.2V battery, therefore, product A is clearly superior" is incorrect. The voltage of the internal battery doesn't determine sound quality. It doesn't determine useful battery life either. What's important is what's done to the battery voltage inside the unit. As we've demonstrated with our other products (thank you for pointing this out) we can take 5V off USB in DACport and ramp that up to +/-9V for the analog circuitry. In this case the original 5V becomes irrelevant, because the audio circuitry doesn't see it. It sees +/-9V instead. Similarly, with DACmini, we completely decouple the input voltage (9...19V) from the +/-15V which is seen by the analog circuitry. Sophisticated feedback design and optical isolation are used to make the output voltage fully disconnected from the input voltage. Input voltage becomes irrelevant to sound quality and that's what you saw in your experiments with DACmini.

 

What we need to publish is not the internal "kitchen" of various voltages running around inside the unit (there may be a dozen in HiFi-M8, which would be very confusing), but rather simple specs of how many hours the unit runs on a fresh battery charge and what the output power is going to be (we will publish those specs once they are firmed up.)

 

Then, you will be able to compare Product A with Product B on the basis of objective parameters:

1) How long does it run on a full charge? 2) What headphones can it drive?

 

Q: Here's hoping ... that the voltage at the rails does not decrease with battery state of charge - which would be a first in portable amps, to my knowledge.

A: Yes, that's what we have.

 

Q: I want the HiFi-M8 to deliver its maximum performance all the time, with all power sources, internal or external battery, or plugged into an AC outlet - just like my DACmini CX!

A: Again, that's exactly what we have done and frankly, we wouldn't want to have it any other way. The thought of sound quality changing based on what is currently powering the unit sends shivers down my spine... That's unprofessional. :)

Edited by mgoodman - 9/30/12 at 11:34pm

Michael,

This is wonderful news! I had only asked my 2nd question as a contingency should your answer to the 1st question not be what I had hoped. Given your response to that 1st question, the second question is almost moot.

I'm absolutely thrilled that CEntrance will be carrying the DACmini's "constant supply voltage" technology (for lack of a better term) into the HiFi-M8! This thing's going to be killer!

Thanks for a dream come true! This means no more toting external battery packs and voltage regulators just to maintain best possible performance while "portable."

It's sounding more and more like a portable, balanced DACmini CX, every day, with switchable gain, output impedance, and tone control, no less. I'm very, very impressed!

Mike

I need to say that it will be hard to fight a beefy external battery. It will always win, by definition. There is only so much space inside our unit... :)

But we will do our best to help you leave that beefy battery at home.

Concerning the battery, how easy is it to user-replace? I like good gadgets that last forever, and being able to replace the battery without shipping the unit back to CEntrance will be a bonus.

Edited by eron - 10/1/12 at 5:57am

I would be extremely interested in a true line out option on this letting me send the signal to my home amp and using the internal amp for my portable. Is it a possibility? Even a single ended line out plus a single ended headphone out would be great for me.
Edited by mitsu763 - 10/1/12 at 6:47am