[alxw0w]

That's not what I meant.
DAVE's smpt was designed to receive an AC current.
Instead it receives a DC current, which is something it was not designed to do (as far as I know).
Why is that apparent mismatch OK in practice?

Actually SMPS are capable of working on DC power, hence you can connect Dave direct to DC power source.

 

[LucyWu]

Good to read that my suggestion to run Dave's original SMPS on DC has this result

Im still hesitating to build the same or ditch the SMPS and feed +5, +15 and -15 vdc direct off batteries.

My opinion is still that the 0.5A max on -15v limits the dynamics.. i heard Farad's effect on the low freqs cause of more reserve in supercaps

In my experience (using shunt regulators where I can set the total current available from the output rails at + and - 15v) Dave does not draw anywhere near half an amp on either rail. My one caveat to this statement is that I haven't tried with a heavy load on the headphone output. (I use RCA outs only.)

Batteries generally do not offer the lowest noise, nor the lowest output impedance at any frequency. Lithium polymer packs with many cells in parallel can improve this but you would need to spend a lot of time matching cells and ensure all soldered joints have identical characteristics (otherwise you end up drawing more current from some of the cells and balanced charging becomes critical). And more cells means more noise. And you still have to regulate the voltage - it's a lot of work. If you are trying to get only the benefit of isolation from the mains, it may be worth it (but it's been tried and found to lack the ultimate performance of a high performance regulated mains supply (Sean Jacob's DC4/ARC6 - there was a write up over on AS as I recall).

 

[LucyWu]

Actually SMPS are capable of working on DC power, hence you can connect Dave direct to DC power source.

So you achieve galvanic isolation but still have the smps. Win one, lose one?

 

[alxw0w]

So you achieve glavanic isolation but still have the smps. Win one, lose one?

I wouldn't call it win one lose one.
As we can read from @stemiki impressions effect was rather very positive.

Another question is whatever it is better to have DC battery powering stock Dave SMPS or it's better to use something like farad3/Sean Jacobs dc4 - that's something I cannot and probably nobody can answer without direct comparisons.

 

[Reactcore]

Dave does not draw anywhere near half an amp on either rail. My one caveat to this statement is that I haven't tried with a heavy load on the headphone output. (I use RCA outs only.)

Its not about drawing the max current..
but about the voltage being more steady and not fluctuating with the music output.. even a variation of micro volts can be noticable.. its a form of noise modulation.

 

[Triode User]

The benefit is not having a switching ac converter in the battery pack.
So cleanest power possible.

But one still has a switch mode power supply within the Dave and bearing in mind that when I tried an experiment to locate that in an external case it gave an improvement so my guess is that feeding external DC to the Dave is not an all healing magic bullet.

Another question is whatever it is better to have DC battery powering stock Dave SMPS or it's better to use something like farad3/Sean Jacobs dc4 - that's something I cannot and probably nobody can answer without direct comparisons.

Agreed, only direct comparison is valid. Audio memory is too fickle. Recently I have been trying a 'stock' DC4/ARC6 powering the Dave compared to the same power supply but with something special loaned to me by SJ to try and added inside the Dave. I had to borrow a second Dave from a friend so we could compare side by side due to otherwise having a delay whilst the innards were changed. (The 'something special' made me realise that almost everything can be subtly improved, even the DC4/ARC6. Unfortunately I had to agree with SJ not to spill the beans until his embargo expires on Mon 3rd Oct so I will post a piccy then but just lets say that I bought it and will not be sending it back!).

 

[Reactcore]

But one still has a switch mode power supply within the Dave and bearing in mind that when I tried an experiment to locate that in an external case it gave an improvement

I was planning to try that too once.. place the smps outside Dave. But then with supercaps added in that separate box.

So the advantage of SMPS native RF filtering combined with low Z current reserve

 

[stemiki]

As for these latest posts on using lithium battery for DAVE, i would like to make some considerations.

It all started after reading a few months ago that the internal SMPS would accept DC current.

I therefore decided to deepen this discourse trying to understand if it was possible to make a battery with these characteristics for this purpose.

As I proceeded with the research, I realized that it was quite complex.
I had emailed many companies specializing in the sector, but all of them gave me negative results, except one.

Perhaps because the owner is also passionate about Hi Fi, he decided to help me in this realization.

The realization of this battery has been very accurate in the smallest details, from the junctions of the individual cells, made by computerized robots, to the BMS used inside it, certified free from generating EMI / RFI disturbances that cost more than the cells themselves, to which it is possible also connect a display to monitor the charge status with management via Bluetooth.

But there is a premise to do. Before running into this adventure, I asked an opinion from a person I trust and that if he hadn't given me a positive opinion I would have abandoned everything.

Obviously this person is Rob.

And that was the only path I would take with regards to a possible improvement of DAVE.

Because Rob many times over the past few years has always advised against the use of linear power supplies with detailed explanations as to why not to take this route.

The internal SMPS, once powered by the battery, I don't think generates major EMI / RFI disturbances.
And in any case always much less than these linear power supplies also used in external boxes.

The result with the use of headphones via the internal amplifier is spectacular.
The precision in the micro details and the complete removal of the brightness allows you to increase the volume while maintaining a full-bodied and soft sound.

Maybe Rob if he is reading these last posts can provide some technical clarification about it.

 

[801evan]

As for these latest posts on using lithium battery for DAVE, i would like to make some considerations.

It all started after reading a few months ago that the internal SMPS would accept DC current.

I therefore decided to deepen this discourse trying to understand if it was possible to make a battery with these characteristics for this purpose.

As I proceeded with the research, I realized that it was quite complex.
I had emailed many companies specializing in the sector, but all of them gave me negative results, except one.

Perhaps because the owner is also passionate about Hi Fi, he decided to help me in this realization.

The realization of this battery has been very accurate in the smallest details, from the junctions of the individual cells, made by computerized robots, to the BMS used inside it, certified free from generating EMI / RFI disturbances that cost more than the cells themselves, to which it is possible also connect a display to monitor the charge status with management via Bluetooth.

But there is a premise to do. Before running into this adventure, I asked an opinion from a person I trust and that if he hadn't given me a positive opinion I would have abandoned everything.

Obviously this person is Rob.

And that was the only path I would take with regards to a possible improvement of DAVE.

Because Rob many times over the past few years has always advised against the use of linear power supplies with detailed explanations as to why not to take this route.

The internal SMPS, once powered by the battery, I don't think generates major EMI / RFI disturbances.
And in any case always much less than these linear power supplies also used in external boxes.

The result with the use of headphones via the internal amplifier is spectacular.
The precision in the micro details and the complete removal of the brightness allows you to increase the volume while maintaining a full-bodied and soft sound.

Maybe Rob if he is reading these last posts can provide some technical clarification about it.

As I've been saying with the internal SMPS performance and that of the.HP amp. Great success on the battery project.

 

[Reactcore]

Go check my Choral mscaler thread.
Its assembled.

 

[Ciggavelli]

Go check my Choral mscaler thread.
Its assembled.

Link?

 

[DJJEZ]

Link?

https://www.head-fi.org/threads/my-choral-housed-chord-mscaler.964931/post-17167873

 

[Somatic]

I’m using a Siltech Double Crown power cable and although it’s a “clone”of the original it sounds just like how the original is described in various reviews. It adds much needed body to Dave, increased holographics, analog flow, and super accurate timbre reproduction, it just might be an end game power cable… I have no desire to purchase an aftermarket power supply like the farad or the various Sean Jacob's PSUs. In fact, I’d be willing to wager it comes dangerously close to those aftermarket power supply’s for a fraction of the price ($300). Might be the best value in high end audio especially for those who want a huge improvement in sound without spending an arm and a leg and ofcourse you are not invalidating your warranty either. Just wanted to share this for the more budget oriented Dave owners looking for a huge upgrade

I respectfully doubt that. I didn’t try that exact AC cable but the upgrade I’m getting I don’t think can easily be replicated with a power cord.

 

[LucyWu]

Its not about drawing the max current..
but about the voltage being more steady and not fluctuating with the music output.. even a variation of micro volts can be noticable.. its a form of noise modulation.

I agree - and that voltage stability is directly a function of the output impedance of the battery. I've used batteries on and off over many years and generally been quite pleased with the results. I was just expressing the view (based on my experience and the basic engineering factors) that batteries are not an easy panacea. And you really do need to consider the voltage regulation because batteries which offer the specific voltages Dave needs are not available. And even if they were battery voltage has generally a direct correlation with charge so with start above nominal and sag over time.

 

[Triode User]

I agree - and that voltage stability is directly a function of the output impedance of the battery. I've used batteries on and off over many years and generally been quite pleased with the results. I was just expressing the view (based on my experience and the basic engineering factors) that batteries are not an easy panacea. And you really do need to consider the voltage regulation because batteries which offer the specific voltages Dave needs are not available. And even if they were battery voltage has generally a direct correlation with charge so with start above nominal and sag over time.

These are all good points. Indeed there have been posts in other forums where batteries were used with DC4 regulators to directly power Dave but in the end they were outdone by the transformer powered ARC6 power supply. From what I have read in those posts the motive for designing the ARC6 was to achieve a better power supply for Dave than could be got with the batteries.