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iBasso OEM Project - Page 3

post #31 of 497
7/28/08 at 2:45pm
Quote:
Originally Posted by jamato8 View Post
It isn't just power supply but how the power is used. You can run off of the battery, a fairly pure DC source and get excellent home sound. It is all about implementation. The Woo 6 is a home amp but I showed and have proved how implementing a good change in the power supply totally changed the amp. It can be done with a battery supply in the OEM being discussed. A wall wart isn't really a good source of power, imo.

That makes sense. I was always under the impression that a battery, that needs to be concerned about charge and life, is not as consistent as plug in options.

But I do not want to derail the thread. I know so little about design impacts.
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post #32 of 497
7/28/08 at 3:07pm
Quote:
Originally Posted by Dash View Post
That makes sense. I was always under the impression that a battery, that needs to be concerned about charge and life, is not as consistent as plug in options.

But I do not want to derail the thread. I know so little about design impacts.

Yes but you have a good idea. The ability to use an external power supply with excellent DC might be great. Something like the Lisa II. Very, very doable. The thing is the carrying capacity of the DC in section needs to be of almost no capacitance and resistance in value. What I mean by this is that traces can often impose their own signature due to capactance of the PCB and other factors. Separated traces, maybe a four layer board.
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post #33 of 497
7/28/08 at 3:23pm
I just think if you are going for home based sound do not skimp on the power.
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post #34 of 497
7/31/08 at 1:17pm
Summary of power supply was formed
Our requirement, we need more than 5 hours standability.
In order to reduce costs, we'll use same 4 cells as P2's (7.3V 520mAh) in series-parallel.
It will have 14.6V/1040mAh (when full-charged, it gets 16.4V) ability.

About virtual ground, refer below image.
http://photo4.avi.jp/photo/7/396928/...-140456-pc.jpg
So, OPAMP in GND-Channel will be single like OPA134P.

And, I suggest gold-plated DIP socket and 1/8 jack.
In output, I'm thinking to add 1/4 jack......how do you think

Volume, it's one of anxious item on P2.
It brings about most deterioration of signal.
I wanna use ALPS's one.
Do you have any recommendation about it, jamato8?
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post #35 of 497
7/31/08 at 1:32pm
I would go with a 1/4 and 1/8 for the output jacks. There is a very fine volume pot that tracks almost perfect, I just have to think of the name and model. It would fit in a D1 case. I would think a matt finish would be nicer than a glossy one but that is my opinion.

I also think, and it is easy, to have a DC in that disconnects the batteries and uses any outside power supply of a certain DC range would be excellent as a person could invest in a high quality external supply if they wanted to by either building or buying it premade.
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post #36 of 497
7/31/08 at 1:59pm
I like matt-finish too.

Are you saying me not to sell the amp with charger because to connect external charger/battery as one's like?
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post #37 of 497
7/31/08 at 2:29pm
Quote:
Originally Posted by ryuzoh View Post
I like matt-finish too.

Are you saying me not to sell the amp with charger because to connect external charger/battery as one's like?
No, an adapter is inexpensive and I think any amp that has an internal battery should come with one. But, having the ability to bypass the internal battery and use a high quality external DC source is also a very nice way to go for home or office use.
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post #38 of 497
7/31/08 at 3:52pm
Quote:
Originally Posted by jamato8 View Post
No, an adapter is inexpensive and I think any amp that has an internal battery should come with one. But, having the ability to bypass the internal battery and use a high quality external DC source is also a very nice way to go for home or office use.
Agreed. That's what I was trying to say, Jam was just more eloquent.
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post #39 of 497
7/31/08 at 10:13pm
Quote:
Originally Posted by jamato8 View Post
But, having the ability to bypass the internal battery and use a high quality external DC source is also a very nice way to go for home or office use.
I see
To solve the issue, how is this?
http://photo4.avi.jp/photo/7/396928/...-140470-pc.jpg
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post #40 of 497
7/31/08 at 10:34pm
Yeah, but even diodes create noise and small but resistance and I would prefer not to have them in the DC line if only there for protection. If you double up on them you decrease their resistance and it all matters.
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post #41 of 497
7/31/08 at 10:45pm
I am very interested if the amp will be better then any other near 200 buck amp
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post #42 of 497
7/31/08 at 11:14pm
Okay, but I can't ignore protection for this "expensive" circuit.
So, I would connect diodes triple-parallel on the amp side.

Just doing it as much as the budget allows
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post #43 of 497
7/31/08 at 11:31pm
I understand. I do think though that special implementation of the opamps and output buffers should be investigated as far as possible with even some new ideas to transcend what has gone before. I am sure you are addressing this but that is the way to be a step above, IMO.
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post #44 of 497
8/1/08 at 12:50am
Yes, and please let me know more your ideas too.

Other requirements at present from Japan as below pics.
http://photo4.avi.jp/photo/7/396928/...-140501-pc.jpg
http://photo4.avi.jp/photo/7/396928/...-140502-pc.jpg
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post #45 of 497
8/1/08 at 8:30am
I find the more switches in the signal the more corruption. Why gold? Silver and copper are better conductors and I have never found gold to enhance signal delivery over the standard platings. I know why gold is used but it tends to wear off pretty fast unless flashed with a quality thickness. Copper for jacks is rare and silver plating isn't common. The one thing to look for is a nonmagnetic jack, which is of a better pursuit for music.
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