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jasonhanjk

Sgheadphones DIY A47 pocket amp kit

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In a month, a few newbie join our forum and the passion for never ending music. Normally they are only equipped with a PCDP and the original ear phone. Their crave for music are always against their wallet, especially headphone amps currently selling in the shops are always above $100. So a few of us (currently me + Tropical), are on the quest to market a DIY pocket amp kit at $25.00 (hopefully). wink.gif

 

This is a suggestion thread so everyone are welcome to voice their input. Remember that the kit would only cost $25 so it is very challenging to keep the price down and kindly do not escalate the discussion to those super duper max out Cmoy that cost more than $100.

 

The design would be a Cmoy variant with buffered ground.

 

The $25 parts would be as below without casing:

 

3 x NJM4556AD ($7.50)

2 x 1uF 50V polyester film cap ($2.00)

2 x electrolitic cap ($1.00)

13 x film resistor ($1.00)

3 x 8 DIP IC holder ($0.30)

2 x stereo female plug ($2.00)

1 x 9V battery plug ($0.50)

 

Total $24.30

 

 

The $40 parts plus casing:

 

3 x OPA2134 ($13.50)

5 x 1uF 50V polyester film cap ($5.00)

2 x 1000uF 6.3V FC electrolitic cap ($2.00)

13 x film resistor ($1.00)

3 x 8 DIP IC holder ($0.30)

2 x stereo female plug ($2.00)

1 x 9V battery plug ($0.50)

1 x carbon volume pot PCB mount Farnell 919147 ($4.50)

1 x PCB ($10)

1 x Casing ($5.00)

 

Total $43.80

 

 

user posted image

 

user posted image

 

Edit 1: Update price for items.

Edit 2: Update price again and add more pic.

Edited by jasonhanjk

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Please do not put sgheadphones logo on any PCB unless you have the permission from both the designer of the circuit and ablaze to do so.

 

I wish you both luck in your noble endevour.

Edited by Rameish

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was going to start a new tread but u beat me to it laugh.gif

any way heres what i got so far wink.gif

 

this tread is for a possible DIY PCB for a Cmoy/A47 amp, it all started with Jason's tread on guide for DIY PCB & my Cmoy/A47 amp, we thought it would be a good idea to combine the 2 and see what we get tongue.gif

 

this would be an ongoing/progressive tread, we'll be exploring ideas as well as feasibility of the project, everyone is welcome to contribute any ideas or suggestions yes.gif

 

i think keeping price of the amp or amp-kit to $20 will be difficult, parts alone cost about that no.gif

 

i'll start exploring the project itself and leave the costing side till the end, or we might end up with a sub-standard kit/amp if we restrict ourself to $20

 

first off : size

the final product should be a able to fit into a case small enough for portable use (eg. Alt**ds tin) but do we need to go SMD size?

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Nice comment there Rameish. Will wait for Ablaze approval.

 

So far I had thought of having the sgheadphones trademark would do a few good things:

Forum members will feel the belonging of our community

Our forum would be much wide spread

 

Removing it would also be fine. wink.gif

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Yes, tropical. SMD are possible. Do take note we need to take care of some aspect:

 

Tolerence are normally 5%.

Power rating are much less.

The output 47ohm need to be change to lower value.

Harder solderbility.

 

The advantage, very small footprint and height.

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belly good idea.

At that price, I am tempted to own one too.. for my portables.. and also coz it has 'trademark' from sgh tongue.giflol.giflol.gif

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Thanks for supporting Blues. laugh.gif You make me wanna cry... lol.gif

Something like the previous Sgheadphones water bottle.

Edited by jasonhanjk

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i think SMD component might be a little too demanding a job for most if its a kit form. i also had some problems when working with these tiny chips

 

user posted image

 

even my camera had problems with focus due to the size of the chip tongue.gif

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Ya, how good is our newbie gonna solder those small thing. At the end it may do more harm.

 

Had check headwize and we need to get the author permission to use his design. Of course these things can negotiate untill we are profitable. Normally design ideas cost $1 dollar for each board market.

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Im all for it!....will be one of the first customers for sure. biggrin.gif

 

I do think that smd will be too challenging for those taking a first step into diy... i think that the normal size will do just fine and it shud fit a normal size altoids tin just fine.

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what if we change the design? or improve on it, then it wouldn't be an A47 anymore rite? almost all the amps that i've built are variants of another variant smile.gif

 

the 47ohm on the output of the design is not critical, i left it out on all my amps and they still sound fine, even the sr80

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I will certainly support your endavours. Looking forward to try out the kit.

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I'm all for it! Hey, I might even pose as a student and be your customer. biggrin.gif

 

I've met a few students in my time and discovered they are pretty rich.........looking back the years of my time.........pathetic! sleep.gif

 

If $20 is not a realistic target, I reckon U guys can up the budget to $30-40 and yet retains mass appeal.

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