DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

I was bored and i have my health issues causing me to remain stationary, so i decided to use my time to complete a project i have been planning for some time, an ADD ON amp (can be made to fit inside mugen cover), this amp is a 2x3W class D i bought from DX for 5-6$!!!

The Setup:
The WMA2012 amp is soldered directly to the jack plug so it is very stationary, and as you can see the power is drawn directly from my charge plug (Goto Battery Thread Post #2 for more info), the charge plug is always connected to the Dual Scud so this serves as a power source for many things if needed (Amp, HIGH Power flash-light etc.).
Attachment 21051

WMA2012 Info:
This amp is simply awesome and take it from someone how has been building HIFI for 10+years (AMPS, Speakers, Filters A & D and even speaker units), this amp delivers very good power and it does it from 2.5V-5.5V making it ideal for single cell lithium operation or USB powered.
Can be bought from DX (LINK) for only 5.30$ shipped

Attachment 21052

Power Usage:
Well not much, there is no heat loss because the amp is VERY efficient and even on full this ADD ON will rock the party long time :D


And since were on the subject can't resist to throw my home amp in here as well
Attachment 21053
Attachment 21054
HOME AMP: 2x 250W+ (4 Ohm), lets just say when connected to previous speakers handling 500W (2 Ohm) with no distortion at all.
The amp is build up in 2 stages, A TDA7294 and A HIGH Power transistor stage helping the power along, the transistors + TDA7294 can handle 600W+ (MAX Power) together, besides that if 4 or 8 Ohm is needed it can be bridged to 1x 1000W (4 Ohm)
But with the current transformer it is limited by input power to something like 2x 300W+ Max Power

Here are the schematics and more pictures of my home amp.
Attachment 23913
NOTE: The pictures are from the old version (same as the current one in use, just that the current is 2x on one cooling plate (Pentium 4 Cooler :) )

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Haha, home amp use ATX power supply cover, doesn't it? Or in fact it uses that as own power supply and just share same box?

Fine thing with portable amp, but are You sure it'll fit into mugen cover inside with dualSCUD mounted at the same time? It seems for me that there is not much space left...

Anyway, it's always possible to carry it with You on pocket - it's really small. Incorporating also jack port on the other side make it compatible with big jack/jack speakers as well :)

On the other hand, they're are many real life situations for using this? Most things that You connect N900 to through 3.5 jack got own amplifiers inside... Still, nice mod :)

Long time ago i worked on pocket amplifier (old days when pocket mp3 players weren't obsolete), people we're designing really nice small amplifiers. Although i remember, that most of the time they recommended to use standard batteries instead of rechargeable - due to some kind of voltage stability and different audio sound on different SoC of accu (some kind of distortions, but harder to catch due to being stable at given SoC). How well your amplifier handle this? It's really cheap, and if it would be immune to voltage changes (our Li-Po provide very different voltage during discharging) it would be indeed great. I know it operates at vide variety of voltages, but doesn't it "calibrate" itself on start to given voltage, and voltage change during long playback will distort sound?

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Yes the home amp is in a ATX case, was big enough so why not :D
The power comes from a 150W Ring Transformer that inside there also, the hole amp assembly is very "small"
Attachment 21055

With some creative placement the amp can just fit in the cover....
But having it inside still create other problems, like having the audio connection go out and in etc....

But this amp is just awesome and just wanted to share it, and also throw my home amp in, been using the home amp for over 2 years now... it's really good.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Well no matter what you connect to this chip it just delivers and all battery's i have can easily deliver the MAX 5W it takes.

And the Audio Quality is just awesome, really no change from this and my home amp, no matter if it is small speakers or 12"+ you connect or if it is 4 or 8 Ohm it just plays and remember if you have VERY good speakers (High Sensitivity) 1W is more then enough to play really LOUD :)

Tomorrow i will attach it to my main speakers (3 Ohm) and let it rip, but not now, the wife and son are asleep and it is almost 2 at night.

And on the power note, have been playing for 1 hour+ at very low volume, someplayer and screen off and i cannot see any drop in batt %

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

some really great modding there, nicely done.
id love to see how it looks with in the mugen cover.

makes me want to finish some old projects i have lying around

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

About placing it inside mugen cover and audio cables going in and out - solution may be to solder it into N900 mainboard and use dead-flashing pins slot (under battery) to put cables inside mugen cover without outside route. If cable is flat enough - and audio cables may be very flat without sound problems - it will not stop battery from fitting in socket. Ho ever, this would need N900 disassembly (no problem at all cause it's easy), and i don't remember how shield was placed around audio jack on N900 = how hard it would be to solder it. Jack plug is quite big as for today's standards, so it shouldn't be too hard, if shielding doesn't permit approach.

If also jack port could be incorporated into mugen cover - just like Your charging plug - then You would have another jack port in N900 cover. Stock jack would be to use without AMP, and the second to use with.

Using an electronic part that i can't recall name for now, You can even make it that, only when something is plugged into amp-jack, they power to amp is activated. You know, switch that activates itself on closing other connection - it will work the same way as headphones detection on N900 (side note - headphones detection can be also relayed to that second jack port).

That would be ultimate maintenance free solution. You just plug something into amp port located on Your cover, and AMP automatically get powered up and start working. You plug into normal N900 audio port, and everything is "regular" way.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Yes but still i will be a pain to operate if it is inside the cover....
Of course further modding and wiring can exclude the jack plug by connecting the input directly where the Mainboard is connected to the 3.5 output. and i do have enough VERY small switches laying around, just need to connect a DUMB jack in so the N900 turns off internal speakers.

Then one could put a 3.5 stereo jack in the cover, this will then be speakers out (AMP), then just make a jack to the clamps i use or to banana plugs etc...

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Hahaha, we bought have written about similar things, except that i don't really like idea of disabling internal speakers once for all. Check my last post (you were faster) maybe You will like some of my ideas or even make them better.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

No not once and for all, just when needed, put in DUMB jack and this turns off speakers because it thinks headset has been connected.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Yea, but check for inserted jack port can be relayed to second jack port also - then no need to using dumb. If, at the same time, we incorporate another check only on second jack port (for example, "probing" other portion of jack plug) and use it to disable/enable amplifier, we got 0 additional effort solution. That electronic parts i still can't remember name for are very small, if used for such a low voltage like <5v.

I really, really can't remember it's name... Is the same thing that start water cooling pumps connected to 230V when computer starts, in desktops sets. Of course ones for 230V are MUCH bigger, but as i said max 5v oneis so small that can be put inside cover with ease.

Of course doing everything like this is little hassle, but after that You don't even need manual switch to turn amplifier on/off. Less cutting on Your cover, less elements that can possibly break due to mechanical moving parts ;)

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

you are amazing!!! damn.......never seen someone mod the N900 so much. :)

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

I was thinking about something in the line of this, would not be hard to do at all.

And this could be one more thing that you can say, your phone cannot do this :D

But the external part works fine, im thinking of making it a little more compact, the biggest part is of course the damm speaker connection, wish i could find smaller..., even looked through most of my boxes of crap and can't find anything yet...
And i want that clamp things because it is easier to manage, else i could place a stereo+ jack (4 PIN) and then have adaptors, like the clamps and banana plugs etc.....

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Oh year i also have this Bluetooth speaker, it has the same AMP and a BT A2DP from DX (LINK) and also here the audio quality is just amazing.

The casing is from a old B&O LX2802 TV, the speakers are from a surround stereo i can't remember the name of.
The Volume control was necessary in the beginning because the BT A2DP was sending noise in the power and the BT and AMP was on the same battery, now the single battery is going to the BT, and the dual battery is going to the AMP.
Attachment 21078
Attachment 21079

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Cool, I love he bluetooth speaker. I've just finished converting an old pair of bluetooth headphones into a unit to stream music from my N900 to my car's stereo. So much better than paying $400+ for a kit to do the same thing from Pioneer! (sorry for the sort of shoddy photos, just finished it a few hours ago)

Back on topic, what have you done with the amplifier in the first post? Does it allow you to connect two speakers directly to your headphone jack and amplify the sound, instead it being fairly quiet?

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Yes the AMP takes power from my dual Scud and audio input from the jack and then directly to speakers, and i just did a test on my home speakers (which are VERY HIFI :D) and you will be amazed of how high it can play and the audio quality, my speakers have a good sensitivity and it helps, i will say that they can play with no distortion from this amp at around 95DB+.

Here's a picture of the the amp.
Attachment 21082
As you can see the amp is attached directly to the Jack, and then there are speakers out and power that goes to the Micro DC plug that nokia phones use.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

As for amp outside cover usage, I would get rid of speaker clap thing, and use stereo+ jack, then add attachment to home speakers, allowing them to get sound from said jack+. That would help in terms of portability.Still, i think inside cover is best, as You've said its another amazing unusual capability, no noe other phone/mobile computer have.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

you should start selling them !!

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Your not the first one to say that, well in the forum you are...
Man the times a day i hear that sentence "you can sell that"...

Anyway, i think that when i get a some time i would complete this by putting it in the cover

And a note on the "play time" at low volume (normal room music volume) with the screen of and dual battery this can play most of the day, that's how little power this amp uses.

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Just made a mock-up of a small audio dock using this amp.

Attachment 21182
Attachment 21183
Attachment 21185
Attachment 21186

This plays more then 2x as load as the N900 itself and it actually plays pretty good for it's size, the speakers are from an acer laptop.

This dock is a good thing for viewing video, it has a good angle and the louder volume is really nice.

Next will be to integrate the amp on the "dock", this will be no problem, still have some amps laying around :)

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Now the Final version, decided to go with the circuit board because it really reaks of DIY :D
Also the total weight comes in at 42grams, yes only 42grams!!!!

Not pretty but gets the job done :)
Only addon/edit there is missing is a retractable stand, right now it is pretty firm.

Attachment 21191
Attachment 21192
Attachment 21193
Attachment 21194

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

i want to make one. could you let me know how much its cost you in total and links to the stuff required? i have some old logitech z323 speakers lying around. i was thinking of taking the speakers out of them and making a n900 dock

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

well you basically just need the amp, if you have 12V available then you can go for the bigger 2x10W one.
Then you need a Jack to whatever (since this end will be cut :D) e.g. jack to phono.
And since you have some speakers to "donate"/mod then you probably have the jack plug here.

so if you have the jack laying around then here's what you need:
Small AMP
Large AMP

If you want to make it so it takes power from the N900 like mine, well then it gets a little more complicated, look into my battery thread for more info on this.

The amp is very simple to solder, it requires NO external components when running of battery, but if you use an adapter then a small capacitor will be needed, and maybe also some filtering if it is "dirty" power coming of the adapter (noise, low freq switching <20KHz)

----------------------------------------------
EDIT:
If you just want something to put together fast then you can use the "complete" versions:

Comes in 2x3W, 2x10W, 2x15W

Again the 2x3W can be used from 2.5-5.5V (battery/USB)
The 10W & 15W needs 10-22V (e.g 12V)

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

That is awesome dr_frost_dk. Breadboard FTW!

Re: N900 Micro amp, when compact power is needed (Yet another Frost MOD :D)
 

Well it is easy to work with, and after the mockup i thought "what the hell" this is alright, and i really like the weight :D, only thing left to do is to make a stand instead of the 1.5mm solid core wire thats there now.

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Just changed the thread tittle, lets get all the DIY audio mods and accessory's in here :)

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Rear speakers based on Tangband W4-657SC elements. I haven't used them much, because they sound even cheaper than I thought :(
http://hosted.laasonen.net/tangband-both.png
http://hosted.laasonen.net/tangband-behind2.png
http://hosted.laasonen.net/tangband-front.png
http://hosted.laasonen.net/tangband-behind.png
http://hosted.laasonen.net/tangband-both2.png

Battery powered portable speaker which I did for my Nokia 5510 when I was about ten. It has two self-made amplifiers, two small speakers, one nine-volt battery, 3.5mm input, on-off switch and power LED. Looks ugly, but it was cool back then :D
http://hosted.laasonen.net/20100813_015.jpg
http://hosted.laasonen.net/20100813_016.jpg
http://hosted.laasonen.net/20100813_020.jpg

Closed subwoofer based on Peerless SLS-10 element and Hypex DS 1.2 Amplifier Module. It sounds great and I have used it tens of thousands of hours. It looks cheap, because I didn't use veeners or planks to make it, because it's next to my chair so it gets hit all the time :( I'll probably redo it, if I get better place for it :)
http://hosted.laasonen.net/IMG_3804.JPG
http://hosted.laasonen.net/IMG_3810.JPG

Sorry for bad quality of the pictures. Dark room and not so good camera :(

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

dr frost - you are awesomeness personified

this thread is full of win !

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Well we modders need some threads our selfs :)

This will be the Audio one, it's DIY Audio for the our phones mostly but don't mind the home stereo ones.

I myself am a modder by heart, i literally don't have anything here at home thats running stock, well my Internet router has not been altered but anything else is.
Also when i buy something it is rarely for the purpose it was intended :D

And if we can contribute to our maemo devices this way then it's something.

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

https://openwrt.org/ :)

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

I must say that the dock i made is use full, when doing the dishes (yes i really want space for a dishwasher) i was watching video's and the volume was more then enough to drown out the sound of dishes...

If i ever suffer a massive brain hemorrhage and get another phone im modding it to have an onboard amp and some better speakers, this is one thing i really like about my N900 is the audio quality stock compared to many phones i have tested/handled through many years, only phone i have ever had that had better sound was my Alcatel one touch gum (db), it had a massive speaker, tho only mono, and also it was before any mp3 and even poly tones....

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Hi there dr_frost_dk. Nice work once again.

I am an audio lover but i don't understand much about electric components.

5 years ago i modded my n-gage tm so that it could have stereo speakers, using the stereo signal from the headphone jack, and i had some sucess with that, except the fact that the volume was really low. At that time i knew that i needed some Amp for that but never found any. Thanks to you i think my search is finally over :)

But now i have other idea, this one related to N900. I have received 2 days ago 2 barebones (without the motherboard) of 2 clevos m570ru-u from a friend, and that laptop have an subwoofer plus 2 speakers.

My idea is to use one of that subwoofer plus the stereo system inbuilt on n900, but i don't know how to use both system's at the same time, since when i plug the jack on the n900, the internal speakers shut down, as normal.

So the amp would be only used to the subwoofer.

This is an extra but is there any way to put some external volume control on the subwoofer?

The only tecnical spec about the subwoofer that i found is this "1x Built-in Woofer 2W".

I want to ask you some advices about this idea, if it has some viability or not, since i love the current sound of the n900, but it lacks some bass :p

Thanks in advance and sorry for the bad english and the wall of text

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

You would need a low-pass filter also, if you can't do it with software.

IMHO laptop with subwoofer sounds ridiculous marketing scam :(

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Isn't that built in in the subwoofer? (sorry for ignorance)
and if it isn't, is it hard to make it with software (i know i don't know how to do it :( )

BTW, i have just upload some photos of the sub to compare size.

http://www.megaupload.com/?d=W1X454C2

I must agreed with you that in the case of this laptop model the sub is indeed weak. I know because i have it, thats why my friend gave me those barebones for future repair, but there are some laptops where the subwoofer gives an extra sound experience.

;)

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

It depends on what you call a subwoofer. Low-pass filter is typically in the amplifier module like this.

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

So if this sub don't have this ( very likely) isn't there any low-pass filters in small sizes that could be attached to that amplifier board?

Thanks for the answers .I have to go for now.

See you later

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

even though I will never do mods like this (my soldering skillz are null) - its awesome to see what some of you guys do

I am an audiophile somewhat - have a vacuum tube system with a maraantz cd player myself, but i wouldnt even think about what you guys are doing lol

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Nice idea with the sub, not going to go to sub freq tho :D

But an easy way if doing it will be to build a passive sub filter, can be done with few resistors & caps.

The sub will be an addon to you N900 right?, it looks to be to big to have in the N900 (mugen cover).

The dock i made gives more bass then stock N900, you could try the other speakers first with the small 2x3W amp.

of course to make an optimal system you need 2x amps, 1 for speakers 1 for sub, of course this amp cannot operate in bridge or parallel (i haven't tried).

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

http://lorienart.pl/cover/schema.jpg

That will do it. Even headphones jack work as before. Of course this is only scheme, You don't necessary need to place in-built speakers outside ;) Red line is left speaker signal, green is right speaker signal, black is ground, and mixed colors cable is one cable with amplified-lowpassed signal from both channels.

Alternatively, You can use only one lowpass-filter, but then You need to place it AFTER amplifier. This way, you amplify all spectrum, then lowpass it - approach with first lowpassing, then amplifying resulted output gives better quality. Ho ever, with such subwoo and speakers, You'll probably don't even notice difference. Still, with both methods, You probably can break window's glasses in 100 meter diameter, on full volume ;)

Placing adjustable resistor just before subwoo allow to calibrate bass volume - as built-in speakers aren't amplified (don't try it, amplifier will blow Your speakers, they're doing their best now), this is probably must-have if You decide to do it as on my scheme.

Re: DIY Audio thread, show you DIY audio 'equipment' (Amps, BT etc...)
 

Thanks for the answers ;)

As i said before, i don't understand much about electronics (building systems with resistors and that sort of things...just know that "this cable" goes "there" and stuff like that :/ ).

The subwoofer would be an add on, but i would like to use the n900 speakers, and i would not like to "toy" with them, because last time i toyed with them i blow up one of them (via software) so i know they are fragile.

My idea wasn't to make one stereo dock because for that i have a set of this speakers that do the job well done : http://www.caie.com.pt/loja/images/X_MINI_II_.jpg. I want to have the internal speakers as normal as they are and to have the subwoofer as an add-on to make the sound better.

I don't mind to use the 3.5 jack to achieve it but when i use it the internal speakers shut down, as normal. I used one way (described in this forum )to use the speakers and the jack at the same time but that was the cause that made my right speaker blow up.

I will make some costum external housing for the sub with some friends with acrylic.

What Estel said was what i made with the n-gage 5 years ago, except the filters and the amp lol. But is there any way to achive the same result without having to open the n900? I don't have problems openning it but it came from the repair shop 1 week ago (repaired usb port = happy n900 owner :) )and because of that i have 6 months of warranty and i don't want to loose them.

And more sugestions for the lowpass filters? are they cheap and small? and without it this subwoofer is just a normal speaker?

Thanks again ;)