CMoy - Pocket Headphone Amp !!

[novice-akki]

thanks for clarification, that's how rolling OPAMPS is possible !!

The local electronics market dont have any OPA's available hence I picked up 6-8 different dual OPAMPS and just now checked that LM386 the one I'm experimenting with is not suitable for CMoy application.



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Mishra Sir,

What I was trying to convey is:

Test: Set your meter to DC volts, apply power to the board, and measure from the virtual ground (marked gnd. in the images) to the hookup wires going to the V+ and V- holes. If youre using a single 9?V battery as your supply (recommended for testing), you should see a positive DC voltage at one cap and a negative voltage at the other cap, and their magnitudes should be nearly identical. For example, if youre using a 9?V battery thats been depleted to 8?V, you should see almost exactly +4?VDC and -4?VDC. If youre off by more than a tenth of a volt or so, you did something wrong in hooking the circuit up. The most common mistake is a solder bridge, which usually causes the full input voltage (8?V in our example) to appear on one side of the power supply and 0 volts to appear on the other side. Fix any problems before continuing.

Also, make sure you get a positive reading between the V+ hookup wire and ground and a negative reading between V- and ground. If not, something is reversed. You can either leave it like it is and just run the wires differently when hooking the power up to the op-amp, or you can find and fix the problem. (This only applies if youre using a digital meter, and you hook its black probe to the gnd. point for both tests. Analog meters generally cant show negative readings, so you end up hooking the red lead to gnd. and the black to V- for that test.)

Unplug the power supply before continuing.

"I get all correct readings upto this point"

Things get messed up here:

Next, take the hookup wires going to the V+ and V- points on the power supply and run them to the V- and V+ points of the op-amp pins 4 and 8. I recommend you do this on the bottom side of the board, since youll be adding a bunch of wires that have to be on the top of the board later. The more wires you can put on the bottom, the cleaner the top side of the finished amp will be, which facilitates later repairs and tweaks.

At this point I get unequal ratings something like -6.5 volts in negative and 2.7 volts in positive, needless to say there's no sound/hiss/click at all.

I first need to make a list of suitable OPAMP for this application and hope I have one/two with me already or get them from the market on my next off.

 

[novice-akki]

Checked the circuit, everythings fine just that the opamp/amps I've aren't appropriate. Lack of time led to ordering parts trough kitsnspares, good part is I found alps pot, neutrik jacks and panasonic caps which I couldn't find in the local market.

Sorry for the red sore in the previous post, can't edit, can I ?


Sent from Samsung Galaxy Note II GT-N7100

 

[suraj]

a TL072 is suitable-it has the same pinout as 2132pa,and is just 8-12 rs for an op amp,but needs atleast 18v or 2x9v batteries to work properly.

As for kits and spares,
how much for the alps pot and the neutrik jacks?What about shipping cost from kits and spares?never ordered from there.

 

[novice-akki]

Thanks for the suggestions Suraj.
Rs 110/- for 10k Alps pot and Rs 126/- for neutrik jack/pc.
Total shipping (post) delivery time 10-14 days Rs 150/- for entire order no courier service.
Good experience, first order with them prompt email replies.

Hope it helps !

Sent from Samsung Galaxy Note II GT-N7100

 

[suraj]

thats it?110rs?how good is the pot?i spent like 180rs a year or two back when i got a alps RK097 10k pot.now its become like rs300.
link please!both the pot and the jack.

 

[novice-akki]

ALPS pot
Neutrik plug

looks alright in the images, haven't received it yet so cant comment on tracking, smoothness etc.

 

[novice-akki]

Hey Akki,

I have a CMOY PCB lying unused. I tried building it and then lost interest. Collected altoids case and most of the parts as well. If you want I can send it for free.

CMOY Board : JDS Labs - cMoyBB v2.03R PCB - Rechargeable

/Arun

Received the courier last evening, many thanks for your kind gesture, have to say, didn't even take a rupee not even for shipping.

Wait for op-amps still continue

 

[doors666]

why dont u put in a ne5532, widely available locally for dirt cheap, great opamp, known to work in this application....

 

[novice-akki]

Have ordered OPA2227PA, 2134PA and NE5532....wait is agonizing

 

[suraj]

one more question,is the charge of rs 150 for shipping fixed or varies?is it per item or number of kgs of the order?

 

[Audioden]

Doing diy on basic head amp is waste of time . The cmoy is over glorified in net.
the home made amp you cannt carry , most likely will be in a funny plastic case
the recharge feature will not be there , not sturdy and you will throw it one day !
picture this you have wasted 1.5k on opamps and components , the amp is
temporary in a project box , time head all spent on an amp that is nothing great aprt from a slight boost.

on the other hand some standard HP amp will be 3k if you can grab the deal well !

 

[sbg]

Doing diy on basic head amp is waste of time . ......

You got some valid points.
but
1.I'm not able to picture 1.5k on opamps and components
guess what. looks like you have not read the first few posts on the FIRST page !.
2."DIY - The Joy Living" for those uninitiated will miss them. its a recommendation to try once.
3. does this cmoy look like

"Funny plastic case
the recharge feature will not be there , not sturdy and you will throw it one day !""

4.Objectives differ for each Individuals.
5.

" the amp is
temporary in a project box , time head all spent on an amp that is nothing great aprt from a slight boost.

on the other hand some standard HP amp will be 3k if you can grab the deal well !"

I've not tried these as listed below,but it is worth looking at these options too. How Do I know that "some standard HP amp will be 3k" is a crap or really a worth 3K or the like that you have mentioned at Aliexpress link?

Beyerdynamic A1,...Head Direct HiFiMan...,HDVA 600/800...,Toucan...

list-of-diy-headphone-amplifiers

vacuum-tube-home-headphone

 

[doors666]

Doing diy on basic head amp is waste of time . The cmoy is over glorified in net.
the home made amp you cannt carry , most likely will be in a funny plastic case
the recharge feature will not be there , not sturdy and you will throw it one day !
picture this you have wasted 1.5k on opamps and components , the amp is
temporary in a project box , time head all spent on an amp that is nothing great aprt from a slight boost.

on the other hand some standard HP amp will be 3k if you can grab the deal well !

well, thats because of the expensive opamps... i made one initially, using ne5532 and sp road component on a gp pcb, probaly didnt even cost 150 bucks. works great for ipod and the likes... for serious listening, got an o2.
but the learning is there which is an important part..

 

[Audioden]

sbg ,
the words came out from careful observations from past DIY

the price will be spent on opamps and capacitors by newbies
there are many opamps that are in 200Rs range sound good too

"DIY - The Joy Living"

doesnot mean we should invest time on some things that dont turn out good .
[it is something like why people go diy for making a cloth iron , because it is not worth it]

does this cmoy look like

well can you make one rightnow ? if not dont consider dream enclosures.
the chepest enclosure that looks 'like a HP amp'is the extruded aluminum case.
Then the metal cutting etc add to the cost also hassle .

Objectives differ for each Individuals.

As i know there is one main objective better sound quality
isnt it or is it like my soldering iron is idle i have to do diy?

There is a confusion on the which is a better HP amp to build
well the net is full of resources there is no rule you must start with cmoy !

here is i would have done
* take better design , you want a name take pimeta V1
*do a PCB at home
*get nice 2-3 opamps from ebay or locally in 400-600
case part is still tricky easy one is black ABS case from element14

plan to put it on 9v rechargeable

doors ,
using ne5532 and using good candiadate form Analog devices AD series there is a night and day difference in SQ
those things go 700Rs /pc

 

[novice-akki]

Audioden,

Already have a Fiio E7 that does the job for portable DAC/amp.
Wanted to try DIY just for the fun element and for a learning curve.
Didn't even know how to solder, in this process learnt soldering and have successfully fixed my broken Sony HP, re-cabled and modded my Sony MDR XD200 [damping the cups] making it a very, very good sounding HP from an average HP.
Always knew about the limitations of the CMoy but had to start somewhere so here I am and truthfully no regrets on the money spent.

Cheers

 

[sbg]

the words came out from careful observations from past DIY

As i know there is one main objective better sound quality
isnt it or is it like my soldering iron is idle i have to do diy?

I See your point.
So, no comments hence forth.
cheers!

 

[Audioden]

--deleted--

 

[Audioden]

sbg,
some people have their own logic , i wish good luck for them

novice-akki
i were you i will go for agood superlux varieant for modding
the sony is no where near capable , superlux is not too expensive !
sony is a general consumer oriented HP , will not read near superlux .

i have superlux and so comments are not assumptions,
and have been checked by sony owners.
If you are still in brand chooser grab an audio technica from an india vendor
many decently priced ones of ATH series ,will always better than sony

 

[novice-akki]

Audioden,

Sony's were bought approx 7 yrs ago only because they were from a decent brand and had a 3+ meter cable wich was a requisite as the main purpose was to watch telly at night and costed 1.4k from sony showroom and the reason I modded them was because they were broken and needed re cabling when I opened them up I thought of damping them with a spare sheet of damp mat I had lying around which was bought from gearheads forum and that there was a tutorial on modding with damping sheets on head fi.

Neither my solder iron was lying idle nor I was feeling adventurous and definitely had simple logic behind it-they were broken and I had acquired the skills of basic sodering and had simple DIY tools around.

Don't really fancy buying a new pair of average HP just for modding as that'd be a waste of time and money. Saving up for something more like Senn 650, beyer's or used denon's etc and then look for proper amplification for them.

Thanks for the suggestion though.


Sent from Samsung Galaxy Note II GT-N7100

 

[Audioden]

oh
novice-akki your sig shows all... ok i will leave the thread for cmoy builders , no more OT .