sorry to have ask, is there any tutorial for newbs to make an portable amp for mp3 players and etc?

i've searched the forum, hardly find one, any guidance from sifus here?
please do not flame me

tangentsoft.net/audio

Look for the CMOY article.

And basically the older thread has more information for newbies so you have to PM scotty to get the older compilation.

Pretty bad move to baleet the old thread IMO.

guys recently i build 2 identical CMOY amps,the problem is when i connect the battery,the battery heats up and r-side is a lot louder than left-side,i have to max the volume on the knob to get decent sound,wat m i doing wrong leh?plus help i hav almost 0 electronic knowledge....

amp 1




amp 2




above is the image of under side of my pcb board and top view......help sifus!!!

what opamp?

Recheck soldering and reflow it, make sure you do not short V+ to V-

This post has been edited by LittleGhost: Nov 11 2009, 03:02 PM

anyone done a tube pre-amp project before?

i'm planning to reverse engineer one... i'm in the stage of buying the components...

just a quick question, is it easy to get the tube female socket to hold ECC83/82 tubes? if yes, roughly how much will it cost?

When I was at NIXIE in Jalan Landak/Pasar last, I saw some tube sockets there. Don't know how much they will cost.
Care sharing the amp model that you're trying to reverse engineer? What would be your anticipated co$t?

I never built the tube version power amplifier. Latest project I have made at 2006 is CLASS A current feedback amplifier with emitter follower (0.98 x gain) plus high frequency Bipolar type.

well for the input buffer I have re-design the Class A Doz preamp, so i will have a big gain with a regulated supply of 72Vdc.

Well this setup make the sound more in natural way (without any filter). The sound more bright. The Class A with a current feedback have a lower S/N ration as i concern. Even without any casing, it really hard to find a Humming sound.

For the modified Class A DOZ preamp, the bad is ,I will never turn it off or the sound will litle shy..

Hopely I will make a tube type amp someday...

What type of tube socket you need, chasis mount or PCB mount. For ECC82/83 it need the 9 pin tube socket.

this is the pre amp i will reverse engineer; at this link: http://www.hometheaterhifi.com/volume_8_2/...ier-4-2001.html

the tube socket i will not mount it on PCB. i will translate the PCB trace into a point to point wiring using copper wires...
cost, should be around rm100 plus not counting the ecc83 tube cost.

This post has been edited by ora-ito: Nov 13 2009, 10:55 PM

I am fascinated by tube amps.. Used to have one China made headphone/preamp tube.. but sold it off a while back.. too darn hot.. could definitely fry an egg!(maybe two!)

ora-ito,
If thats the price, well I want to make one too!
BTW, any particular reasons why you chose this amp?
There are other simple tube preamp to build...

This post has been edited by jazzy939: Nov 13 2009, 11:51 PM

well, its because i own the actual unit. it gave me some problems on each channel.
i managed to troubleshoot and repair it. so at the same time i took the time to understand the circuitry and took some measurements during my troubleshooting.

this tube pre amp brand is very well known in singapore coz it was designed by a singporean musician cum audiophile enthusiast. a totally musical piece of equipment and can be compared to very high end pre amps.
Brand new pricetag is SGD1.4k if you have read the link i posted.

however that price i quoted does not include the ecc83 tube.
so far i have about 12 tube collections ranging from china to russian, mullard & telefunken
they can cost from rm50 to rm350 per tube that's the catch hehe

here is another link for more Q&A on this pre amp brand: http://www.echoloft.com/soulofmusic/divafaq.htm

This post has been edited by ora-ito: Nov 14 2009, 12:09 AM

ora-ito,
thanks for the update and links!
keep us posted...