Beginner headphone amplifers

[jasonhanjk 0]

The board is still available. I am looking into a single 4556 opamp, 4 470uF cap and some resistor, still designing and testing stage.

Maybe some kind soul can help me test?

 

PS: The design idea I got is from my Marantz CD7300.

[aaron-xp 0]

The board? As in this:

http://www.sgheadphones.net/index.php?showtopic=2351 ?

[jasonhanjk 0]

This.

http://www.sgheadphones.net/index.php?show...19&hl=cmoy&st=0

[siriuz 0]

Ah, one and a half year ago

 

My first headphone amplifier was the cmoy 2..

Together with my PX200.

 

Never imagined it'd have led me down this path of bankruptcy

[jasonhanjk 0]

Ohh, my fault.

[siriuz 0]

Hahaha ..

It wasn't meant that way

 

But actually, I think it was more of finding sgheadphone and headfi forums that contributed.

[jasonhanjk 0]

Then I am much more luckier. I can hear up to frequency of 19.5k. Yet I cannot hear the details of the music.

 

Meaning if there is 2 tone (1k and 10k), a -20dB difference between them would sound nothing to me. Other guys here can go higher.

[pegasus21 0]

Actually I'm interested in getting a board too. Already sent tropical a pm just that farnell has no stocks for both colours of the hammond casing.

 

Wonder what other casings would be suitable. Another thing, why use 2 x OPA2134? At least in the schematics I didn't see the need for 2 chips since OPA2134 is a dual op-amp.

 

So I take it that WIMA caps are pretty good? Think I can get some off tropical too?

 

LOL

[gin. 0]

i guess he has just been flooded by PM. cause i sent mine , that i would like to have 2 boards too. hahaha.

[pegasus21 0]

lol. Hopefully he still has boards... but the casing is sold out as I've mentioned earlier. So your board will either be left in the open or you will have to make a casing yourself...

 

I think I'll need to study the trace... Anybody got the trace diagram? I want to see if I can use one of the browndog adaptors in the slot... otherwise i'll probably have to rewire the pcb a bit...

[heady 0]

lol. Hopefully he still has boards... but the casing is sold out as I've mentioned earlier. So your board will either be left in the open or you will have to make a casing yourself...

 

I think I'll need to study the trace... Anybody got the trace diagram? I want to see if I can use one of the browndog adaptors in the slot... otherwise i'll probably have to rewire the pcb a bit...

 

Hi,

1. The CMOY2 follows the A47 schematic and not the CMOY, so one dual opamp is for one channel only which is why you need two 2134 for L/R.

 

2. I personally don't recommend the casing specified as it is a little too small for the panel components ie. jacks, volume pot and LED. If you solder the pot onto the pcb, then for sure using this case is going to be a pain.

 

3. A browndog won't fit as the pcb is really small and compact.

 

4. Sound quality of the CMOY2 using standard chips - VERY good especially if you consider the cost to build this. It is a whole lot better than a CMOY but not quite as good as a standard Pimeta.

 

That's my opinion.

 

[pegasus21 0]

Ok, had another look at the schematics. Yeah I get the 2nd op amp in a single channel thing now. The 2nd op-amp looks like it's just a buffer.

 

Anyway, in terms of power requirements, which design has a lower consumption. CMOY or A47? Cos I remember jason or tropical saying that they get like 6hours or so with this.

 

Was thinking of using 8066 or 8620 with this. They are pin compatible just that they come in SOIC only so I'll just have to see how to get it in the circuit. The browndog with SOIC won't work huh then maybe I'll just use solder on a breadboard cut to size.

 

627/637 would be too expensive in this setup since I'll need 4 of them unless I mod the circuit. 843 might still be alright.

 

Just hope tropical replies soon.

 

Oh yeah the casing. I was thinking of getting the volume pot with switch like someone did so that should fit just nice in that case. That's assuming there's somewhere I can still get the Hammond from. Got any casing that's slightly bigger or know where to get the Hammond? I'll like to know the place to get too.

 

Thanks.

Edited August 21, 2006 by pegasus21

[jasonhanjk 0]

Link here:

http://www.sgheadphones.net/index.php?showtopic=3220

 

I remembered had tried more than 12 hours continous on that, I think.

[jasonhanjk 0]

Hi,

1. The CMOY2 follows the A47 schematic and not the CMOY, so one dual opamp is for one channel only which is why you need two 2134 for L/R.

 

2. I personally don't recommend the casing specified as it is a little too small for the panel components ie. jacks, volume pot and LED. If you solder the pot onto the pcb, then for sure using this case is going to be a pain.

 

3. A browndog won't fit as the pcb is really small and compact.

 

4. Sound quality of the CMOY2 using standard chips - VERY good especially if you consider the cost to build this. It is a whole lot better than a CMOY but not quite as good as a standard Pimeta.

 

That's my opinion.

 

I would agree on point 2. I never built the prototype with a "casing" and end up this way....

If a pot is needed then the stereo jack have to shift to the side, making it ugly. My bad.

 

Thanks on the point 4. Luckily I still have a proper casing.

[aaron-xp 0]

Yay... Should start on some serious work on this soon. Formed a small group specially for this also...

Will need some special "education" from you guys then.

 

Thanks in advance...