*** The DIY Audio Thread ***

[gurusan]

I used a pretty good araldite epoxy, I don't think it's going to go anywhere. And are you sure? I only had the thing on for a few minutes and the heatsinks got warm...? Anyway I'm just going to drill a few holes on the top and a few on the bottom to let warm air rise out.

As for the opamp, that me just ripping it out...I didn't really care. It's the stock JRC one and I can't see it ever being used again.

 

[MikeHunt79]

It wouldn't really hurt to add ventilation, the 5v reg does get a little warm as it has more voltage to drop.

 

[gurusan]

I think it might be fine with a metal enclosure, but I am using an acrylic one and it seals up nearly perfectly....would imagine in a few hours it would be mighty toasty

 

[p4radox]

good good, how is the amp10 coming along?

The AMP10 is ready to be plugged into some speakers. It's finally passed the mute test which has taken days of debugging! I'm going to finish modding the DAC tomorrow as well.

It's all coming together finally, now I just need to figure out my rather complex source selection and indicator circuit.

 

[Katoom]

How does an Amp 10 sound compared to an Amp 6?

 

[Kanifee]

How does an Amp 10 sound compared to an Amp 6?

Also interested in amp6 vs lm3886 gainclone, i dont have much need for an amp6 at the moment but i may need another amp soon so id like this an option because of the price, just dont know how it would hold against the gainclone.

P4radox, id be really interested in how you get on with source selection and indication, im searching for something to do this job for me and havnt found anything that tickles my fancy yet. Would you be so nice as to share build plans and photos

 

[ChrissyT88]

damian - i'm thinking of trying the gainclone, although at the moment as i dont have the cash! The ones from chipamp.com look like good kits, but the kits by peter daniels also seem to have a good reputation. Reading on diyaudio (on the class D section, so opinion may be biased) someone asked which would be better - class D or gainclone. Several people mentioned that the gainclone has a lot more power than some of the class d amps (amp 6 included), and hence was better for certain types of music, but others said they had switched away from their expensive gainclones to class d amps (pairted with good a quality SMPS). Still, i would like to give it a go. Im still waiting on my control kit from dantimax... its been nearly three weeks since i ordered, and i cant seem to get hol dof the owner...

 

[gurusan]

guys i think the chinese DAC definitely needs some ventilation.

After about 10 min the large heatsink was 58C...and a few minutes later evened out to about 60C...and this is outside the case! The other ones barely put off any heat...they stay about 30-35c or less

.....does anyone know the temp specs for these VRMs?

On another note, this DAC sounds seriously good! Going from Winamp playing FLAC rips -> ASIO -> Optical out -> DAC -> CMOY -> HD-580

I have swapped a LME49860 in (LM4562) and it sounds MUCH better...but I would like to bypass the output stage completely and for the signal to go straight to my CMOY.

How can I do this?


and another sidenote, I changed out the .1uF output caps on my CMOY to 2.2uF caps and OMG I didn't realize how much my bass was lacking before. Now my -3dB point is at 7.23Hz instead of 159! lol!

 

[Kanifee]

Great news, what what shop did you get those enclosures from, an how much?
Looks pretty good, like its compactness.

 

[gurusan]

can't name them as they are a competitor but think radioshack of the UK

They are cheap and one thing to note is that there is a casting flaw on one side of the case where they injected the plastic in, it's very minor though and I have it on the rear side so it's not seen...and I'm sure it can be removed if you really wanted to.

You can see it just below the LED in this post http://forums.overclockers.co.uk/showpost.php?p=12441607&postcount=369
Obviously on the cmoy enclosure I didn't realize it was in the front until too late. Oh well

They are between 3 and 9 quid I think, depending on the size.

 

[Kanifee]

I do quite like that, would do nicely for a little desktop amp once my main system is built, might have to invest in another chinese dac and a amp6 as that doesnt need heatsinks as far as i know!

 

[MikeHunt79]

I do quite like that, would do nicely for a little desktop amp once my main system is built, might have to invest in another chinese dac and a amp6 as that doesnt need heatsinks as far as i know!

The amp6 gives off very little heat and can use an Alu case as a heatsink, but even then it's only really needed when driving 4 ohm loads.

I wouldn't use it in a plastic case with no heatsink however...

 

[Kanifee]

The amp6 gives off very little heat and can use an Alu case as a heatsink, but even then it's only really needed when driving 4 ohm loads.

I wouldn't use it in a plastic case with no heatsink however...

some mesh ventilation at the rear with some aluminum angle as a heatsink should be fine yes?

 

[Katoom]

@ p4radox

I've bypassed the output stage by removing the 4 caps and running it direct from L and R, but now my volume has shot up, like it was before fitting the Pot.
On yours, it looks like you have removed another 4 caps and bridged the two smaller ones. Is this also needed?

 

[Kanifee]

The extra 4 caps that p4radox has removed are merely for the power circuit of the opamp and as the opamp is removed the caps are no longer needed, that said they are not compulsory to remove either. I cant comment on volume as i havnt removed mine yet though i would expect the removal of the opamp to effect the volume in some way.

 

[gurusan]

I'm confused on this output stage thing. I currently have the DAC connected to my CMOY, and later on it will be connected to whatever other headphone amps I build (next is Millet Starving Student)

What's the point of the output stage? Doesn't the DAC just need to convert the signal to analogue then send it over to my headphone amp?

 

[Kanifee]

the output stage works as a weak universal preamp/headphone amp. because its crammed onto the small board with the rest of the dac and made to be universal to the users needs be it headphones or output to a power amp its a bit poo. By taking away the output stage you do away with any influance the opamp has on the raw converted signal of the cirrus chips and leave that job to your more adequate/quality pre/headphone amp that follows the DAC.
I think i got that rite!

 

[MikeHunt79]

^

Yep you've summed it up rather well... Remember op-amps add a small amount noise so bypassing the output stage on the DAC means you are getting a cleaner signal into your CMOY/Millet.

some mesh ventilation at the rear with some aluminum angle as a heatsink should be fine yes?

Yep that should be fine... I think looking at the datasheet the tripath chips have thermal shut down, but I'm not sure if I'd like to be the one to see if it works. What impedance are your speakers?

Once you have the amp up and running, try it out with your intended speakers, with the volume pretty loud - the Alu angle should only get warm. If it burns your finger something is not right...

 

[Kanifee]

4ohm drivers with 8ohm tweeters, not sure what you would work that as though im going to upgrade them soon but the hifi first

 

[gurusan]

thanks for the explanation guys, that's sort of what I figured...but how do you bypass it? I tried just unplugging the opamp but get a lot of background noise. When I touch my hand to the 3.5mm plug it goes away and the sound "changes' when I move my hand around my headphone amp?