*** The DIY Audio Thread ***

[gurusan]

Mr. Brightside, well done...glad to see other people on OcUK have built the Alien DAC, as I've just ordered a kit.

I was tempted to construct an amp as well, but the little dot 2 looks like such a nice deal and i think i'll just go for that.

 

[ChrissyT88]

Paradox, i would be interested to hear how the amp10 sounds (plus how easy it is to build!) - it does look like a nice kit, although judging by the volume of the amp6, 100w of power would be pretty over the top for me!

Im thinking about replacing the caps on the amp6 with black gates (provided they are the correct sizes) as these seem to get good 'reviews' from almost everyone. Is it more important to replace the input or output caps (since the black gates are a little pricey)?

Thanks for the aikido suggestion Adam, but i think tubes may be a step too far for me just yet. I think i just need a passive preamp - can you suggest anything?

 

[adamau5]

passive?

just get a good stepped pot - ebay has plenty that are cheap.

 

[p4radox]

Paradox, i would be interested to hear how the amp10 sounds (plus how easy it is to build!) - it does look like a nice kit, although judging by the volume of the amp6, 100w of power would be pretty over the top for me!

Im thinking about replacing the caps on the amp6 with black gates (provided they are the correct sizes) as these seem to get good 'reviews' from almost everyone. Is it more important to replace the input or output caps (since the black gates are a little pricey)?

So far it's been fine, although my iron is on its way out and the tip is a bit too fat. I'll order a new one tomorrow probably. It's all through-hole although some of the pads are tiny!

On the cap front: I've got no idea to be honest. Ill be doing some mods myself at some point, but I want to get it sounding good without any first.

 

[Kanifee]

" "

Very excited about this build, Glad everything arrived sharpish!

 

[ChrissyT88]

Ill be doing some mods myself at some point, but I want to get it sounding good without any first.

Yeah, i agree totally! I made the mistake of writing off a working kit and ordering another, so i'll have one to mess around with, hence the interest in modding. As i mentioned, i would be interested in the sound, since this looks like the only real upgrade from the amp6 (that uses through hole stuff!). Looks like it will be a cool project - did you decide on a headphone amp/enclosures you going to use?

 

[p4radox]

Looks like it will be a cool project - did you decide on a headphone amp/enclosures you going to use?

The headphone amp is an interesting one really. It's another one of those things I'm thinking about, but if possible I'd rather add a separate output stage from the Class D that's suitable for the high impedance/low power of my headphones. I'll have to look into it, and probably end up asking on here for advice, after I've got the amp and the DAC working and talking to each other correctly.

If I were to end up with a separate headphone amp, I might even look into tube amps: they're just so awesome looking.

As for the enclosure I'd like something from modushop, probably:

http://www.modu.it/pesante.html

in black:

http://www.modu.it/pesante_nero.jpg

The Pesante Dissipante looks even better with its massive heatsink sides, but the class D really doesn't need them and I'd be throwing my money away.

 

[Kanifee]

I'd be throwing my money away.

Thats all this hobby makes you do


Definatly the correct choice in enclosure, stunning for the money arnt they. Just a shame im going to need 4 with new machined front and backs doesnt stay cheap for long does it.

 

[MikeHunt79]

Paradox, i would be interested to hear how the amp10 sounds (plus how easy it is to build!) - it does look like a nice kit, although judging by the volume of the amp6, 100w of power would be pretty over the top for me!

Have you seen the amp 9? It's basically an amp 6 gone mad.

 

[ChrissyT88]

4x100w would probably be a little too much . Still, the basic model looks like it would be (relatively) easy to build and very similar to the amp6, your right. I tried my amp6 using my pc as the source w/ a volume control pot, and had to set the soundcard to 8/100 else it was painfully loud (and clipped a LOT at higher volumes - but i guess thats to be expected). I presume the main advantage in having a much more powerful amp is that you stay within the linear amplification range at higher volumes.

Im still deciding on enclosures and the passive pre. The modushop cases do look nice, and i think i will probably go for one eventually (although the machining will add even more to the price... ). I have sent an email to the people at dantimax to ask a few questions about their pre amp kits - they look pretty good.

I also got some new speakers yesterday, but i must admit im paranoid about hooking up the amp6 to them! I was looking at some speaker protection circuits too (for peace of mind). Do any of you guys use these?

 

[MikeHunt79]

In older PA and car amps speaker protection is pretty simple... A relay trips if there is too much DC on the speaker output. You can also add a timer to the relay to prevent turn on thump (if there is any).

 

[ChrissyT88]

Cheers, thanks mike. Another quick question: the new speakers have a nominal impedance of 8ohms. I understand that the amp6 will give half power at this higher impedance, but that the frequency response could be hampered by the output filter caps. I presume i can change these to optimise the amp for 8ohm speakers, but how do i work out what i need to match the impedance of the speakers?

 

[MikeHunt79]

I remember seeing an online calc somewhere on the 41Hz forums, I think it makes very little if any difference (it apparently effects frequencies outside you hearing range)...

I've used mine with 6 an 8 ohm speakers, no issues (apart from reduced power). What speakers are they?

 

[ChrissyT88]

B&W 685s. The spec says they have a nominal impedance of 8ohms.

 

[MikeHunt79]

They will be fine. Just looked them up and they have a minimal inpedance of 3.7ohms also, if I were you I'd leave output filter caps as they are.

 

[ChrissyT88]

Okay, cheers mike. I didnt notice the minimum impedance in the spec. I think its just as well - its proving pretty hard to find caps that people over at DIYaudio rate as 'audio grade' that are small enough to fit on the board (and are reasonably priced). I think i may change some of the input caps for black gates as they dont seem too pricey, and it will be interesting to see if they make a difference at all. Although i must admit, some of the recommended audiophile brands charge ridiculous prices (my fav is the Audionote 3.3uF silver foil cap: £880). Id consider £5 for a cap to be a heck of a lot!

 

[MikeHunt79]

As far as caps go, I quite like OSCON's myself, I've found it pretty hard to tell a difference really tho... Experiementation is the key. Having a 2nd amp will be perfect, as you'll be able to compare them side by side.

I'd be interested to know of any differences once you get around to it.

 

[ChrissyT88]

Sure, i'll let you know. I should get the second amp sometime this week, but i get the feeling i'll probably be waiting on the new caps + some solder before i can get started. Hopefully by this time next weekend i should have an answer.

 

[p4radox]

Oscons are what I'm planning for the DAC and for the AMP10. When I get around to it.

I've just placed a rather large order at *. The only thing missing are the knobs for my volume pot and input selector. I found some gorgeous black brushed aluminium ones from a popular high street electronics store:

The problem is I've ordered everything else from the other store and I don't want to have to pay delivery for only a couple of items.

The front panel on the modushop case is something I'm going to do myself. I've got access to a very good workshop at the moment, and all I really need are some accurately drilled holes, which shouldn't be a problem.

*edit: might be a competitor too.

 

[ChrissyT88]

Quick question before i actually buy the black gates - can you replace, say a 16v cap with a 100v cap with no consequences, or is it best to match the voltage ratings as closely as possible?