*** The DIY Audio Thread ***

[Founder_film]

Haven't tested it from the TV. Used it to watch some DVD's though, very clear sound as with music but lacks the impact of a full 5.1 system. Although I am thinking a 5.1 channel gainclone would be great, future project maybe .

 

[Yaka]

so that would be a 5.1/7.1 processor -> a 5 chan gainclone amp?

 

[adamau5]

yaka, did you fix your millet SS.

If not, i dont mind giving it a go.

 

[Yaka]

not yet think the caps would need discharging. and judging by how it sparked up, it was sparking in circles around the heat sink somat is prolly dead either the chips or the tubes . totally regret rushing my self when doing it. crapped out a brick when it happnend. worse is that i sold my cmoy in the members market as well:/

 

[adamau5]

you'll need replaement mosfets. Were they insulated from the heatsink? they need to be.

Hopefully the tube will have survived. they are very tough.

check shorts to gournd from the 48v

 

[Founder_film]

so that would be a 5.1/7.1 processor -> a 5 chan gainclone amp?

I was thinking of buying a DVD/Blueray player that had analog outputs then have a mono gainclone for each channel (be it 5 or 7). As for the sub I would probably buy a prebuilt sub amp and make the enclosure etc.

I haven't done any research to check if this would work yet, but it is only a future plan.

 

[adamau5]

anyone got an chassis they want to sell, i need one for a preamp.

 

[Yaka]

not sure if its suitable i have empty shuttle case minus the front plate. they are preety easy to hack down to size. i hacked one down to size for an intel atom based pc. you can have it for nowt if you want.

and as for mosfets no i dont think i isolated them, i used a dab of thermal paste and screwed them on. i dint order the transistor mounting hardware as mouser was out i take that is what isolates it from the heatsink?

 

[adamau5]

yep, thats where you went wrong, the tabs carry 48v on them!

Cheers for the offe ron the shuttle case, but i am after something more like a hifi2000 case or, hammond.

 

[Yaka]

guess its part of the learning process for thicko like who didnt read things through properly.
is there anyone in the uk selling the mosfets and mounting kit or is mouser the place to irder from?

 

[adamau5]

farnell, or rapidonline, ebay, lots of places.

 

[Yaka]

cool rapid have em in stock.

 

[adamau5]

rapid are excellent.

 

[MikeHunt79]

Do anyone know anything about LM3886 chip amps (aka gainclone?). I only have experience with Class D (tripath) amps...

I bought some Event TR8 studio monitors recently, and they sound nice, and they have LM3886's inside! They're biamped...

I was wondering if there was anyway of getting more power out the amp some how... Bridging maybe?

The woofer is getting 50W and the tweeter is getting 30... I'd love to double the power if possible. The woofer is 4 ohms and the tweeter is 8.

I'm tempted to keep the PSU part, and maybe just replace the LM3886's with an Amp1 or something.

Finished my passive preamp to go with my gainclone. The knobs are temporary until I find some to mach the enclosures, also I will replace the pot with a better quality one or a proper attenuator.

Nice pre, quick quesition how have you wired the volume pot? I've heard a shunt resistor it meant to work better, but then so if active (buffered)... I'll post a pic of my 4 chan pre that uses Tuna cans as a case when I get round to it!

 

[Founder_film]

Nice pre, quick quesition how have you wired the volume pot? I've heard a shunt resistor it meant to work better, but then so if active (buffered)... I'll post a pic of my 4 chan pre that uses Tuna cans as a case when I get round to it!

All the channels groung signals are switched with the main signal, therefore the ground are isolated from each channel. I have litteraly wired the grounds directly for each channel.

The performance of the preamp is very good and there is still room for improvement. For example mounting the POT and switch closer to the connectors or rewiring with 99.99% silver wire. And of course using an attenuator.

I bought the same enclosure for the pre as I did the gainclone, not only cause it matches, but so I could add a buffer circuit if I wanted to make it an active pre.

 

[adamau5]

founder, there is a group buy on at diyaudio forums for a great nelson pass design, the ns10. Also some useful regulator circuits - may be of interest.

 

[Founder_film]

founder, there is a group buy on at diyaudio forums for a great nelson pass design, the ns10. Also some useful regulator circuits - may be of interest.

Thanks Adam, I saw that but buying the enclosure wiped me out of money for the moment (exchange rates suck!). Think I am going to make some interconnects next.

 

[Dr.EM]

Hmm, I regret not making just one 6 channel amp instead of 3 stereo ones. I couldn't have done it well when I started my first one but after having built the 3 I know I could do it now. The problem is I already have these 3 and couldn't really do anything alternative with them.

A 6 channel unit would have halved space requirements, avoided grounding issues, simplified circuits (like speaker protection and soft start, which are repeated by making seperate units) and just generally have been tidier. Would also have been less cotly from the outset. Ah well, learning is all part of it

 

[Founder_film]

Made myself some interconnects today. Very simple and sound great. Finished my project pretty much now though . Will have to start a new one!

 

[Dr.EM]

I recognise those parts (used to work in that shop ). They solder ok?

Start a 3 way triamplified system and build the amps, crossover and speakers yourself; there's a good chance you'll never finish !