*** The DIY Audio Thread ***

Well, it's been fine for the last 4 days or so, just with some background hiss.

In trying to eliminate this I tried:

Shielding
Twisting cables
Resoldering decoupling caps
Replacing decoupling caps
Resoldering the output filter inductors
3 different sources

Tonight I was attacking the inductors again. I plugged it in and think heard a small crack. It won't unmute again. Can't see any shorts anywhere. It just gave up on me.:(

The question now is, how much more time, money and frustration do I spend on this piece of crap for it to keep disappointing me?:mad:
 
I've just made the very hard decision to abandon my AMP10 board. It's had so much playing around done, that I fear I'll just be creating more problems by fixing it again.

I think I'll order an AMP10 BASIC tonight, unless someone can convince me otherwise, ie: an LM3886 kit.

I really like the idea of class D, and would love to have it working, but this kit has seriously dented my confidence in 41Hz.com. The schematic is inconsistent with the assembly instructions in some places, which makes debugging a complete chore.
 
Rod Elliots PCBs are also worth considering. I've built a few P101's and he makes it really to construct them, once you buy his PCB it gains you access to the construction document which you can print and work from:

http://sound.westhost.com/projects-1.htm

Will take a little longer to recieve the PCB obviously and might be a bit more tricky to order, plus you need to source the components yourself. Once you've done this though construction is very straightforward, all my P101s worked flawlessly from the off :)
 
Thanks Dr, that's something I'll consider for the future I think.

I've got a week and a half left until I go back to uni and I want a finished product by then really, so a complete kit is probably the best option right now.
 
Its a shame to heat about your amp10 p4radox. I was thinking about maybe giving it a go, either that or a gainclone. The amp6 basic does sound good if you are after a kit, and only really takes a few hours to assemble. Theres also the added advantage that both Mike and Adam have built one! Its not as powerful as the amp10, but with my PC as a source, i have to set the volume through the card at ~10-15% otherwise its way too loud for me!

Im headed off to uni next week and would really like to take a decent amp too - whilst my amp6 works, it just isnt cased up or anything. I would really like to carry on with the DIY, but its my final year this year and i have a feeling it could be a little distracting.
 
Oh yeah - id completely forgotten. The basic only uses an SMPS power supply - i was told that you could use one that you would use on a laptop/LCD monitor, but RS/the bay have some good ones (in fact on their web site in the pic they are using some generic laptop psu). I have a spare if you are interested, although you are right in that it would be waste of the traffo you bought.
 
I put my bedroom setup together tonight, using the chinese dac, and the amp 6 basic, through jbl monitors. Cracking little setup. It embarrasses my main setup in the detail department.

The amp 6 basic is very easy to build, although the boards arent that easy to solder too (poor quality).
 
What transformer do you have?

The amp9 basic is very nice, it has the same power as the amp 10 and 2 extra channels... plus it runs for anything between 12v up to 24v. It's a pretty simple circuit too, with only a few more components than the amp6.
 
It's a 22V 160VA toroidal transformer. I think this is too high for the AMP 9 unfortunately - it states a 27V supply, but my rectified 22V rail would give 31V.
 
Well it's not that far off... There will be a small amount of voltage dropped at the bridge rectifier, (around 1v) plus there are more protection diodes on the PCB itself... each one adding an extra 0.5v or so voltage drop.

You could always add another 3 or 4 diodes in series to drop an extra couple of volts in order to get under 27v. It would waste a bit of power but at least you wouldn't have to get another toroid.
 
So everyones making amps for Uni? Same here :D . Not making anything big or fancy though, just a small amp to power a 2.1 speaker set i'm building (mentioned the sub earlier). Am building the crossovers including notch filter, baffle step correction etc, at the moment. Amps are based on Velleman K4003 kits, couldn't be any simpler if your feeling fed up! Haven't done much testing of sound quality though specs suggest it'll be pretty average even with an improved power supply. Heres where I am now; finished by Saturday? Doubt it :o

 
The speakers are looking really good Dr. EM - your thread at DIYaudio is a really good read (plus the pics are nice too!). I would be interested to see what you think of them when your done. Have you made the curved backs? How did you do it in the end?
 
I really should update over at DIY Audio. Unfortunately theres no real news on the satellites, the paper backs haven't worked out and also i'm stuck with just 1 driver, may have to order from the US to get the second in a reasonable length of time :( .

My crossovers are nearly done now, the half finished board on the left of that photo is now finished and working apart from odd connectors. Do need a third board for the subs signal combiner though, can't believe I thought it'd all fit on one board initially! Also need to make the PSU block for that amp/crossover part as its not all self contained; the transformer doesn't fit in the transformer case though :( . Its not looking good for this being finished tomorrow :D;)

On the plus side the filters seem to be working nicely and this should be a very listenable system when finished. Gives me an excuse to come back at weekends I guess to finish this :)
 
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