ChipAmp Completed!

[fiat79]

So, finally completed my chipamp and thanks to all here who provided me with help! I will post pics as soon as I figure out how to do so on this site. I am pretty pleased with it turned out, overall. I could have done a better job on laying out/ drilling holes in the casework but other than that............

Just to bring everyone up to speed, this was a four channel amp with a dual 2-way electronic crossover built-in. The unit is being driven by a Squeezebox Duet through an Alps 10k pot. I used 4 boards from Chipamp.com along with one of Brian's PS boards as well. I did not use the individual diodes but elected to use seperate bridges instead. I populated Brian's boards as he recommends on Chipamp.com, deviating only to follow Danielwritesback's suggested zobel values.

The sound is just fine, as compared to the Denon mid-fi receiver it replaces. The bass is deep, the mids and highs are clean and clear. Iwas able to keep the dreaded ground loops at bay, with next to no hum or other noise. If I could wish for anything to be better, it would be the overall dynamics/ transients would be of a higher impact. They seem slightly soft compared to the Denon. I don't have the proper transformer installed yet and that may be all it is or I might need to start tweeking caps, etc. I'm also wondering if I should change the input resistor network on my boards - perhaps I don't even need them???

[fiat79]

I've made a few improvements, namely installing the correct, higher current trans. in place of the "test trans.", made a big difference! Next, I added 4700uf to each rail of the ps and also the 4.7uf cap, a mylar, across the +- rails as recommended by danielwritesbac.

I'm very pleased with the result; I would like to try a few more mods, like eliminate R1 to increase the drive level a bit but I hate to stop listening.

[irishlyrucked]

to post pictures, just add them as attachments.

[fiat79]

Okay, so I will give this a try. Hopefully, the pics turn out - let me know if I do something wrong.

[wintermute]

Hi Fiat79, Nice job I'd probably have placed the volume pot further from the powersupply, but if it isn't picking up noise then no worries

What are you using for the filter circuits?

Tony.

[Studio Au]

Looks good,

I've been wanting to build some chip amps for ages now, making do with eBays finest Class T and and old slightly broken, very hummy Rotel amp.

How hard was the build process, my electronics knowledge is zilch and soldering skills quite poor.

Would you recommend the chip amps kits, as i keep on swaying to the dirt cheap finished boards on eBay, which must be of inferior quality.

Well done.

[fiat79]

Thanks for the very kind comments. I put the pot where I did as there was already a 1/2 inch hole there - I would have preferred mounting the pot in the center of the panel, fo looks, but then, what to do with the large hole? In any case, it's not picking up any noise -this amp is quiet thanks to all the help I got here with the grounding, etc.

I'm using kits from Marchand Electronics for the filters; they are very reasonable and I've dealt with them for years. I have 2 way ribbon/woofer loudspeakers I built and am using 650hz crossover points.

No doubt, you can't go wrong using chipamp boards from Brian or Peter among others - their quality is high and the kits make it painless. That said, you do need to be able to solder. Perhaps you could get the kits and find someone to help you with the soldering?

I find it hard to experiment/tweek my amp as I hate to turn it off - I just want to listen to it! Later this winter, I will rework another enclosure I have (and do a better job!!) and move everything over. I want to squeeze in another set of input jacks and run my dvd into it. Maybe by then I can turn it off!

[wintermute]

hehe not a bad thing at all that you don't want to turn it off! That to me says you got it right and tweaking (at least for now) is not something you should be worrying about. Usually for me the thing that sets me off on a quest for better sound is having heard something noticably better than what I already have. So at least for me, the key to keeping the bliss, is to not listen to anything else (Better)

Tony.

[katana2112]

Nice work!

[fiat79]

After much listening, I decided to lower my cx point to 450 hz; this turned out to be the icing on the cake! The bit of extra "fullness" in my midrange disappeared and it appears I've gained a bit of soundstage as well.

While I was tweeking, I tried playing a particular track and removing/inserting the 4.7uf cap across the +v and -v. Unbelievable! With the cap out, everything shrunk up a bit and it seemed as if the freq. range was slightly tilted up. With the cap in, everything opened up and there was even more midbass! I can't explain it but there was no denying it.

I'm more than satisfied now so I think I will just sit back and listen.