[__redruM]

I have just finished DaKiller's TPA6120 based amp. I put it in the 1455N1201 case, and used Kobiconn 3.5mm in/out jacks to connect to my ipod. The build went really smooth, and the SMD stuff was easy. The heat pad on the bottom of the TPA6120 was tough though.

I had two issues durring the build. I put one of the 10uf caps on backward, and this caused voltage level issues. After I fixed that, I found that the -12v pin on the TPA6120 wasn't soldered down. Luckily, no damage was done, and with these issues resolved, the amp sounds great.
I really like the built in power supply, and the blue LED is really, really, bright, and looks great. I glue-gunned all the bare 120V portions, and I'm still trying to decide on what to ground the case too? Input Ground, or A/C (Earth)Ground.

DaKiller was a lot of help and answered a ton of PMs.
Thanks, DaKiller!

 

[JWFokker]

So the super tiny SMD components weren't an issue?

 

[Garbz]

I was scared of super tiny smd components too at one stage. I love them now. I SMD everything. THey are sooo much easier to work with. No leads to clip no holding componets in while u turn board upside down.

It's all just pre solder the square, grab part in tweesers, place on, tap with iron, and done. No fuss, and the only problem may arise if you drop them (they are hard bastards to find on a dirty floor)

Nice work btw.

 

[Syzygies]

Quote:

Originally Posted by Garbz and the only problem may arise if you drop them (they are hard bastards to find on a dirty floor).

Been there. I felt like I was looking for someone's contacts.

Of course, try repairing a bike on a Fire Island deck over a patch of poison ivy. If a part falls through the cracks you find another one.

 

[__redruM]

Those resistors are tiny, but I was very carefull not to drop them on the floor. Once I figured out how to hold them down with the tweezer, I went through them pretty quickly.

I'd like to try to design one similar, that's all or mostly smd, and target the smallest hammond case. Guess I'll have to figure out eagle-cad first...

 

[Kenny12]

i think smt is actually a lot faster than normal parts

 

[DaKi][er]

They are a-walk-in-the-park-on-a-sunny-day sized smd components on there compared to what else is out there in the world

I don’t see why you could really be scared of this stuff, going down to SSOP and 0806 or 0604 sized components will be getting very fiddly and I wouldn’t recommend to anyone unless they had a good lot of experience

Very nice work there __redruM, nice to see someone manage to actually get the evil pot shaft extender going and apart from not having the input connector on the back panel you got just about the layout I designed it for
But more importantly, how’s it sound?

 

[Jazper]

when I built my dtpa killer I grounded the case both to the input and the earth on the ac *Shrugs* no harm in being extra safe -no difference in sound quality

 

[__redruM]

I'm really happy with it, it sounds great. Gotta give it some time to be sure, but it sounds on-par with my pimeta or PPA. The bass is solid, and the mid and trebble is crystal clear.

I'm surprised how little hiss there is. Usually with my very sensitive shure e5c, I hear hiss, but even with a gain of 8, the hiss level is almost inaudible, and non-existant with my other phones.

I am getting a little hum from the transformer on the E5c though. Any recomendations? My input wire is shielded. Whats the best way to shield the transformer. I didn't ground the POT, I might try that to see if it helps.

Th extender works fine. I had to play with it a little to stop it from binding, but it's working for me. I always prefer a board mounted POT.

 

[__redruM]

Quote:

Originally Posted by Jazper when I built my dtpa killer I grounded the case both to the input and the earth on the ac *Shrugs* no harm in being extra safe -no difference in sound quality

That would connect the middle output of the transformer to AC ground. I don't know enough about transformers to guess if that's ok, but I guess it is if it's working for you.

I measured the AC Voltage difference between Amp Ground and AC-Ground. Power off I get a 9V(AC) difference and a 16V(AC) difference with power on.

 

[DaKi][er]

Quote:

Originally Posted by __redruM I'm really happy with it, it sounds great. Gotta give it some time to be sure, but it sounds on-par with my pimeta or PPA. The bass is solid, and the mid and trebble is crystal clear. I'm surprised how little hiss there is. Usually with my very sensitive shure e5c, I hear hiss, but even with a gain of 8, the hiss level is almost inaudible, and non-existant with my other phones. I am getting a little hum from the transformer on the E5c though. Any recomendations? My input wire is shielded. Whats the best way to shield the transformer. I didn't ground the POT, I might try that to see if it helps. Th extender works fine. I had to play with it a little to stop it from binding, but it's working for me. I always prefer a board mounted POT.

Defiantly ground the pot. There are a few holes next to it you can use just for that, without it I got massive amounts of humming especially when you touch the knob
Also at least tie the case to the amp ground as well, it will help a lot in shielding of it in general

 

[Garbz]

Quote:

Originally Posted by __redruM That would connect the middle output of the transformer to AC ground. I don't know enough about transformers to guess if that's ok, but I guess it is if it's working for you. I measured the AC Voltage difference between Amp Ground and AC-Ground. Power off I get a 9V(AC) difference and a 16V(AC) difference with power on.

No worries there. Ur tieing 0v to Earth which is normal practice somewhere in the equipment anyway. I personally recify both sides of the transformer then join the two rectifiers and use that as my ground. I keep the ground floating throughout the amp stared to the main amp board, and then tie that to earth at the input jacks.

That fixed the groundloop of my last amp where I screwed the grounding horribly. It sounded much quieter then a ground loop breaker.

 

[DaKi][er]

Quote:

Originally Posted by __redruM That would connect the middle output of the transformer to AC ground. I don't know enough about transformers to guess if that's ok, but I guess it is if it's working for you. I measured the AC Voltage difference between Amp Ground and AC-Ground. Power off I get a 9V(AC) difference and a 16V(AC) difference with power on.

The thing with transformers is there is no electrical connection between the primary side and secondary side at all, so you can make your 'ground' on the secondary side whatever you want really depending on the situation
This situation forces ac ground to be the same as the amp ground if you are connecting a source that has its output signal ground connected to its own ac ground. Though if you connected a source that had no connection at all to mains (like the ipod you got in your pictures) then it would be possible to connect ac ground to any of the voltage rails in the amp, not that you would want to do that but just to point out that it would work in the end

You are measuring between 2 entirely separate circuits that are not connected electrically at all which would be making your meter play up

 

[primer]

daki][er, do you know of any vendors that sell pot shalf extenders in Australia?

 

[DaKi][er]

Quote:

Originally Posted by primer daki][er, do you know of any vendors that sell pot shalf extenders in Australia?

nope, never got one for mine in the end
i think jaycar had some shaft couplers but then you got the problem of bearings to support it on the case end
also http://sound.westhost.com/index.html has a shaft extender but they are quite long and a little pricey