sfogg Posted October 24, 2005 Share Posted October 24, 2005 ..... I built this more to get some experience working with SMT but it really is fairly shocking how tiny this amp really is. Glad I picked up a tiny pair of tweezers before starting this. I have to wind four small torroids and solder in the couple of through hole caps but other then that the amp is basically complete as shown minus a 12v PS. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 24, 2005 Author Share Posted October 24, 2005 Close up... Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 24, 2005 Author Share Posted October 24, 2005 Other side.... the coils will fit in the four unpopulated rectangles. Shawn Quote Link to comment Share on other sites More sharing options...
3dzapper Posted October 24, 2005 Share Posted October 24, 2005 Shawn, good work. I've got a job for you. It pays that whole dime an hour.[] Why? Rick Quote Link to comment Share on other sites More sharing options...
fini Posted October 25, 2005 Share Posted October 25, 2005 Where do the tubes go? Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 "I've got a job for you. It pays that whole dime an hour." Does that come with dental? "Why?" I build a device that is currently all through hole components. Considering moving to SMT (for a couple of reasons) and wanted to see what working with SMT is like without redesigning the boards and spending a bunch of money having new PCBs made. The amp kit was $25. Also wanted to see how quickly SMT can go together. I actually didn't hand solder most of this board, it was done using hot air reflow in an oven. That worked well except I had misplaced the main chip slightly... it wasn't making contact with a couple of pads (couldn't see it through the solder paste). I was able to rearrange that while it was still in the oven but then I needed to clean up a couple of bridges by hand afterwards. As a side benefit I'm sure I can end up using the amp somewhere. I am curious to see what its noise level will be like compared to the Teac for example. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 " Where do the tubes go? " Humm.... what do you think.... tube based PS for a digital amp? Shawn (Knowing that someone is going to end up doing this and selling them way overpriced.....) Quote Link to comment Share on other sites More sharing options...
NOSValves Posted October 25, 2005 Share Posted October 25, 2005 I had a friend bring over a car audio amplifier board the other day that he was trying to solder on and fix. He had someone check it over and advise what needed replacing. It ended up being a couple resistors and one of those 32 pin little parts. You should of seen the look on his face when I just started cutting all those little pins to get the device off the board 30 minutes later the part was installed and it works like a charm much to his surprise. It is a pain to solder on those small connections though. Craig Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 "It is a pain to solder on those small connections though." If you are going to hand solder a chip with a lot of pins it actually can be done easily pretty quickly as long as the board has a solder mask on it. Put a touch of solder on two opposing corner pins. Then place the chip and get it all lined up. Once it is lined up apply heat to each corner pin that you tinned. That will solder the chip in place and hold it for you. Then just quickly go down the line soldering all the pins. If you have a wide tip in the iron you can likely do 5 or six pins at once. Don't worry about bridges between pins yet. After you get them all soldered go back and look for bridges. When you find any put a piece of solder wick over the bridge and hit it with the iron for a couple of seconds and it will come right out easily. Much quicker then worrying about one connection at a time. Or get some solder paste and reflow the board. It is even quicker still and how I did this amp board. http://www.seattlerobotics.org/encoder/200006/oven_art.htm Shawn Quote Link to comment Share on other sites More sharing options...
3dzapper Posted October 25, 2005 Share Posted October 25, 2005 "I've got a job for you. It pays that whole dime an hour." "Does that come with dental? "Sure, you can use the company pliers.-)OK, you reflowed the solder. I pictured you with a hot iron. How do you keep the tny caps and resistors from sliding around as you move the board to the oven? Can you do both sides at the same time?Rick Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 Rick, "How do you keep the tny caps and resistors from sliding around as you move the board to the oven?" The 'solder paste' really is a thick paste. When you put the components into the paste it holds them in place for you. "Can you do both sides at the same time?" There is SMT glue that can be used, if you used that to hold each component in place I'd bet you could do it in one reflow. Using just the paste (before it has been reflowed) don't know if you can do both sides at once. The first four minutes of the reflow process is to dry out the paste... with it dried out it might not hold the components upside down. When I did the amp I did the side without the Tripath chip first then let it cool, pasted/placed the other side then reflowed the board again. Shawn Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted October 25, 2005 Share Posted October 25, 2005 Shawn: Where is this from? Erik Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 Erik, It is the amp3 from www.41hz.com Shawn Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted October 25, 2005 Share Posted October 25, 2005 Shawn: Those look like they would be fun to try. Do you have PSUs already built? Erik Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 Erik, Not really. Was just going to try it with a regulated bench supply I have and maybe see what the noise is like off a battery supply. Shawn Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 BTW... the amp6 (about the same power) is through hole and has the PS built in. Just need to add a transformer to make that one work. Shawn Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted October 25, 2005 Share Posted October 25, 2005 Shawn: Sure, I'll bet that would work fine to try things out. I'm curious how it might compare with the Teac. The efficiency of this technology is pretty amazing. Compared to something like an OTL, the difference is really significant -- SE OTLs in particular. Maybe I should buy a pair of those things from Transcendent -- I really liked them. Even one was enough for the majority of listening we do. Erik Quote Link to comment Share on other sites More sharing options...
sfogg Posted October 25, 2005 Author Share Posted October 25, 2005 Erik, Yeah.. huge efficiency difference between the Tripath digitals and the SE-OTL. The Tripaths are around 80% (and other digitals are even higher) while the SE-OTL is about 1% efficient. Still, I really liked the SE-OTL too, wish I still had the one I built. With the tri-amped setup I think its whole watt or so of output would be plenty. If I put 16ohm diaphragms in the mids I'd have around 3w per channel out of the SE-OTL. Shawn Quote Link to comment Share on other sites More sharing options...
leok Posted October 26, 2005 Share Posted October 26, 2005 Shawn, Nice work. Let us know how it sounds (you didn't say on page one of this thead did you?). Of the "digitals" I'm only real familiar with Tripath. Leo Quote Link to comment Share on other sites More sharing options...
Marvel Posted October 26, 2005 Share Posted October 26, 2005 Leo, All but one of the ones from 41Hz are Tripath chip based. Those are really cool. Bruce Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.