It's hard to see cause the picture is so small but you'll probably need a decent heatsink if you plan on driving 4 ohm loads at higher power levels. The heatsinks shown in my picture were cut from an old Pentium 1 heatsink and turned out to be about 1.25" wide by 2.5" long by 1" high. I marked the hole locations, drilled them out with a drill press with a bit about the same size as the screws, smeared some thermal grease on the chip, and tightened the screws evenly.
After some further listening with different kinds of music, I've stumbled upon an interesting distortion problem. I was listening to piano concertos when I kept hearing this awful blurring of notes that only happened when higher pitch notes were played. It's hard to describe the sound but imagine that a higher pitch key is struck. You can hear the note but it sounds fuzzy and a bit distorted. It also seems to be relatively unrelated to the output power (volume) although I can only test this up to maybe 7W or so since it gets too loud at this time of night. I heard this on more than one recording with piano but I have yet to really hear this distortion with other material that does not have piano in it. The amps sound fine with basses and drums, vocals, and cymbal crashes. I'll do some more listening with classical music to see if I can hear the distortion with any other pieces. I'm not entirely sure what is causing the distortion. It could be related to the boards being so close to each other; particularly two of the output toroids which are about 1" apart with their center lines on top of each other. Hopefully moving the boards further apart or rotating one 90 degrees will get rid of the high frequency hiss and the distortion problem at the same time.
ericallan said:
Another dealer of experimental boards:
http://electroboards.com/index.php
Did several pilot projects with theese boards, perfect solution for me.
BWRX: " .... you'll probably need a decent heatsink if you plan on driving 4 ohm loads at higher power levels. The heatsinks shown in my picture were cut from an old Pentium 1 heatsink and turned out to be about 1.25" wide by 2.5" long by 1" high. ..."
The aluminum plate I planned to use is about 8" x 6" x 1/8" .... laying the board on top, w/'5261 face down touching the plate, caps up ... then using standoffs approx. same height as board clearence (minus a tiny fraction) and a modest amount of heat goop (that white silicon stuff) on the chip, snuggly mounted at the four corners of the board ... plate then deposited in the bottom of the plastic box ... better pictures to come, but I want to fonish off the board assembly first.
This '5261 amp will have an low pass, active crossover ahead of the '5261 input(s). Sub woofer is a 15" Pyle Driver bass speaker = 8 ohms, in a sub woofer case I reserected from the Great Petaluma Flood of 1986 ... still looks great, but the old driver was toast. The Ta-Killya plastic case will sit on top, connected to the sub-woofer via those cute #12 AWG stranded silver wires I sent you ... thump, thump, boom, boom =
The aluminum plate I planned to use is about 8" x 6" x 1/8" .... laying the board on top, w/'5261 face down touching the plate, caps up ... then using standoffs approx. same height as board clearence (minus a tiny fraction) and a modest amount of heat goop (that white silicon stuff) on the chip, snuggly mounted at the four corners of the board ... plate then deposited in the bottom of the plastic box ... better pictures to come, but I want to fonish off the board assembly first.
This '5261 amp will have an low pass, active crossover ahead of the '5261 input(s). Sub woofer is a 15" Pyle Driver bass speaker = 8 ohms, in a sub woofer case I reserected from the Great Petaluma Flood of 1986 ... still looks great, but the old driver was toast. The Ta-Killya plastic case will sit on top, connected to the sub-woofer via those cute #12 AWG stranded silver wires I sent you ... thump, thump, boom, boom =
Congrats on all your hard work!! Seems like the project is coming along nicely. I will be really interested to see how the performance of these boards turn out.
PS. I have a suggestion for your next project based on all of the great knowledge you learned with this one. Check out http://focus.ti.com/docs/prod/folders/print/tas5162.html for a preview of a high power full stereo device.
PS. I have a suggestion for your next project based on all of the great knowledge you learned with this one. Check out http://focus.ti.com/docs/prod/folders/print/tas5162.html for a preview of a high power full stereo device.
mp8: "... suggestion for your next project ... http://focus.ti.com/docs/prod/folde...nt/tas5162.html ..."
Yes, a tidy little package. The TAS5162 would probably make a great "boom box" type driver or possibly as a bi-amp in a self powered speakers ...Higher efficiencies and thermal enhancements = good, but this chip is a little too "preliminary" to get a feel for the possibilities.
Funny thing about the model numbers ...
mp8: You should start a new construction thread for this when the chip is beyond "TBA" ...
Wondering when TI is going to "standardize" on a footprint & pinout for dual channel amps ?
(Personally I am headed in another direction = minimum distortion at rated power, lowest possible crosstalk, highest quality output possible ... although coupling to power MOSFETs is getting there ... )
....
GeWa: Good choice ... I have one of similar design on a goose neck clamped to the bench = works very well.
Speaking of benches: I have a "pre-fab" kitchen counter top on a couple of hollow core doors on saw horses = works quite well and has that neat lump / ridge on the front edge that keeps things from rolling off onto the garage floor.
Yes, a tidy little package. The TAS5162 would probably make a great "boom box" type driver or possibly as a bi-amp in a self powered speakers ...Higher efficiencies and thermal enhancements = good, but this chip is a little too "preliminary" to get a feel for the possibilities.
Funny thing about the model numbers ...
mp8: You should start a new construction thread for this when the chip is beyond "TBA" ...
Wondering when TI is going to "standardize" on a footprint & pinout for dual channel amps ?
(Personally I am headed in another direction = minimum distortion at rated power, lowest possible crosstalk, highest quality output possible ... although coupling to power MOSFETs is getting there ... )
....
GeWa: Good choice ... I have one of similar design on a goose neck clamped to the bench = works very well.
Speaking of benches: I have a "pre-fab" kitchen counter top on a couple of hollow core doors on saw horses = works quite well and has that neat lump / ridge on the front edge that keeps things from rolling off onto the garage floor.
BWRX said:
In the "top part location 1.gif" have a look at D5 and D6. You can see that the stripe for D5 is facing the edge of the board and the stripe for D6 is facing the middle of the board. The stripe on the actual plastic diode body should be facing the same way as shown in the drawing. Sorry about the lack of a silkscreen marking. I thought there was one for that part but apparently there isn't.
BWRX: " ... Are you finding surface mount soldering to be as hard as you thought it would be? ..."
Yes!
Note to kit and board designers: Where ever possible use the R1206 / C1206 or larger package types for surface mounted resistors and caps.
So far I am only up to strip 'o' parts #4 and I have lost two and broken one ... When them teeny tiny buggers are picked loose from the plastic carrier they can flip so far that I don't even think I will get 'em with the vacuum claner ... ... I don't even wanna talk about "how did you manage to break one of those?"
Looks like I'm gonna have to get some more parts somewhere ... fortunately, BWRX has been thoughtful enough to include the Digi parts numbers on the kit BOM list ... but,
Yes!
Note to kit and board designers: Where ever possible use the R1206 / C1206 or larger package types for surface mounted resistors and caps.
So far I am only up to strip 'o' parts #4 and I have lost two and broken one ... When them teeny tiny buggers are picked loose from the plastic carrier they can flip so far that I don't even think I will get 'em with the vacuum claner ...
... I don't even wanna talk about "how did you manage to break one of those?"Looks like I'm gonna have to get some more parts somewhere ... fortunately, BWRX has been thoughtful enough to include the Digi parts numbers on the kit BOM list ... but,
A little tip for removing the parts from the tape (that's what the "cut tape" option means in the digikey search): keep the tape flat on your workbench and hold it down with your one hand with the clear covering face up. GENTLY peel back the clear covering with tweezers if you only want one or two parts. If you want more peel the whole clear covering off. Now gently flip the tape over so the components fall out of the tape. Pick up the tape carefully in case any parts stick to it. If they do carefully tap the tape or carefully remove them with tweezers. The smaller the part, the more care you need to exercise because it's easy to lose them. Also, be gentle with your tweezer grip! You only need a little bit of pressure to pick them up. If you grip them tight you can crack the ceramic substrate of the caps or the alumina substrate of the resistors. Try keeping your forearms on the table when moving parts with tweezers. This decreases your chances of breaking or losing the part and increases your chances of ever finding it again if you do happen to drop it! Another little tip is to use your other hand to steady your tweezer hand when placing parts (if you need to steady it). Avoid drinking beverages with caffeine too, they can make you less steady. If anyone has any tips to add please let us know.
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