I've also done SMD prototypes. These amplifiers are fantastic. Good design doesn't need high power resistors. I use 1206's and maximum power throughout the board is no more than 100 mW. Sure, the amplifier is only designed for 35 W, but it can be changed slightly for 100 W (8 ohms), and still power per device won't change much. I only change the 4 SMD power transistors and the output transistors.
Future boards will have the solder mask, and I'll use solder paste, so things will be a lot neater.
Future boards will have the solder mask, and I'll use solder paste, so things will be a lot neater.
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Mrcloc
Nice small little board
What drivers have you used ?
Regards
Thanks, small was the idea. On this board, I have MJD340 and MJD350. They're identical to MJE340/50 TO126 transistors, and are actually better than people think. The MJE datasheets don't give a lot of information, but the MJD datasheets show they have Ft of 10 MHz.
Anyway, the actual drivers I use are BCP53 and BCP56 (SOT223). The footprint is for DPAK, but SOT223 is a drop-in replacement on that footprint, but fits better.
I just lift the middle leg.Interestingly, I use only 10k and 330E resistors throughout. The only change is a 15E 2512 on the output and then obviously the 0E27 power resistors. Total part count (excluding quantities) is only 16.
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That's just a nice bit of electronics to look at. Beautifully neat layout.
Just received the new boards, couldn't resist to solder a few tiny parts
Very-very nice lookig!
I like the compact power supply & protection board.
What is this new amplifier?
Very-very nice lookig!
I like the compact power supply & protection board.
What is this new amplifier?
The amplifier --> it is a variation of well known baby aksa55 found on this forum, with EF3 output on it. I have build a few prototypes and they are measuring nice so before I will listen to it I prefer the amplifier is made proper way (not a few bits and pieces on the timber board). It looks very similar to the commonly used amplifiers in 5.1 or 7.1 sinema amplituners. The PSU --> I have added ''direct path'' same as all other my amplifiers, found it to work perfect.
Some measurements bellow.
jamesfeline
I found SMD's are very easy and fast to populate, for the protection and less important circuits there are OK.
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Hello . just for the record I was not knocking your work but referring to my ageing eye site .. just to damn small and fiddly for me
Hello . just for the record I was not knocking your work but referring to my ageing eye site .. just to damn small and fiddly for me
LOL! You should see the gigantic magnifier I use to do my SMD soldering. These things are so tiny! I always buy some spare since dropping one on the floor is almost impossible to find. Also, when you grab them with the tweezers, if you're not careful and you don't grab them properly they fly in the air as if there was a spring. The positive side is you can get the parts for very cheap and thin film resistor in 0.1% for not too expensive as well.
But nothing beats good old TH parts!
Do
Fantastic idea! Best technique I have heard yet!
LOL!!! Very good idea indeed!!! +1
