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Amplifier Modules and PCBs For Sale

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Deleted member 148505

Prototype sample pics. Heatsink mounting test (not yet drilled and tapped)
 

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AlexScan

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Joined 2011
JLesterP said:
It's cheaper and looks like construction is the same, I'll look for more inductors which are cheaper.
Click to expand...

Ok the specs of 7G17A as the same... but the B version as lower DCR and same Isat... but its' difficult to find...

According to datasheet another Sagami may suitable for better performance :

https://www.sagami-elec.co.jp/file/08D-AMP_7G.pdf

Can you put some 7G23/31 in size ?
 
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AlexScan

Member
Joined 2011
JLesterP said:
1d17a and 1d23a's prices are similar on mouser. If I will put 1D23A I have to remove the fuse to open up some pcb space, maybe I should remove it? since most power supplies have fuse on them already.
Click to expand...

Yes all smps have fuse (or on DIY case IEC input), don't worry remove them for put big size choke...

1d23a is good for the price...
 
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amplidude

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Joined 2016
Started assembling the "simple killer amp" heatsink is from an old pa amp, there are two and they will be cut in half to accommodate 4 modules, outputs are mounted with spring clamps, I believe they do a better job than bolts, they apply constant pressure regardless of heat/cold, also a leftover from pa amp, a nice feeling putting it together..;) will post the finished amps also, sure they will be a stunner, both visually and audio wise.
 

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D

Deleted member 148505

AlexScan said:
And for the tank capacitor which model you choose ?

Pana FC is good choice for the price on mouser... and it's sound good.
Click to expand...

Will use decent lelon caps for tank capacitors, i'll just leave the upgrades to the users.

amplidude said:
Started assembling the "simple killer amp" heatsink is from an old pa amp, there are two and they will be cut in half to accommodate 4 modules, outputs are mounted with spring clamps, I believe they do a better job than bolts, they apply constant pressure regardless of heat/cold, also a leftover from pa amp, a nice feeling putting it together..;) will post the finished amps also, sure they will be a stunner, both visually and audio wise.
Click to expand...

Wow nice build :cool:

That's why I don't write product build guides anymore (only schem and BOM), because builders / DIYers have better ideas than mine :eek:

I will try spring clamp on my build. Thanks!
 

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amplidude

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Headed into trouble again.
I recieved from you two boards more, and finished one yesterday, it is build from exact same parts as the other 4, except the output mosfet are from Harris intersil, still very close in vgs on.
My problem is again oscillation, and a stubborn one, it oscillate at 6 mhz, with shorted input and 8 ohm dummyload connected, I tried your suggestion with no connected ground solder point, instead a short wire from ground to 10 ohm resistor, didn't do anything, I suspect the n channel mosfet from harris have high gate charge and that might cause instability, the 6mhz oscillation increases as I increase bias, what to do? Gate/drain capacitor something to slow it down? I also checked the zobel, inductor/capacitor are okay, checked bad solder points, I put 100nf across large capacitors also with no change.
By the way I didn't have 47 ohm gate resistors so used 56 ohm, same as the other 4 which work.
 
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Deleted member 148505

amplidude said:
Headed into trouble again.
I recieved from you two boards more, and finished one yesterday, it is build from exact same parts as the other 4, except the output mosfet are from Harris intersil, still very close in vgs on.
My problem is again oscillation, and a stubborn one, it oscillate at 6 mhz, with shorted input and 8 ohm dummyload connected, I tried your suggestion with no connected ground solder point, instead a short wire from ground to 10 ohm resistor, didn't do anything, I suspect the n channel mosfet from harris have high gate charge and that might cause instability, the 6mhz oscillation increases as I increase bias, what to do? Gate/drain capacitor something to slow it down? I also checked the zobel, inductor/capacitor are okay, checked bad solder points, I put 100nf across large capacitors also with no change.
By the way I didn't have 47 ohm gate resistors so used 56 ohm, same as the other 4 which work.
Click to expand...

Putting 100nf across large capacitors is not advisable as it can form resonance circuit which might trigger oscillations too. Please remove it.

To rule out PCB parasitics, put 100nf capacitor on source pin of each mosfet: Solder 1 pin of 100nf very close to source pin of mosfet, then connect the other pin of 100nf to ground (ground near amp output).

Also check bias with no load connected.

Regards,
Lester
 
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