Nice idea, I did a similar thing using the heatsinks for side walls and a 2U blank panel for the front for my Vhex+ amp. A plywood base and you have yourself an $8 case (cost of the 2U panel). Everything else you need to get whether or not you are using a nice case. I put all connections on the front panel for easy access (except the 120vac inlet socket).
These last couple of pages are a great gaggle of ideas how to get an ACA up, running, and looking good for very little money.
The kit chassis' are very nice but the most important thing is to build a lot of ACAs! We've broken down the kits into a parts kit and chassis kit now to make it easier if you want to roll your own box...
The kit chassis' are very nice but the most important thing is to build a lot of ACAs! We've broken down the kits into a parts kit and chassis kit now to make it easier if you want to roll your own box...
My Deadbug ACA
Threw this together and it is singing right now. It is running hot though so need to double check values. I measure 1.9v across the resistor network or 3.3amps quiescent current (that's too much right?). This is with the 2.2k resistor mod between E & C of the ZTX450. I adjusted Vd of Q1 to be 10.0v. I must have a resistor value incorrect somewhere.
Playing music:
Edit: I think I found the mistake: emitter of Q3 connected to middle of resistor network, when should be drain of Q1.
Yep, fixed it. 0.83v across the resistors for 1.43amps. Much cooler.
Threw this together and it is singing right now. It is running hot though so need to double check values. I measure 1.9v across the resistor network or 3.3amps quiescent current (that's too much right?). This is with the 2.2k resistor mod between E & C of the ZTX450. I adjusted Vd of Q1 to be 10.0v. I must have a resistor value incorrect somewhere.
Playing music:
Edit: I think I found the mistake: emitter of Q3 connected to middle of resistor network, when should be drain of Q1.
Yep, fixed it. 0.83v across the resistors for 1.43amps. Much cooler.
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Nice work X!
How does it sound?
Thanks, Zman.
Like an ACA - great bass and smooth mids and clear highs - but you need a sensitive speaker.
Do you have an ACA?
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Not yet... but joined the M2 Clone GB... and look forward to experiencing a Nelson Pass design
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Not yet... but joined the M2 Clone GB... and look forward to experiencing a Nelson Pass design
As you can see, a nice Pass class A can be made with an SK170, a ZTX450, and a pair of IRFP240's with a handful of parts from your spare parts bin in about a couple of hours. Truly an easy amp to make.
Thanks Niceonecyril , wrk971, and all who commented. I was surprised how sturdy this little assembly is. Someday I may get around to wrapping some metal around the middle to make it look finished. I also utilize plywood as a base in many of my prototypes. It is a great material. Variac I was thinking also that these dead bug circuits have an artistic quality when done well. I love the three dimensionality.
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Bangla.
Looking at these deadbugs..... now I'd like to put two aca's on one heat sink for an active speaker project. I'm considering the 24v smps's, or even a traditional toroidal psu.
In the DIYstore, there's a 200x165mm heat sink, and another that's 200x210mm. Would the smaller of the two be good, or should I buy the larger one to be safe? Or is there a better suggestion? The smaller the better, but it still needs to do the job.
In the DIYstore, there's a 200x165mm heat sink, and another that's 200x210mm. Would the smaller of the two be good, or should I buy the larger one to be safe? Or is there a better suggestion? The smaller the better, but it still needs to do the job.
I use small heatsinks and augment with a small 50mm 12v computer fan fitted with 100ohm 2w resistor to drop speed to very low inaudible but still effective for cooling. I use a 7812 to drop the 19v to 12v then the 100ohm.
Big heatsinks are expensive and heavy. Fans cost $1. Forced cooling is hundreds of times more efficient than natural unforced convection.
I have to say I like my dead bug ACA a lot more than the one that uses a perf board. They sound exactly the same but for the office desk the bug gets the style points.
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