ACA Redux

[Variac]

One could put a tiny dab of a paint like substance or flour and water, or oil, or pancake syrup, whatever, on the longer standoffs and lower them onto the mirror, centered. Remove and use the marks to drill holes. Then run short 3mm bolts through the mirror holes into the standoffs.

 

[MesaM]

Good thoughts, yep almost took a very similar approach… Then just went with clear Gorilla tape dots 😎

 

[Variac]

Found these feet. No guarantees but probably if you attach them with a 3mm bolt through the mirror they probably wouldn’t protrude outside the mirror diameter. Rather pricey as they are US made…

https://www.amazon.com/dp/B00S4ITB6Y

 

[MesaM]

Just one more, couldn’t resist… Blue LED soldered to board underneath the rearward heatsink LED adds a reflective glow 🌙

 

[sthcoaster]

The nickname "hedgehog" was created by diyAudio member sthcoaster on January 3, 2022 in post #15 of this thread.

For people who want PCBs right now, and who are able to source components (including heatsinks) themselves, this option is available:

Not exactly a Group Buy: bare boards for RACAM (Round ACA Monoblock)

Big smiley face!! Just noticed I was being credited with coining this nickname!! So full of proudness

Been waiting to get some for myself and just received my heatsinks and meanwell smps last week so I'm nearly in business. Just got to collect a few more parts eg. 27k

Can someone point me in the direction of the "best" brand parts selection for these little wonders?

Thanks

C

 

[sthcoaster]

The 27K is for voltage to LEDs right - so not a critical value? I might have other close value

What about C1 & C2? I presume if I have larger uF that fit that would also be ok.

Can the RACAM be given the TungstenAudio values?

 

[N Brock]

The LED resistors are up to you, plenty of wiggle room there. Larger C1 and C2 values are no problem. I've been meaning to build a TungstenAudio spec ACA but haven't gotten around to it, I'd expect any of his suggestions that fit would be fine.

It's not a fussy amp, plenty of opportunity to tinker with values

 

[N Brock]

I have fewer than 10 of these kits left! A huge thank you to everyone who purchased and built a kit. This has been an interesting ride and I'll be thinking about whether I want to go for another batch, take a break, and/or move on to other projects.

 

[PeterI]

My completed pair - I decided to polish off the coated ends of the hedgehog spikes. All blue LEDs. The only mods were putting a 1uf 25V PIO cap in C3 and 47uf in C4.
You could call them the Sonic Hedgehog Twins.
Cheers, friends.

-Pete

 

[jimk04]

Fantastic! And to all the other above builds.....mirrors.... LEDs....all great.

 

[Wardsweb]

 

[Wardsweb]

The bases house an AC Infinity whisper quiet fans.

 

[poseidonsvoice]

@Wardsweb

Been following your builds since the Bottlehead days!

Best,
Anand.

 

[Zen Mod]

Fugly!

 

[von Ah]

I love the Sonic references. I can easily hear the original game’s music when I see those pictures. Definitely Team SEGA.

 

[djn]

A CD could be used instead of the mirrors too.

 

[Dzrout]

Loving this little amps so far. Want to built a nice base for them. Are the brass standoffs M2.5 it M3 thread?

 

[N Brock]

They're M3 thread

 

[Dzrout]

Any suggestions on capacitor value to add across the power switch to eliminate the pop in the speakers when I power them off?

 

[Extreme_Boky]

That's not gonna work..

The output capacitor sits at half of the total voltage rail... so once you switch the amp off, that stored energy will discharge in the form of current, through the speaker coil.