Amp Camp Amp - ACA

kstagger,

Post some pics (close up) of the misbehaving amp and also your working amp for comparison sake if you like. I am a bit surprised if this all came about from a pin hole crack or break in the thermal insulators. The insulators should be comfortably oversized compared to the MOSFETS themselves, and only the thin rubbery pink stuff (no brown backing). Make sure there aren’t any shorts between the MOSFET pins.

I went and removed the troublesome PCB - everything looked pretty good but one or two solder joints looked suspect so I resoldered every through hole and added a touch of solder here 'n' there. No more short (with bias turned all the way down) so I reassembled everything again and so far so good. I'll keep my fingers crossed.
 
One question, the original schematic from 2012 is true now also for 1.6 right?

I can start soldering the parts as in the original article?

Yes, but the most recent guide is a much better resource, as the differences between 1.1 and 1.6 are fairly minor, specifically;

1) PCB layout was changed to accommodate the UMS mounting scheme, which isn't used in any version of the ACA chassis. (it's for the bigger chassis if you wanted to use one...)

2)The power switch is on the front, and the power barrel connector is slightly different.

3)The rear switch can now be used to make single-ended (RCA connector) bridge monoblock.

Aside that, the schematic in the guide is the same, the part numbers are the same, and most of the chassis mechanical is the same.

The biggest difference is how the back panel is wired, and that's limited to power and the switch.

Here is the "old" guide - use this in the time being

Amp Camp Amp V1.5 Build Guide - diyAudio Guides

And here is the link to the gallery with ACA 1.6 photos, some of which will get updated again, because I didn't realize you can flush-mount the XLR connector until Jason told me... whoops 😀 )

aca16
 
Hi fredO
You was asking for not expensive speaker.
After half finishing, longer time back, Paul's Overnight Sensation, i have running it since month now.
For my listening situation i am not use full power of ACA and in all it is a good pair for
my opinion.
Here is the kit: Denovo Audio Overnight Sensation kit

Pauls Project site: Overnight Sensations - undefinition
Only a little help, if you like, for orientation.
Many more and also better options to find.


Regards.
 
You dont even imagine how long i was looking for R15 and R12... omg i am such a noob...
Maybe reading all paper i got with parts is a good idea lol....
Now i know what goes where lol


And 6L6, as always the kindest response...
Now i will take some days to decode all the jargon you wrote there 🙂
 
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Hi fredO
You was asking for not expensive speaker.
After half finishing, longer time back, Paul's Overnight Sensation, i have running it since month now.
For my listening situation i am not use full power of ACA and in all it is a good pair for
my opinion.
Here is the kit: Denovo Audio Overnight Sensation kit

Pauls Project site: Overnight Sensations - undefinition
Only a little help, if you like, for orientation.
Many more and also better options to find.


Regards.


Thanks a lot for your reply!
Now you gonna get me into another trouble... how to get a pair lol
But in fact i always thought that the fostex fe20* speakers with those nice looking cabinets were to ones i would get ... but i never listened to them so now you got me a problem... decisions.... decisions....
 
Jim - doesn't the 1.6 now ship stock with 24V brick supply, with an accordingly higher bias setting? For folks finally getting around to building, or tweaking original kits, or fully rolling their own to current standard, that'd be important to note.
 
I just found this design and I'm intrigued! I've never built an amp before, and am not an EE or even remotely close! I AM very good at cable management, though 😉

I'm thinking of possibly doing the kit, when it becomes available again, and wiring it Balanced as a pair of Monoblocks. I've always wanted Mono's running in a 2-channel system and this looks like it may be a good option!

Can anyone tell me what the overall dimensions of the newest chassis' are?

Thanks!

Scott
 
The chassis a customized Mini Dissipante 230x200. Go to this page, select 230x200 and the 10mm panel, and review the spec table at the bottom (it changes dynamically): Mini Dissipante 2U – diyAudio Store

Jason,

Will the 2U Black Milled Aluminum handles fit on the ACA V1.6 amp? And could they have been preordered along with the chassis originally? Looks like they are only $16.00/pair if ordered with chassis, but $30/pair if ordered separately?

Thanks!
 
Hi,

I can't bias one of the motherboards on my second ACA 1.6 When I checked the wiring the output wires Blue and Black got reversed the black to positive and the blue to negative. I corrected it and still it won't bias. Need help.

Thanks

What is happening when you do try to bias, ie what is the voltage reading? Did you measure the raw voltage? LED power light coming on?

Since you have a working board, you can take voltage readings between the two to narrow down what is happening.
 
The reading goes down steadily until it would settle to these numbers: . 102 or 3. That is instead of going up. The other board is OK at 11.76v. LED power is on.

The blue trimmer is already a replacement one which I ordered from Digikey thinking that the original one is defective.


Thanks.