Amp Camp Amp - ACA

[JRKO]

Thanks for coming to my aid chaps!

Percussive maintenance seems to have solved the issue. Accidentally kicked the little amp and hey presto, sound on both channels!

Must be a duff solder joint. There’s a little hum but it needs a tidy up anyway

 

[Ericc1]

AH, nothing like the good ol' "Fonzi" technique!! And of course, yep.......I think I saw my screw up leading to very small volume, or the kind on gets when you have a point to point wired preamp and can faintly hear the audio bleeding through from another input, etc....but maybe a bit more than that, it's just the best way to describe it. ANyway, yep....it was definitely a resistor issue. Or more precisely an Eric issue of reversing the the resistors R11 and R12.....which blows, since it means I gotta switch the paralleled pF cap from one to the other as well. I forget which picture, but I was using a picture of someone elses build when adding those 2......anyway, I hope that's it.......found it pretty quick due to the member who ordered the 90.9 sans the K, resistor a few pages back, as I was ruling out that same mistake, or me maybe receiving the wrong resistor and not checking it closely enough. And while looking at the board, I was obviously trying to figure out how my feedback resistor could be located in that position etc......and obviously it's because it's not supposed to be in that spot on the pcb.

 

[JRKO]

The Fonzi technique sounds a lot better than punting an amplifier randomly left on the floor 🤣

 

[Ericc1]

Ouch!! I fractured a toe last january...IDK why/reason but I'll forever regret running through my den at 2 am with zero lights, knowing I was compiling a "LOT" that local dealer wanted to purchase, around the far wall......and forgot I pulled an amp out to check something before bed.....then a few days later somehow managed to do the quintessential pinky toe, clipping the coffee table, move as I was hobbling around in the dark. It's a shame, during the past 2 yrs building my "SHould only spend $$ on LPs/Music" system and speakers, to not have the callouses I had as a kid. I've stepped on more AC plugs and other electrical bits that put legos to shame, than have in total, during the previous time I've been alive. Nature of the beast I suppose

 

[CWelsh52]

For a fraction of your budget, if you like what I'd consider a bit of a "tubey" pre-amp... you could do an ACP+ just to see if you like the sonics. Then, if you happen to like it... you can modify the number of inputs / remote solution / chassis etc. If you don't love it, you can likely sell it in the swap meet. The B1K is certainly a bit of a tone box too, IMO...

After a lot of back and forth, I've ordered an ACP+. I really like your suggestion of building something that is a solid foundation that I can later expand on. I did a lot of reading and thinking about the Iron Pre SE, but don't feel confident that my still level is sufficient yet. Someday, though. In the meantime, I will keep following threads and dreaming.

Thanks to everyone who chimed in with thoughts and suggestions.

 

[Wonder Warthog]

Hi there,
because i´ve lost track of ACA, i want ask if someone would be so kind to help me finding BOM/parts-list for 1.6/8.
Allready got Boards and Cabinets and want to finish them before x-mas.
This thread is huge ...

 

[Plott]

Hi,
you'll find everything here: https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.6+Build+Guide/5?lang=en
But for the wiring of the v1.8, follow this: https://guides.diyaudio.com/Guide/Amp+Camp+Amp+V1.8+Change+Information/10

 

[Wonder Warthog]

Thank you Istvan,
but i am aware of this.
I could not find any Bill of Materials anyways.

 

[Stanislav]

Check page 9 of this file:

 

[Wonder Warthog]

Thank you, Stan.
This is the one from way back when.
Are the values still correct?

 

[Stanislav]

They most certainly are.
You can also check Tungsten's upgrades if you want to experiment.
Different thread though.
I'll check my resources tomorrow to see if I can provide you with more info.
Will keep you posted.

 

[Stanislav]

As promised here are some other files that may help building the ACA.
I'm sure some of them will be buried somewhere in this thread, so that'll save you some time.
I can not guarantee it be comprehensive, so reading through the thread is still highly recommended, although becomes tiring after awhile.
Here we go in no particular order:

 

[Wonder Warthog]

Thank you again, Stan.
Ali delivered a first batch:

Regarding the actual circuit, I still have some decisions to consider.
This 3way-switch. Does somebody happen to have a parts-number?

 

[Wonder Warthog]

Found the switch.

 

[Wonder Warthog]

Despite some progress,
my X-mas deadline went out of reach. 😢

 

[CWelsh52]

^^ Bummer! It's hardly right to put a thumbs up on disappointment.

 

[Wonder Warthog]

It is always what it is.
I was sure to have some 170bl´s in my cache.
Turned out they are just J109. XP
Sorry for your excitement.
Get well soon. ;-)

 

[anthonynchandler]

I have completed my ACA v.1.8 build and Channel B sounds wonderful...Channel A, however, has nothing playing.
Before I post a bunch of photos or go too far into metering, I thought I would ask if there are simple places to start?
Both leds light, but the Q1 pin reads 0 on Board A and 10.1 on Board B when I read to bias.
Any places to start will help. If I need to meter each spot, do I need to remove the board from the heatsink or can I read from above?
Thanks in advance!

 

[Loudthud]

On Channel A, check for a short between the middle leg (the Drain) and ground. This could be the part itself is shorted, or it could be a short from the Drain to the Heat Sink. Remove the screw and lift the part away from the Heat Sink to check.

 

[Mooly]

If there were a short on Q1 then Q2 would be running very hot although the bias current would still remain correct.

A fault like this could be many things (but ultimately it will be something simple 🙂).

Measure and record the DC voltage on all four transistors, note them down clearly and post the results. Its a couple of minutes of a job to do that.