Nope, turns out the only cold one was the output cap! The rest of them conduct freely.
Once I touched up the output cap, that channel was up and running. The amp works perfectly now, and boy does it sound good. I can tell why people like class A. I'll post some pics tomorrow, its housed inside my custom enclosure.
Hi Jenghis,
Yes, good news, glad your ACA is working now.
BUT bbm3 is correct, the soldering is poor on your board. It may work today, but after a few on / off (hot / cold) cycles will likely fail again...
As he says a good solder joint should 'fill' the pad and have a cone of shiny solder on 'both' sides. See the build guide picture as an example. You need more heat and more solder to make good joints in future.
Any problems in the future, re-flow all the joints as suggested. Alan
Attachments
Yeah on that board I used a non-leaded solder that flowed very poorly. The other board I used leaded solder, so it was easy to avoid cold solder joints.
If that channel does stop working again in the future, I'll know what to do!
As long as they are the correct value and voltage (and correct lead spacing to fit the board) then there will be no operational or audible difference between the two.
How different are they out of interest? Piccy
Thanks for the info. Kinda what I thought but it seemed weird. Photo attached.
Attachments
That is slightly weird I agree, weird because the shrink wrap looks absolutely identical in every way. I wonder if there was a production change of the cap by the manufacturer.
OK everyone who is interested... what do your ACA kit caps look like? What is the height dimension of your caps?
OK everyone who is interested... what do your ACA kit caps look like? What is the height dimension of your caps?
Finally got my ACA finished about two months ago, I've been enjoying it since. My impressions are that it sounds wonderful. Vocals, acoustic guitar, mandolin and other stringed instruments, and drums all sound amazing. It does feel like the bass is sometimes lacking, compared to my other amplifier (Sansui 1000A). Not sure if has anything to do with my speakers being 4 ohms or some other factor. I considered building another one and running them in parallel mono to see if that made a difference. I drilled a few holes and put real feet on the bottom of mine, I also used an orange LED with a 24k resistor to get the ambient glow to match better with the tube equipment. Thanks to JeffreyD for posting the laser engraving files I was able to have a local engraver label the rear panel, also thanks to everyone that has participated in this thread I have learned a lot reading through it, and looking at other people builds is always a motivator. I have made a time lapse of my build process I will link below if anyone is interested.
p.s. I now have the itch to try an M2X build
YouTube
p.s. I now have the itch to try an M2X build
YouTube
Attachments
Another thought came to me. If you are drilling and tapping, you'd do well to get guides to help you do the job so that it's plumb and true.
I recently bought (at considerable shipping expense relative to the items), a set of drill and tap guides from Big Gator Tools. Haven't used them yet but a Mech Eng at work who makes odds and ends for his sailing boat that he races, gave them a thumbs up. So, I've taken reassurance from that.
I trashed the heatsink drilling the screw out. It had to be problematic all the way through. Drilled the core once perfectly, but couldn’t get husk out, refused to fold in on itself. I begrudgingly went one bit up and plowed completely through the heatsink with it. I ordered a replacement already. Oh well.
That sux dude. I feel your pain. Maybe put that heat sink in your bone yard and plan a dummy resistor load build or something else that may come along.
Given that shipping will be favourable for you given you live in star spangled banner land, the drill and tap guide suggestion might help down the track. Keep it in mind for later maybe?
Here's another way of skinning the cat:
Thread repair kit for M4 threads | Jaycar US Site
You'd just need to match the thread size ... M3 I believe, so the above won't help you other than to give you an idea of what could be achieved.
Perhaps unacceptable or undesired, but could you just drill the hole through, and use a longer bolt to attach the rail to the heatsink. I did not use the
amp camp case complete because I built the kit inside another case, but looking at my heatsink, it looks like the original holes are between the outside fins.
Apologizes for this late suggestion.
amp camp case complete because I built the kit inside another case, but looking at my heatsink, it looks like the original holes are between the outside fins.
Apologizes for this late suggestion.
Ok so the amplifier works. Thanks all.
Though I wasn't able to perform anything other than a real quick late night test. A few thoughts... the LEDs are too bright, always are. The startup and turn-off noises aren't an issue for me. I am sure the amplifier could use a preamp with gain, as testing with my iPhone as source absolutely required the volume higher than midpoint (93dB dinosaur speakers for testing). My original plan was to add a Korg B1 to the ACA chassis, but that would be a ridiculous tight squeeze for a novice such as myself to pull off. Does the dummy plug for the back switch fit anybody else's chassis?
Though I wasn't able to perform anything other than a real quick late night test. A few thoughts... the LEDs are too bright, always are. The startup and turn-off noises aren't an issue for me. I am sure the amplifier could use a preamp with gain, as testing with my iPhone as source absolutely required the volume higher than midpoint (93dB dinosaur speakers for testing). My original plan was to add a Korg B1 to the ACA chassis, but that would be a ridiculous tight squeeze for a novice such as myself to pull off. Does the dummy plug for the back switch fit anybody else's chassis?
I used a 49K resistor for the LED supply instead of the 10K. It tones them down nicely,
though I built the amp in another case, so I don't see the LED's anyway, but 49K
works OK. I am able to use a passive preamp with the amp, but my DAC puts out around 1.5 volts, and my open baffle speakers are fairly efficient.
though I built the amp in another case, so I don't see the LED's anyway, but 49K
works OK. I am able to use a passive preamp with the amp, but my DAC puts out around 1.5 volts, and my open baffle speakers are fairly efficient.
Hey All, I hope you don't mind me asking a quick questions about adding CPU fans to cool my Amp Camp Amp...
I purchased the Amp Camp Amp parts kit and power supply, but not the chassis because I wanted to build my own.
I have assembled the kit and it sounds AMAZING! however the heatsinks I am using are getting pretty hot. I'm planning on buying some 24V CPU fans like these to help cool the heatsinks: https://www.amazon.co.uk/WINSINN-Br...u+fans&qid=1564069624&s=computers&sr=1-6&th=1.
Will I be able to simply connect the positive/ ground wires to the same power supply as the amplifier? Will the power supply be able to handle the additional load of 2 CPU fans?
I purchased the Amp Camp Amp parts kit and power supply, but not the chassis because I wanted to build my own.
I have assembled the kit and it sounds AMAZING! however the heatsinks I am using are getting pretty hot. I'm planning on buying some 24V CPU fans like these to help cool the heatsinks: https://www.amazon.co.uk/WINSINN-Br...u+fans&qid=1564069624&s=computers&sr=1-6&th=1.
Will I be able to simply connect the positive/ ground wires to the same power supply as the amplifier? Will the power supply be able to handle the additional load of 2 CPU fans?
The Meanwell 5A 24 volt supply will easily cope with those fans but they aren't really needed for the ACA. Although it might seem to run HOT, its actually well within safe limits for reliability. The fans will just add acoustic noise and detract (imo).
Yes, 24v fans go across the 24 volt rail but there is then the theoretical issue of whether they will add any electrical noise of their own to the rails... you could feed each of them via a 10 ohm/1watt resistor decoupled with a high quality low E.S.R. 47uF cap. Be sure to get the ground return of the fans correct i.e. so that it will not interfere with the signal grounding.
Yes, 24v fans go across the 24 volt rail but there is then the theoretical issue of whether they will add any electrical noise of their own to the rails... you could feed each of them via a 10 ohm/1watt resistor decoupled with a high quality low E.S.R. 47uF cap. Be sure to get the ground return of the fans correct i.e. so that it will not interfere with the signal grounding.
As others have mentioned the ACA can work with HPs, in fact im really impressed with how good it sounds, I have never heard such fleshed out mids and bass from my headphones, that includes high impedance ones too. As is it seems like a really good HP amp, only there is so much unnecessary gain which is a safety issue for headphones/ears more than anything.
Feedback is 39K now and the lower it can go the better, whats the most feedback anyone has ran with the ACA?
Feedback is 39K now and the lower it can go the better, whats the most feedback anyone has ran with the ACA?