I hope to make my own design but likely some diyaudio design will be the spring board. I have an old inter-m PA amp that I'm going to use the transformer, case and heatsink for a 200+ watt power amplifier. That is the grail but that is far off in the future.Building amps is fun!
What’s you next project? Any of the Firstwatt amps are clear upgrades and improvements from the ACA, which makes it a simple path with obvious benefit.
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Lars,
they are alternatives for the 10kΩ R13. They reduce the light level of the very bright blue LEDs.
Attachments
I finished building my first ACA today. I was having some problems bc I’m not that experienced at soldering. However I think I managed to get everything in place and with good connection (?)
Anyway, when I power up I get sound in both channels, but there is a scraping noise in both channels. It sounds to me like Poisson noise, similar to radioactive decay or rain for that matter.
I hear it in both channels.
Both channels reproduce the input well, with the exception for the noise of course.
Any ideas what this could be about?
Anyway, when I power up I get sound in both channels, but there is a scraping noise in both channels. It sounds to me like Poisson noise, similar to radioactive decay or rain for that matter.
I hear it in both channels.
Both channels reproduce the input well, with the exception for the noise of course.
Any ideas what this could be about?
Good to know! Thanks!
There was a "chirp" the first time I started it with a speaker.
It seems to be pretty persistent. I ran it for about 5-10 minutes and it just kept going.
I am using the mean well trafo that is part of the kit.
Yes the start up noise should be gone after a couple of seconds. ACAs are normally silent in use.
Eliminate the obvious things.
As Mooly says remove the inputs, is the noise still there?
If yes 'short' the inputs to ground. (Paper clip or similar and link the centre of the RCA to the outer gold ring.) Is the noise still there?
Make sure it is from both channels, pull the speaker leads from one side at a time. Does the noise come from both sides?
Then try unsoldering the +ve lead from one of the boards. Do you still get the noise from the other still powered board?
Let us know what you find. Alan
Eliminate the obvious things.
As Mooly says remove the inputs, is the noise still there?
If yes 'short' the inputs to ground. (Paper clip or similar and link the centre of the RCA to the outer gold ring.) Is the noise still there?
Make sure it is from both channels, pull the speaker leads from one side at a time. Does the noise come from both sides?
Then try unsoldering the +ve lead from one of the boards. Do you still get the noise from the other still powered board?
Let us know what you find. Alan
Is the noise like what you would hear in between stations on the radio? Or more consistent like a motor noise?
If it's like radio then something in the circuit could be acting like an antenna picking up RF. If it's more like a droning motor noise it could be AC noise coming from the power supply.
The right way to find out would be to hook the output up to an oscilloscope but I'm not sure if you would have access to that.
I managed to locate and fix the problem.
While soldering, I used solder paste which I didn’t clean away. It turns out that it’s actually conductive under certain conditions. This led to the popping noise that i heard.
I think these current leaks destroyed the Ztx450. Twice.
I certainly learnt a thing or two in the process. I must have spent 40 hours soldering, assembling, disassembling, unsoldering, soldering, assembling and so on…
But the result was definitely worth it! Boy, does it sound good!
While soldering, I used solder paste which I didn’t clean away. It turns out that it’s actually conductive under certain conditions. This led to the popping noise that i heard.
I think these current leaks destroyed the Ztx450. Twice.
I certainly learnt a thing or two in the process. I must have spent 40 hours soldering, assembling, disassembling, unsoldering, soldering, assembling and so on…
But the result was definitely worth it! Boy, does it sound good!
Mono RCA Bridged connections reversed
I don’t know if I did something wrong, but my Mono RCA Bridged connections only work correctly (no hum, music plays) when I’m connecting my RCA in to Input B, not Input A on the back panel. And this is with the center switch in the UP position for Bridged. Any ideas why that might be? I should also point out that I've got the speaker cable red plugged into Output A (black) and speaker cable black into Output B (black). Is it ok for me to be backwards? I kinda live that way anyway......
See attached photos of my back panel wiring.
I don’t know if I did something wrong, but my Mono RCA Bridged connections only work correctly (no hum, music plays) when I’m connecting my RCA in to Input B, not Input A on the back panel. And this is with the center switch in the UP position for Bridged. Any ideas why that might be? I should also point out that I've got the speaker cable red plugged into Output A (black) and speaker cable black into Output B (black). Is it ok for me to be backwards? I kinda live that way anyway......
See attached photos of my back panel wiring.Attachments
Your wiring looks fine compared to the build guide.
I would post your question in the Amp Camp - ACA thread as you'll get more traffic: Amp Camp Amp - ACA
I would post your question in the Amp Camp - ACA thread as you'll get more traffic: Amp Camp Amp - ACA
Good morning...
First, I've spent countless hours reading these forums and learned so much! Thank you all for your tireless work here!
I bought and built a ACA 1.6 in early '20. This winter I bought a 1.8 back plate upgrading it to 1.8, and bought a 1.8 ACA to complement my 1st, bi-amp and play with the modes. I used the blue LED's on the 1st and will with the new one.
I understand changing the resistor value to dim the LED's in the kit, but I want to match the brightness of my 1st amp.
Are the blue LED's in the 1.8 kit different and in fact brighter than the ones in my earlier 1.6 kit? If not I'll use 10k resistors, instead of the 33.2k resistors supplied.
Thanks!
Kelly
First, I've spent countless hours reading these forums and learned so much! Thank you all for your tireless work here!
I bought and built a ACA 1.6 in early '20. This winter I bought a 1.8 back plate upgrading it to 1.8, and bought a 1.8 ACA to complement my 1st, bi-amp and play with the modes. I used the blue LED's on the 1st and will with the new one.
I understand changing the resistor value to dim the LED's in the kit, but I want to match the brightness of my 1st amp.
Are the blue LED's in the 1.8 kit different and in fact brighter than the ones in my earlier 1.6 kit? If not I'll use 10k resistors, instead of the 33.2k resistors supplied.
Thanks!
Kelly
Yes, the newer LED are probably brighter… LED technology and fabrication is in constant flux and improvement, and more brightness for a given current is something all the manufacturers are going to regard as beneficial for all users.
So as Zen Mod says, you are going to need experiment a little and adjust the resistor to taste. More ohms = dimmer.
So as Zen Mod says, you are going to need experiment a little and adjust the resistor to taste. More ohms = dimmer.