Thanks Alan!
I’m building from the kit and feel like a dunce for not mentioning I was worried about R6 on the PCB. It became unnecessarily complicated because I’m short 4 resistors on the kit count. I need to buy replacements but started to doubt which ones I’m missing.
Thanks so much for responding; much appreciated.
Cheers,
pplater.
I’m building from the kit and feel like a dunce for not mentioning I was worried about R6 on the PCB. It became unnecessarily complicated because I’m short 4 resistors on the kit count. I need to buy replacements but started to doubt which ones I’m missing.
Thanks so much for responding; much appreciated.
Cheers,
pplater.
No problem - do not feel like a dunce. Best to measure all the resistors and match them to the list before starting...
R6 needs to be 100 ohms.
The 33.2k resistors fit in the R13 location. They replace 2 x 10k resistors in the V1.8 kits. (They make the LEDs less bright.) Everything else is the same.
Here is an updated parts list:-
R6 needs to be 100 ohms.
The 33.2k resistors fit in the R13 location. They replace 2 x 10k resistors in the V1.8 kits. (They make the LEDs less bright.) Everything else is the same.
Here is an updated parts list:-
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Just finished building a pair of ACAs and a B1 Korg over the past couple of days. Everything went smoothly. Build guides were great. I burnt everything in a bit yesterday and am running them through a pair of Altec 604Cs for now. All I can say is wow.
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Don't laugh... but I listened a few times and was going to say I can't actually hear what exactly the problem is.
You see I had been silently following this:
well you can see how easy it could be to get confused
wrong thread and all that.
It sounds great and I could listen to that all day... its a very nice set up and the doggy seems to approve as well
You see I had been silently following this:
well you can see how easy it could be to get confused
wrong thread and all that. It sounds great and I could listen to that all day... its a very nice set up and the doggy seems to approve as well
I'm questing for small speakers for my new Amp Camp/ B1Korg. They sound amazing on the 604Cs, but they can live there. I need some small bookshelf speakers. I ordered a pair of Sony Core SS-CS5 on Amazon for $73/pr and a pair of Klipsch R-51M from Best Buy for $144/pr. Both cheap enough. I also notice the Triangle Borea Bro3s for a bit more and then there is the Buchardts 300 and 400s.
I'm building a pair of these as soon as the drivers are despatched from two different sources I'm trying to get them from:
DECWARE Tiny Radials
Bought the plans from Decware but Steve Decard and others building from his plans seem to have snapped up all the drivers for now.
Can't get much smaller - some woodworking skills needed - or 3D printing
DECWARE Tiny Radials
Bought the plans from Decware but Steve Decard and others building from his plans seem to have snapped up all the drivers for now.
Can't get much smaller - some woodworking skills needed - or 3D printing
I would say a lot depends on the impedance of the 'phones. High impedance models would probably be OK 'as is', at least at a basic level. Low impedance might need an attenuation network on the output... two series resistors which can be pretty low in value and with the 'phones connected across the lower one.
The switch on noise (thump) could be an issue but one that is easily solved with a simple relay delay on the output (and which can be configured to short the output on this amp).
For high impedance 'phones the speaker coupling cap could be lowered in value as appropriate.
The switch on noise (thump) could be an issue but one that is easily solved with a simple relay delay on the output (and which can be configured to short the output on this amp).
For high impedance 'phones the speaker coupling cap could be lowered in value as appropriate.
Connection wise you would use ground in the ACA (so that is the POSITIVE terminals) as the headphone common ground.
The ACA markings are arbitrary and simply to correct absolute phase when using speakers and so realising this you need to understand that the ACA will be inverting of phase when used with headphones... does that matter... imo I would say you would not be able to tell any difference.
The ACA markings are arbitrary and simply to correct absolute phase when using speakers and so realising this you need to understand that the ACA will be inverting of phase when used with headphones... does that matter... imo I would say you would not be able to tell any difference.
Hi guys looking for some advice have built 2 ACA amps and both have same problem it sounds like the output stage isnt working as all 4 boards are the same its obviously something i have done wrong i get a low level sound output that fades in and out. Have removed one of the pcb to test.Have done a resistence check as per fault finding info and everything is in spec.Output transistors dont get warm and there is no switch on thump so pretty sure its the output stage.
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Hi Brian,
Umm, not getting warm is odd.
Do the leds 'pulse' on and off with the 'sound output'?
Could you set the 'bias' voltage to 12 volts?
Have you checked the voltages as per the troubleshooting section of the build guide?
Have you got the transistors in the right places and the right way round? Have you got the capacitors in the right way round?
Best post some good pictures of your build.
Alan
Umm, not getting warm is odd.
Do the leds 'pulse' on and off with the 'sound output'?
Could you set the 'bias' voltage to 12 volts?
Have you checked the voltages as per the troubleshooting section of the build guide?
Have you got the transistors in the right places and the right way round? Have you got the capacitors in the right way round?
Best post some good pictures of your build.
Alan
Right, this is what I want to avoid.. when kickdrums hit I want the transient spike to be positive pressure
I was asking if there's a way to easily fix this and use this amp as a headphone amp, because I thought I remember seeing or hearing Nelson Pass say some people were using this as a headphone amp
The only way to correct the phase without additional parts is to rewire the headphones, either at the drivers or at the plug. That is because 99% of headphones share a common ground connection in the plug.
With parts and its a case of building an inverting buffer stage to go in front of the ACA.
With parts and its a case of building an inverting buffer stage to go in front of the ACA.