I built the
(Link Deleted- Mods) and it works , all parts were as pictured, the carbons film are at least decent looking quality with copper leads.
For simplicity sake I used the 2SK246 (K30) JFET included, this was measured as a replacement for 2SK170 here , it wasnt as good but fairly close.
The amp is not sounding the best, pretty gritty/grainy. R15 is not added yet and its using 19V (2.3A per channel laptop PS) but I think it should still sound better.
The first move will be replacing the included output cap which is only rated for 16V, after that changing JFET to BF862... Im just really hoping the use of carbons films isnt the main cause of SQ issues.
oh and there is a low buzzing coming from the speakers, could that be the SMPS noise?
actually I can test with a 50W linear supply to see, and find or rule out another source of the SQ issues
(Link Deleted- Mods) and it works , all parts were as pictured, the carbons film are at least decent looking quality with copper leads.
For simplicity sake I used the 2SK246 (K30) JFET included, this was measured as a replacement for 2SK170 here , it wasnt as good but fairly close.
The amp is not sounding the best, pretty gritty/grainy. R15 is not added yet and its using 19V (2.3A per channel laptop PS) but I think it should still sound better.
The first move will be replacing the included output cap which is only rated for 16V, after that changing JFET to BF862... Im just really hoping the use of carbons films isnt the main cause of SQ issues.
oh and there is a low buzzing coming from the speakers, could that be the SMPS noise?
actually I can test with a 50W linear supply to see, and find or rule out another source of the SQ issues
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The nichicon audio caps are either real or fakes that are indistinquishable from the real thing.
Also someone else bought this kit and said the mosfets tested ok so I had some hope but you are probably right, and regardless if they are fake or not they are all the wrong parts.
Ill replace them all and see how it sounds then
Also someone else bought this kit and said the mosfets tested ok so I had some hope but you are probably right, and regardless if they are fake or not they are all the wrong parts.
Ill replace them all and see how it sounds then
Laserscrape:
We don't allow links to unauthorized kits for the ACA Amp.
Nelson Pass donated the ACA design to diyAudio to be sold as a fundraiser. We try to be reasonable when people make up kits for a themselves and a few friends, after all we WANT people to build them.
However it's a bad situation when people order cheap kits from places that are not authorized and only interested in selling our design for profit. And as you see, this leads to posts like yours where the thing doesn't work, and now you ask for help, and probably the problem a lot of the parts are wrong or counterfeit.
We don't allow links to unauthorized kits for the ACA Amp.
Nelson Pass donated the ACA design to diyAudio to be sold as a fundraiser. We try to be reasonable when people make up kits for a themselves and a few friends, after all we WANT people to build them.
However it's a bad situation when people order cheap kits from places that are not authorized and only interested in selling our design for profit. And as you see, this leads to posts like yours where the thing doesn't work, and now you ask for help, and probably the problem a lot of the parts are wrong or counterfeit.
Understood but I wasnt asking for help, really it was a report on the quality of kit.... poor.
it does work, just not well, the process of improving it will be more rewarding to me than building the official kit but I understand that that isnt appropiate to discuss here.
We do not want to go down that path for sure. When HeadFi was big into diy headamps the same thing with clone boards was happening. Several of the major designers decided to quit offering their designs up for the community because people were cloning them for profit then not supporting their clone boards. Now the only diy there is basically cables.
You get what you pay for, you want cheap, you got cheap. When I left working for Brand N auto manufacturer, we did an audit of "original parts" which we purchased off the net. 100% were fake in very official looking packaging. Not one single part met the manufacturers spec's. Brand N's or the suppliers.Some were downright dangerous, especially the braking system parts. Have fun with that when you hit the brakes hard and they fail!
As I said: "We try to be reasonable when people make up kits for a themselves and a few friends, after all we WANT people to build them"
Our objection is to:
-people not affiliated with diyAudio, making kits just for profit
-people making large quantities of kits or boards to sell, which makes profit appear to be their motive.
-"cheap" kits with nonstandard, substandard, and/or counterfeit parts, which damage the reputation of the ACA, and which can clog the threads with questions on how to make a functioning amp.
The post you linked to was:
-By a known member of diyAudio
-Not an exact copy of the amp, but significantly modified
-The PCBs were also not direct copies of the "official" boards
-The parts kit had different parts and upgraded parts and again, from a known person.
-The price for the (non-standard) boards was reasonable and don't appear to be something that's going to be a large seller.
When Nelson says he doesn't care, it doesn't necessarily mean that diyAudio doesn't care
I'm not yelling at laserscrape, just trying to be clear about our preferences and beliefs, warning people about how the cheapo kits are often next to worthless, and asking people to support diyAudio. We try to offer lower budget solutions such as separate PCB's, and a separate parts pack (with all parts having a pedigree!)
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Exactly. This is what I consider to be "the vibe".
From my perspective, the diyAudio community should support, encourage and nurture DIYers who innovate and advance the state of the art.
Please support those people who spend countless hours making something new and interesting for the community and share it for a reasonable price. If you do, we'll all benefit from them offering something else in the future.
Please do not support (or link to) those who prey on community member's efforts and stifle them, profit being their only motivation. If you do that you are ruining it for everyone and we all suffer the consequences. Support those who feed the community.
Additionally as mentioned ad nauseam, those super cheap kits on eBay inevitably have fake parts and linking to them is a disservice to newbies who don't know any better. The only reliable filter these days is to use a Tier 1 supplier like Digikey/Mouser that have trusted supply chains and QC in place.
If in doubt, ask the designer. Things here are rarely black and white, but to touch on the 3 examples just given in the posts above, I'd say:
A member making and sharing a limited run of boards which have a substantial change/improvement/differentiation? Probably good for the community.
A member doing a limited run of a super dooper version that wouldn't otherwise be available, and just for beer and pizza money? Probably good for the community, assuming the original designer has been consulted and won't be discouraged from contributing in the future.
An eBay listing containing a wholesale copy of a community member's design, probably full of fake parts, and not innovating, advancing the art or contributing otherwise? I think this is probably short sighted and chips away at the health of the community.
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Off course. However, encouraging members to explicitly ask for permission from original designer before announcing their modified version for sale seems appropriate.
Hey all,
I successfully built a stereo ACA 1.6, but got annoyed with the turn on/off noises, so recently took it apart to add in a speaker protect with (on-delay and instant-cut when the power drops).
Anyway, in doing so, I seem to have messed up the ACA modules. LEDs both come on, the heatsinks both warm roughly at the same rate they did before, but the sound is very very quiet and distorted, with a lot of cross-channel pollution (if I only feed it with one channel, I can hear it faintly out of both speakers). Not sure what I've done, but this is the case even with the speaker protect disconnected.
Trying to think back, at one point I tested the speaker protect (with everything wired up...) by bridging the 24VDC + power line onto the RIN+ (not GND) of the speaker protect, and it correctly engaged and cut the relay. However, this at the same time would have placed the 24VDC+ on the positive OUTPUT of the right amp board... maybe this screwed it? Both channels have the same problem though and I did not do this to the left.
Any help would be appreciated. I have a decent MM, but no scope and am something of a beginner.
Thanks!
I successfully built a stereo ACA 1.6, but got annoyed with the turn on/off noises, so recently took it apart to add in a speaker protect with (on-delay and instant-cut when the power drops).
Anyway, in doing so, I seem to have messed up the ACA modules. LEDs both come on, the heatsinks both warm roughly at the same rate they did before, but the sound is very very quiet and distorted, with a lot of cross-channel pollution (if I only feed it with one channel, I can hear it faintly out of both speakers). Not sure what I've done, but this is the case even with the speaker protect disconnected.
Trying to think back, at one point I tested the speaker protect (with everything wired up...) by bridging the 24VDC + power line onto the RIN+ (not GND) of the speaker protect, and it correctly engaged and cut the relay. However, this at the same time would have placed the 24VDC+ on the positive OUTPUT of the right amp board... maybe this screwed it? Both channels have the same problem though and I did not do this to the left.
Any help would be appreciated. I have a decent MM, but no scope and am something of a beginner.
Thanks!
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Not sure I quite understand the problem, but when you first installed the delay circuit, did the ACA function correctly? Or has it not worked properly since you installed the delay circuit?
Next as they both have the same 'fault' it is more likely a connection problem. Have you tried going back to the build guide configuration, with no delay circuit at all?
I assume you have measured +24 volts on the V+ connection on both boards and the 'bias' is still about +12 volts on both?
Then, please post some good clear pictures, so we can see the wiring and show us what type of 'delay' you used.
Alan
