It seems really strange that two power supplies would both be "bad " in the same way. We've had very few failures, and a few more with hum, but never two I. One order that both didn't work right, in the same way......Were the SMPS supplies connected in the same way as the linear supplies? Did you use the power jacks for the switcher bricks and not the linear supplies? Were the SMPS putting out voltages about 19v each?
We'll get you replacements but they might have to be sent directly as the store may be out of separate supplies. I'll keep you informed...
We'll get you replacements but they might have to be sent directly as the store may be out of separate supplies. I'll keep you informed...
Caps
In my build i use a Nichicon HiSound 3300uF-35V- not cheap but sounds real
good for me.
The 1000uF-16V should not be so critical- mine is Nichicon FG- don't no if 105°
low ESR has influence?
Any guys here (in different Pass Amps) using 10uF Elna Silmic II on input.
Add a little 10n polyprop film cap as bypass- my favorite is a 715P orange drop. This one needs 100-150hrs, like any others- MKP10 too, to burn in and plays so good than.
Next i will test the Nichicon QXP 10n as bypass- it is also a good one.
Cheers Bangla.
Hi aradan.
In my build i use a Nichicon HiSound 3300uF-35V- not cheap but sounds real
good for me.
The 1000uF-16V should not be so critical- mine is Nichicon FG- don't no if 105°
low ESR has influence?
Any guys here (in different Pass Amps) using 10uF Elna Silmic II on input.
Add a little 10n polyprop film cap as bypass- my favorite is a 715P orange drop. This one needs 100-150hrs, like any others- MKP10 too, to burn in and plays so good than.
Next i will test the Nichicon QXP 10n as bypass- it is also a good one.
Cheers Bangla.
Vatic, Im happy to send to you for testing. Though I bought the linear supplies. It wasn't my 1st choice and would love to be able to use as specified too.
The SMPS were hooked up the same way as the linear. We started out with the SMPS... lots of noise and only 1 watt. Hooked up to the bench power supply... adjustable, linear and regulated supply... no noise and 6 watts.
Used signal generator, into amps. amps into dummy load with BNC back to scope.
The amps are stock. Only diff was I used Teflon wire and added a connector for the LED. All connectors used and wired as specified.
The SMPS were hooked up the same way as the linear. We started out with the SMPS... lots of noise and only 1 watt. Hooked up to the bench power supply... adjustable, linear and regulated supply... no noise and 6 watts.
Used signal generator, into amps. amps into dummy load with BNC back to scope.
The amps are stock. Only diff was I used Teflon wire and added a connector for the LED. All connectors used and wired as specified.
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6 Channel ACA
I've got 6 ACA boards going into a single amp case, mounted to a large heatsink. I'm wondering about where to mount them. My heatsink is 340x360mm with the fins running along the long dimension. The base is 10mm think and the 30 fins are 70mm high.
Do I spread them equally around the baseplate or is there some 'ideal' mounting scheme I should follow?
I've got 6 ACA boards going into a single amp case, mounted to a large heatsink. I'm wondering about where to mount them. My heatsink is 340x360mm with the fins running along the long dimension. The base is 10mm think and the 30 fins are 70mm high.
Do I spread them equally around the baseplate or is there some 'ideal' mounting scheme I should follow?
Well, I have a couple of thoughts regarding your project and question. If we take a clue from Papa's original design, it would perhaps make sense to mount all six across the bottom of the sink provided there is room to do that. Otherwise maybe spreading them out equally around the sink might be a good way to go also. If your base is a good enough conductor it may not make a lot of difference. Just an opinion. If I were you I would consider trying to connect two sets of three ACA's in parallel, inputs to inputs, outputs to outputs like Papa mentioned early on as a way to increase output. I have been tempted to do just that ever since reading his recommendation. Are you planning to use the six in a tri-amplifed system? If so, the output capacitors could be different on the mid and highs channels than on the bass. Just thinking....I've got 6 ACA boards going into a single amp case, mounted to a large heatsink. I'm wondering about where to mount them. My heatsink is 340x360mm with the fins running along the long dimension. The base is 10mm think and the 30 fins are 70mm high.
Do I spread them equally around the baseplate or is there some 'ideal' mounting scheme I should follow?
Please let us know what you do and how it works.
ACA Troubleshooting
I took some screen shots of the scope when trying different supplies. The stock supply photo shows the amplifier with 500mV Peak input the output is shown at the bottom of the screen. Notice the noise, when I try to put in more than 500mV the amp starts to distort really bad. I tried the replacement supplies with the same input conditions and the Rep1 and Rep2 are the outputs. I tried the linear supply I bought but it turned out to actually be a switching supply. I took a screen shot with this power supply under the same input conditions. The wave looks a little better and I got a bit more output, but it is still noisy. Last I tried the linear bench supply and the output is much better. The Lin500 photo is of 500mV in and the last photo is Lin1500 shows the full output of the amplifier before onset of distortion. The input voltage is 1.5V peak. All tests were done with 1 kHz on the input.
I took some screen shots of the scope when trying different supplies. The stock supply photo shows the amplifier with 500mV Peak input the output is shown at the bottom of the screen. Notice the noise, when I try to put in more than 500mV the amp starts to distort really bad. I tried the replacement supplies with the same input conditions and the Rep1 and Rep2 are the outputs. I tried the linear supply I bought but it turned out to actually be a switching supply. I took a screen shot with this power supply under the same input conditions. The wave looks a little better and I got a bit more output, but it is still noisy. Last I tried the linear bench supply and the output is much better. The Lin500 photo is of 500mV in and the last photo is Lin1500 shows the full output of the amplifier before onset of distortion. The input voltage is 1.5V peak. All tests were done with 1 kHz on the input.
Attachments
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I've been wondering if there is an off the shelf linear power supply that would be an improvement over the stock one. My knowledge is way insufficient to even know if any of the specs can be different. Stock is 19v, 2.74A. Can either of these variables be lesser or greater without adversely affecting operation or sound quality?
@justinsweber: I see you ordered 19v linear PS on ebay. Can you share a link or searchable terms for that particular one? TIA
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Question!
I (and my fairer half) built a Amp camp together a while back. I'm wondering how far the idea has been hotrodded as I've a medium sized chassis here with reasonable heatsinking that I could transplant the aca boards into.
When I say hotrodded, I'm talking bias and supply voltage limits, without changing parts on the PCB's.
Thanks for any help!
I (and my fairer half) built a Amp camp together a while back. I'm wondering how far the idea has been hotrodded as I've a medium sized chassis here with reasonable heatsinking that I could transplant the aca boards into.
When I say hotrodded, I'm talking bias and supply voltage limits, without changing parts on the PCB's.
Thanks for any help!
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The above changes can be made without any change of values or rating of the existing parts?
Thank you. More questions for you or anyone who can answer. Probably very basic but I am just learning.
At least looking on eBay, it looks like 24V PS are available, though with amperages between 1A and 4A+. I will assume that I just need a minimum of 4.74A and a greater value is fine. Is this correct?
And... is 24V a preferable way to go over 19V? subjective difference? Provide greater gain and/or power and/or headroom? It does look like, for example, a LPS is available that can be factory configured as either 19V, 4.2A or 24V, 3.3A.
Thanks in advance!
Edit: oops, had the current spec wrong. Changed to 4.74. That apparently makes the example PS as insufficient current. But questions still apply. Thanks.
And another! Anyone have the specs of the DC plug to the amps (polarity and diameter)?
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Because what happens with use 24V rail voltage could maybe better explain
ACA active speaker project the member behind this project- he is doing this.
I don't can with little knowledge, but understand a bit what was explained me.
In my third build i will do so too.
With Aleph mini my opinion is a little different- but not biased to high level- only 0,8A.
ACA active speaker project the member behind this project- he is doing this.
I don't can with little knowledge, but understand a bit what was explained me.
In my third build i will do so too.
With Aleph mini my opinion is a little different- but not biased to high level- only 0,8A.