Adding such a feature would be a huge design effort almost comparable to that of the whole amplifier. I'd leave that homework to the student to work out. https://www.ebay.com/itm/234438388952 Or search "buck-boost".
That will provide your 25V - no matter what - it'll drain your batteries right past their point of no return minimum voltage. You'd have to catch that during the party and swap out battery packs...
@jjasniew
Maybe I'm wrong but those converters look pretty inefficient. And while I agree that adding this would require more design work, I think it's just the natural development of the project. Integrating as many features as possible on a single board just like most portable speaker manufacturers are. I've seen 50W speakers powered by a single 18650, so they're obviously using a voltage booster.
Not sure what you mean by draining the batteries past their allowed discharge voltage. With battery packs everyone should use a BMS which will take care of all these safety parameters, no need to keep an eye on the packs voltage.
Maybe I'm wrong but those converters look pretty inefficient. And while I agree that adding this would require more design work, I think it's just the natural development of the project. Integrating as many features as possible on a single board just like most portable speaker manufacturers are. I've seen 50W speakers powered by a single 18650, so they're obviously using a voltage booster.
Not sure what you mean by draining the batteries past their allowed discharge voltage. With battery packs everyone should use a BMS which will take care of all these safety parameters, no need to keep an eye on the packs voltage.
Well, between a step up converter and say, uP controlled BMS it's a lot of added design work. Another book full of failure and interaction modes to be responsible to. That would also rail the product into a more specific use case; that of a portable system. Significant cost adder, I'd predict. Maybe double.
Some customers (like me) use it in a mains powered application - perhaps along with a gigantic, heinous, old-school, can only afford used linear power supply. Just to get whatever benefit there may be from a non-switching power source. Given that a big 'ol used linear is practical, affordable and attainable (at least here in the US), I wouldnt touch a switcher powering it.
I can run my AIO4CH off a battery pack, but that's just for the academic purpose of proving to myself that the linear sounds just fine.
I'll admit I'm maybe...an unusual customer. I've got power to burn in my use case - and I'd burn it too if it makes the amplifier sound better. Like the tube and class A guys are as willing to do. It's a very nice sounding amp and saves me 100's in x-over component costs. $100 plus ship X 2 for just coils - versus typing in a number savings... I'm sure many others would want that outside of the portable sound system space.
Some customers (like me) use it in a mains powered application - perhaps along with a gigantic, heinous, old-school, can only afford used linear power supply. Just to get whatever benefit there may be from a non-switching power source. Given that a big 'ol used linear is practical, affordable and attainable (at least here in the US), I wouldnt touch a switcher powering it.
I can run my AIO4CH off a battery pack, but that's just for the academic purpose of proving to myself that the linear sounds just fine.
I'll admit I'm maybe...an unusual customer. I've got power to burn in my use case - and I'd burn it too if it makes the amplifier sound better. Like the tube and class A guys are as willing to do. It's a very nice sounding amp and saves me 100's in x-over component costs. $100 plus ship X 2 for just coils - versus typing in a number savings... I'm sure many others would want that outside of the portable sound system space.
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I didn't say he should add a BMS circuit on the amp board, that definitely belongs separately on the battery pack. Plenty to choose from on Ebay and very cheap.
Maybe when adding the step up converter, he could also add connectors After it for those like you that use linear PSUs and don't need any voltage boosting. Just an idea, not sure if that would work.
Maybe when adding the step up converter, he could also add connectors After it for those like you that use linear PSUs and don't need any voltage boosting. Just an idea, not sure if that would work.
I went to the Instagram page off the Zoudio website and there are pictures of a Zoudio branded device between a set of what's apparently 18650 batteries and an amplifier. However the product isnt listed for sale on their main page. It has a high-frequency inductor on the board. Perhaps an outboard version of such a converter product was given a try...
Mean old Instagram locked the page (with no alternative except to create an account) on my visit before I could grab a screen shot. When you behave like that - Instagram - I just click the "x" and never look back -
Mean old Instagram locked the page (with no alternative except to create an account) on my visit before I could grab a screen shot. When you behave like that - Instagram - I just click the "x" and never look back -
One question, I got the link from Jesse and thought he would be active here but he isn't right now as it seems. Actually the questions are also concerning my last order, the "always on option" would be helpful in this case (as I said I already use a step up converter with success, but it takes a second switch (otherwise the step up converter would eat the batteries in idle even if the amp is switched off).
To all of you guys who responded: I think an optimized step up converter (the right pwm mode for the amp, right frequencies and the right size/efficiencyy) would be a great upgrade for the battery mode. Actually first I thought the low battery voltage function would be nice but it is rather useless because a) who wants substantial less output if the batteries are almost drained and b) if you use liion in series a protection for the whole pack needs a BMS nonetheless.
Step up converter have come a long way and if they can provide power for PCs they sure can power amps which work in PWM mode too today 🙂 Here is one crazy high powered step up: https://www.360customs.de/2019/03/ltc3784-1200w-polyphase-boost-converter/
To all of you guys who responded: I think an optimized step up converter (the right pwm mode for the amp, right frequencies and the right size/efficiencyy) would be a great upgrade for the battery mode. Actually first I thought the low battery voltage function would be nice but it is rather useless because a) who wants substantial less output if the batteries are almost drained and b) if you use liion in series a protection for the whole pack needs a BMS nonetheless.
Step up converter have come a long way and if they can provide power for PCs they sure can power amps which work in PWM mode too today 🙂 Here is one crazy high powered step up: https://www.360customs.de/2019/03/ltc3784-1200w-polyphase-boost-converter/
@superlian
Nice that you got it working, I'm glad the amp was not damaged in the process.
@subkultur
No problem!
1) That is true. It currently requires special firmware, but I plan on putting it in the default firmware.
2) With the AIO438 it's possible, but it's easier to just request it in the order notes.
It avoids you having to set up all kinds of custom developer software.
Hopefully in the future I can reverse engineer the protocol and put it in the configtool.
3) The green/red led now matches the blue led. About 3 or 4 amps went out with R24 being 1k ohms.
If you want to change the brightness you can swap out R24 for a 100R 0603 resistor.
4) Maybe in the future. TI is planning on releasing some chips which have a feedback signal for when the amp starts clipping.
This can be used to boost the supply voltage when needed (like class-h). There it can have significant benefit.
It would be a great product, but I'm afraid we will have to wait a while with the whole shortage going on.
5) Does not sound familiar to me. I can't really help you with that I'm afraid.
@tommus
What @KaffiMann points out is true. It's not a problem at nominal voltage, only when fully charged.
@jjasniew
That product was a prototype which never made it to the market.
Nice that you got it working, I'm glad the amp was not damaged in the process.
@subkultur
No problem!
1) That is true. It currently requires special firmware, but I plan on putting it in the default firmware.
2) With the AIO438 it's possible, but it's easier to just request it in the order notes.
It avoids you having to set up all kinds of custom developer software.
Hopefully in the future I can reverse engineer the protocol and put it in the configtool.
3) The green/red led now matches the blue led. About 3 or 4 amps went out with R24 being 1k ohms.
If you want to change the brightness you can swap out R24 for a 100R 0603 resistor.
4) Maybe in the future. TI is planning on releasing some chips which have a feedback signal for when the amp starts clipping.
This can be used to boost the supply voltage when needed (like class-h). There it can have significant benefit.
It would be a great product, but I'm afraid we will have to wait a while with the whole shortage going on.
5) Does not sound familiar to me. I can't really help you with that I'm afraid.
@tommus
What @KaffiMann points out is true. It's not a problem at nominal voltage, only when fully charged.
@jjasniew
That product was a prototype which never made it to the market.
@tommus et al. I have a lot of first hand experience with sensitive electronics causing problems when fed slightly higher voltages, I have seen some devices that are approved and working fine at 24.0V for years, but if you try to feed them 26.0V it can fail within a few months, I've seen even quite basic locking mechanisms can also fail prematurely if you just provide 1 Volt more than what is supported in the datasheet.
In the old days 24V was anything from 20-29V, 12V anything from 10-15V and nobody understood why some things lasted while other things broke down fast.
In modern electronics where it says 12-24VDC or 12-26VDC: 24V is 24.00V and 26V is 26.00V, and for 12V it's never a hair above 13.2V, I've seen some circuits fail at 14.5V but work fine "forever" at 13V.
Ofcourse there are circuits/devices that do work perfectly slightly or sometimes a lot over voltage, but it's not wise to blindly assume this is always the case. In most scenarios, and especially involving devices with IC's, the voltage limits should be seen as absolutes.
So for these circuits by lutkeveld/Zoudio I highly recommend to stay below 26V and view that as a "hard limit" that should not be crossed.
It's probably very fun if you have made a boombox and have driven it slightly over limits for a long while since it worked just fine doing that and you got just a smidge more output, and you're ready to have a party with your buddies only to find the thing suddenly doesn't work.
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This is not to dissuade people from playing with voltages a bit, but it's usually much cheaper to stay within the specified limits than to see them as general guidelines.
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@MKSounds I know, but I'm hoping the TAS5828M will be available soon. The QFN package of the 25m/25p is a bottleneck which would be nice to avoid.
@KaffiMann True, although 26.4V is the recommended maximum operating voltage, and the absolute maximum is higher, for longevity 24V is a great voltage to settle on. The difference in output power between 24V and 26.4V is almost negligible.
@KaffiMann True, although 26.4V is the recommended maximum operating voltage, and the absolute maximum is higher, for longevity 24V is a great voltage to settle on. The difference in output power between 24V and 26.4V is almost negligible.
I have a battery pack consisting of two, 12V 8AH gel cells. I charged it up using the charger for a 24V electric lawnmower, having two 18AH, 12V batteries. Using my brain, I took the time to measure the open circuit voltage across after the charge; 27.3. I decided "better not" and, that wasnt even the Zoudio amp I was considering connecting it to, just some $12 class D job I got off ebay.
(Battery power makes things easier to test; no earth ground and its loops, no power supply noise - and all the current in the world...)
What I need is a charger that'll take the batteries up to 26, then stops providing any more current into the battery. I havent tried such to see what actually happens and when I do, I'd still measure before plugging it in - to avoid getting tricked by some unanticipated battery chemsity thing. Unsure how charging to just 13V / cell effects the battery, when it perhaps wants that extra 0.2V to be "fully" charged.
There's also the possibility of designing a circuit that drops whatever the battery is at to 26, then the 0.005 Ohm RdsON pass-element turns on hard from that voltage on down. I'm sure someone could design it such that a 9V battery would last essentially its 10 year shelf-life powering the device, with the super low power actives available these days.
(Battery power makes things easier to test; no earth ground and its loops, no power supply noise - and all the current in the world...)
What I need is a charger that'll take the batteries up to 26, then stops providing any more current into the battery. I havent tried such to see what actually happens and when I do, I'd still measure before plugging it in - to avoid getting tricked by some unanticipated battery chemsity thing. Unsure how charging to just 13V / cell effects the battery, when it perhaps wants that extra 0.2V to be "fully" charged.
There's also the possibility of designing a circuit that drops whatever the battery is at to 26, then the 0.005 Ohm RdsON pass-element turns on hard from that voltage on down. I'm sure someone could design it such that a 9V battery would last essentially its 10 year shelf-life powering the device, with the super low power actives available these days.
Why complicate yourself so much? Just build a 6S pack with 18650 cells. That will give you 25.2V (4.2V x 6) when fully charged and the charger won't go higher than that. Need more capacity? just add a cell in parallel making it 6S2P, or 3P if needed. 25.2V chargers are cheap and specifically made for this application. Don't forget about the BMS though. And speaking of that, your two gel batteries in series might not charge/discharge at the same rate and go out of balance, another thing to look out for with your method.
Edit: You don't even have to build the pack yourself, I just checked aliexpress and some even sell packs with the charger included. Example: $56 for 6S3P 10Ah pack + charger
Edit: You don't even have to build the pack yourself, I just checked aliexpress and some even sell packs with the charger included. Example: $56 for 6S3P 10Ah pack + charger
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Yes indeed, the easiest way to drop voltage a little bit is using a couple of diodes.
I let the batteries rest for a couple days and the voltage dropped to 25.4. So I connected it. No magic smoke.
General update:
- All orders up to 14 februari have shipped now. Shipping continues 🙂
- The updated configtool has been available for some time now via zoudio.com/configtool
General feedback seems to be pretty good.
- Lots going on behind the scenes with regards to manufacturing.
We are in talks with a European boardhouse, which hopefully will take over manufacturing soon.
Although having our own pick-and-place is nice, it is not automated enough to handle full scale production in an efficient manner.
- Getting chips has been a hassle. Except for the a buckconverter IC, we were able to get decent stock of all chips, although sometimes for 4 times the price.
The switch to a new buckconverter luckily went smooth.
- This todo list still stands, we are working hard on getting production streamlined, after which we will have time to roll out some extra features in the DSP and bluetooth firmware.
- All orders up to 14 februari have shipped now. Shipping continues 🙂
- The updated configtool has been available for some time now via zoudio.com/configtool
General feedback seems to be pretty good.
- Lots going on behind the scenes with regards to manufacturing.
We are in talks with a European boardhouse, which hopefully will take over manufacturing soon.
Although having our own pick-and-place is nice, it is not automated enough to handle full scale production in an efficient manner.
- Getting chips has been a hassle. Except for the a buckconverter IC, we were able to get decent stock of all chips, although sometimes for 4 times the price.
The switch to a new buckconverter luckily went smooth.
- This todo list still stands, we are working hard on getting production streamlined, after which we will have time to roll out some extra features in the DSP and bluetooth firmware.
Finally all the practial work is done.
Now i can work with measurements and DSP.
(The loudspeaker has only 10 mm thin walls and 20 mm front baffle, its a leaky construction like Harbeth. I also use carpet glue, bitumen and thick felt. Its dead and the ressonant frequency is one octave lower than normal. The tweeter is Seas DXT, the woofer a new old stock Vifa M21 which a refoamed with foam instead of rubber.)
Now i can work with measurements and DSP.
(The loudspeaker has only 10 mm thin walls and 20 mm front baffle, its a leaky construction like Harbeth. I also use carpet glue, bitumen and thick felt. Its dead and the ressonant frequency is one octave lower than normal. The tweeter is Seas DXT, the woofer a new old stock Vifa M21 which a refoamed with foam instead of rubber.)
Back on the bad track again 🙁
it powered up with blue light for a short time.
now its dead except the red light on the red light on the usb interface
it powered up with blue light for a short time.
now its dead except the red light on the red light on the usb interface
One of mine became unresponsive after I thought I could reprogram it on the fly, i.e. while playing music. It didnt like that and I had to get the bootloader reflashing program from Lutkeveld and with running that, I was able to bring it back to working again.
Since the board will be powered via the USB for reprogramming, I always disconnect the main power - physically - when updating filter parameters. I've never had another bricked board issue again. Unsure if this is what happened above, but I think the chances for recovery are good.
Since the board will be powered via the USB for reprogramming, I always disconnect the main power - physically - when updating filter parameters. I've never had another bricked board issue again. Unsure if this is what happened above, but I think the chances for recovery are good.
'Bootloader reflashing' is probably 'eeprom wiping' 🙂 The bootloader stays in place always.
In most cases where the AIO4CH is unreponsive it was a memory issue, which could be solved by wiping the settings and uploading again.
The AIO4CH supports uploading during runtime, but it might just be that the error occurs less often when doing it while the main PSU is off like Jjasniew mentioned.
Anyway, @superlian You can send me an email and then I can send you the memory wiping instructions, and if that does not fix it we will have to look at a different option.
In most cases where the AIO4CH is unreponsive it was a memory issue, which could be solved by wiping the settings and uploading again.
The AIO4CH supports uploading during runtime, but it might just be that the error occurs less often when doing it while the main PSU is off like Jjasniew mentioned.
Anyway, @superlian You can send me an email and then I can send you the memory wiping instructions, and if that does not fix it we will have to look at a different option.