Hi all,
(TLDR - can I use the same 19.v PSU to power both the amplifier and the DSP board?)
I am putting together a 2.1 system for a friend and I am in the stage of making the sub amp.
The system uses a Sonos Connect amp with a fixed 80hz XO. In order to integrate a sub I have had to use a Sure ADAU1701 to adjust the curve of the sub XO which gives me a bit of a power challenge. My plan is to use a TDA7498E board powered by a 6.7a 19.5v Dell Laptop PSU and also power the ADAU1701 board from this as well.
Will a simple step down buck converter be OK to go from the 19.5v to the USB micro 5v that the ADAU1701 needs? My worry is that most buck converters look like switching circuits and I know two switching amps cannot be run from the same PSU without clock sync which I want to avoid if possible.
Attached are images of what I have/intend to use. If anyone had any advice it would be greatly appreciated, thanks!
(TLDR - can I use the same 19.v PSU to power both the amplifier and the DSP board?)
I am putting together a 2.1 system for a friend and I am in the stage of making the sub amp.
The system uses a Sonos Connect amp with a fixed 80hz XO. In order to integrate a sub I have had to use a Sure ADAU1701 to adjust the curve of the sub XO which gives me a bit of a power challenge. My plan is to use a TDA7498E board powered by a 6.7a 19.5v Dell Laptop PSU and also power the ADAU1701 board from this as well.
Will a simple step down buck converter be OK to go from the 19.5v to the USB micro 5v that the ADAU1701 needs? My worry is that most buck converters look like switching circuits and I know two switching amps cannot be run from the same PSU without clock sync which I want to avoid if possible.
Attached are images of what I have/intend to use. If anyone had any advice it would be greatly appreciated, thanks!
Attachments
Hi
yes you can use it. but think about the current which is drawn by the Xo board= Ixo=?...
so you have about 19,5V and you need 5v --> you "wasting" about 14,5V.
the regulator is strong enough to deliver about 1,5 up to 2Amps (there a some videos which 2A or 3A where th chip died).
setup this regulator with load on its output!
ADAU1701 board
Power Consumption between ADAU1701 vs. ADAU1761 - Q&A - SigmaDSP Processors and SigmaStudio Development Tool - EngineerZone
lets say....so if you need about 100mA Ixo- your power loss on the regulator is about 14,5 *0,1 = 1,45 Watt...so its fine
other small LDO regulator not in your hand?
chris
yes you can use it. but think about the current which is drawn by the Xo board= Ixo=?...
so you have about 19,5V and you need 5v --> you "wasting" about 14,5V.
the regulator is strong enough to deliver about 1,5 up to 2Amps (there a some videos which 2A or 3A where th chip died).
setup this regulator with load on its output!
ADAU1701 board
Power Consumption between ADAU1701 vs. ADAU1761 - Q&A - SigmaDSP Processors and SigmaStudio Development Tool - EngineerZone
lets say....so if you need about 100mA Ixo- your power loss on the regulator is about 14,5 *0,1 = 1,45 Watt...so its fine
other small LDO regulator not in your hand?
chris
Thanks!
I have not yet ordered the DC board, is there one you would recommend?
Would the wasted 14.5v effect the power that is being supplied to the amplifier at all?
Cheers.
Does it? Sures website is so awful, I can't even get hold of a manual for the Sure DSP board.
Would something as simple as this suffice?
DC Linear Converter Buck Step Down LM317 Low Ripple Module Power Supply CF UK | eBay
yes...here is the same...first connect a load -then setup the output voltage.
Hi graham
what subsoniks mean is that your laptop brick might be poor to delivery quick power for the amp while pushing the sub. so for useing a psu "brick" (slow and weak regulation) its better to stabilise the voltage with cap like 10.000µF....
chris
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I see. I was led to believe that amps were the recourse needed for low frequency reproduction. TBH I am getting very good sound with the sub and boundary gain.
Thanks, that would be super handy!
Would anyone be able to recommend a safe chassis socket and connector for the DC 19.5v 6.7a PSU? I have removed the Dell connector as it has the third pin. Finding something with a high amp and high voltage rating seems to be tricky!
Thanks Jake and chermann.
I have ordered the board. Looking forward to setting it up.
The tda7498e board has a BTL mode that is easy to engage. It will be a mono amp, will it be worth putting in to use?
Edit : found the answer and it is yes.
7498E BTL Mode Question
I have ordered the board. Looking forward to setting it up.
The tda7498e board has a BTL mode that is easy to engage. It will be a mono amp, will it be worth putting in to use?
Edit : found the answer and it is yes.
7498E BTL Mode Question
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Board arived and all fired up however, the DSP board showed no sign of output via the Sure expansion board. I am guessing this is for one of two reasons:
- The J4 input does not power the expansion board. I will have to go via the 10 pin PH2.0 connector for that.
- Perhaps the DC converter is not supplying enough amps to power both the DSP and the expansion board.
The real result of this is that it worked BUT the DC board heat sink got incredibly hot. Is this heat sink undersized? The excess energy needs to go somewhere and maybe the tiddly heat sink supplied isn't up to it?
I happened to have ordered another DC board a week ago for something else, perhaps this one might yield cooler results?
DC-DC CC CV Buck Converter Step-down Power Module 7-32V to 0.8-28V 12A 300W Ou 4894462276426 | eBay
I do however, have a couple of spare TPA3116 and TDA7492 boards I can pull heat sinks from for the LM DC board.
- The J4 input does not power the expansion board. I will have to go via the 10 pin PH2.0 connector for that.
- Perhaps the DC converter is not supplying enough amps to power both the DSP and the expansion board.
The real result of this is that it worked BUT the DC board heat sink got incredibly hot. Is this heat sink undersized? The excess energy needs to go somewhere and maybe the tiddly heat sink supplied isn't up to it?
I happened to have ordered another DC board a week ago for something else, perhaps this one might yield cooler results?
DC-DC CC CV Buck Converter Step-down Power Module 7-32V to 0.8-28V 12A 300W Ou 4894462276426 | eBay
I do however, have a couple of spare TPA3116 and TDA7492 boards I can pull heat sinks from for the LM DC board.
I hadn't tried powering the dsp on the J4 connector with the expansion board so it may well be the case that it doesn't provide power to the expansion board - should be able to check with a multimeter. DC converter is more than capable of powering several DSP/expansion boards.
The regs do get quite hot, hotter the more voltage your dropping v power drain, heatsink is live but could use insulators and mount against the chassis if you using one or make an 'L' shape metal bracket to extend the heatsink, if you google lm317 temperature you will find a few posts regarding temperature of these devices.
The regs do get quite hot, hotter the more voltage your dropping v power drain, heatsink is live but could use insulators and mount against the chassis if you using one or make an 'L' shape metal bracket to extend the heatsink, if you google lm317 temperature you will find a few posts regarding temperature of these devices.
Thanks. I need to see if the PH2.0 connector supports 12v in as this will alleviate some of the dissipation from the LM317 instead of all the way down to 5v. I'm going to experiment with heat sinks this weekend.
Also, after digging around a bit I took your advice and ordered a Nichicon 35v 10,000uf cap to play about with.
What puzzles me is that if I add a capacitor in line from the PSU to the amp board won't I be lessening the capacitor reservoir as it will be in series with the on-board caps, not parallel?
I also have a blue board Feixang TDA7492 that I will be removing the on-board 1,000uf cap and replacing with this Nichicon to see what effect it has on LF response. It would be nice to run this lower output board on a 3A (ish) PSU for space reasons.
The cap is a 105c version. UVZ1V103MRD | Nichicon 10000μF 35V dc Aluminium Electrolytic Capacitor, Through Hole 22 (Dia.) x 50mm +105degC 22mm 10mm | RS Components
Also, after digging around a bit I took your advice and ordered a Nichicon 35v 10,000uf cap to play about with.
What puzzles me is that if I add a capacitor in line from the PSU to the amp board won't I be lessening the capacitor reservoir as it will be in series with the on-board caps, not parallel?
I also have a blue board Feixang TDA7492 that I will be removing the on-board 1,000uf cap and replacing with this Nichicon to see what effect it has on LF response. It would be nice to run this lower output board on a 3A (ish) PSU for space reasons.
The cap is a 105c version. UVZ1V103MRD | Nichicon 10000μF 35V dc Aluminium Electrolytic Capacitor, Through Hole 22 (Dia.) x 50mm +105degC 22mm 10mm | RS Components
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Why not? computational load can be very bursty going from sleep mode to full GPU action in microseconds!
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