BeoCreate 4-channel amp/dsp

[olu78]

I briefly wrote about this audio add-on board, when I received it in November, while awaiting an official release date and price announcement. Born of a collaboration between Bang&Olufsen and Hifiberry, the BeoCreate is a 4-channel amplifier board with some pretty unique features! Equipped with 3)Tpa3128 ic's, the amplifier has 2x30w channels alongside 2x60w channels. With a 1) toslink input and 1) toslink output, the BeoCreate can be used as a simple digital amplifier, fed by a Chromecast. When a Raspberry Pi is mated to the BeoCreate's gpio interface, the true capabilities can be harnessed. The onboard dsp core can be utilized with the basic programs provided on Hifiberry.com, to 'upcycle' selected Bang&Olufsen speakers. For more advanced users familiar with SigmaStudio, very complex and powerful programs can be implemented. Imagine designing linear-phase FIR filters, dynamic limiters, linkwitz-transforms, or simple 2-way active xovers; there is enough power on-hand to make this a reality. Wireless programming of the dsp is possible, as is Airplay, Bluetooth, and Spotify capabilities, and much more. The Roadmap for this amplifier will include greater support from the manufacturer to include additional sound profiles, possible wireless syncing of stereo-board configurations, and interfacing with REW. Though I am not affiliated with the manufacturer of this product, if I can answer any questions, I am happy to give it a shot. Sent from my SM-G935T using Tapatalk

[kenny_k]

Do you know which DAC it uses?

[ernperkins]

A very interesting product. I see it's selling for $189 on the Hifiberry site. Do you know what DSP chip it uses? Some chips (e.g. ADAU1701) are good for IIR filters, but not FIR. The mini-Sharc chips on the other hand are more suitable for FIR filters. I would be interested in using SigmaStudio to program the DSP chip so I'd need a Raspberry Pi for that. It sounds like you run SigmaStudio on a PC and the Pi provides a wireless connection to the PC (just my guess). Will be watching for developments. And I'm glad they're making the SW open source.

[olu78]

The BeoCreate uses the Analog Devices ADAU1451, and not one of the more powerful, and expensive mini-Sharc processors. In order to program the dsp, a Raspberry Pi is required. Once the program is saved in the on-board eeprom, the amplifier can be operated without the Pi. And you are correct about the PC and the wireless Pi programming.

[dst]

It is an interesting proposition, for sure, and priced low for all you get. The big question is how solid a crossover can you obtain via the AD chip and associated software. It will certainly outperform an old, useless speaker. With the price/performance ratio of the digital audio world improving so rapidly, it will be crazy what we will have in a few years.

[Millstonemike]

To achieve the 60 W output rating, you need a 4 ohm driver.

[ani_101]

what do you get with the 2Ohm driver(s) configuration. The 60W can drive 2ohm, but I couldn't find the power spec at a glance

[dcibel]

http://www.ti.com/lit/ds/symlink/tpa3129d2.pdf

[Millstonemike]

what do you get with the 2Ohm driver(s) configuration. The 60W can drive 2ohm, but I couldn't find the power spec at a glance

First, I believe the chip for the "2x60W" outputs is the TPA3129d2 as the TPA3128d2 does not support 60 W.

The 60 W rating is the chip's thermal limitation. So exceeding that may be a problem. Having said that, the thermal limitation is spec.'d using a sine wave. Typical music is never as power dense as a sine wave, maybe 1/2 to 1/3 as dense on average. Heat dissipation for the TI TPA3129 is accomplished via the PCBs ground plane as the heat sink. And the sink has thermal inertia to carry over temperature rise during the most power dense passages. Having a well ventilated PCB also aids in heat dissipation. I had wanted to experiment with adding a "stick on" heat sink to the top of a similar chip with an analogous thermal limitation. But I never did as I junked the amp for other reasons.

So at 2 ohms and 24 volts, it's possible to exceed well over 100 W rms output into 2 ohms; likely tripping the chips internal failsafe until it cools and resets. Will it support the equivalent of an 80 W rms capable amp during peaks? Most likely.

YMMV.

[olu78]

The BeoCreate employs 3) TPA3128D2 chips, one for the 2x30w rated channel, and each of the 60w rated channels has a dedicated chip. According to the TI datasheet referenced above, the 2 ohm rating is quite a bit more than the 4 ohm output rating, though Hifiberry does not claim this. Likely, this is because of the thermal limitations stated by 'Msm' above, and potential warranty issues. I have taken numerous up-close images of my board, and they absolutely are using the TPA3128D2 chip.

[ani_101]

Can an external one be added to the heat sink. The high power at 2 ohm stable opens up real possibility of making small long throw woofers go really low/

[Millstonemike]

The BeoCreate employs 3) TPA3128D2 chips, one for the 2x30w rated channel, and each of the 60w rated channels has a dedicated chip. According to the TI datasheet referenced above, the 2 ohm rating is quite a bit more than the 4 ohm output rating, though Hifiberry does not claim this. Likely, this is because of the thermal limitations stated by 'Msm' above, and potential warranty issues. I have taken numerous up-close images of my board, and they absolutely are using the TPA3128D2 chip.

My bad. I actually got the '29 and '28 chips reversed. It is the TPA3128.

[olu78]

Hello ani_101. I see no reason why an aluminum or external heat-sink cannot be added to the board, either directly atop the amplifier chips, or on the opposite side of the pcb 'behind' the solder pads. I have been trying to source a suitable 24v power supply adapter, with current capability sufficient enough to allow for as close to rated power output as possible.

[olu78]

My bad. I actually got the '29 and '28 chips reversed. It is the TPA3128.

No biggie. It happens to us all, at some point...

[Millstonemike]

Hello ani_101. I see no reason why an aluminum or external heat-sink cannot be added to the board, either directly atop the amplifier chips, or on the opposite side of the pcb 'behind' the solder pads. I have been trying to source a suitable 24v power supply adapter, with current capability sufficient enough to allow for as close to rated power output as possible.

Pic of the underside of the PCB in the vicinity of TPAs would be helpful ...

I've been working with several "cheap" TPA311x amps from China. And I noticed on some that the wave soldering didn't quite fill all the thru-holes used to connect the chip's underside pad to the ground plane in a middle PCB layer. So that's one thing I would check and repair is necessary. Adding a heat sink there would help as that's the chips designed path to dissipate heat. I do have ideas on the best way to do it. When I mentioned a "stick on" heat sink on top, that was easy but of unknown value as the chip isn't designed to efficiently dissipate heat through the top of its case (but it couldn't hurt). I have several extras and could mail some to a member ...

Keeping the PCB cool is paramount. That means it can't be confined in a small, low airflow enclosure. Ideally the PCB should be vertically oriented allowing heat to rise up instead of horizontal where the heat is trapped under the PCB (vertical is even better than upside down).

I presume "source a power adapter" means either a power "brick" or "cage" type PS. 2x30 plus 2x60 translates to 7.5 amps at 24 V. Peaks will require more if you plan to exceed the watt rating. A switch mode PS will cut out when it's amp rating is exceeded and peaks will cause that (I've experienced that on some test beds; a short outage of ~1 sec. then the PS recovers and continues on). One defense against that is adding PS bypass capacitors. They can "absorb" (i.e., deliver) short peak power demands. Having said all that, the largest 24 V "Brick" I've seen is rated at 5 amps (available at PE). I don't think that will do for maximum output. So that means going to a Meanwell cage type supply. And the $$$ difference between 6.5 amps and 8.8 amps is $6. For a total $50, you can get 14+ amps @ 24 V and will handle anything the board can deliver. As a side note, the Meanwell supplies have a voltage adjustment that can be adjusted up a couple volts circa 26 V. That will add a few extra watts and provide some extra headroom - never a bad thing. Just check that all the larger caps on the board are rated at 35 V, not 25 V (I've done 26 V on some TPA3116 amp modules without issues).