What is it

Louder Esparagus is a top-of-the-range Esparagus model that uses modern, highly capable TAS5805M DAC together with ESP32 MCU and is aimed to be paired with medium-to-large speaker systems. With 25W per channel stereo output, it packs a punch and can easily enlive living quarters or dorm rooms.

It is highly efficient but much more demanding for power when cranked, therefore, it uses either a USB-C Power Delivery to pull up to 65W from the wall power adapter or an external power source for the NOPD variant.

It can be used both with Wi-Fi and Ethernet (to make sure bad Wi-Fi would not interrupt the stream)

USB-PD	NOPD

 

Motivation

I did few audio projects in the past, some using ESP32, some using larger Orange Pi and Raspberry Pi devices. Each has its pros and cons, and with each iteration, I'm trying to focus on the details that were working best for me, while actually using them.

What I like about ESP32 is how lightweight it is. It barely draws power, so you may not care to turn it off at all. It boots in seconds and is ready for use in a snap. Still, it is capable and works at par with Linux SBC solutions for audio applications while costing a fraction of their price. Combined with a proper Hi-Fi DAC, you would not tell the difference between it and commercial devices standing side by side and costing much more.

Over the last few years, I have seen a few amazing software products created to deliver audio on the ESP32, like squeezelite-esp32 or Euphonium. Esparagus media center devices are designed specifically to run these great pieces of software and bring new life into aging audio equipment that most of us have at home but do not use that much these days since it is not working with Spotify and the family.

Features

	HiFi Esparagus	Loud Esparagus	Louder Esparagus
Image
MCU	ESP32-WROVER-N8R8	ESP32-WROVER-N8R8	ESP32-WROVER-N16R8
DAC	PCM5100A 32bit Stereo DAC -100 dB typical noise level	Dual I2S DAC (MAX98357) with built-in D-Class amp	Stereo I2S DAC (TAS5805M) with built-in D-Class amp
Output	Non-amplified stereo output, 2.1V RMS	2x 5W (4Ω), 2x 3W (8Ω)	2x 32W (4Ω, 1% THD+N), 2x 22W (8Ω, 1% THD+N)
Power	5V over USB-C, 2x LP5907 3.3 V Ultra-Low-Noise LDO for analog section	5V (up to 2.5A) from USB-C	Up to 20V from USB-C PD (PD version); Up to 26V from external PSU (NOPD version)
PSRAM	8MB PSRAM (4MB usable)	8MB PSRAM (4MB usable)	8MB PSRAM (4MB usable)
Connectivity	WiFi + BT4.2 + BLE	WiFi + BT4.2 + BLE	WiFi + BT4.2 + BLE; W5500 Ethernet
Size	80 x 50 x 20mm	80 x 50 x 20mm	100 x 80 x 38mm
Software support	Arduino samples, squeezelite-esp32, snapcast, ESPhome config	Arduino samples, squeezelite-esp32, snapcast, ESPhome config	Arduino samples, squeezelite-esp32, snapcast, ESPhome config

Onboard PSRAM

Audio streaming requires proper buffering to work, and even with ESP32 500K of RAM, it is challenging. All Esparagus boards are based on WROVER modules that have an onboard PSRAM chip.

Board Pinout

Audio

Peripheral - OLED Screen and W5500 Ethernet (Louder Esparagus)

TAS5805M DAC (Louder Esparagus)

Other Peripheral (Louder Esparagus)

Software samples

In the software section, two firmware examples are provided.

• esp32-i2s-bare is base I2S implementation based on ESP-IDF implementation directly.
• esp32-i2s-esp8266audio is based on the excellent ESP8266Audio library (it works with the whole ESP range, don't get fooled by the name), providing minimum code implementation.
• esp32-i2s-web-radio is based on the same library, providing a minimum web-radio stream player. It expects a playlist as an input in the 'data' folder.

Platformio IDE

All samples are provided as Plarformio IDE projects. After installing it, open the sample project. Select the proper environment based on your dock. Run the Build and Upload commands to install necessary tools and libraries, and build and upload project to the board. Communication and proper upload method selection will be handled by IDE automatically.

Arduino IDE

Follow the ESP8266Audio library guide.

ESPHome and Home Assistant

Being an ESP32-based device, you can easily integrate it into your Home Assistant using ESPHome. Please find detailed instructions on the linked github

Squeezelite-ESP32

Squeezelite-ESP32 is a multimedia software suite that started as a renderer (or player) of LMS (Logitech Media Server). Now, it is extended with

• Spotify over-the-air player using SpotifyConnect (thanks to cspot)
• AirPlay controller (iPhone, iTunes ...) and enjoy synchronization multiroom as well (although it's AirPlay 1 only)
• Traditional Bluetooth device (iPhone, Android)

And LMS itself

• Streams your local music and connects to all major online music providers (Spotify, Deezer, Tidal, Qobuz) using Logitech Media Server - a.k.a LMS with multi-room audio synchronization.
• LMS can be extended by numerous plugins and can be controlled using a Web browser or dedicated applications (iPhone, Android).
• It can also send audio to UPnP, Sonos, and Chromecast. All Esparagus boards are tested with Squeezelite-ESP32 software. It can be flashed using nothing but a web browser. You can use Squeezelite-ESP32 installer for that purpose.

How to flash and configure

Use the Esparagus Squeezelite-ESP32 installer to flash the firmware. It has been preconfigured to work with Esparagus boards and will configure all hardware automatically.

Please find detailed instructions on the linked github

Hardware

Louder Esparagus

Please visit the hardware section for board schematics and PCB designs. Note that PCBs are shared as multi-layer PDFs as well as Gerber archives.

Boxed

Louder Esparagus

Louder Esparagus NOPD

PCB

Louder Esparagus

BTL and PBTL mode (TAS5805M DAC)

TAS5805M DAC allows 2 modes of operation - BTL (stereo) and PBTL (parallel, or mono). In Mono amp, we will use a completely different modulation scheme and basically will fully synchronize output drivers. Jumpers on the board allow both output drivers to connect to the same speaker. The most important step is to inform the Amp to change modulation in the first place via I2C commands. In the case of sqeezelite DAC controlsset value is the following:

dac_controlset: {"init":[{"reg":3,"val":2},{"reg":3,"val":3},{"reg":2,"val":4}],"poweron":[{"reg":3,"val":3}],"poweroff":[{"reg":3,"val":0}]}

compared to default:

dac_controlset: {"init":[{"reg":3,"val":2},{"reg":3,"val":3}],"poweron":[{"reg":3,"val":3}],"poweroff":[{"reg":3,"val":0}]}

One can test audio with a single speaker connected between L and R terminals (plus on one side and minus on the other). Optionally, jumpers on the board will effectively connect the second driver in parallel, doubling the current capability.

An important point: this will send only one channel to the output; that’s just how the DAC works. True mono as (L+R)/2 is possible via a more in-depth configuration (very poorly documented), but I haven’t managed to configure that on the stand. I’m still working on that. (Along with a few more really cool DSP features that this DAC has, like EQ, subwoofer mode, and tone compensation settings)

	BTL	PBTL
Descriotion	Bridge Tied Load, Stereo	Parallel Bridge Tied Load, Mono
Rated Power	2×23W (8-Ω, 21 V, THD+N=1%)	45W (4-Ω, 21 V, THD+N=1%)
Schematics
Speaker Connection

Starting from Rev E, an additional header is exposed to allow datasheet-specced connectivity

Image	Legend
Stereo Mode - leave open
Mono (PBTL) Mode, close horisontally

TAS5805M DSP capabilities

The TAS5805M DAC has a very powerful DSP that allows doing lots of data processing on the silicon that otherwise would take a considerable part of your CPU time. As of the moment of writing, it is mostly an undiscovered part of the DAC since, unfortunately, TI is not making it very easy for developers. (A minute of complaint) To be more specific, you need to be (A) a proven hardware manufacturer to get access to the configuration software, namely PurePath. (B) you need to apply for a personal license and go through an approval process, and after a few weeks of waiting, you get access to one DAC configuration you asked for. (C) You find out that it will work with TI's own evaluation board that will set you back $250 if you'd be able to find one. Otherwise, all you have is a list of I2C commands that you need to transfer to the device on your own cost. No wonder no one knows how to use it.

But moanings aside, what do you get after:

• Flexible input mixer with gain corrections
• 15 EQ with numerous filter configurations
• 3-band Dynamic Range Compression with flexible curve configuration
• Automatic Gain Limiter with flexible configuration
• Soft clipper
• and a few other things

At this moment, it is very experimental. In a perfect world, you should be able to adjust all of those settings to make your speaker-enclosure setup work the best it can and even apply your room factors into the equation. But with athe bove disclaimer I can only deliver a limited set of configurations corresponding to the most common use cases:

• Stereo mode with enabled DRC (Loudness) and AGL settings
• Full-range Mono mode with DRC (Loudness) and AGL settings
• Subwoofer Mono mode with few filter frequency options
• Bi-amp configuration with few crossover frequency options

All of the above are available right now for experimentation. I'm keen to hear your feedback while I move forward with porting this to other software options

• [X] - Bare I2S TAS5805M library
• [X] - espragus-snapclient software (You may use Louder-ESP32 firmware for the Louder-Esparagus)
• [ ] - squeezelite-esp32 <- to do
• [ ] - flexible configurations with on-the-fly configuration changes

Louder Esparagus power considerations

The Louder Espragus can be quite a power-hungry device; simply using 5V over the USB-C is clearly not an option. The intention for using a PD-enabled power adapter to run the board is simplicity and ease of use for customers. Ideally, you should supply a 20V 3.25-Amp capable power source, which is common for modern laptops (Dell, HP, and Lenovo have all tested and work perfectly). However, pretty much any 9V/12V/20V PD-enabled power adapter will work, most typically phone chargers with a quick charge option. The smallest of the family is a 25W model, which is plenty enough for a living space.

The interesting part was that all the phone and laptop chargers I used for the test (around five different makes of each) sounded great, with no hissing and no popping. (Apart from the Apple ones, they didn’t work. Likely they have Apple-specific PD protocol). This is probably because modern devices have become so noise-sensitive that manufacturers have been forced to do good work on noise levels.

Tested and perfectly working models are (others may be available)

Model	Image
65W USB-C Lenovo ThinkPad Laptop Charger Replacement Power Adapter
65W 45W 20V 3.25A Type-C PD Laptop Charger
120W Gan Type-C PD Charger
45W Type-C PD Mobile Phone Wall Adapter

Because USB-PD is a bit of a Wild West in terms of standards, sometimes, not everything goes as designed. Some people have run into this with power adapters that aren’t fully PD-standard compliant. In most cases, the worst that happens is the PD chip doesn’t trigger the 20V mode, so the Esparagus runs at around 5W per channel (which you might not even notice). One person reported that an older adapter somehow triggered just 1V on the USB-C power line, shutting down the Esparagus shortly after plugging in. Thankfully, we’ve confirmed that it works correctly with newer laptop adapters.

Louder Esparagus NOPD

The “hammer-style” solution I came up with is a new NOPD version of the Louder Esparagus that lets you use a barrel power jack to supply raw voltage directly. The catch? Standard 2mm pins can’t handle high currents, so I’ve gone with a 2.5mm pin instead — it’s a bit unusual, but still common enough in the laptop world.

With this setup, you can supply more than the 20V limit of PD, giving you a bit more power for the speakers. You probably won’t hear much difference (thanks to the way human hearing works), but it could help larger speakers that need a bit more to really “open up." Other than that, the NOPD version works just like the PD version — no software changes are needed.

External voltage selection

The power adapter specs depend on the speaker you're planning to use. DAC efficiency is close to 100%, so just take the power rating of your speaker (say 2x10w), and impedance (say 8 ohms) and you'd need at least 9 volts rated at 1.2 amps per channel, round up to 3 total amps.

It is not recommended to go beyond the voltage your speakers can take, otherwise, the amp will blow your speakers in no time.

The absolute maximum voltage for the TAS5805M DAC is 30V, but it is not guaranteed to be thermally stable in this condition.