From: Svjatoslav Agejenko Date: Sun, 12 Apr 2020 21:01:16 +0000 (+0300) Subject: Documented portable audio amp. X-Git-Url: http://www2.svjatoslav.eu/gitweb/?a=commitdiff_plain;h=75bf28c9bc446868acb6a7cf65d133c2eb5230c0;p=physical.git Documented portable audio amp. --- diff --git a/index.html b/index.html index 2a0f1ea..839a08a 100644 --- a/index.html +++ b/index.html @@ -2,7 +2,7 @@ Physical projects - + @@ -258,6 +258,13 @@ git clone https://www2.svjatoslav.eu/git/physical.git

2.1 Miscellaneous

diff --git a/index.org b/index.org index a57e9b5..8134439 100644 --- a/index.org +++ b/index.org @@ -40,6 +40,10 @@ Collection of physical projects. Electronics, 3D designs etc.. :PROPERTIES: :ID: 0482740b-0f2e-4138-804d-37c7025124d3 :END: + ++ [[file:misc/Portable%20stereo%20active%20speaker/index.html][Portable stereo speaker]] + + [[file:misc/Portable%20stereo%20active%20speaker/make.png]] + + [[file:misc/CAT%20B30%20phone%20cover/index.html][Cover for CAT B30 phone]] + [[file:misc/CAT%20B30%20phone%20cover/make.png]] diff --git a/misc/Portable stereo active speaker/20V upstep module/1.png b/misc/Portable stereo active speaker/20V upstep module/1.png deleted file mode 100644 index b63097d..0000000 Binary files a/misc/Portable stereo active speaker/20V upstep module/1.png and /dev/null differ diff --git a/misc/Portable stereo active speaker/20V upstep module/make.png b/misc/Portable stereo active speaker/20V upstep module/make.png new file mode 100644 index 0000000..b63097d Binary files /dev/null and b/misc/Portable stereo active speaker/20V upstep module/make.png differ diff --git a/misc/Portable stereo active speaker/battery holder/assembled.png b/misc/Portable stereo active speaker/battery holder/assembled.png deleted file mode 100644 index e15bb6c..0000000 Binary files a/misc/Portable stereo active speaker/battery holder/assembled.png and /dev/null differ diff --git a/misc/Portable stereo active speaker/battery holder/make.png b/misc/Portable stereo active speaker/battery holder/make.png new file mode 100644 index 0000000..e15bb6c Binary files /dev/null and b/misc/Portable stereo active speaker/battery holder/make.png differ diff --git a/misc/Portable stereo active speaker/index.html b/misc/Portable stereo active speaker/index.html new file mode 100644 index 0000000..510d483 --- /dev/null +++ b/misc/Portable stereo active speaker/index.html @@ -0,0 +1,805 @@ + + + +Portable stereo speaker + + + + + + + + + + + + + +
+

Portable stereo speaker

+ +
+

1 General

+
+ +
+
+ +
+

2 Project description

+
+

+I had pair of good compact stereo speakers lying uselessly around as +well as secondhand TDA2030 Chinese knockoff audio amplifier chips. +Also I wanted to test modular construction approach: motherboard with +shared bus and functionality realized via pluggable modules. So I +built stereo speaker: +

+ + +
+

make.png +

+
+ +

+Indicator on the front panel shows available power within the +system. Ideally it should be at the maximum. It drops when batteries +run empty or when consumed power (too loud music) is greater than +onboard power supply or batteries can handle. It has on/off switch and +stereo audio input. Audio input impedance is about 100 ohms. +

+ + +
+

make,%20side.png +

+
+ +

+Idea for the holes on the top and smaller ones on the bottom back is +to enable air flow for passive cooling. +

+ + +
+

make,%20back.png +

+
+ +

+Entire construction is made of parts, no larger than +120x120x120mm. Maximum for my printer. +

+
+
+ +
+

3 Battery holder

+
+

+Device is powered by 4 times AA NiMH batteries (1.2V each). +

+ + +
+

schematic.png +

+
+ +

+I happened to have AA battery adapters lying around with different +bottom hole configurations. Therefore this weird hole design: +

+ + +
+

battery%20holder.png +

+
+ +

+Download: +

+ + +

+Result: +make.png +

+ +

+Attaches to the back of the body: +mounted%20on%20the%20back.png +

+
+
+ +
+

4 20V up-step module

+
+

+Battery pack voltage is routed through main on/off switch on the front +panel, and then it goes to the 20V up-step module. +

+ + +
+

schematic.png +

+
+ +

+It uses ready made upstep module, but adds extra voltage filtering via +inductor and capacitors. +

+ + +
+

make.png +

+
+
+
+ +
+

5 Main board

+
+

+Voltage upstep above sits on top of main board (motherboard). It has +uniform central bus that spans all connectors. +

+ + +
+

internal%20bus.png +

+
+ + +
+

bus%20on%20the%20bottom,%202.png +

+
+ +

+First row of the main board is special IO terminal (for connecting +speakers, front panel, etc..) +

+ + +
+

IO%20terminal.png +

+
+ +

+Remaining rows are for connecting boards: +

+ + +
+

1.png +

+
+ +

+To provide structural support, main board is attached to frame: +

+ + +
+

board%20fixator%20body.png +

+
+ +

+Download: +

+ + +

+And boards plugged into main board are fixed at the top, using clip: +

+ + +
+

board%20fixator%20top%20clip.png +

+
+ +

+Download: +

+ + +

+Result: +

+ + +
+

bus%20on%20the%20bottom,%201.png +

+
+ + +
+

board%20fixator.png +

+
+
+
+ +
+

6 Mono audio amplifier module

+
+

+Design uses scavenged secondhand Chinese TDA2030 audio amp +clones. Each chip is mono audio amplifier. Therefore 2 almost +identical audio amp modules had to be built, one for left speaker, one +for right. +

+ + +
+

schematic.png +

+
+ +

+I like to build on top of prototype PCBs. Gives results much faster +for one-off projects. Before soldering, I solve component layout on +paper: +

+ + +
+

PCB%20layout.png +

+
+ +

+Result - front: +

+ + +
+

assembled%20front.png +

+
+ +

+Result - back: +

+ + +
+

assembled%20back.png +

+
+ +

+Here copper tape is used as improvised heatsink. +

+
+
+ +
+

7 Speakers

+
+

+High frequency small speaker and medium frequency bigger speaker are +combined. +

+ + +
+

schematic.png +

+
+ +

+Capacitor acts as high-pass filter on top of tiny PCB: +

+ + +
+

PCB%20layout.png +

+
+ +

+Speaker enclosure: +

+ + +
+

speaker%20enclosure.png +

+
+ +

+Download: +

+ + +

+Speaker enclosure cover: +

+ + +
+

speaker%20enclosure%20cover.png +

+
+ +

+Download: +

+ + +

+Result: +

+ + +
+

make.png +

+
+
+
+ +
+

8 Front panel

+
+

+Initial idea was really simple panel: +

+
    +
  • on/off switch +
    • +
  • system power indicator +
    • +
  • stereo audio input +
    • +
+ +

+But, since I'm using "agile" approach, during load-testing, it become +clear that active fan based cooling would be nice (when playing loud +music). I found tiny cooler fan that needs 5 volts to operate. Also I +need to power backlight for power indicator. For both of these cases, +I decided to add another voltage up-step module (target voltage output +set to 6V). This time directly on the front panel. +

+ + +
+

schematic.png +

+
+ +

+Front panel case: +

+ + +
+

front%20panel,%20front.png +

+
+ + +
+

front%20panel,%20back.png +

+
+ +

+Electronics fits inside: +

+ + +
+

front%20panel,%20back,%20make.png +

+
+ +

+Front view: +

+ + +
+

front%20panel,%20front,%20make.png +

+
+ +

+And attaches to the remaining components: +

+ + +
+

attachment.png +

+
+
+
+ + +
+

9 Extra capacitors

+
+

+Another thing that become clear during load-testing: output +power/volume can be further enhanced by adding high power capacitors +to even out load on primary 20V up-step module. +

+ + +
+

extra%20caps.png +

+
+ +

+Download: +

+ + +

+Extra caps are mounted on top of the speaker and electrically attached +to the main board. +

+ + +
+

make.png +

+
+
+
+ +
+

10 Center box

+
+

+Last physical part, to attach it all together: central body. +

+ +

+Front: +front.png +

+ +

+Back: +back.png +

+ +

+Download: +

+ +
+
+ + +
+

11 Conclusions / TODO

+
+

+These things could be done better: +

+ +
    +
  • Instead of using undersized heatsinks on the audio amplifiers and +need for active cooling as a consequence, it would be better to try +to mount audio amplifier chip on top of speaker metallic body. It +would provide plenty of cooling and reduces power losses within +cable, since amplifier would be as close to the speaker as possible. +
    • + +
  • I used agile design. That is, implemented functionality ad-hoc. If I +had done design in advance, then I could have had smarter connector +layout between main board and front panel. That is: Instead of +multiple smaller cables, one wide (multi connector) cable. +
    • + +
  • Screw holes are too close to the edges on the front panel. +
    • + +
  • It would be better if screw heads were slightly buried within +construction body. +
    • +
+ + +

+Overall, it was good learning experience and I was able to test +various ideas on it. Will add cooler later :) +

+ + +

+Photo of initial PSU + audio amp test: +

+ + +
+

initial%20test.png +

+
+
+
+
+
+ + + diff --git a/misc/Portable stereo active speaker/index.org b/misc/Portable stereo active speaker/index.org new file mode 100644 index 0000000..e85fa1f --- /dev/null +++ b/misc/Portable stereo active speaker/index.org @@ -0,0 +1,276 @@ +#+TITLE: Portable stereo speaker +#+AUTHOR: Svjatoslav Agejenko +#+LANGUAGE: en + +* (document settings) :noexport: +** use dark style for TWBS-HTML exporter +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: +#+HTML_HEAD: + +* General ++ DISCLAIMER: I DO ELECTRONICS AND 3D DESIGN SOLELY AS A HOBBY. THERE + COULD BE ERRORS THAT CAN RESULT IN ALL KINDS OF DAMAGE. USE THESE + DESIGNS AT YOUR OWN RISK. + ++ This design is released under Creative Commons Zero (CC0) license. + ++ Author: + - Svjatoslav Agejenko + - Homepage: https://svjatoslav.eu + - Email: [[mailto://svjatoslav@svjatoslav.eu][svjatoslav@svjatoslav.eu]] + ++ See also: + - [[../../index.html][Other physical projects in this repository]] + - [[https://www.svjatoslav.eu/projects/][Other projects hosted at svjatoslav.eu]] + +* Project description +I had pair of good compact stereo speakers lying uselessly around as +well as secondhand TDA2030 Chinese knockoff audio amplifier chips. +Also I wanted to test modular construction approach: motherboard with +shared bus and functionality realized via pluggable modules. So I +built stereo speaker: + +[[file:make.png]] + +Indicator on the front panel shows available power within the +system. Ideally it should be at the maximum. It drops when batteries +run empty or when consumed power (too loud music) is greater than +onboard power supply or batteries can handle. It has on/off switch and +stereo audio input. Audio input impedance is about 100 ohms. + +[[file:make,%20side.png]] + +Idea for the holes on the top and smaller ones on the bottom back is +to enable air flow for passive cooling. + +[[file:make,%20back.png]] + +Entire construction is made of parts, no larger than +120x120x120mm. Maximum for my printer. + +* Battery holder +Device is powered by 4 times AA NiMH batteries (1.2V each). + +[[file:battery%20holder/schematic.png]] + +I happened to have AA battery adapters lying around with different +bottom hole configurations. Therefore this weird hole design: + +[[file:battery%20holder/battery%20holder.png]] + +Download: ++ [[file:battery%20holder/battery%20holder.FCStd][FreeCAD file]] ++ [[file:battery%20holder/battery%20holder.stl][STL file]] + +Result: +[[file:battery%20holder/make.png]] + +Attaches to the back of the body: +[[file:battery%20holder/mounted%20on%20the%20back.png]] + +* 20V up-step module +Battery pack voltage is routed through main on/off switch on the front +panel, and then it goes to the 20V up-step module. + +[[file:20V%20upstep%20module/schematic.png]] + +It uses ready made upstep module, but adds extra voltage filtering via +inductor and capacitors. + +[[file:20V%20upstep%20module/make.png]] + +* Main board + +Voltage upstep above sits on top of main board (motherboard). It has +uniform central bus that spans all connectors. + +[[file:main%20board/internal%20bus.png]] + +[[file:main%20board/bus%20on%20the%20bottom,%202.png]] + +First row of the main board is special IO terminal (for connecting +speakers, front panel, etc..) + +[[file:main%20board/IO%20terminal.png]] + +Remaining rows are for connecting boards: + +[[file:main%20board/1.png]] + +To provide structural support, main board is attached to frame: + +[[file:main%20board/board%20fixator%20body.png]] + +Download: ++ [[file:main%20board/board%20fixator%20body.FCStd][FreeCAD file]] ++ [[file:main%20board/board%20fixator%20body.stl][STL file]] + +And boards plugged into main board are fixed at the top, using clip: + +[[file:main%20board/board%20fixator%20top%20clip.png]] + +Download: ++ [[file:main%20board/board%20fixator%20top%20clip.FCStd][FreeCAD file]] ++ [[file:main%20board/board%20fixator%20top%20clip.stl][STL file]] + +Result: + +[[file:main%20board/bus%20on%20the%20bottom,%201.png]] + +[[file:main%20board/board%20fixator.png]] + +* Mono audio amplifier module + +Design uses scavenged secondhand Chinese TDA2030 audio amp +clones. Each chip is mono audio amplifier. Therefore 2 almost +identical audio amp modules had to be built, one for left speaker, one +for right. + +[[file:mono%20audio%20amp%20module/schematic.png]] + +I like to build on top of prototype PCBs. Gives results much faster +for one-off projects. Before soldering, I solve component layout on +paper: + +[[file:mono%20audio%20amp%20module/PCB%20layout.png]] + +Result - front: + +[[file:mono%20audio%20amp%20module/assembled%20front.png]] + +Result - back: + +[[file:mono%20audio%20amp%20module/assembled%20back.png]] + +Here copper tape is used as improvised heatsink. + +* Speakers + +High frequency small speaker and medium frequency bigger speaker are +combined. + +[[file:speakers/schematic.png]] + +Capacitor acts as high-pass filter on top of tiny PCB: + +[[file:speakers/PCB%20layout.png]] + +Speaker enclosure: + +[[file:speakers/speaker%20enclosure.png]] + +Download: ++ [[file:speakers/speaker%20enclosure.FCStd][FreeCAD file]] ++ [[file:speakers/speaker%20enclosure.stl][STL file]] + +Speaker enclosure cover: + +[[file:speakers/speaker%20enclosure%20cover.png]] + +Download: ++ [[file:speakers/speaker%20enclosure%20cover.FCStd][FreeCAD file]] ++ [[file:speakers/speaker%20enclosure%20cover.stl][STL file]] + +Result: + +[[file:speakers/make.png]] + +* Front panel + +Initial idea was really simple panel: ++ on/off switch ++ system power indicator ++ stereo audio input + +But, since I'm using "agile" approach, during load-testing, it become +clear that active fan based cooling would be nice (when playing loud +music). I found tiny cooler fan that needs 5 volts to operate. Also I +need to power backlight for power indicator. For both of these cases, +I decided to add another voltage up-step module (target voltage output +set to 6V). This time directly on the front panel. + +[[file:front%20panel/schematic.png]] + +Front panel case: + +[[file:front%20panel/front%20panel,%20front.png]] + +[[file:front%20panel/front%20panel,%20back.png]] + +Electronics fits inside: + +[[file:front%20panel/front%20panel,%20back,%20make.png]] + +Front view: + +[[file:front%20panel/front%20panel,%20front,%20make.png]] + +And attaches to the remaining components: + +[[file:front%20panel/attachment.png]] + + +* Extra capacitors +Another thing that become clear during load-testing: output +power/volume can be further enhanced by adding high power capacitors +to even out load on primary 20V up-step module. + +[[file:extra%20capacitors/extra%20caps.png]] + +Download: ++ [[file:extra%20capacitors/extra%20caps.FCStd][FreeCAD project]] ++ [[file:extra%20capacitors/extra%20caps.stl][STL file]] + +Extra caps are mounted on top of the speaker and electrically attached +to the main board. + +[[file:extra%20capacitors/make.png]] + +* Center box + +Last physical part, to attach it all together: central body. + +Front: +[[file:center%20box/front.png]] + +Back: +[[file:center%20box/back.png]] + +Download: ++ [[file:center%20box/center%20box.FCStd][FreeCAD file]] ++ [[file:center%20box/center%20box.stl][STL file]] + + +* Conclusions / TODO + +These things could be done better: + ++ Instead of using undersized heatsinks on the audio amplifiers and + need for active cooling as a consequence, it would be better to try + to mount audio amplifier chip on top of speaker metallic body. It + would provide plenty of cooling and reduces power losses within + cable, since amplifier would be as close to the speaker as possible. + ++ I used agile design. That is, implemented functionality ad-hoc. If I + had done design in advance, then I could have had smarter connector + layout between main board and front panel. That is: Instead of + multiple smaller cables, one wide (multi connector) cable. + ++ Screw holes are too close to the edges on the front panel. + ++ It would be better if screw heads were slightly buried within + construction body. + + +Overall, it was good learning experience and I was able to test +various ideas on it. Will add cooler later :) + + +Photo of initial PSU + audio amp test: + +[[file:initial%20test.png]] diff --git a/misc/Portable stereo active speaker/main board/1.png b/misc/Portable stereo active speaker/main board/1.png index 4c258bc..ca7c160 100644 Binary files a/misc/Portable stereo active speaker/main board/1.png and b/misc/Portable stereo active speaker/main board/1.png differ diff --git a/misc/Portable stereo active speaker/main board/2.png b/misc/Portable stereo active speaker/main board/2.png deleted file mode 100644 index ca7c160..0000000 Binary files a/misc/Portable stereo active speaker/main board/2.png and /dev/null differ