diyAudio http://www.diyaudio.com/forums/gallery Mon, 20 Feb 2017 15:03:18 -0500 PhotoPost Pro 6.02 revised connection diagram http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14737 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14737" target="_blank"><img title="2nd_Spring_fig_14_rev_B.png" border="0" src="http://origin.dastatic.com/forums/gallery/data/2243/thumbs/2nd_Spring_fig_14_rev_B.png" alt="2nd_Spring_fig_14_rev_B.png" /></a><br /><br />by: bwaslo bwaslo Fri, 17 Feb 2017 16:42:33 -0500 mortenhoe http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14735 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14735" target="_blank"><img title="mortenhoe.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/500/thumbs/mortenhoe.jpg" alt="mortenhoe.jpg" /></a><br /><br />by: serafis serafis Fri, 17 Feb 2017 16:30:02 -0500 23 - Modified AV Receiver with pre-amp outputs http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14696 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14696" target="_blank"><img title="14_AV_Receiver_with_preamp_outputs_shunted.JPG" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/14_AV_Receiver_with_preamp_outputs_shunted.JPG" alt="14_AV_Receiver_with_preamp_outputs_shunted.JPG" /></a><br /><br />by: serafis<br /><br />Description: I modified my Onkyo TX-SR606 7.1 channel AV receiver to provide pre-amp outputs (and power amp inputs) and mde some insulated shunts to connect them so I could still use it normally while building the Baking Tray Amplifier (and in case I want to sell it in the future). Not a hard modification, but required some disassembly of the receiver. serafis Wed, 15 Feb 2017 23:26:24 -0500 01 - The Baking Tray Amplifier http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14697 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14697" target="_blank"><img title="P10700181.JPG" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/P10700181.JPG" alt="P10700181.JPG" /></a><br /><br />by: serafis<br /><br />Description: The Baking Tray Amplifier is a 7-channel Class-D power amplifier based on LJM L15D modules, delivering 125W RMS into 8 ohms and 200W RMS into 4 ohms. It has speaker DC protection and infrared remote power on/off, and is designed as a high-power home theater power amplifier. Looks not bad, sounds just fantastic. The other photos in this gallery describe the build in more detail. serafis Wed, 15 Feb 2017 23:26:24 -0500 The Baking Tray Amplifier http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14698 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14698" target="_blank"><img title="P10700181.JPG" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/P10700181.JPG" alt="P10700181.JPG" /></a><br /><br />by: serafis<br /><br />Description: The Baking Tray Amplifier is a 7-channel Class-D power amplifier based on LJM L15D modules, delivering 125W RMS into 8 ohms and 200W RMS into 4 ohms. It has speaker DC protection and infrared remote power on/off, and is designed as a high-power home theater power amplifier. The other photos in my personal gallery describe the build in more detail. serafis Wed, 15 Feb 2017 23:26:24 -0500 17 - Adjusting the L15D switching frequency http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14695 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14695" target="_blank"><img title="Switching_freqeuncy.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/Switching_freqeuncy.jpg" alt="Switching_freqeuncy.jpg" /></a><br /><br />by: serafis<br /><br />Description: When using more than one IRS2092 board, it's important to set the switching frequencies very accurately, or make sure that they're at least 25KHz apart to avoid audible inter-channel interference. I replaced the 270 ohm resistors with a multi-turn trimpot and set all seven channels switching frequencies to be within &lt;1Hz of each other using a cheap DMM with frequency meter (Victor VC921 with a 1.5 Kohm resistor in the positive probe). I did this on a test bench setup, with inputs shorted and an 8 ohm load on the outputs - I used 10W resistors, but be careful that the inputs really are shorted or they may start smoking!. Important to set frequencies after everything has reached normal operating temperatures as they drift a bit; and of course I did all of this before installing the phase inverters or putting the modules into the Baking Tray enclosure - it would have been impossible afterwards. One installed and 'run in', I re-checked the switching frequencies on the speaker outputs and all channels were between 399.6 and 400.2 Hz - I think a 0.6Hz difference is close enough! serafis Wed, 15 Feb 2017 22:37:23 -0500 15 - Phase inverter connections to L15D boards http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14694 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14694" target="_blank"><img title="Phase_inverter_connections.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/Phase_inverter_connections.jpg" alt="Phase_inverter_connections.jpg" /></a><br /><br />by: serafis<br /><br />Description: I re-used the input connectors from the L15D boards on the phase inverters, and connected the output wires to the L15D boards where the input connector used to be. I took the +5V supply from the +ve end of the positive rail 5.6V zener, and the -5V supply from the -ve end of the negative rail 5.6V zener. serafis Wed, 15 Feb 2017 22:30:32 -0500 16 - Infrared Remote Power Switch http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14690 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14690" target="_blank"><img title="08_All_Mounted_rsz.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/08_All_Mounted_rsz.jpg" alt="08_All_Mounted_rsz.jpg" /></a><br /><br />by: serafis<br /><br />Description: I mounted a miniature 5V switching supply on a piece of protoype board, powering a learning infrared remote switch (both from from Aliexpress) to provide remote control power on/off. I removed the IR receiver from the board, extended its leads and glued it to the front panel, exposing it through a suitable size hole I drilled. I also mounted a momentary SPST push switch on the front panel wired to the manual on-board on/off switch. serafis Wed, 15 Feb 2017 22:17:55 -0500 14 - Phase Inverter component layout http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14691 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14691" target="_blank"><img title="Phase_Inverter_Layouts.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/Phase_Inverter_Layouts.jpg" alt="Phase_Inverter_Layouts.jpg" /></a><br /><br />by: serafis<br /><br />Description: I built the phase inverters on small pieces of protoype board. This shows the top and underside views of the boards. I re-used the input connectors from the L15D boards, and soldered the output wires to the holes where the connectors used to be. +5V and -5V came from the L15D positive and negative rail 5.6V zeners. serafis Wed, 15 Feb 2017 22:17:55 -0500 13 - Phase Inverter schematic http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14692 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14692" target="_blank"><img title="Phase_Inverter_Schematic.JPG" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/Phase_Inverter_Schematic.JPG" alt="Phase_Inverter_Schematic.JPG" /></a><br /><br />by: serafis<br /><br />Description: Phase inverters must be used on alternate channels that share the same power supply, with their speaker connections also reversed, to avoid bus pumping. I took the schematic from page 32 of the IRAUDAMP7S reference design. It works perfectly and I can't hear the difference between phase inverted and normal channels. serafis Wed, 15 Feb 2017 22:17:55 -0500 12 - Speaker Protection Circuit http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14693 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14693" target="_blank"><img title="Speaker_Protection_Circuit.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/Speaker_Protection_Circuit.jpg" alt="Speaker_Protection_Circuit.jpg" /></a><br /><br />by: serafis<br /><br />Description: I bought these as kits from Aliexpress - they provide a delayed start (muting) and DC protection for speaker outputs. I ran them from the +15V outputs on the PSU - they're designed for AC input but I just removed and bypassed the rectifier and connected directly to the 12V regulator instead. Note that they have a common speaker ground, so when reversing speaker connections on phase-inverted channels do it AFTER the protection circuits, not before, to avoid unintended speaker shorts. I learned this the hard way, which cost me a power supply and a L15D board (fortunately I was able to repair the latter with a new IRS2092 chip, mosfets and 5.6V zeners). serafis Wed, 15 Feb 2017 22:17:55 -0500 04 - Powerpoint template for front panel http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14687 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14687" target="_blank"><img title="Front_Panel_Template_Powerpoint_.jpg" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/Front_Panel_Template_Powerpoint_.jpg" alt="Front_Panel_Template_Powerpoint_.jpg" /></a><br /><br />by: serafis<br /><br />Description: I used Powerpoint to make a scale template of the amplifier front panel. I printed this and used it as a cutting and drilling guide. serafis Wed, 15 Feb 2017 21:46:13 -0500 25 - Baking Tray Amplifier - back view http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14688 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14688" target="_blank"><img title="P1070015.JPG" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/P1070015.JPG" alt="P1070015.JPG" /></a><br /><br />by: serafis<br /><br />Description: And finally, the back view of the finished project. Pretty neat eh? Looks just like I planned it. serafis Wed, 15 Feb 2017 21:46:13 -0500 24 - Baking Tray Amplifier - front view http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14689 <a href="http://www.diyaudio.com/forums/gallery/showphoto.php/photo/14689" target="_blank"><img title="P1070018.JPG" border="0" src="http://origin.dastatic.com/forums/gallery/data/2238/thumbs/P1070018.JPG" alt="P1070018.JPG" /></a><br /><br />by: serafis<br /><br />Description: The front view of the finished project. A nice minimalistic look with pinlight indicators for standby, power, the 7 L15D PWM LEDs, and the speaker protection circuits. You can also see the IR receiver and the standby on/off button. serafis Wed, 15 Feb 2017 21:46:13 -0500