Hello all! Lots of very interesting and creative builds here, nice work!
To contrast here's my very ordinary looking build 😱 . There's some neat tech in here though. It's a modular design with a module for each of the 6 channels, the amplifier is based on LME49830 paired with lateral MOSFET outputs. Each module also includes a balanced line receiver, DC offset detection and solid state output relay.
It's a common linear power supply with 750VA toroid and 60,000uF per rail smoothing, voltage is +/-51V. It has 2-stage soft-start with a brief AC inrush limit (300mS) and slow charge of the capacitors via resistors which are shorted out (after 1.8S) by DC solid state relays. This is all PIC controlled, and this PIC also connects to each module to facilitate power-on muting. Additionally, if a DC error is triggered the PIC holds the mute for 10 seconds after normal operation resumes. It also connects to a thermal sensor on each heatsink which trips at 58C, if it stays tripped for 4 minutes the amp shuts down, you will get over-temp or DC error indication by an orange front panel LED. The amp mutes and shuts down with loss of AC and is turned on and off by GPIO.
The aim was a simple looking design which is actually very capable, set-and-forget sort of idea! It's serving very well, measured output of 100W RMS per channel into 8-Ohm. Bias is set to safest value (for thermal stability) of 110mA per module. The amp in use will sit at around 38-40C, despite the appearance of this being modest heatsinking no music signal is ever likely to push it to 58C, especially aided by its use as a multi-way DSP system amp, so 4 channels are mids and tweeters.
Sound is just neutral really, effortless and open!
To contrast here's my very ordinary looking build 😱 . There's some neat tech in here though. It's a modular design with a module for each of the 6 channels, the amplifier is based on LME49830 paired with lateral MOSFET outputs. Each module also includes a balanced line receiver, DC offset detection and solid state output relay.
It's a common linear power supply with 750VA toroid and 60,000uF per rail smoothing, voltage is +/-51V. It has 2-stage soft-start with a brief AC inrush limit (300mS) and slow charge of the capacitors via resistors which are shorted out (after 1.8S) by DC solid state relays. This is all PIC controlled, and this PIC also connects to each module to facilitate power-on muting. Additionally, if a DC error is triggered the PIC holds the mute for 10 seconds after normal operation resumes. It also connects to a thermal sensor on each heatsink which trips at 58C, if it stays tripped for 4 minutes the amp shuts down, you will get over-temp or DC error indication by an orange front panel LED. The amp mutes and shuts down with loss of AC and is turned on and off by GPIO.
The aim was a simple looking design which is actually very capable, set-and-forget sort of idea! It's serving very well, measured output of 100W RMS per channel into 8-Ohm. Bias is set to safest value (for thermal stability) of 110mA per module. The amp in use will sit at around 38-40C, despite the appearance of this being modest heatsinking no music signal is ever likely to push it to 58C, especially aided by its use as a multi-way DSP system amp, so 4 channels are mids and tweeters.
Sound is just neutral really, effortless and open!
Attachments
Last edited:
Thanks! It's the front panel, top panel and heatsinks from MODU (I'd prefer the Fischer Elektronik 150mm type but they're expensive!) along with plain aluminium for the bottom and back (4mm and 3mm thicknesses). I did the metalwork myself including the brackets for front panel, the construction of the MODU 4U chassis obstructs too much heatsink area for a 6-channel amp like this. I just tapped directly into the heatsink edges, the result is very solid and stable, weight is 17kg 🙂
Very nice, what you are using for final transistors? Did you etch your pcbs?
Member
Joined 2009
Paid Member
"RaimondAudio"(Raimond it is my name) on the CNC router , the rest of the letters on the laser machine.