I'll take and post up some pictures as soon as I have time. I hate to admit it but I just ordered a pair of 500 Watt mono class D boards from China. Those 2 boards plus a huge toroidal transformer was only $100. I don't expect the SQ to be as clean and accurate as the ClassDaudio boards, but hopefully they make good subwoofer amps. We'll see... not too much invested if they suck
I might have some time to snap and post some amp pictures this weekend... but mostly my time this weekend is dedicated to getting the supercharger back on the Mustang and firing that bitch up on the alky/gas mix! Haven't heard that blower whine in quite a while.
One of my goals on this project was to lay it out so that signal wires, power wires, and speaker wires are as far away from each other as possible. Where the speaker leads must pass near the DC+/com/DC- leads I made sure they crossed each other at 90 degrees to minimize coupling. The line level cables are shielded with aluminum foil and a full copper braid.
What is the reason the input is floated from the chassis? I don’t know much about amp design so I’m just curious what dictates when they are isolated or not.
I float the input line level RCA's so that I don't create a ground loop. The chassis is tied to earth ground on the primary side of the transformer and tied to the common side of the secondary after the rectifier. That is all for safety so that if there is ever a short circuit the mains fuse will blow first and protect any wiring from becoming heating elements. It also ensures that the metal chassis can never be floating at any voltage potential (always grounded for human safety).
The shield on the line level cables could be tied to the chassis. However I've had really great experience grounding the shield to the line level common at the input RCA's. I've done this on all my solid state and tube amp and preamp projects and they have all been very quiet.
??? - bridge rectifier, 1 amp, 300 PIV I take the 12 Vac aux winding off the torroid transformer and rectify it for the muffin fan.
Fan speed control module from Ebay - Super cheap, pwm, adjustable 5-30 Vdc, 1.5 amp, voltage regulator board from Ebay. I think I bought 5 of them for $9.00. The blue Bourns 10 turn pot sets its output voltage. I have it set at about 3 volts and it runs the 12 Vdc muffin fan nice and slow. It's moving air but it is dead silent.
What is this? - 10 Amp RFI/EMI filter module. About $5-10 from Mouser or Allied or Digikey. This one is separate. Sometimes I buy my IEC input jack with the fuse and RFI filter built in.
Comments
If anyone is interested in what I purchased:
https://www.aliexpress.com/item/IRS2092S-500W-Mono-Channel-Digital-Amplifier-Class-D-HIFI-Power-Amp-Board-High-Quality/32803925812.html?shortkey=ya2AnaYV&addresstype=600
I might have some time to snap and post some amp pictures this weekend... but mostly my time this weekend is dedicated to getting the supercharger back on the Mustang and firing that bitch up on the alky/gas mix! Haven't heard that blower whine in quite a while.
One of my goals on this project was to lay it out so that signal wires, power wires, and speaker wires are as far away from each other as possible. Where the speaker leads must pass near the DC+/com/DC- leads I made sure they crossed each other at 90 degrees to minimize coupling. The line level cables are shielded with aluminum foil and a full copper braid.
I float the input line level RCA's so that I don't create a ground loop. The chassis is tied to earth ground on the primary side of the transformer and tied to the common side of the secondary after the rectifier. That is all for safety so that if there is ever a short circuit the mains fuse will blow first and protect any wiring from becoming heating elements. It also ensures that the metal chassis can never be floating at any voltage potential (always grounded for human safety).
The shield on the line level cables could be tied to the chassis. However I've had really great experience grounding the shield to the line level common at the input RCA's. I've done this on all my solid state and tube amp and preamp projects and they have all been very quiet.
??? -
bridge rectifier, 1 amp, 300 PIV
I take the 12 Vac aux winding off the torroid transformer and rectify it for the muffin fan.
Fan speed control module from Ebay -
Super cheap, pwm, adjustable 5-30 Vdc, 1.5 amp, voltage regulator board from Ebay. I think I bought 5 of them for $9.00. The blue Bourns 10 turn pot sets its output voltage. I have it set at about 3 volts and it runs the 12 Vdc muffin fan nice and slow. It's moving air but it is dead silent.
What is this? -
10 Amp RFI/EMI filter module. About $5-10 from Mouser or Allied or Digikey. This one is separate. Sometimes I buy my IEC input jack with the fuse and RFI filter built in.