I inherited a subwoofer in a nice cabinet. The plate amp is junk. I don't want to buy an amp. There are three boards. One for inputs, one with controls (I'm assuming that is the equalization, and the amp itself. The equalization board has two tiny wires going the amp. I would like to connect those outputs to one set of the RCA jacks and the driver to the other two. So what I need is a really powerful mono transistor amp kit to power the thing. Any Ideas?
Something like this 600 watt Class-D amp:
It requires a 25 to 52 VDC power supply, which you might salvage from your plate amp or a computer, or purchase along with it.
It requires a 25 to 52 VDC power supply, which you might salvage from your plate amp or a computer, or purchase along with it.
It looks like that's @ Parts Express:
https://www.parts-express.com/Sure-...30-Class-D-Amplifier-Board-320-311?quantity=1
https://www.parts-express.com/Sure-...30-Class-D-Amplifier-Board-320-311?quantity=1
Thanks, I thought it looked like the Parts Express website. One question though. I'm a tube guy so in this case would you need voltage more like 50 volts to get maximum power out of it?
52 volts and at least 500 VA of transformer.
Unless you think your really gonna put 600 watts into a speaker then more like 600 to 800 VA
Assuming 600 watts is a Class D fantasy and more like 1% to 10% distortion at 350 watts
Then 500 VA is more than fine.
There is of course switch turd power supplies, depending on the rating buy one that is twice the rated fantasy power.
Then you get the actual real world needed power for normal listening around 60 to 150 watts
and not have the class D amp or switch turd supply overheat and shut down.
So like many others you can get away with a relatively weak switch mode supply.
Or just use a tried and true overkill linear supply that lasts 25 years not 3 to 7 years 12 if lucky
and wont overheat on party nights or loud movies
Unless you think your really gonna put 600 watts into a speaker then more like 600 to 800 VA
Assuming 600 watts is a Class D fantasy and more like 1% to 10% distortion at 350 watts
Then 500 VA is more than fine.
There is of course switch turd power supplies, depending on the rating buy one that is twice the rated fantasy power.
Then you get the actual real world needed power for normal listening around 60 to 150 watts
and not have the class D amp or switch turd supply overheat and shut down.
So like many others you can get away with a relatively weak switch mode supply.
Or just use a tried and true overkill linear supply that lasts 25 years not 3 to 7 years 12 if lucky
and wont overheat on party nights or loud movies
Last edited:
Do you know what kind of load your sub will draw? At 8 ohms, the specs for that amp say it’ll do 101-250 watts. I think 600 watts is into 1.5 ohms.
I cancelled the class D amp. As for the driver impedance it is unknown. It's a Canadian Energy brand Micro Star MS 12.1. I guess whoever 'designed' the amp just ripped off the Hafler Sunfire plate amp. Klipsch sold Energy and Energy wiped any published material form the website and won't even talk about it. I have an Adcom GFA 555 which could do the job but it's driving the woofer's in my Snell type A's. My hearing loss in my left ear is classed as severe and my right as profound. Mostly in the low frequencies. At 100hz my good ear is down 70db and my right 90. I plan to modify the original plate amp and bi pass the amp section as described above and use the GFA to see if the driver is any good.
If you can't hear low frequencies, you may want to consider using tactile transducers (bass shakers) that can give you the feel without requiring so much sound output as a subwoofer.
Allow me to back up a bit. The subwoofer was given to me by the owner of the company I work for. He was told the driver is fine but the amp is dead. Without a schematic it is really hard to diagnose anything. What I did suspect was the electrolytics. There were only five in the whole amp. Two huge ones which I assume are filter/reservoir caps and three small ones on the different boards. I found that one of the large ones had been leaking. I thought that would fix it. No soap. When I tried to drive it I had nothing. No output of any kind. That's when I did some research and found out the amp is an orphan. Energy gave me the name of a company in Michigan that used to repair the amps for $150. I assumed they all had the same problem. But there was no one there that knew how to work on it any longer.
One thing I wondered about before I gave up on it is was it really on? There is a power light on the front of the cabinet but that means nothing. There is a pair of screw terminals labelled "12 volt trigger" not sure what that is about. There is also a three position toggle switch labelled "On, Auto Off" does that sound like a power switch? That switch is on what I think is the equalization board. Someone told me that most powered subwoofers sense input and power up on their own. Any Ideas?
One thing I wondered about before I gave up on it is was it really on? There is a power light on the front of the cabinet but that means nothing. There is a pair of screw terminals labelled "12 volt trigger" not sure what that is about. There is also a three position toggle switch labelled "On, Auto Off" does that sound like a power switch? That switch is on what I think is the equalization board. Someone told me that most powered subwoofers sense input and power up on their own. Any Ideas?
I was reading some threads and found the three position switch is actually a power switch. I don't remember if I toggled it, it was a year ago, but today it was in the auto position. Ill try it again with the power switch ON an see what happens.