HIGH Power Sub amplifier?

[kASD]

reply

check this out

 

[Kilentra]

I don't think I changed any other parts, but if I remember any I'll tell you. Be careful selecting the right parts sizes and formats for the PCBs - I had some too large capacitors, wrong format potentiometer, etc.

I also re-built the amp with slightly different mounting configuration, to allow direct mounting of Mosfets to a flat heatsink:

An externally hosted image should be here but it was not working when we last tested it.

I would maybe want to try a slightly different combination of resistors for the biasing circuit, to allow easier adjustment with the IRF devices. But the values in Anthony's schematic work fine.

 

[Killjoy99]

Resistor Values

I can't seem to find the wattage for the resistors in his manual. I found all the resistance for each but not sure if they should be 1/4 watt, 1/2 watt, or 1 watt, ect, ect.

 

[Kilentra]

In my amp R7 and R14 (both 10k) are 1 watt metal film. R24-31 (0.22 ohm) are 5 watt wirewound (sandcast?), but 3 watt non-inductive resistors would work too if you can get them. All the rest are 1/4 watt.

 

[rlg_200]

av400 dont have zobel network. if I put zobel network like a av800, is there possible problem?

 

[The Saint]

The Av400 was designed so it didn't require a zobel nework on the output.
It is uncondiftional stable into any load from 4 to 16 Ohms
It is 2 Ohm stable but is not recommended...

 

[rlg_200]

hello saint,

I'm planning to build ur amp design soon av400/av800, because I heared it is sounding good. I have a question, what is the total output power of av400 if I connect in bridge mode.

I have a simple calculation to find the output power bridge mode type as follows!!!.

bridge mode type.
@ 16 ohms=400 watts
@ 8 ohms =800 watts
@ 4 ohms =1200 watts--- it is possible to connect in 4 ohms load?

many thanks,

rlg

 

[The Saint]

I have tested the AV400 in bridge mode with a single 625VA transformer. It produced 700 watts RMS into 8 Ohm load.
Driving a 4 Ohm load with this amp is not recommended.
However it is possible with a lower supply rail.
Say +-50 volts

Have fun

 

[rlg_200]

saint,

Many thanks for ur reply,


rlg.

 

[HiFiddle]

Well why not try Greg's GB300D SKA amp?

He rates it quite conservatively at 300Wrms into 8 ohms or 4 ohms, but it uses 1200W of complementary MOSFETs in the outputs.

That's enough for over 400Wrms in other amps. He has a sub crossover circuit as well.

 

[rlg_200]

hello' guys'

pls. help, I just built av400 I make my own pcb of this version. my problem is during pre test the amp is ok. it read 1.6 vot at R2 , R4, but when I put the power mosfet the fuse was blow.

anyone can help, I expect that the op is damage. but I dont know on how to check the mosfet.

rlg.

 

[TonyTecson]

hello' guys'

pls. help, I just built av400 I make my own pcb of this version. my problem is during pre test the amp is ok. it read 1.6 vot at R2 , R4, but when I put the power mosfet the fuse was blow.

anyone can help, I expect that the op is damage. but I dont know on how to check the mosfet.

rlg.

mosfets, gets easily zapped when there is nothing at the gate, i learn'ed that the hard way. make sure gate biasing is ok, and set not to high.

if fuse blows, check the mosfets drain and source, it shuld be a diode forward biased one side and infinitely high reistance at the other side, that is when using your ohmmeter when cheking.