100W/8Ohm working design needed

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Jump to Latest
D

DigiSoft

Member
Joined 2010
Hi. I am looking for some good and tested 100W on 8 ohm design. That design should have maximum of 4 power transistors (2 pairs)

I prefer IRF.

Thank you.

PS: I know I should use search button and I was, but like already said the forum has too many example projects and I can't decide which is good and which not.
 
apexaudio

apexaudio

Member
Joined 2010
If you realy want build 100w 8R amplifier with IRFP240/IRFP9240, in my thread " DC servo mosfet amplifier" is schematics and PCB layout for amplifier based on Harrison X1000. I made over 200 PCBs in last 10 years for service and building amps. I have long list caffe bars and discoteque's in Serbia and Montenegro were this amps still works.
Regards
 
Last edited:
danspy

danspy

Member
Joined 2007
No IRF but probable the shortest way to get 100W-R8.:D
 

Attachments

  • mosfet100rt2.jpg
    mosfet100rt2.jpg
    59.7 KB · Views: 313
D

DigiSoft

Member
Joined 2010
Very good generic design "danspy" but with that supply voltage only one output pair will have very hard time on 100W and certainly NO WAY to survive on 4 ohms!
Click to expand...
So not good lol :)

Hmmmmmmmmm

Boro, can I use SubZero on 8 and 4 ohms without modifications?
I want schematic like SubZero but only with two pairs and little lower voltage. Can I modify that?
 
Last edited:
W

wahab

Member
Joined 2009
DigiSoft said:
Ok I don't mind to use other components. But what do you think? Is this good schematic? Don't you think it is very slim in components?
Click to expand...

It will work, but it s a basical amp , so don t expect
exceptionnal perfs...

The main drawbacks are clear :

Poor power supply noises rejection ,

Input stage with high gain but poor linearity.

Output stage with high distorsion, since
a pair of emitter followers to drive the mosfets
are necessary to reduce THD.

Two power devices are not enough for the
+-50V supply..
 
D

DigiSoft

Member
Joined 2010
Whab thanks for the answer.
bora so I understand now.

I can use SubZero but with lower votage so it can be used with 4 ohm speakers right? What voltage do you suggest for Sub zero so I can run it on 4 and 8 ohm speakers. I know it will drop power for 8 ohm but that is what I want.

> Izlazna snaga (RMS)-------------200-210W na 8 oma
> Izlazna snaga (RMS)-------------300-320W na 4 oma
> Izlazna snaga (muzička)---------240-250W na 8 oma
> Izlazna snaga (muzička)---------410-430W na 4 oma
> Ulazna osetljivost/impedansa----0,6V/47koma (za 200WRMS/8 oma)
> Frekventni opseg-----7Hz-112KHz /-3dB(pri izobličenjima ispod 0.01%)
> THD-------------------<0.003% (pri 180WRMS na 8 oma)
> THD-------------------<0.005% (pri 300WRMS na 4 oma)
> Odnos S/N------------>95dB (u odnosu na 100WRMS)
> Damping faktor------->300 (pri 200WRMS na 8 oma)


The schematic is for +-75V.
If I use +-50V what power I get on 8 ohm and on 4. Is it possible to run this amplifier on lower voltage then 75 without modifications?
 
D

DigiSoft

Member
Joined 2010
boraomega said:
In that case, supply voltage shouldn't be less than +/-45-46V DC to reach about 100W on 8ohms resistive load and count on about 160W on 4ohms resistive. There are 3 output pairs so with hefty a heatsink you should be on a safe side even with real world loads except maybe some crazy extremes in reactivity direction.
Click to expand...

Great so I can use +-50V power supply without modifications. I'll use all 3 pairs of transistors.
there is no need of changing some resistor values or something right?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Top Bottom