Have a look at this design

[clovi_kate]

hi to everyone..i have this design and i planned to used other design higher than this..i could not get a better power to this amp..i used 2 18"double magnet instrumental crown(500-1000w) every channel..
the power supply is +98vDc 0 -98vDC..

anyone familiar with this amp? it looks like a design of M250 but the difference is the supply and at the 2nd stage design..

take a look with this..
any comment to everybody..
thanks in advance...

ryan jan

[AndrewT]

Hi,
there are components missing from the schematic.

+-98Vdc seems too high for the devices you have shown. A1011/C2344 are 160Vce0.
What is the voltage ratings of A970 & C2240?

What current can each of these devices carry when using your +-98Vrails?

On pair of 2sa1943/c5200 will only be able to drive a resistive load impedance greater than about 36ohms and reactive impedance greater than 150ohms to about 25W.

What are you planning to use this for?

The M250 has about 8pairs of output devices and about half the Vrail voltage.

[clovi_kate]

sorry i got a mistake..there are 5 on npn and 5 for pnp power transistors..all in all it has a 10 power transistors..as of now i am searching for the specification of smaller transistors..this is the design made by one person and i suppose to email this in her for the mistakes of this design..

[deleveld]

There are a couple of things wrong with the design and a couple of very wierd things:

wrong 1) The input transistor of the differential has no DC path to ground. The 1.1k resistor should go from the base to ground.

wrong 2) One pair of output devices is not enough for +-98 volt outputs

wierd 1) The current mirror thing (C2240) will lead to very unbalanced differential currents.

wierd 2) The current sources A970 and MJ350 depend strongly on hfe which is highly variable. There should be diodes or a resistor from 1k/100 to ground.

wierd 3) What are the 1n4941 diodes supposed to do?

Hope this helps,

Doug

[AndrewT]

Hi,
5pairs of a1943/c5200 will drive 33ohms to 100W @ 45degree phase angle at 50degC SOAR.

and manage 8ohms resistive but only just.

The problem is mismatch between chosen devices and Vrail.


edit;
1943/5200 have a 230Vce0 rating but are terrible when working at high voltage eg. <=400mA @ 100Vce @ 25degC.
They suit lower voltage amplifiers only.

[clovi_kate]

the circuitmaker i used is a student version thats why i cant put everything based on the real design..thanks for all the help.. if this design works properly in its complete circuit even at risk with vrails, what should be the maximum power i got?..

thanks a lot... ryan jan

[AndrewT]

Hi,
5 pairs could manage about 400W into 4ohms.
Vrail about +-65Vdc.

To achieve this you need some mighty hardware.

Allow about eight to ten times the cost of the stuffed PCB.

[clovi_kate]

Is there anyone has a better design than this?..
someone suggest to use the super leach amp but i dont even see the schematic diagram and specification of this that amp..

any suggestion for a good amp?...

tnx..

ryan jan..

[clem_o]

ryan jan,

Learn what a simulator can and can't tell you. For example, it won't show you that your transistors have gone up in smoke. The simulation isn't that sophisticated - even for the professional version of Circuitmaker.

Cheers!

Clem

ps: I've found that the simulators also hardly ever tell you that your design is potentially (or IS) unstable. The effects are subtle, often a convergence issue.

[still4given]

Leach SuperAmp

Blessings, Terry