difference between these two amplifiers

[badcompany2all]

Hi fellas

could anyone tell me that is there any difference in these two amps???
between this 400W amp:




and this 250W amp:

http://www.free-circuit.com/300-watt...wer-amplifier/

is there noticeable difference between the power of these two amp because I already built that 250W amp and I like to build the 400W amp because I want more power and more windows shaking (this amp as sub amp)
my sub RMS power is 400W and maximum power is 1200W

[ingenieus]

Uhm, the APEX drawing says 240W in the top left corner....

Upgrading from 250W to 400W will give you a system that plays about 2dB louder.

Punch this into your calculator to verify
10*log10(400/250)

Hardly worth the trouble.

[Mooly]

As above...
So how much power do you really need for domestic listening ?

[juma]

Originally Posted by badcompany2all

...
and this 250W amp:

300 Watt MOSFET Real HI-FI Power Amplifier – Free Electronic Circuit Schematics....

That's a nice amp but far, far away from 250W. With PS of +/-55V and only 2 pairs of k1058/j162 you can have about 100W RMS at 8Ohms speaker and a bit more at 4 Ohms.

OTOH, HV23 by Apex will do what is says.

[MiiB]

The second one is essentially a type of goldmund clone...

[juma]

Goldmund came much later. That schematic originates in Hitachi's application note for lateral MOSFETs (1977 or 1978)

[MiiB]

Then the goldmund is essentially a clone...)

anyway the devil is in the details...and so is the sound of a given schematic...

[Nico Ras]

How is thermal compensation achieved? In APEX design, those are HEXFETs?

[a.wayne]

Originally Posted by ingenieus

Uhm, the APEX drawing says 240W in the top left corner....

Upgrading from 250W to 400W will give you a system that plays about 2dB louder.

Punch this into your calculator to verify
10*log10(400/250)

Hardly worth the trouble.

While correct, it's very misleading when discussing ( music) practical use. The 400 watt amp will have better dynamics and control ( all parameters being equal). Typically he will be using between 20-40 watts RMS for standard Din, the bigger amp will allow double the volume ( 10dB ) right up to 40 watts rms, much better dynamically with no compression vs the 250 watter, representing more than a 2 db difference when playing music.


Regards,

[Nico Ras]

Hi badcompany2all,

The RAS300 is my design published around 1989 on my bulletin board at the time (before internet) and later on my web site. The schematic is based on the Hitachi app note at the time when L-MOSFETs became popular. That particular circuit and PCB layout was hi-jacked from my site some years ago. The the 300 is a number which means nothing, I give numbers to my designs, what you read into it is your business.

It is a very nice sounding amp and my later RAS-ELD and some other commercial amps that actually licensed it is based on that circuit with some refinements. Yeah, Goldmund could be a close clone, maybe they also hi-jacked the circuit.

It is good for about 250 watt peak into 8 ohms with 55VDC rails and and 300 watt peak into 4 Ohms with 42 watt rails. Even the text was badly copied on that site.

If you like the rest of the information e-mail me and I will send it to you.

Regards

Nico