design..

[clovi_kate]

check this amplifier i found it her before.. it looks like krell,not really..
any suggestion with this amp.. i will really appreciate your comments upgrading this amp..
vrail is +-55v, what will be the power drawn with load4ohms and 8ohms?..

tanx..

[Gordy]

You can work out the power from the equation:
Power = Voltage (squared) / Resistance.

Hence halving the resistance will double the power.

However, in practice there will be a finite limit to the output power available, according to the maximum current that the amplifier can deliver (by it's design) when swinging maximum voltage across a low impedance load. (Power = Current x Voltage).

[clovi_kate]

any comments to this design?..somethings missing to this i think..

[Tony]

Originally posted by clovi_kate
check this amplifier i found it her before.. it looks like krell,not really..
any suggestion with this amp.. i will really appreciate your comments upgrading this amp..
vrail is +-55v, what will be the power drawn with load4ohms and 8ohms?..

tanx..

Without power supply info, power delivered to a 4ohm load will be hard to tell, power delivery will depend much on how stiff your power supply is.

have you built this amp?

[Conrad Hoffman]

Well, it's a single channel, and no power supply is shown, but it looks like a complete power amp circuit. As for the design, I haven't built it, but my armchair comment is that it looks like a competent design that should be reasonably robust. IMO, it has the appeal of visual symmetry, but this is often an illusion due to the differences in N and P channel devices. I think the 100uF cap in the feedback network is too small for good low frequency phase and amplitude response, but again, that's personal preference. I'd want to simulate it or gather comments from somebody that's built it, before choosing it over some other design, but it looks very reasonable.

[clovi_kate]

yes i already built this amp and working at Vrail +/- 55v with transformer 500VA.. of course 2channels driving 2 15inches per channel(4 in all).. it works fine..but i need o consult to all for any comments regarding this design..

i use this amp for midranges driving at crossover and other equipment.
in driving at max level with 4ohm load draws a output voltage about 30v for continues and 40-45v at peak..
frequency range at input is about 500-3.0KHz..

and i replace output transistor instead i use the familiar 2SA1943 and 2SC5200 having 4 Q per channel(8transistors all in all)..
i also replaced 2N5550 and 2N5401 to MJE340 and MJE350..

correct me if my replaced Q is not capable in the circuit..

regards..

[Bonsai]

I've done quite a bit of work on this type of topology (I'd say many hundreds of hours). Its a pretty conventional fully symmetrical design.

Pretty robust, straight forward topology
Symmetrical drive to output stages
Many older commercial designs based on this approach
Loop gain tends to be on the low side, so ultimately this limits distortion performance.
The non-symmetrical loading of the diff amp stage also detracts from the circuits linerarity.
More up todate deisgns that follow this overall design theme use a folded cascode VAS stage or buffer the diff amp before driving the VAS transistors.
A great enhancement is to use a differential VAS stage.
Some further improvements to linearity can be gained by employing a cascode in the VAS stage.

Take a look at th e Leach Amp for a practical DIY implementation that has had the bugs ironed out over many years (lots of threads on this website you can tap into and PCB's I think also avaialble).

Basically, a good solid amp. Good luck.

[clovi_kate]

could you elaborate further with regards to enhancement?..
this amp works great even at minimum signal applied..it sounds clear and nice to hear.. the only thing i am concern is on upgrading this design into great one..so i need your comments and suggestion guys..

tnx

[clovi_kate]

anyway thanks bonsai..