Which one of these amps to drive my sub?

[-_nando-_]

I want your opinion, about these two amps...

http://sound.westhost.com/project3a.htm (Elliot's)
http://www.ampslab.com/c200.htm (ampslab)

Which one is better, in overall terms ? I'll use it to drive a nice 4 Ohms subwoofer, and in your opinion, which one is better at lower frequences, and are better designed?

I was determined to build the c200, but I found recently this amp at the elliot's site, and it appears to be better in my opinion.

I bought the transistors to build the c200, but they were all fakes So, now I can choose again which amp I'll build !

c200 is more powerful, but not in my system, cause it will be supplyed with 32+32v only...


Thanks !!

[MikeB]

Go for the P3A, that's a proven design, like the C300 the C200 also shows "fatal" design flaws... The C200 will give you unacceptable high DC-offset...
If you're interested in ampslab, go for the BI-series.

With 32v, you could also go for a symasym. (click my www)

Mike

[richie00boy]

The C200 and C300 seem to no longer exist? What is the flaw with these circuits?

[MikeB]

The C200 is COMPLETELY unbalanced (for example: 47k at input,10k at feedback with low gain inputdevices), and the C300 has some properties that might blow it when driven into clipping, and is not really stable.

Mike

[Tube_Dude]

Originally posted by MikeB
The C200 is COMPLETELY unbalanced (for example: 47k at input,10k at feedback with low gain inputdevices),

This can be easily fixed , using a 47k feedback resistor instead of the 10k and changing the lower arm feedback resistor , for the same overall gain.

[-_nando-_]

So ?

[richie00boy]

P3a is a good amp, tried and tested. It is also simpler. There is a dedicated ESP forum where you can get help as well.

However the ampslab ones come as a kit so there's no issue sourcing the right parts. However the kit could cost more than you buying the parts yourself, I don't know what's available in your country or what prices are like.

[Tekko]

I´d go with the subwoofer amp on the esp site, as its spesificlly designed for the purpose.

[richie00boy]

There is no need for that extra expense, size and complexity given his small power supply and power requirements.

[mcp]

Originally posted by nando
c200 is more powerful, but not in my system, cause it will be supplyed with 32+32v only...

The c200 is not designed for this voltage.

Originally posted by MikeB

...the C300 the C200 also shows "fatal" design flaws... The C200 will give you unacceptable high DC-offset...

The C200 is COMPLETELY unbalanced (for example: 47k at input,10k at feedback ...

There are no design flaws. Without resorting to servos and trimpots, these "unbalanced" values actually minimise the DC-Offset that is inherent in such topology. Set both at 47K and DC Offset will exceed 100mV.

the C300 has some properties that might blow it when driven into clipping, and is not really stable.

The c300 is very stable. It will even survive a dead short at the outputs.