another power amplifier- lm675 questions

Hi!

I'm constructing the "Non-inverting amplifier" in page 1 of the attached datasheet. In my circuit I replace the 20k ohm resistor with a 1k ohm resistor since I actually need a voltage gain of 2.
1. If the motor is set to turn forward, the voltage gain is correct, but if I set the motor to turn backward/ reverse, I do not get the correct voltage gain. What is my mistake? From my observation, if I increase the current from my power supply (I use +-8V), it will also affect the voltage gain. What is the correct current that I should set at my power supply unit?
2. I have two motors whose power needed to be amplified. I am using 2 units of LM675. I have only one set of power supply unit, so I just connect the first LM675's pin5 to the second LM675's pin5 and then to the VCC. Then I also connect the first LM675's pin3 to the second LM675's pin3 and then to the VCC. Is this right? I do not get the correct voltage gain with this connection. What is the correct way of connecting the amplifiers, since I only have one set of power supply unit?
3. What is the effect of 0.1mircroF capacitors at VCC and VEE? Is it ok not to use any capacitors at all at VCC and VEE?

Thanks.

hi,
The gain should remain the same.
When driving in reverse, assuming that you are using a +/-8V supply, does the -8V supply voltage fall.??

The capacitors are essential. one each for each LM675's +v/-v, close to the LM675 device pins.

hi thanks.

when driving in reverse, the -8V supply volatge does not fall but the voltage gain was not correct in which it should be R2/(R1+R2), R1=1kohm, R2=1kohm, but it wasn't.

The data sheet states that the amplifier is stable at a gain of 10 or higher. Perhaps it is oscillating? Try reducing the input and raising the gain to 10.