This worked great so what changed?
Another quick comment on this grounding. Note the signal flows from left to right so any inductance in the ground path will tend to 'buck' the input feeding into pins 5 and 6. If you cascade these amps you are to tie the input of the next stage to the point where 7 and 8 are grounded and separate 5 and 6 of the next IC.
With a SA602 you would apply this and see pin 1 and 2 are the input 3 is ground 4 and 5 are the output. So feed the end with pin 1 and take the output from the pin 4 end. ground is in between. 6 and 7 are the oscillator connection and are as far from the input as possible. Remember NEVER feed a trace under the chip from input or output or you just killed the isolation.
It's not rocket science or magic . We just need to remember to separate the input and output and keep those leads short.
Now what to do with that board I made for show and tell? Oh I will use a LM386 audio amp so I can get away with some longer leads and such.