al.diorio:

I understood but there is the last question:

1) i bought a Y cable
2) i put the single end of it in the send of my amp
3) i put the doubled end, one in the input of time factor and the other in the input of space

This
much is correct. You will not be able to use a Y cable from the pedal outputs back
to the amp, you will need a mixer here. Y cables don't work for summing audio
as one device will load down the other not to mention ground loops etc.

The RJM mini mixer that I have is what I would recommend. It is
very transparent and noise free and you wouldn't want to put your great
Eventide pedals into anything less.

That said, if you're on a tight budget you could settle for any
small line mixer that you have around or get something like this:

http://www.musiciansfriend.com/pro-audio/nady-mm-141-4-channel-mini-mixer

for $23 it would be worth a shot.

Best of luck!

Marco