Connecting guitar with amp to Mac problem

[Zagi]

I connected guitar to amp (Ibanez Troubadour t10) and amp to iMac OSX 10.9.4 (Garageband 10.0.2). Amp doesn' have "normal" output, so I use headphones output (with mono adapter). I use another adapter to connect to Mac. My settings are all fine (built-in input), but I don't hear the guitar, it doesn't record. I don't have that problem when I connect a piano. Is it a problem because of using 2 adapters(both work) or something else? Thank you!

 

[Steenamaroo]

What mac have you got? Is it a combo input/output socket on the mac, or separate jacks for in and out?

While it's plugged in, can you hear anything? iTunes, volume changes etc?
The mac may think you've headphones plugged in......Stab in the dark.

I know you weren't asking but a cheap sm57 copy and simple 2 channel usb interface will almost certainly yield a better sounding result.
Taking headphone or emulated outputs from an amp usually kinda sucks.

 

[Zagi]

iMac, 2009
Processor 3,06 GHz Intel Core 2
DuoMemory 4 GB 1067 MHz DDR3

I hear everything fine except guitar.

 

[Steenamaroo]

I hear everything fine except guitar.

Ok. It's process of elimination then.

Use the guitar amp output into something else to confirm that the former works. Headphones or another amplifier, perhaps?
Plug something else into the iMac input to confirm that the latter works. iPod maybe?

If they both check out OK, that points to your cable and adapters.
Are the adapter TS or TRS? Is the cable TS or TRS?

 

[Zagi]

Amp and headphones work, cable and adapters are TS.

 

[Zagi]

I don't want to record with mic... Is there a cable that I can use?