wax&wires

Amp Simulator For The iPhone

Check out iRock 1.0 in the Apple App store. It’s a guitar amp simulator for the iPhone and iPod touch.

You can plug in a headset with a microphone to sing and modulate your voice through the amp sim, or hook in a cable with the proper pin-out to play your guitar through it. The tough part is finding a cable that will route the signal from your 1/4″ unbalanced guitar cable to the iPhone’s 1/8″ TRRS connector.

A guitar cable sends ground down the sleeve, and signal down the tip of the cable. Putting a simple 1/8″ adaptor on the other end won’t cut it, as the iPhone pin out sends headphone left audio down the tip, headphone right audio down the first ring, ground down the third ring, and microphone input down the sleeve. What that means is that your ground from the guitar cable would actually route to the microphone input of the iPhone, and the signal from your guitar would route to the left output designed for headphone signal from the iPhone.

That’s not to say the app isn’t usable, but simply that finding the right cable to actually hook up your guitar might prove a bit more difficult that it’s worth. Essentially, you need a cable that enables headphone use too. You would thus need the 1/8″ TRRS end to be:

Tip: Left Headphone Out (to some sort of output jack to plug in headphones)
Ring 1: Right Headphone Out (to same output jack as above)
Ring 2: Ground from the sleeve of 1/4″ (guitar) end
Sleeve: Guitar input from the tip of 1/4″ (guitar) end

And then, even if you click all of that in to place spot on, you would still be pumping the line level signal of your guitar into the mic level input on the iPhone, potentially causing a lot of digital clipping. You might then need to figure out some sort of pad to incorporate to get the signal down to an acceptable level. All that likely means more work than it’s worth.

So if you find a cable that will do the job, and are wiling to fork out the $16.99 for the app, you’ll gain access to:

• 6 amp types
• 5 cabinet emulations
• Hi, Mid & Low tone controls
• Gain & Drive controls
• Stereo Echo with LFO modulation
• Tap tempo
• Presets
• Recording and playback
• Built-in file server for downloading recordings
• And a built-in audience if you need someone to perform to

I really like the GUI and the features it lists, especially with the tap tempo, LFO modulation, storing of presets, and ability to record clips. Mark’s Recording Studio really did a great job thinking through what a guitarist would want in an amp sim, and worked in all of the most desirable features. Again, if you can’t get your guitar signal into the device properly though, all of that is moot.

You can check it out here. Let me know what you think, or if I’m way off base with my cable talk.

This entry was posted on Wednesday, February 25th, 2009 at 4:53 pm. It is filed under wires and tagged with amp, amp simulator, app, guitar, iphone. You can follow any responses to this entry through the RSS 2.0 feed.