In IPA, what is the difference between ə and ʌ?

In all the examples I've seen they seem to be the same sound.

Examples of ə:

• a in about
• a in comma

Examples of ʌ:

• u in run
• o in won

I am trying to decipher the difference between these sounds but they seem identical to me. Is it because of my dialect (American English), or is there a very subtle difference that I should look out for?

In English, the only real difference between these two is that [ʌ] occurs in stressed syllables, and [ə] occurs in unstressed syllables. There is a slight acoustic difference between the two ([ʌ] is supposed to be a tiny bit lower and possibly backer than [ə]), but it is so slight that it is virtually indistinguishable.

Also note that many full vowels become [ə] when unstressed in English (e.ɡ. [sɔlɪd], but [səlɪdɪfaɪ]).

(This distinction is only for English, in other languages these phonemes can pattern completely differently.)