Subtle individual variation
Vowel sounds are notorious for varying between one variety
of English and the next, often being a key element in what we
recognize as different accents.
You may not make a significant distinction between the
central vowels [ə], called “schwa,” and [ʌ], called “wedge.” If
you’re trying to transcribe, just use schwa [ə]. In fact, in casual
speech, we all use schwa more than any other single sound.