No, it is not. The English sound transcribed as "schwa" (ə) is known to be quite variable. There are a number of things that affect how it sounds.
In American accents, it's common for a "schwa" to be more similar to an an [ɪ] sound (the "i" in "trick") when it's in the middle of a word. For many American English speakers, there is no consistently perceptible contrast between /ə/ and /ɪ/ in unstressed word-internal syllables (this has been called the "weak vowel merger"). Sometimes the merged vowel is transcribed as [ɨ].
A "schwa" before an /n/ is often realized as a "syllabic nasal consonant", which can be transcribed as [n̩].
Here's a previous answer post I wrote that has some more details: When should I use /ə/ or /ɪ/ and why does it seem like they're not used correctly?
Here are some additional comments about IPA transcription, since some comments and other answers have brought up that topic. IPA can be used either to represent certain phonetic vowel qualities (in this use, it is an approximation, since vowels differ along a multi-dimensional continuum but IPA letters are discrete), or to represent certain distinctive features of elements of a language's sound system (this is a "phonological" transcription). In generic transcriptions of the kind you find in a dictionary, it doesn't necessarily represent your pronunciation, or the pronunciation that you are used to hearing; it might represent a conventionalized standard or the way that the word used to be pronounced. So there is potentially a lot of space between an IPA transcription and the actual phonetic form of a word's pronunciation. The use of the symbol "schwa" in a transcription could mean "this word is pronounced with a phonetically mid-central vowel", or it could mean "this word acts in the phonological system of (some variety of) English like it has a fully unstressed vowel in this position", or it could mean "in the most influential historical accents of English, this word was pronounced with a phonetically mid-central vowel".