Is playing in an orchestra/band a good way to start a solo career?
Yes! Any exposure to professional musical life will always help with contacts. The more open-minded you are about working as a musician, the more likely you’ll have a long and secure career. Consider doing one or two for a small fee (expenses) or even for free – quite often you will meet dedicated professionals within these groups who have had (or continue to have) excellent contacts within the world of music. You will meet a huge variety of diverse musicians with many different interests whilst playing in ensembles. If you get a chance, try to experience as many different ensemble situations as possible too to broaden your own musicality.
However, never give up on a goal either – just because you playing fourth Tuba (is there such a thing?!?) in a local brass band, it doesn’t mean you shouldn’t practice and aspire to being a soloist in front of the LSO! Many, many artists start this way and many gradually pick up solo work – first from amateur organisations progressing gradually to professional well-publicised performances.
That said, don’t be dissatisfied with ‘only’ playing in an ensemble – there are many worse careers to be had!
Some local (Hampshire based) groups worth contacting about vacancies (NB: very good sight-reading is required for all) – these are all amateur and unlikely to pay well:
Havant Symphony Orchestra(s) – www.havantorchestras.org.uk
Dave Pearson’s Big Band – http://bborch.org.uk/about.php
City of Southampton Orchestra – http://www.csorchestra.org
Hyde Brass Band – http://www.hydeband.co.uk