Replacement parts question

a few quick parts related questions:
1-Is a BC550 a suitable replacement for the ZTX109
2-Is there a single source where these components (or equivalents)can be purchased? (i tried mouser already).
i prefer to consolidate my orders to keep the shipping costs down and make it worthwhile for the parts distributor
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ZTX 109;
JE1692;
MC1458(easy)
TL072(easy)
MC14053B(prob locating)
MC14016B(prob locating)
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it's rough getting in a repair that who-knows-how many other 'techs' have had a crack at already; and have to get past the poor craftsmanship, damage and failed expirements they left behind before being able to address the service problem.
but this website and forum are excellent. thanks to Steve

What amp are you working on ! Did mouser say this BC550 is a replacement for the ZTX109? You want
NTE123AP for the ZTX109---
511-4053 for the MC14053B---
511-4016 for the MC14016B---
511-2N6488 for the JE1692---
All parts are from Mouser!!!!!!