This is a howto find a replacement for 2SA1106

1. Search for 2SA1106
2. 
3. Open the ECA data sheet with data search icon
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5. Open the search value on the upper left corner
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7. It starts with the standard setting, but you can change it for your needs
8. Click on the Submit query icon
9. A list with will appear, which is sortable on each column
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11. I would recommend to sort the list on IC
12. Select some useable types by clicking on the checkbox in the first column.
13. Press the compare button
14. 

All selected types will listed on the screen and you can compare direct the difference between the transistor, the best replacement type is near the original type. The most relevant values for audio transistor are UCE, IC, Ptot and the gain hFE, 2SA1186 is a very good replacement for 2SA1106, but you can also use FJA4210 (minimal different package form) or 2STW1695, 2STA1695. Please try it an let me know if you have questions or problems.

More info at Parametric search