Your filter cap's lost capacitance and the noise on that rail is driving you nuts. This Jaycar 22µF tantalum at 16VDC gives you the extra storage your circuit needs without going to a bulkier electrolytic. Thru-hole mount, resin-dipped case. Solder it in and the ripple's gone
| brand | JAYCAR |
| sku | RZ6658 |
| capacitance | 22µF |
| voltage_rating | 16VDC |
| type | Tantalum |
| mounting | Thru-hole |
| case | Resin-dipped |
| category | ELECTRONICS & COMPONENTS |
| subcategory | ELECTRONIC COMPONENTS |