7025WBHG TAD selected preamp tube 7025WB high grade (RT093-HG) 7025/E83CCR TAD selected preamp tube 7025/E83CC Redbase (RT-7025) ECC83PSVA TAD selected preamp tube PSVANE ECC83 (PS-ECC83) ECC83PSVSYM TAD selected preamp tube PSVANE ECC83 12AY7 TAD selected preamp tube 12AY7 / 6072a (RT007) 5751HG TAD selected preamp tube (RT090) ECC81/AT7CZ TAD selected preamp tube ECC81/12AT7-Cz balanced (RT052) 12AT7WTCNOS TAD selected preamp tube 12AT7WC NOS-selection balanced (RT004) 12AU7 TAD selected preamp tube 12AU7 / ECC82 (RT005) 12AU7WA TAD selected preamp tube 12AU7WA / E82CC (RT065) 12DW7 TAD selected preamp tube 12DW7 / 7247 (RT044) EF86 TAD selected preamp tube EF86 / 6267 (RT-EF86) 6922 TAD selected preamp tube 6922 / E88CC (RT-6922) 6SN7GT TAD selected preamp tube (RT980)