Auto Bias Modules The Auto Bias webpage is down for maintenance and update, effective April 7, 2025. If you need assistance with an Auto Bias Module please contact us directly- the on-line Shopping Cart for these products is being updated. AB-Qi-M125 module shown Remote LED modification $45.00 Add to cart Module AB-4 for 4 tubes, PP & PPP amps, requires 6.3VAC & bias supply from the amps circuit, with TTL error signal output. $96.00 Add to cart Module AB-2 for 2 tubes, PP & Single Ended amps, requires 6.3VAC & bias supply from the amps circuit, with TTL error signal ouptut. $85.00 Add to cart Module ABS-Qi+ for 4 tubes, PP & PPP amps, with a built in 6.3VAC AND bias supply, 115V or 240VAC powered transformer, fully autonomous. $100.00 Add to cart Module AB-D-MKII for Dynaco MKIII amp chassis $62.00 Add to cart Module AB-Di-MKIV. This module has been designed to fit the Dynaco MKIV amp chassis! $70.00 Add to cart Module AB-Qi-M125 fit for M125 mono block power amp $85.00 Add to cart Module AB-Qi-ST70/ST120 for Dynaco ST-70 chassis – ST-70 and ST120 Stereo Amps $85.00 Add to cart Module AB-Oi for 8 tubes, PP & PPP amps, with a 1:1 isolation transformer for use in amps $80.00 Add to cart Module AB-Di for 2 tubes, PP & PPP & Single Ended amps. with a 1:1 isolation transformer for use in amps $75.00 Add to cart Module AB-Qi for 4 tubes, PP & PPP amps, with a 1:1 isolation transformer for use in amps $80.00 Add to cart Module AB-Q for 4 tubes, PP & PPP amps, requires 6.3VAC & bias supply from the amps circuit $75.00 Add to cart ST-120 Auto Bias Module w/LED Extension (bias 0.50V/500mV for KT88) $149.95 Add to cart
