dmp
Well-known member
I picked up some original transformers for a RCA BA21 preamp. I'll post some pictures along the way.
This is a 40 dB fixed gain preamp with 20dB of negative feedback, fed from a tertiary winding on the output transformer, using two 12AY7 tubes.
Input measures 1:10 (600:60k)
Output measures 5.33:1 (secondary ~17k:600) and 10:1 (tertiary)
The output inductance measured 66 H at 100Hz on Instek LCR-821
The input measured "OVER" which I haven't seen before.
I'll investigate running this with input/output pads and variations of the feedback / no feedback.
This is a 40 dB fixed gain preamp with 20dB of negative feedback, fed from a tertiary winding on the output transformer, using two 12AY7 tubes.
Input measures 1:10 (600:60k)
Output measures 5.33:1 (secondary ~17k:600) and 10:1 (tertiary)
The output inductance measured 66 H at 100Hz on Instek LCR-821
The input measured "OVER" which I haven't seen before.
I'll investigate running this with input/output pads and variations of the feedback / no feedback.