watchnerd
Grand Contributor
I thought this was fun.
I asked ChatGPT a number of SUT optimization questions, graph the answers.
Q: Rothwell Audio Products claims that SUTs have less distortion in higher frequencies than active gain stages, but more distortion in the bass vs active gain stages. Can you quantify this for the low (15:1) and high (30:1) gain stages of the HM7?
Q: I have 3 ft of LC-1 cable between SUT's secondary and amp. If I change to 2 ft of [Blue Jeans Cable] LC-2 (shorter, lower capacitance), what is the expected impact on the SUT's high frequency electrical environment under both low and high gain, given the 320 pF input of the L-590AXII?
Q: What is the divider loss, and resultant output, of the HM-7 at 15:1 and 30:1 vs the MM input sensitivity of the L-590AXII?
I asked ChatGPT a number of SUT optimization questions, graph the answers.
Q: Rothwell Audio Products claims that SUTs have less distortion in higher frequencies than active gain stages, but more distortion in the bass vs active gain stages. Can you quantify this for the low (15:1) and high (30:1) gain stages of the HM7?
Q: I have 3 ft of LC-1 cable between SUT's secondary and amp. If I change to 2 ft of [Blue Jeans Cable] LC-2 (shorter, lower capacitance), what is the expected impact on the SUT's high frequency electrical environment under both low and high gain, given the 320 pF input of the L-590AXII?
| Cable | Capacitance per foot | Length | Cable Capacitance | MM Input Capacitance | Total Capacitance (Ctotal) |
|---|---|---|---|---|---|
| LC-1 | 17.3 pF/ft | 3 ft | 51.9 pF | 320 pF | 371.9 pF |
| LC-2 | 11 pF/ft | 2 ft | 22 pF | 320 pF | 342 pF |
| Cable | Total Capacitance | fres (Hz) |
|---|---|---|
| LC-1 (3 ft) | 371.9 pF | ~673 kHz |
| LC-2 (2 ft) | 342 pF | ~695 kHz |
Q: What is the divider loss, and resultant output, of the HM-7 at 15:1 and 30:1 vs the MM input sensitivity of the L-590AXII?
| Mode | Final Output | Luxman MM Sensitivity | Headroom (if any) |
|---|---|---|---|
| 15:1 | 2.58 mV | 2.5 mV | Slightly above (just right) |
| 30:1 | 4.02 mV | 2.5 mV | ~3.1 dB hot — but not overloaded |
