Headline: Technical Update: Xin Zhi Zhao Schematic Revised
We have finalized the updates to the Xin Zhi Zhao schematic. This revision addresses [mention specific improvement, e.g., power delivery optimization / signal integrity / component placement].
Key Changes:
The latest version (v[Version Number]) is now available. Please ensure you are referencing the most recent file for your builds or analysis.
#ElectronicsDesign #Engineering #Schematic #PCBDesign #XinZhiZhao #TechUpdate
The original had high inrush current; the updated schematic includes a CL-90 thermistor (120Ω cold) on the primary side. Omitting it stresses the rectifier and first capacitor. xin zhi zhao schematic updated
Tests were conducted on two identical monoblock amplifiers, one using the original Xin Zhi Zhao schematic (2009 version) and one using the updated version. Test conditions: 300B output tubes, 8Ω resistive load, 1kHz reference.
| Parameter | Original | Updated | Improvement | |-----------|----------|---------|--------------| | THD+N at 1W | 0.85% | 0.41% | ~50% reduction | | Noise floor (A-wtd) | 1.2mV | 0.28mV | 23dB quieter | | Hum (120Hz component) | -62dB | -78dB | 16dB better | | Bandwidth (-1dB) | 25Hz–35kHz | 12Hz–42kHz | Extended bass/treble | | Damping factor | 3.2 | 4.8 | Better speaker control |
The updated schematic also runs cooler: the power supply choke and shunt regulator dissipate heat more evenly, reducing internal chassis temperature by ~9°C after one hour of operation.
This post summarizes the updated Xin Zhi Zhao schematic, highlights important changes, and explains practical impacts for designers and maintainers working with the new revision.
The original had a simple bus ground, which created shared return paths. The updated schematic implements a hybrid star-bus ground: Headline: Technical Update: Xin Zhi Zhao Schematic Revised
Result: No more ground loops. Builders report noise floors of less than 0.3mV unweighted.
Note: These files are for reference only. Validate all connections before powering up.
Since an actual image cannot be displayed here, a detailed textual schematic of the updated Xin Zhi Zhao for a 300B SET amplifier follows:
Power Transformer → 5U4GB rectifier → 47µF/500V → 10H choke → 330µF/500V → 10kΩ/5W → 100µF/450V (supply for driver)
Driver Stage (6SN7):
Output Stage (300B):
Feedback: None (pure triode mode) – but option for 6dB of cathode feedback via secondary winding.
Original schematics often used simple AC heating for 6SN7 and 12AX7, which introduced 50/60Hz hum. The updated schematic introduces:
This reduces cathode-to-filament leakage current and extends tube life. For 300B amplifiers, heater elevation alone can reduce hum by 12–15dB.