A legendary classic machine - Marantz 7 (M7) pre-biliary, sound quality is known for its mellow, medium-frequency sweet and natural, bold and strong
For the players who are in the pre-level, the pre-levels are mostly the legendary three-handed entry (M7, SRPP, Matisse). The comparison between the three is undoubtedly the M7 wins.
M7 is only good on the Internet, it is wrong, it is wrong, carefully adjusted M7, is very comprehensive, dynamic is also very good. Vocal, natural, delicate, smooth strings, stretch, positioning and imagery. The high and low frequencies extend into place, and the low frequency dive is deep and powerful without lack of flexibility.
The circuit of our shop is derived from the classic M7 circuit, and the necessary modifications and adjustments are made according to the characteristics of modern devices (mainly coupling capacitors) and old capacitors;
Many people in the pre-biliary class are very easy to make the noise that can&x27;t be eliminated. It is very noisy. We use our own strength, reasonable layout and routing, and a little grounding, so that this product has no annoying noise, it is very quiet.
A lot of electronic tube preamps on the Internet, its design is not too reasonable, the main performance is that the distance between the bile ducts is too close, we suggest that the distance of the bile duct center point is greater than 40MM
Input voltage: high voltage group: AC200-220V, not less than 15MA
Filament group: AC12-14V group, not less than 0.8A (for filament)
This version uses DC filament power supply. If the filament supply voltage is too high, the heat sink will be very hot.
Recommended tube: 12AX7 and its compatible tube
This version of the listening is relatively loose, low-frequency softness is better than PRT07A, better than the M7 machine with exposed bile duct
PCB size: 152*177*1.6MM FR4 Class A plate
Note: This is a pair of finished boards and tested, does not contain tubes and transformers