Introduction to T2500 Pure Class A Fully Balanced Tube Preamplifier
This preamplifier is a pure Class A tube preamplifier newly developed by our store. It is designed to be matched with our flagship T2500 split pure power amplifier (of course it can also be used with other power amplifiers, the price of this preamplifier is slightly more expensive) T2500 The biggest advantage of the preamplifier is that both the static operating point and the power supply are in pure Class A mode. It has the warm, dynamic and calm atmosphere of the tube amp, and the symphonic performance is not inferior at all! Thanks to the pure Class A regulated power supply. The high voltage of the electronic tube supplies power to the parallel Class A voltage regulator 2801. The electronic tube is equipped with a soft start (the filament rises slowly at startup and is heated for about 20 seconds before the temperature of the electronic tube rises before the high-voltage power supply is connected). The front-end output has protection measures such as delay and instantaneous disconnection at shutdown, which can better extend the service life of the electronic tube and improve the performance of the electronic tube. The next level amplifier has no impact. The circuit consists of 2 E88CC and 2 ECC82 to form a CCS-PRO architecture (constant current sinks). It has excellent frequency response characteristics and low output impedance. It has extremely strong load capacity and can make the traditional tube preamp perform poorly. The shortcomings are well compensated (the output impedance of the traditional common-cathode output tube preamplifier is high, several K or even dozens of K, the load capacity is weak, and the symphony cannot keep up with the dynamics)
This preamplifier is a pure Class A tube preamplifier newly developed by our store. It is designed to be matched with our flagship T2500 split pure power amplifier (of course it can also be used with other power amplifiers, the price of this preamplifier is slightly more expensive) T2500 The biggest advantage of the preamplifier is that both the static operating point and the power supply are in pure Class A mode. It has the warm, dynamic and calm atmosphere of the tube amp, and the symphonic performance is not inferior at all! Thanks to the pure Class A regulated power supply. The high voltage of the electronic tube supplies power to the parallel Class A voltage regulator 2801. The electronic tube is equipped with a soft start (the filament rises slowly at startup and is heated for about 20 seconds before the temperature of the electronic tube rises before the high-voltage power supply is connected). The front-end output has protection measures such as delay and instantaneous disconnection at shutdown, which can better extend the service life of the electronic tube and improve the performance of the electronic tube. The next level amplifier has no impact. The circuit consists of 2 E88CC and 2 ECC82 to form a CCS-PRO architecture (constant current sinks). It has excellent frequency response characteristics and low output impedance. It has extremely strong load capacity and can make the traditional tube preamp perform poorly. The shortcomings are well compensated (the output impedance of the traditional common-cathode output tube preamplifier is high, several K or even dozens of K, the load capacity is weak, and the symphony cannot keep up with the dynamics)
specification
Frequency response: 5HZ-135KHz (+0/-1dB)
Input Impedance/Sensitivty:100K/2V
Output Impedance: 200 ohms
Total Harmonic Distortion:0.015%
Signal-to-Noise Ratio:115dB
Power consumption: static 38 watts, maximum 80 watts
Amplification working method: Pure Class A
Magnification: 8 times (18dB)
Net weight:8.75KG
Chassis material: all aluminum oxidation brushed
Frequency response: 5HZ-135KHz (+0/-1dB)
Input Impedance/Sensitivty:100K/2V
Output Impedance: 200 ohms
Total Harmonic Distortion:0.015%
Signal-to-Noise Ratio:115dB
Power consumption: static 38 watts, maximum 80 watts
Amplification working method: Pure Class A
Magnification: 8 times (18dB)
Net weight:8.75KG
Chassis material: all aluminum oxidation brushed
Reasonable layout
(inside the machine)
Two 60-watt transformers (total 120 watts) are equipped with shields on the left side, and heat-generating electronic components such as rectifier power supply regulators are separated by heat sinks.
This reduces the possibility of interference in signal amplification to the minimum, and the purity and signal-to-noise ratio of the signal are further guaranteed.
(inside the machine)
Two 60-watt transformers (total 120 watts) are equipped with shields on the left side, and heat-generating electronic components such as rectifier power supply regulators are separated by heat sinks.
This reduces the possibility of interference in signal amplification to the minimum, and the purity and signal-to-noise ratio of the signal are further guaranteed.
Tube power-on preheating function
The working mode of the electron tube is that preheating the bile duct can extend the service life of the electron tube. The cathode emits electrons: if the cathode temperature is not hot enough, it will be detrimental to the electron tube to apply high voltage electricity. After turning on the power, the filament is powered on for about 20 seconds (at this time, the temperature of the cathode filament and other filaments has been heated enough) and then the high voltage is turned on.
The high voltage is a parallel pure Class A 280V stabilized voltage. The Class A stabilized voltage is stabilized only after the temperature rises slowly to further protect the electronic tube. After about 20 seconds, the front stage turns on the output; at this time, the operating point is basically stable and will not affect the next stage. The power amplifier causes impact; and after shutdown, the output relay can be disconnected instantly, functioning as a power-on delay and shutdown instant-break function to protect the power amplifier.
Therefore, the front and rear stages do not need to strictly follow the power on and off sequence and there will be no impact.
The working mode of the electron tube is that preheating the bile duct can extend the service life of the electron tube. The cathode emits electrons: if the cathode temperature is not hot enough, it will be detrimental to the electron tube to apply high voltage electricity. After turning on the power, the filament is powered on for about 20 seconds (at this time, the temperature of the cathode filament and other filaments has been heated enough) and then the high voltage is turned on.
The high voltage is a parallel pure Class A 280V stabilized voltage. The Class A stabilized voltage is stabilized only after the temperature rises slowly to further protect the electronic tube. After about 20 seconds, the front stage turns on the output; at this time, the operating point is basically stable and will not affect the next stage. The power amplifier causes impact; and after shutdown, the output relay can be disconnected instantly, functioning as a power-on delay and shutdown instant-break function to protect the power amplifier.
Therefore, the front and rear stages do not need to strictly follow the power on and off sequence and there will be no impact.
Transformer filter plate
The exclusively developed mains filter board can effectively filter the damage caused by mains DC pollution to the transformer and the impact of spike pulses on the rectifier board and electron tubes, and has a certain lightning protection function.
Two 60-watt Nippon Steel transformers with shields; improve separation and reduce the impact of electromagnetic interference on the tubes.
The exclusively developed mains filter board can effectively filter the damage caused by mains DC pollution to the transformer and the impact of spike pulses on the rectifier board and electron tubes, and has a certain lightning protection function.
Two 60-watt Nippon Steel transformers with shields; improve separation and reduce the impact of electromagnetic interference on the tubes.
The volume potentiometer is ALPS imported from Japan with a motor for remote control. The balance is very good! It is also the key to good sound. Although the gear switching potentiometer has the advantage of high separation (more precise resistors can be used), it also has a fatal disadvantage that it is non-linear: depending on the individual system, the sound of one more bar is too loud and the sound of one less bar is too loud. Disadvantages such as being too small. The 27-type ALPS potentiometer is linear and does not have this problem, and the separation is also very good! Considering this solution comprehensively, this is the best combination that our store believes.
Four imported electronic tubes (E88CC+ECC82) in the front stage form our newly developed amplifier architecture CCS-PRO. The sub-architecture can not only maintain the soft taste of the amplifier itself, but also have the characteristics of symphonic dynamics! It can be both civil and military. Thanks to the pure Class A parallel mode power supply and very low output impedance, the load capacity is very strong!
The standard configuration is a combination of 2 E88CC + 2 ECC82 (the positions of different models are marked on the internal circuit board of the preamplifier)
Different tube models have slightly different timbres. The standard ones in our store are determined after many times of tuning and debugging. It is not recommended for customers to replace them. If the customer has a corresponding tube and likes to mess with it, he can try the E88CC. The regular model that can be replaced is smaller. Multi: 6922: 6H23 (Soviet Union): 6N11 (domestic): ECC88; 6DJ8; CCA (Europe and America) ECC82 can be replaced with 12AU7.
Different tube models have slightly different timbres. The standard ones in our store are determined after many times of tuning and debugging. It is not recommended for customers to replace them. If the customer has a corresponding tube and likes to mess with it, he can try the E88CC. The regular model that can be replaced is smaller. Multi: 6922: 6H23 (Soviet Union): 6N11 (domestic): ECC88; 6DJ8; CCA (Europe and America) ECC82 can be replaced with 12AU7.
NOTE: This unit does not include any cables.
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