Classic AUDIONOTE circuit replica 300B single-ended type A tube amplifier, power 8W *2 output impedance 0-4-8Ω
World classic amplifier
AUDIO NOTE KIT ONE (Reissue Version) 300B Tube Amplifier
there have 2 type of transformer for choose， only the transformer is different ， the other parts are same，
Standard Transformer type : Power transformer 300W114 *
70 British Red Jinsha Tablets 1pcs, choke 76 * 50 (British
notch Red Bull iron core), output transformer 30W British Red Transformer Golden Sands 96 * 45 * 2pcs
update transformer type ： Power transformer 300W114 * 70 (upgraded British notch Red Bull iron core), choke coil 76 * 50 (British Sands non notch), output transformer (British amorphous 8c alloy iron core)
Chassis: 1.5MM thickness, more expressive sound, quieter background
Electron tube: 300B (Voice of the Noble HI-FI), 5687 (GE), 6H8C (6sn7) (Soviet Union). 5Z3j original box (Dawn)
RC accessories: 100K (alps27), coupling
capacitor (large S, rifa), cathode capacitor (Dutch capacitor),
resistance (produced by Taiwan), 300B socket (US CMC)
Power: 8W + 8W
Three dimensions: 400 * 300 * 60 (mm)
Weight: 16.8Kg
Function: High-voltage protection function with a delay of 20 seconds
Output impedance: 0-4-8Ω
Process: pure hand-built shed
Let's discuss the circuit of the world's
famous classic machine 300B above. I believe that everyone who has used
the original machine will definitely praise it, but most of the
enthusiasts bought it are domestically produced replicas. The results
were disappointing. The circuit of this machine is extremely mature, but
it is also an extremely designed circuit. If you do n’t read through
the connotation of the circuit, no matter how you imitate it or put
expensive supplements, there will not be good results, because the
manufacturer is Designed by combining the winding method of the output
cow with the circuit! The key points of this kit are two points: one is
the first-stage 6SN7, because this pipe is very linear, and the British
manufacturers are also designed to a limit parameter value. If the
internal resistance of your pipe is not low enough, follow the original
circuit's The value must be changed, and the operating point must be
changed. It is also working in a poor linear region. If this level goes
wrong, all the efforts will be made later. Therefore, it is recommended
to use imported tubes produced early. There are still some objections to
canceling the first-stage female capacitor. The theoretical noise and
gain will not change much, and the distortion will be reduced. But why
not cancel it? Because it becomes current-type negative feedback after
cancellation, the output impedance exceeds the 100K impedance of the
original machine! The second point: the load impedance of the output
stage transformer. It ’s not that our normal circuit ’s random load
impedance is not a big problem, it ’s just the power level and the
distortion changes are not large. But why does this circuit strictly
require an operating point? Because the original machine is designed at
the limit of 80MA circuit level, if you want to change the parameters
randomly, the voltage must rise, and the previous working points have
all been changed. The cathode voltage of the previous stage increased,
and the current decreased proportionally. We know that the smaller the
current, the thinner the texture of the sound. The more terrible
original machine also used a lot of deleted limiting current resistors.
There are many, many domestic manufacturers in order to avoid the time
and cost of manual scaffolding, and they want to reproduce the form,
using a PCb board design, but you must know that the PCB medium
processed in our country is very different from the original Material,
so high frequency attenuation is serious. From the above points, it is
proved that the famous machine needs to be engraved. It is necessary to
understand the design connotation of the original machine to control the
original machine! The AN circuit machine engraved in this section must
not be at the same level as similar domestic products. The machine
engraved in this section has a fine texture, strong texture penetration,
and low-frequency line feeling is just right. Overall, it tends to be
noble.
Standard Transformer type ：
update transformer type ：
