It was one dispute, what solid amplifier can’t be made without feedback in signal path. After several tests I devised balanced topology that works well. I made more then ten copies of such amplifiers with different power supplies, servo and variations. My last variant has no any servo. But it demand of accurate selection of transistor in pairs.
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I add several information
Max output power of this amplifier is 20-25 W
Damping factor = 4
Frequency response 5 Hz - 67 kHz by -3 dB
1% harmonic distortion is reached on 7 W
Harmonic level and spectrum is not depend on frequency.
THD level as function of frequency on different levels represents on figure
Max output power of this amplifier is 20-25 W
Damping factor = 4
Frequency response 5 Hz - 67 kHz by -3 dB
1% harmonic distortion is reached on 7 W
Harmonic level and spectrum is not depend on frequency.
THD level as function of frequency on different levels represents on figure
Attachments
bigwill, yes it has sound likes very good triode PP amplifier in class A, but without tube's colour.
Parameters of transistors:
2Ï903
power disipation - 6W
max ds voltage - 20V
S=50-60mS (Id = 50mA)
Cgd=13pF
Cgs=15pF
2Ï926A (SIT, triode characteristics)
power disipation - 50W
case - TO-3
max Uds - 450V
Ri = 270 Ohm
Parameters of transistors:
2Ï903
power disipation - 6W
max ds voltage - 20V
S=50-60mS (Id = 50mA)
Cgd=13pF
Cgs=15pF
2Ï926A (SIT, triode characteristics)
power disipation - 50W
case - TO-3
max Uds - 450V
Ri = 270 Ohm
Output transformers and interstage inductors we made in our laboratory (www.lampovik.ru). Power transformers and power inductors made in Russia by order. Input transformer-attenuator made in Moldova by Vorobiev, it's analog of Sowter 9335. Transformer after attenuator for variable output is Sowter 3575.
Attachments
Kostya-M said:
We decided to make devices in wood cases. Wood creates warm atmosphere around.
Sure. And it has very interesting shielding properties
There are several reasons.So, why use solid state then?
1. Variety. This is one more amplifier type.
2. Sound. It has specific sound. It resembles on triode PP amplifier in softness and purity. It has the same soft clipping. But it has no tube coloring. Comparing with tube amplifier it has much more resources.
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