Original Marconi Forerunner Williamson Review
Publicado em 1956
Quality amplifier
Versão redesenvolvida do original de W.T. Coking de 1934.
Pequenas alterações são propostas no amplificador de Coking
Para melhoria em seu desempenho. Edições anteriores: 1934, 1936,1938 e 1943.
Sem realimentação.
Transformador de saída – Z Primário = 3000/4000 W
Z Secundário = Falante
Transformador de interestágio= 10 KW /100 Hy min com derivação central.
Potência 12W
Transformador de fonte: 2x390V + filamento retificadora
Transformador de filamentos: 6.3V/3A min. + 2x 4V/2A cada todos com C.T.
Transformadores recomendados
Lynx Audio
Saída TS30
Interestágio: AT10K650PP 10k/125Hy
Força: TF390
Choque L1= C10H180
Choque L2= C3H100
Necessita um transformador de filamentos: Primário: rede local; Secundário: 2x4V/2A ambos com derivação central.
Características das válvulas:
PX4. M-OV (1929)
-L63 = 6J5GT-
Sugestão para modernização: ECC88 placas , grades e catodo em paralelo.
PX25. M-OV (1933)
U12
(U50- octal base)
U12/U50=5U4
Sugestão para modernização: retificadoras 2 x 2D22S, 6DL3 ou EY500A
Poderemos também usar duas EY ou PY 88 com transformador adequado para o filamento. Preferencialmente aumentar valores os eletrolíticos da fonte.
Edições atuais das válvulas de saída:
Elektronenroehren
AlesaVaicVacuumTechnology de
-AV-8B = PX4-
|
AV-8B Filament Ratings |
|
|
Filament Voltage |
5 Volt (AC or DC) |
|
Filament Current |
1.3 Ampere |
.
|
AV-8B Maximum Conditions |
|
|
Plate Voltage |
400Volt |
|
Plate Current |
60mA |
|
Plate Dissipation |
11Watt |
|
Power Output in Class A |
3,6Watt |
.
|
AV-8B Typical Data |
|
|
Plate Voltage |
350V |
|
Plate Dissipation |
11 Watt |
|
Plate Current |
31mA |
|
Grid Voltage |
-37Volt |
|
Plate Impedance |
1500 Ohm |
|
Amplification Factor |
8 |
|
Transconductance |
5,5 mA/V |
|
Load Impedance |
4000 - 8000 Ohms |
|
Grid Resistor |
100k Ohm |
|
Operating Lifetime |
40.000 hours |
.
|
AV-8B Mechanical Data |
|
|
|
Size 170 x 60mm (Incl.Socket) |
|
Weight |
130 Gram |
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|
PX25 Filament Ratings |
|
|
Filament Voltage |
4 Volt (AC or DC |
|
Filament Current |
2.2 Ampere |
|
PX25 Maximum Conditions |
|
|
Plate Voltage |
500Volt |
|
Plate Current |
150mA |
|
Plate Dissipation |
25Watt |
|
Power Output in Class A |
8Watt |
|
PX25 Typical Data |
|
|
Plate Voltage |
350V |
|
Plate Dissipation |
20Watt |
|
Plate Current |
57mA |
|
Grid Voltage |
-26Volt |
|
Plate Impedance |
1140 Ohm |
|
Amplification Factor |
8,8 |
|
Transconductance |
7,8 mA/V |
|
Load Impedance |
3000 - 5500Ohm |
|
Grid Resistor |
max. 50k Ohm |
|
Operating Lifetime |
40.000 hours |
|
PX25 Mechanical Data |
|
|
|
Size 190 x 60mm |
|
Weight |
145 Gram |
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Emission Labs
KRaudioproducts
The PX25 is an ultra-linear, low frequency, high power triode tube capable of
producing 6-10 watts of pure class-A power.
A replica of the early PX25, this tube is available in both a UX4 base and the
original 4 pin B4 English base (PX25A).
The PX25 may just be the best of both worlds, i.e. the clear and
pristine midrange of a 2A3 or 45 tube
along with the bass and dynamics of a 300B.
Alternativa:
300B
.
-300B-
|
300B- Filament Ratings |
|
|
Filament Voltage |
5 Volt (AC or DC) |
|
Tolerance on filament voltage |
4% |
|
Filament Current |
1.5 Ampere |
.
|
300B Maximum Conditions (Voltage and current not possible simultaneously - this is not a recommended operating point) |
|
|
Plate Voltage |
550Volt |
|
Plate Current |
160mA |
|
Power Output in Class A |
23Watt |
|
Grid resistor |
max.50k Ohm |
.
|
1) High Power application
Recommended operating point. |
|
|
Plate Voltage |
500V |
|
Plate Dissipation |
55Watt |
|
Plate Current |
110mA |
|
Grid Voltage |
-105Volt |
|
Plate Impedance |
615 Ohm |
|
Amplification Factor |
4.0 |
|
Transconductance |
6.1 mA/V |
|
Power Output in Class A |
18.3Watt |
|
Load Impedance |
1200 - 3000 Ohm |
|
2) Medium Power application
Recommended operating point. |
|
|
Plate Voltage |
400V |
|
Plate Dissipation |
40Watt |
|
Plate Current |
100mA |
|
Grid Voltage |
-74Volt |
|
Plate Impedance |
670 Ohm |
|
Amplification Factor |
3,9 |
|
Transconductance |
5.8 mA/V |
|
Power Output in Class A |
13,3Watt |
|
Load Impedance |
1300 - 3000 Ohm |
|
3) 300B operated as standard WE300B tube.
Any other bias point will be just like |
|
|
Plate Voltage |
350V |
|
Plate Dissipation |
11 Watt |
|
Plate Current |
31mA |
|
Grid Voltage |
-37Volt |
|
Plate Impedance |
1500 Ohm |
|
Amplification Factor |
8 |
|
Transconductance |
5,5 mA/V |
|
Load Impedance |
4000 - 8000 Ohms |
|
Grid Resistor |
100k Ohm |
|
Operating Lifetime |
40.000 hours |
.
|
300B Mechanical Data |
|
|
|
Size including Socket:
175 x 63mm |
|
Weight |
170Grams |
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