Alpha-Standard W alt (RE134)
Schaub und Schaub-: Alpha-Standard W [Radio] ID = 943712 933x549
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| Year: 1930–1932 | Category: Broadcast Receiver - or past WW2 Tuner | ||||
| Valves / Tubes | 6: RENS1204 REN1004 REN804 RE134 RE134 1801 or RGN504 |
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| Main principle | TRF with regeneration; 1 Special; 2 AF stage(s); Anode bend detection |
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| Tuned circuits | 2 AM circuit(s) |
| Wave bands | Broadcast (MW) and Long Wave. |
| Details | |
| Power type and voltage | Alternating Current supply (AC) / 110-220 Volt |
| Loudspeaker | - This model requires external speaker(s). |
| Power out | |
| from Radiomuseum.org | Model: Alpha-Standard W [alt ] - Schaub und Schaub-Lorenz |
| Material | Metal case |
| Shape | Tablemodel, low profile (big size). |
| Dimensions (WHD) | 395 x 180 x 295 mm / 15.6 x 7.1 x 11.6 inch |
| Notes | Im Schaltbild gezeigte REN904 ist der spätere Universalersatz für die Originalbestückung REN804 und REN1004. |
| Price in first year of sale | 232.00 RM ! |
| Source of data | Katalog Radio-Zentrale Prohaska 1930/31 (dick) / Radiokatalog Band 1, Ernst Erb |
| Circuit diagram reference | Röhren in FS-Bestückungstabellen |
| Mentioned in | Kat.Radio Arlt 1931 |
| Literature/Schematics (1) | Katalog Radio-Zentrale Prohaska 1931/32 |
All listed radios etc. from Schaub und Schaub-Lorenz
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Forum contributions about this model
Schaub und Schaub-: Alpha-Standard W
Threads: 2 | Posts: 4
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Hits: 3433 Replies: 2
schaub: W; Alpha-Standard
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Dirk Bladt
24.Mar.11 |
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Can anyone explain how this radio does the AM detection ? Grid of REN804 ? thanks for your attention, Dirk Bladt
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Dietmar Rudolph
25.Mar.11 |
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Two (or more) circuits TRF sets used an anode bend detector. A description of this type of detectors may be found at "Ghriardi, A.A.: Receiver Circuitry and Operation, Rinehart, 4th printing, 1955".
A bias or „square-law“ (weak signal) plate detector is shown in the schematic circuit diagram, Fig. 3-13 (A). It employs a tube which is operated exactly like a Class A amplifier except that the grid is biased sufficiently negative to make the operating range fall on the curved "bend" of the grid-voltage plate-current characteristic curve, as shown at (B) of Fig. 3-13. Bias resistor R1is shunted by by-pass capacitor C1 to prevent degenerative effects.
When a signal is applied to the grid of such a detector, the positive half-cycle causes much greater plate-current changes than do the negative half-cycles. This makes the plate-current pulses lopsided or distorted as shown.
 The r-f components in the plate current are by-passed by capacitor C2, which is of the order of 1,000 μμf (pf). The demodulated audio component flows through plate load R2, which is of the order of 50,000 ohms, causing an amplified voltage drop to appear across it. This is the a-f voltage that is fed to the audio amplifier through coupling capacitor C4. Observe that the demodulation takes place in the plate circuit - hence the name "plate detection."
Notice that in this detector, as in the grid-leak type, amplification of the signal takes place. The amplification applies mainly to the r-f wave (modulated carrier) because the demodulation does not take place until the signal has passed into the plate circuit.
The principal disadvantage of this type detector lies in the fact that the tube characteristic departs widely from linearity unless the plate current flowing through it is large. At small input-signal levels, operation is over the portion of the characteristic where the plate current is approximately proportional to the square of the grid voltage, with the result that distortion of the a-f modulation results. Hence the name "square law" plate detector is applied to this detector when weak signals are being detected.
Dietmar |
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Dirk Bladt
25.Mar.11 |
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A very big thank you for this cristal clear explanantion to you, Mr Rudolph. Dirk Bladt
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Hits: 1634 Replies: 0
schaub: W; Alpha-Standard
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Dietmar Rudolph
08.Jun.07 |
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Die Alpha Geräte haben ein "elegantes Schleiflackgehäuse", während die Beta Geräte ein "luxeriöses Edelholzgehäuse" haben, wie im Prohaska Katalog von 1930/31 nachzulesen ist (Nr. 3126 & 3127). Bei beiden Gehäuseformen gibt es für das Chassis die Varianten "Standard" und "Kraft", die sich in der Endstufe und für Wechselstrom auch im Gleichrichter unterscheiden. Für beide Chassisarten gibt es eine Wechselstrom- und eine Gleichstromvariante. In den Serviceunterlagen der Fa. Schaub wird daher in den Schaltbildern nur zwischen "Standard" und "Kraft" und "G" und "W" unterschieden. Hier zunächst "Kraft G"  Für "Standard W" und "Kraft W" gibt es Schaltbilder.   Da die Empfänger ursprünglich nur den alten Frequenzbereich der Mittelwelle umfaßten, gab es von Schaub auch noch eine Anweisung, wie auf den Bereich 510 KHz bis 1620 KHz umzustellen sei:
Frage an die Modell-Admins: Wo sollten die Schaltbilder hingeladen werden? Jeweils zu Alpha oder zu Beta oder zu beiden? MfG DR |
Schaub und Schaub-: Alpha-Standard W
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