Essanay Bantam 80 1937
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2174
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I am desperately in need of a schematic if any one needs one please. EK2, EBF1, EI3N and EZ2 is the valve lineup from the HRSA.
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6761
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2174
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I actually have it up and going now. Desperately needs realigning though.
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Location: NSW
Member since 10 June 2010
Member #: 681
Postcount: 1301
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There is an 8B Bantam with that valve lineup in HRSA Radiowaves July 2001 issue according to HWS Radiohistory. Can look this up for you later today.
No Essanay in AORSM.
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Location: NSW
Member since 10 June 2010
Member #: 681
Postcount: 1301
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Have looked up the article in Radiowaves July 2001. The circuit in the radiomuseum entry is that from this article. The radios are very similar in appearance, though not exactly same radio as the dial escutcheon screws are in a different position and the ARTS&P label numbers are different.
With regard to alignment, the author's best estimate of IF using a signal generator was 455kHz. The set lacks AGC and the author comments on resultant output variability across the band. So adding adding AGC might be a useful modification if it is to be a general use radio, though I leave it to others to comment on whether this really possible with this circuit.
Can scan and send if you like.
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Location: NSW
Member since 10 June 2010
Member #: 681
Postcount: 1301
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What I mean by leave it to others to comment is that this radio is one of those that uses a wire wound variable resistor to control volume by simultaneously controlling the aerial signal and the cathode bias of the first two valves.
While the author says there is no AGC, I can see a path from the diodes of the EBF1, through a 0.5M resistor to the grid of the EK2, but I don't think this would have much AGC effect given the volume control setup. However others have more expertise.
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5389
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You may get AGC from a diode detector and delayed AGC may be more effective from the last IF valve plate. However, the normal method in those days was a DX switch. Albeit I have worked on an AWA with both.
In the case of an early STC where it had been hacked, and the switch was missing, with no circuit. I in conjunction with an Oscilloscope I found that for the local stations it needed 68pF in series with the antenna to avoid overload & distortion. It has that same cathode bias volume control. The AWA had three steps & for a station 100Km away (day) it had to be on the centre one.
Marc
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Location: NSW
Member since 10 June 2010
Member #: 681
Postcount: 1301
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If Tallar does need this article scanned, will submit the circuit.
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2174
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STC830 any help is gratefully accepted. I do have this little set working. But it does need aligning. I managed to replace the original volume pott with a 1.5k on/off volume pott and this works quite well.
The cabinet is getting the once over and this little set gets to live.
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Location: NSW
Member since 10 June 2010
Member #: 681
Postcount: 1301
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Scanned the article. If you open your email will pass on.
On saving the scanned article discovered that I had another Essanay Bantam file because I had drawn up a circuit for one in 2013 from another source. Will pass this on too.
If you search Essanay Bantam in the forum there are two other threads than this one.
Essanay Bantam Circuit Diagram
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2174
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I did the search and it only brings this thread up?
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Location: NSW
Member since 10 June 2010
Member #: 681
Postcount: 1301
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7395
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Document uploaded to Post 10.
‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...
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Location: Latham, ACT
Member since 21 February 2015
Member #: 1705
Postcount: 2174
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I will send photos of this little set soon. A friend has kindly offered to do the case for me.
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Administrator
Location: Naremburn, NSW
Member since 15 November 2005
Member #: 1
Postcount: 7395
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Photos uploaded to Post 14.
‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...
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