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    Building, troubleshooting and testing of these amplifiers should only be
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OTL turntable EL86 speaker wiring

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For comparison, here is a UK model from 1959 made by Plessey for several brands. Note that we had AM sound back then so needed an impulse limiter.
It seems very basic now...

Sorry for drifting off topic
 

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It is far more sophisticated than most competitors models that I know of. The annotations are in German; was this model sold in Italy?
Yes. But I'm still scratching my head what this additional flyback transformer winding in the +2 supply does, and why this TV wastes more than 10 watts in the rectifier tubes' heater circuit :confused:. Some other TV's used two PY82's in series with all the other tubes, or two UY82's in parallel with a 550 ohms resistor and all together in the series heater chain.

Best regards!
 
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I believe that it wasn't. Philips had a successful local manufacturing presence in Italy but it was focused mostly on low-end products. The affluent consumers were drawn mostly by products with beautiful cabinets built to higher standards. According to Radiomuseum this specific TV was on the expensive side. I researched this unusual schematic because the tubes are still available today at low price (even the 6V filament version) and the high impedence speaker string could maybe be replaced by a Hammond 119DA transformer or a ungapped standard transformer. I was unable to find any measurement, but it may eventually sound good, altough is pretty low on power capability. I guess that the only way to find out is to build it.

edit: There are 21 tubes in this 220V B/W TV set. Not enough voltage to connect the rectifiers at the same heater chain.
 
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I believe that it wasn't. Philips had a successful local manufacturing presence in Italy but it was focused mostly on low-end products. The affluent consumers were drawn mostly by products with beautiful cabinets built to higher standards. ..

edit: There are 21 tubes in this 220V B/W TV set. Not enough voltage to connect the rectifiers at the same heater chain.

Thank you for the info, most interesting. I came to that conclusion about the use of 100ma rectifiers.

Yes. But I'm still scratching my head what this additional flyback transformer winding in the +2 supply does, ...
Best regards!

My best guess it that it's some sort of hum dinger - adding some out of phase ripple to compensate fohttps://www.google.co.uk/url?sa=t&r...21TD144A.pdf&usg=AOvVaw0KqLttD3CzlUFDvyq8XiPVr some effect they noticed.

The complete manual is available here:
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=13&cad=rja&uact=8&ved=2ahUKEwiShoXTiLrjAhWWEMAKHbyPC-oQFjAMegQIARAC&url=https%3A%2F%2Ffrank.pocnet.net%2Finstruments%2FPhilips%2FHR%2FTV%2FTV-docs%2F21TD144A%2F21TD144A.pdf&usg=AOvVaw0KqLttD3CzlUFDvyq8XiPV
 
OTL turntable el86 fault finding

hi again all,

am still working on an old mono philips hi-z stand alone turntable, ez80, ef86/ ecc83, and two el86. I think pp or self balancing, not single ended.

Bought it a while back and its was playing music except it was making some swishing noises like wind the blowing if you lived in a light house.

I have re-capped many old amps and just re-capped this one and have noticed the first el86 plate glowing (enough to notice with when the lights are on). It may have been glowing before i replaced the caps though I would not have noticed when the turntable was fitted.

the symptoms are stronger than before. im guessing because there is less Voltage loss now. the storm ocean sound will start then get louder then a loud pop then go quiet for a short while then the windy storm white noise sound will start up again. there is no music signal from the speakers now.

not sure if it is a faulty tube and do not want replace it with a spare one incase it ruins the the spare.

if anyone has repaired an amp with similar symptoms and has any advice on where to start, that would be awsome. I cant find a schematic though can trace it out if needed. :hypno1:

the amp is about 1957 judging by the style of turntable. the photo is from before the amp was re-capped. the glowing tube is first el86 on the bottom left near the ecc83. if you would like more photos just ask, thanks
 

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With reference to the schematics in #19: There are three chokes, called S53 to S55. S53 is directly connected to fuse Si2 and 'lytic C178, while S55 connects via that strange flyback transformer winding called S37-S38.

Maybe we need to know the complete schematics to decipher :confused:.

Best regards!
 
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If you mean output transformers when you say "power transformers": The Philips AG9015 (and the AG9018) were made for both 800 Ohm and 8 to 16 Ohm loudspeakers. The double choke and the secondary winding for the 8 to 16 Ohm output share a common core. I think it pretty much works like Mona's circuit.

Greetings, Robert
 
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