ECL82 valves for Sansui 220

El Sid

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I have the opportunity to buy a Sansui 220 receiver for a pretty good price. But before committing, I'd like to find out if the ECL82 output valves it uses are at all available locally? They can be had from various websites but are pretty pricey, enough that if a full set of 4 valves is required it's almost not worth getting the amp....
 

marantz123

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There is the Russian version of this valve, except for a slight variation in the dissapation. Look at the 6f3p which is a close enough equivalent of the ECL82 as an alternative. After costs in bringing a quad of them in, you may still be close to the expense of finding a quad of ECL82 locally anyway. (FWIW in 2016 I got a quad of 6f3p in for about R500).
 

El Sid

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Thanks Marantz and Charles! I think I will buy the amp - hopefully i won't need any valves...
 

kubusi

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A nice tuner amplifier I have 2 of them, over the years one particular fault I have come across a few times, (not implying it is a common fault) is the failure of the wire wound resistor mounted above the chassis. As it is now about 60 years old most of the coupling and bypass capacitors will need to be replaced as they will be very leaky.

The valves that  normally came with the tuner amplifier were Matsushita snd seemed to go on for ever, not surprising at all as Matsushita was partly owned by Philips at the time who I believe set up the factory after the end of WW2

If you need the circuit diagram I can send it to you.
 

El Sid

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Thanks Kubusi. By the time I had finished fannying about with all these questions the unit had gone. I'm not upset though - it wasn't in great shape and I want one rather than need one
 

handsome

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Going to need more than doubler to get 16VDC from a 6.3VAC winding
 

fredeb

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handsome said:
Going to need more than doubler to get 16VDC from a 6.3VAC winding

Rectified and doubled should do , or no ? Providing the filament tap has enough juice . [member=24540]V4lve Lover[/member] designs some pretty impressive LDO regulators , he seems to be obsessed with these and HT regs , sometimes designing 2 or 3 a day .  ;)


 

V4lve Lover

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Yeah i can be quite productive, feel free to ask for an invite into the Dutch telegram audio groups too so you can see what im working on.

 

kubusi

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Use a tripler circuit and experiment around with the value of the electrolytics until you get the correct voltage across the heaters and you may end up with a low value resistor in series with the heaters. Trial and error to get it spot on.
 

kubusi

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As an additional note to my suggestion that a tripler be used for the 16 volt heaters of the PCL82 valves there is another way they can be powered, a method I have used previously in restoration of older valve radios which were known as the All American 5 that were transformerless operating straight across the 110 volt  mains. For local use a resistance line cord was used or a large wire wound resistor was installed to reduce the voltage. A number of British radios also used internal dropping resistors.
To overcome the heat generation and power wastage I  modified the radio by using the capacitance method of reducing the voltage  which could also be used on the PCL82 valves with their heaters either in parallel or series through an isolation transformer as it would be too dangerous straight off the mains. There is no power loss across the series capacitor.

Unfortunately the formula for calculating the value of the capacitor is a bit involved and complicated and would be too difficult to try and type it in via this phone. Anyone who may wish to get the formula from me I can write it out and email or Whatsapp to you
 

fredeb

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Here is [member=19010]kubusi[/member] 's formula for calculating capacitor values :

Voltage-tripler-cap-formula.jpg




 

charles

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My advice, if possible stay with the original ECL82 (6BM8) valves. 

The modification of four valve heaters in an already cramped set may be somewhat difficult regarding the wiring changes and power supply modification.

Then the set will then not be original and may not have a good resale value.
 
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