PYE P 35

[pwdrive]

I think he's referring to the max. DC working voltage of that capacitor which is 12 volts according to the snippet of the parts list he posted.

Lawrence.

[Lindsay]

Yes, I was simply quoting what was written on the manufacturers list. I did not comprehend it either as I too thought it was connected to earth.

[Lindsay]

I am more confused than ever! I have the 4.7nF capacitors which are small and have no polarity marked on them.
I think I should be using an electrolytic capacitor attaching the positive end to the cathode of the output valve and the other end to earth.
The manufacturers picture shows a big fat thing whereas my capacitors are wee 5p sized things. C46 on the diagram.
Does the polarity not matter? Can I use one of my little 4.7F capacitors or should I get another from the internet?
The other thing worrying me is where PW Drive mentions a capacitor with polarity 'C56' . That one is not on my diagram but maybe you mean C46?
Sorry to be such a pain.
You will all be pleased to know that an old Sansui Amplifier AU70 - its R channnel has gone dead so I drove over to Glasgow yesterday and gave it to a chap to look at - he said he could fix it. So both you all and I have been spared a much more complex problem! Lindsay

[pwdrive]

Sorry, my mistake, yes, should have typed C46.

Capacitors seem to be confusing you, a 4.7nF capacitor will not be polarized, electrolytics (most of them) are polarized.

Polarity connection with polarized electrolytics matters.

Lawrence.

[Crackle]

Here is a part of the manufacturers circuit diagram.
   
You can see on the schematic which are the electrolytics, they have a + and - symbol to identify which way round they are connected.
In your case, for C46 the cathode bypass capacitor I would think that 47uF 16v axial capacitor would be the type to get.
https://www.ebay.co.uk/itm/391895981507?

The capacitor which is critical and should be changed immediately if it is a wax paper type or any paper type of capacitor is C40 0.005uF which is a non polarised capacitor. This type is the sort I often use. https://www.ebay.co.uk/itm/191644809241?

Mike

[Murphyv310]

Hi
C46 is a 50uF 12 volt Electrolytic not a 4.7nF non electrolytic. You can use a capacitor above the marked voltage but not less than that.
Electrolytic capacitors are also in the main polarity conscious as will all of them be in this set.
This will do perfectly its a 47uF 25V using the modern day nomenclature. https://uk.rs-online.com/web/p/aluminium...s/1701099/ (Slightly dearer if bought singly)
Or pop me a PM with your address and I'll send you a few.

You should have given me a PM rather than go to Glasgow to get the amp fixed, Kilmarnock is nearer and the tea and biscuits free!!!!!

[Terry]

Lindsay, I'm not sure why but you keep getting confused. The 4.7nF is for the capacitor C40 coupling the anode of V3 to the grid of V4 (via the junction of R19/R20, actually) which you have been advised to change as your first priority.

I'm not sure what the problem is with C46, the cathode bypass, but that has a capacity of 47uF at 12V or greater and yes, it is an electrolytic capacitor.

The 4.7nF caps are not electrolytic and, therefore, will not have polarity markings and can be fitted either way round.

[Crackle]

Trevor, those capacitors from RS come in a bag of 500 pieces at £40. But are out of stock.

Lindsay
I was too long editing my post and 2 more posts were added after, but the 2 different capacitors I linked to on Ebay should be fine.


Mike

[Murphyv310]

Hi Mike.
Yes I know. I just realised but not to worry I have PM'd Lindsay anyway. If he gets stuck he is more than welcome to pop here and I'll go through the set with him. Pity he took the Sansui Valve amp to Glasgow, the only decent chap is now closed down up there that fixes valve amps, just hope it's not the person that did the world amp I had to rebuild a couple of years ago.

[Crackle]

He could always go and get it back.

Mike