Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

So far as I can make out from the photos and the OP's drawing, the switch for the 2nd RF transformer is connected to an HT feed, maybe the OP can confirm with a better photo showing the top of the 0.1uF,0.1uF,0.5uF capacitor block and the surrounding countryside so to speak?

It appears to have been modified around V2 as there is no grid bias for the gram input.....

Lawrence.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Could you try to explain to me in very simple terms how I could check to verify if the heaterwiring is the same in mine as the AH34? And btw; is heaterwiring something different that the wiring to the filament. It's all new to me so I still struggle with the terminology...

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

The terms heater and filament are frequently interchanged.

I prefer to use the term heater for indirectly heated valves where a heater heats a separate cathode and filament for directly heated valves where the filament is also the cathode.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

The heater connections for the three amplifying valves are the same in your receiver as they are in the AH34, that's to say they are all connected in parallel across a common voltage source, that being one of the 4 volt secondary windings on the mains transformer.

The heater connections for the rectifier valve are connected across a separate voltage source, that being the other 4 volt winding on the mains transformer.

In the AH34, the rectified HT from the rectifier is taken via a centre tap on its heater supply winding, in your drawing showing the rectifier the rectified HT is taken directly from one side of the rectifier's heater.

If you're unsure about the meaning of parallel connections/circuits etc then take a look at this video, well worth watching:

https://www.youtube.com/watch?v=UfZu5F4u7Ns

Lawrence.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Just altered the blueprint to make printing easier.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

George's diagram is looking good...just the reaction to sort out and I am not so sure about the 50K for cathode bias on V1.

The AL1 modification just needs to be changed by removing the 2x 700 and the electrolytic and wiring direct to chassis. The bias will need to be checked once the set is running as we don't know the HT voltage, the 500 ohms can be adjusted to suit.

What we do need is some better pictures around V1 and the volume/reaction control so that last bit of the circuit can be finished.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

If I take a close up picture of the rectifier valve socket, with it's 4 wires going back into the secondary transformer would you be able to tell if it is taken from a centre tap or not? I wouldn't trust my drawing as it is probably anything but accurate.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

A photo should show what's what, also more photos of the chassis underside and top side and from the front to show all the controls etc.

Lawrence.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

I'll see if I can do that later tonight.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Here are the first 5 in a series of photos. Will have to post multiple replies here to upload all of them. Here you can see the coil that is close to the largest capacitor block. You can also see the underside of the rectifier socket and the 4 wires that comes from the secondary of the PT to the rectifier. As you can see, it is one thick wire, and three equally thinner wires. If that can be of any help. More later.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

5 more photos.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Even more..

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

More coming in..

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

A few more..

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Almost done...

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

There!

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Excellent:thumbsup:

Lawrence.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

The rectifier valve socket photos confirm that your drawing for the rectifier and HT take off point is correct.

Lawrence.

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

Which in essence means it is not wired properly?

Re: Aga Baltic AH37. Need help identifying old capacitor from 1930s radio
 

So far as I can make out from the photos the base is wired correctly.

Lawrence.