1958 Philips F5C10A Tube Amp / Speaker

[Kaaskop]

Please share the AD**** type # that is on the driver magnets. This will allow us find the driver specs and confirm if they were meant for OTL operation or not. Also check if they are connected independently to the amp chassis or together in series or parallel.
Regards,

See attached pics. AD****type # looks like AD3800A. There are 4 speakers 2 per side/channel and they are connected in series.

 

[Kaaskop]

So am I correct that the speakers run off and OT and a choke?

 

[s-petersen]

I have not seen a circuit that used a choke with an output transformer, but the choke could be connected to b+ at the same point as the output transformer, to power the other part parts of the amp / preamp

 

[analogadict]

You have one AD3800a and one AD3800am. Both are 800 ohms impedance drivers. These are mostly used in OTL ( output transformer Less) application . The am version is extended range or full range , it has a whizzer cone and goes upto 18k .

The chassis layout plan that is pasted on the cabinet shows the speaker output connector with independent connections for LF and HF. The components that you are identifing as a opt and choke appear to be next to this connector. It is very much possible that what you are looking at are actually inductors of crossover , and not opt or choke.

There is a link to a schematic in reply # 2 . Am not able to open that , if you can , it would be better to study that and share an image here of the output side.

Regards,

 

[s-petersen]

I was able to open the schematic, and it does seem to use an output transformer and inductor in the output circuit, the schematic looks close enough to your amp to use for repair.

 

[Kaaskop]

You have one AD3800a and one AD3800am. Both are 800 ohms impedance drivers. These are mostly used in OTL ( output transformer Less) application . The am version is extended range or full range , it has a whizzer cone and goes upto 18k .

The chassis layout plan that is pasted on the cabinet shows the speaker output connector with independent connections for LF and HF. The components that you are identifing as a opt and choke appear to be next to this connector. It is very much possible that what you are looking at are actually inductors of crossover , and not opt or choke.

There is a link to a schematic in reply # 2 . Am not able to open that , if you can , it would be better to study that and share an image here of the output side.

Regards,

I converted the Schematic to a Jpeg incase it's useful to anyone else. The info the the speaker's helpful and intriguing.

 

[Kaaskop]

I was able to open the schematic, and it does seem to use an output transformer and inductor in the output circuit, the schematic looks close enough to your amp to use for repair.

OPT and inductor, ok great that clears it up, and I thought the same about the schematic being suitable for next steps. Thanks for your direction on this. I won't have time to work on it for a bit but I'll see how far I get when I do.