I am in the middle of restoring an AGE Bandmaster from 1936 which contains a chassis made by AWA for their Radiolettes. It's going well however I find the tone from the loudspeaker horrendous. It is rather tinny and harsh. Even though it is only a 100mm speaker I would have expected a better tone from what would have been a fairly upmarket mantel radio in its day.

Is this tone the norm for these and the R29 Radiolettes or should I expect better?

I have worked on several. Tiinny & harsh does not compute.

I would make sure there are no errors in the caps, what is it eg 457DE ? or are you saying it's based on R29 R71

Warble like can be a polling speaker and the audio can sound odd if the IF's or voltages are out. Plate resistor of det audio would be first port of call.

Do you have a circuit R29 is listed as 1935

That has a 42 output tube, I believe, do you know the number on the speaker transformer? eg TG113D may be on the circuit diagram.

Marc

G'day Marc,

I'll check all these tonight though I can confirm it's an R29 chassis (stamped on back) inside an AGE cabinet. The speaker is in good nick and the recapping went well using values as per the circuit diagram, which has been used as a reference for a black Radiolette that is working well. Circuit has been checked for the usual nasties like shorts and dry joints and I've changed the valves to ensure they are working.

See http://vintage-radio.com.au/default.asp?f=1&th=389 for a photo of the set.

Now the plot thickens:

One of the reasons many of those dials burn is the replacement of the dial globes. Most of those used a round globe like the Krypton (SL-3211 Jaycar).

By using the common long glassed ones (Jaycar SL-2654) this brings the hot globe closer to the celluloid.

By using a series resistor of 5.6R at about half a watt for 1 globe on the circuit, you could reduce the voltage for a 4.8V globe. Note: to the Scotch, if you use one resistor for several globes, you risk blowing the lot if one fails.

The other thing I have done is cleared the base and used a mini lamp SL 2673, which is not as bright, but can be set lower.

The self bias on the 6V6 at 400 Ohm is wrong at 250V plate. It normally has around -12.5V on the grid not -16.5 and draws more current.

If you have a 6F6 use that, it's a 42 with a different base. 6V6 normally has a grid stopper.

If that is an electrodynamic speaker, remove the wires from the OP transformer secondary & hook them to a PM speaker. That will eliminate speaker as cause.

If it is "hissy" & lacks sensitivity, valves like 6D6 are horrors for radiation problems if not shielded, and will sometimes play up with goat shields on them.

Not withsanding some of those early AWA's had the valves in Faraday cages.

Marc

Yes, I forgot to mention that someone had got rid of the 42 and substituted a 6V6G. I think I will get that changed back before looking any further at the rest of the chassis. Most of the passive components are new, some by me and some by others.

Radios with 100mm speakers aren't really expected to be HIFI though this model shouldn't sound any worse than a 500M. The reason I am keen for this set to sound good is because I want to use it in my office at work.

I am looking forward to showing it off. It will replace a 500M which has been in service every day for 5 1/2 years but I think that beast needs a rest.

Visitors to my office are often amazed that the device pumping out the music is older than they are and they sometimes ask to see 'the guts' to verify that it is the real thing.

Visitors to my office are often amazed that the device pumping out the music is older than they are and they sometimes ask to see 'the guts' to verify that it is the real thing.



I wonder how they'd react to a coffin set of the 1920s?

It's a bold thought but yeah... I have a Little Astor from the mid 20s which is a huge box with a small radio inside. It'd take some effort to rebuild it though.

Clearly as there is a 6V6 in there the socket will be changed. putting the 6F6 in will not require a socket change.

I repaired a Kriesler a while back, which had two speakers. The filters & a dial light & a short were sorted.

The speakers were ok despite it being a daily driver since the early fifties. Only one cap had been changed.

My usual is to get rid of every paper & eletctrolytic cap in the set & check resistors as best as.


If that has the old wafer type Mica? I did put a Bandmaster back into service a few weeks ago with all of it's original mica's of that type. none HV tested failed.

If you have a CRO and a clean sig gen, that is a way of seeing distortion.

Marc