Rolls Radio Transistogram

[Paul Mathew]

Hi, 
I have come into possession of a portable radio/record player. I believe the company is from Australia, closing shop around 1980. 
This model was clearly made for the South African market.
Interesting that they called it a "Transistogram" when it is a valve unit.
The valve line-up is DK96, DAF96 & DF96.
Should anyone have any additional info and a schematic I would be very grateful.
Thank you.
PS. I don't see any option to attach pics. 

[Refugee]

We;come to the forum.
From the valve lineup it looks like a battery set.
The pic upload controls are at the bottom of the preview post screen.

[Mike Watterson]

Was it really called a "Transistogram"?

These are the only ones I find
https://www.radiomuseum.org/r/ultra_6312.html
Which is transistor based.

And
Pye Portable Transistogram

And
https://www.kapitimuseum.org.nz/virtual_...889790.htm

And
https://auctions.goldingyoung.com/lot-de...Fpage%3D14

[Mike Watterson]

It probably also has a DL96.

There were some 4 valve battery radios in UK that also had wind-up gramophone variants. Alba made one.
This is the earlier 50mA type battery valves Alba 707. There were single, multispeed and export versions
https://www.radiomuseum.org/r/balcombe_alba_707.html
DK92 DF91 DAF91 DL92

Later models of the same idea would have been using:
DK96 DF96 DAF96 DL94 or DL96

The DL94 takes the same filament current as the DL92, but has much more audio power than the DL96

The DK96 is almost always only in radios (Mixer & Osc).

It's possible there is also a transistor model in the same case.

See
https://www.radiomuseum.org/r/vidor_vaga...cn_43.html
vs
https://www.radiomuseum.org/r/vidor_gem_cn440cn_44.html

Transistor sets existed several years before the 1957 Vagabond, but cost more than valves.

[Mike Watterson]

Supersonic was the big local African brand sold in South Africa. Originally battery valves and later transistors.
https://www.radiomuseum.org/dsp_herstell...ny_id=4378

I have one Supersonic battery valve set that was bought new in SA by a friend's mother.
This one, which works well. https://www.radiomuseum.org/r/mullard_d11.html

[Paul_RK]

Interesting that they called it a "Transistogram" when it is a valve unit.
The valve line-up is DK96, DAF96 & DF96.

Well, it needs an output stage: are there a pair of OC72s or similar hiding somewhere, which would give it the same complement of devices as the HMV 1410 / Marconi P60B hybrid portables and justify the name?

Paul

[Mike Watterson]

Well, it needs an output stage: are there a pair of OC72s or similar hiding somewhere, which would give it the same complement of devices as the HMV 1410 / Marconi P60B hybrid portables and justify the name?

I wondered about that, but it seemed unlikely with a DAF96, as surely that would also be replaced with a 3rd cheaper transistor and a diode.

[Paul_RK]

It isn't in those EMI hybrid sets, for whatever reason... perhaps one factor was that a 3V rather than 4.5V LT supply wouldn't have been as suitable for the OC72s?

[Mike Watterson]

It isn't in those EMI hybrid sets, for whatever reason... perhaps one factor was that a 3V rather than 4.5V LT supply wouldn't have been as suitable for the OC72s?

I see what you mean. Perhaps they had a load of DAF96 in stock, or it was still cheaper than a transistor and diode. Or your theory that they needed 4.5V anyway is correct.
https://www.radiomuseum.org/r/marconi_ma..._60_b.html

Is RM incorrectly listing 1.5V rather than 4.5V battery?

I see the HMV is listed with 4.5V
https://www.radiomuseum.org/r/hismasters...410_g.html

I presume the two sets only differ in badge?

EDIT:
I've suggested on RM org that the 1,5V is a mistake.

[Paul_RK]

Is RM incorrectly listing 1.5V rather than 4.5V battery?...

I presume the two sets only differ in badge?

Yes, mine is a P60B - first of these I've ever met, turned up on our small town flea market three or four years ago - LT is from three U11 (i.e. 'C'  cells) in series, HT a B139.