Tobey & Dinsdale amp in Wireless World

[DouglasSelf]

I have just added some more amplifiers to the archive, including the "88-50" pre and power amps, (KT88s) and the Tobey & Dinsdale transistor amp of 1961.

The Wireless World Archive

 

[Mooly]

Interesting reading... particularly the home made transistors 🙂
Yes it is surprising no one has wanted a comeback of point contacts... now that could be a challenge ! a blameless amp made from homemade transistors.

As a youngster I remember seeing if two diodes connected "as a transistor" could be made to have any "transistor" action...

I've picked a bit more up since then though 😉

 

[lineup]

Tobey & Dinsdale 1961 Transistor Audio Power Amplifier

I am working in SPICE to make a clone of the old Tobey & Dinsdale.
I think it is possible even if the original uses Germanium, I think.
I post schematic here when I get it to work..

 

[lineup]

I made my clone of Tobey & Dinsdale.
Closed Loop Gain was decreased to ~15.
Amp was compensated with 1000pF. But my cloone need only 10pF.
Amp shows rather low dist at 1 Watt 8 Ohm.
Was a nice exercise to try modernize this old antique design.
🙂

 

[latala]

I do not suppose that you have any spice models of the old germanium devices
I have often thought that a lot of modern amplifier improvement is due to better devices rather than improved design
I have built many silicon Tobey Dinsdales with good results I am a bit old fashioned and still prefer the inherent safety in capacitor coupled designs
regards Trevor

 

[lineup]

Right. The ideas they had were not all wrong.
With todays devices they can perform.

I have looked for Germanium SPICE models.
But looks as there are no working around.
At least good working.

 

[Tekko]

I suppose this is really similar to the old el cheapo posted on the ESP site, or even the same one.