Mat101 - UK Vintage Radio Repair and Restoration Discussion Forum

jim_jobe · 13th May 2007, 2:56 pm

Does anyone have one or two MAT101s lurking in their junkboxes please? Or failing that are AF106s or 109s possible substitutes?I have a few of these.
Cheers,
Jim

paulsherwin · 13th May 2007, 3:43 pm

I don't have any and don't have a data sheet, but they were RF Ge PNP transistors produced by Plessey in the 60s. The production process generated lots of rejects so they were a popular transistor in hobbyist circuits. Clive SInclair famously used them.

What is the circuit? A wide range of transistors might work, including PNP silicon types.

Paul

jim_jobe · 13th May 2007, 6:38 pm

Hi Paul,
You're right about the rejects - I have some of those. They work well in OC44 type reflex circuits but I want to try some of Sir Douglas Hall's designs and I think the rejects' gains at low collector currents is too low for most of those -that's why I want some full spec. devices. It's just for interest's sake really.
I think they were a development of Surface-Barrier type transistors which even at their best had very low gains and low Vcemax.
Jim

paulsherwin · 13th May 2007, 6:42 pm

Ah, the Spontaflex! He did design some versions of the circuit using silicon transistors. Some of the silicon types he used aren't that common now either, but they're more common than MAT101s, and you're more likely to find technical data on them.

http://freespace.virgin.net/spontaflex.reflex/

Paul

13th May 2007, 2:56 pm	#1
jim_jobe Heptode Join Date: Nov 2004 Location: Ripon, N.Yorkshire, UK. Posts: 782	Mat101 Does anyone have one or two MAT101s lurking in their junkboxes please? Or failing that are AF106s or 109s possible substitutes?I have a few of these. Cheers, Jim

13th May 2007, 3:43 pm	#2
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Mat101 I don't have any and don't have a data sheet, but they were RF Ge PNP transistors produced by Plessey in the 60s. The production process generated lots of rejects so they were a popular transistor in hobbyist circuits. Clive SInclair famously used them. What is the circuit? A wide range of transistors might work, including PNP silicon types. Paul

13th May 2007, 6:38 pm	#3
jim_jobe Heptode Join Date: Nov 2004 Location: Ripon, N.Yorkshire, UK. Posts: 782	Re: Mat101 Hi Paul, You're right about the rejects - I have some of those. They work well in OC44 type reflex circuits but I want to try some of Sir Douglas Hall's designs and I think the rejects' gains at low collector currents is too low for most of those -that's why I want some full spec. devices. It's just for interest's sake really. I think they were a development of Surface-Barrier type transistors which even at their best had very low gains and low Vcemax. Jim

13th May 2007, 6:42 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,966	Re: Mat101 Ah, the Spontaflex! He did design some versions of the circuit using silicon transistors. Some of the silicon types he used aren't that common now either, but they're more common than MAT101s, and you're more likely to find technical data on them. http://freespace.virgin.net/spontaflex.reflex/ Paul