In article , Bob Eager
writes
On Tue, 7 Sep 2004 19:02:44 UTC, "Dave Plowman (News)"
wrote:

OC81 comes to mind. I had some here till recently...

IIRC, OC82 was an output transistor in an ally can. OC71 was the common
general purpose type.

Thinking about it, I'm sure you're right. I remember filing round the
base of the glass, removing it, getting the jelly off, scraping the
glass clean....lo, a phototransistor (terrible characteristic, but...)

Rather than removing the glass/jelly, I once scraped the paint off an
OC71, and centrifuged the jelly to the bottom. Of course, Mullard then
changed to opaque glass, then tin cans.

ISTR the OC71 cost 1/6d (or was it 2/6d ?), whereas the "proper" OCP71
cost 17/6d.

--
Frank Erskine
Sunderland

In message , John
Rumm writes
Owain wrote:
"John Rumm" wrote
| Andy Hall wrote:
| "for grown ups"). The librarian looked down her nose at me and
| suggested that I would be better off with Janet and John or Noddy.
| Not as daft as it sounds though... When I was I guess about 10, I
| had a Ladybird book called "How to build a transitor radio!" ;-)
...
| Alas the full design never did work,
I'm glad you told me that; I had the same book but never tried
making it up.
Now I know it wouldn't have worked anyway, I don't feel I missed as much.

I think one of the problems was the components used were so old in
design that the spec had altered by the time I managed to find examples
of them. The transistors used (can't remember the number at the mo)
were in glass domed cases with a black finish (about 3mm diameter by
7mm tall).

OC71 ?


--
geoff

In message , Bob Eager
writes
On Tue, 7 Sep 2004 19:02:44 UTC, "Dave Plowman (News)"
wrote:

OC81 comes to mind. I had some here till recently...

IIRC, OC82 was an output transistor in an ally can. OC71 was the common
general purpose type.

Thinking about it, I'm sure you're right. I remember filing round the
base of the glass, removing it, getting the jelly off, scraping the
glass clean....lo, a phototransistor (terrible characteristic, but...)

Aah memories ...

blue / white stuff IIRC

As for the 10,000 diodes for a tenner ...

--
geoff

In article ,
Frank Erskine wrote:
ISTR the OC71 cost 1/6d (or was it 2/6d ?), whereas the "proper" OCP71
cost 17/6d.

I can remember red spots costing 10/6d. Perhaps something like 10 quid in
today's money. One used heatsinks when soldering them - and held your
breath.

--
*A bicycle can't stand alone because it's two tyred.*

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Andy Wade
writes
Dave Plowman (News) wrote:

IIRC, OC82 was an output transistor in an ally can. OC71 was the common
general purpose type.

And the audio line-up in a good transistor radio of that era was an OC71
feeding an OC81D driver feeding a pair of OC81s in push-pull
(transformer coupled in and out). For the RF side you had an OC44
self-oscillating mixer and two unilateralised OC45 IF stages.

Nostalgia...


And the AF115 for the VHF or was it 114 ???

And the AF139 in yer TV amp

Them were the days...
--
Tony Sayer

Bancom Communications Ltd U.K. Tel+44 1223 566577 Fax+44 1223 566588

P.O. Box 280, Cambridge, England, CB2 2DY E-Mail

On Tue, 7 Sep 2004 23:37:01 UTC, tony sayer wrote:

Nostalgia...

And the AF115 for the VHF or was it 114 ???

And the AF139 in yer TV amp

Them were the days...

So who remembers EF91s...EL91s...and I forget the others...

--
Bob Eager
begin a new life...dump Windows!

On Tue, 07 Sep 2004 15:36:39 +0100, John Rumm
wrote:

Owain wrote:
"John Rumm" wrote
| Andy Hall wrote:
| "for grown ups"). The librarian looked down her nose at me and
| suggested that I would be better off with Janet and John or Noddy.
| Not as daft as it sounds though... When I was I guess about 10, I
| had a Ladybird book called "How to build a transitor radio!" ;-)
...
| Alas the full design never did work,

I'm glad you told me that; I had the same book but never tried making it up.
Now I know it wouldn't have worked anyway, I don't feel I missed as much.

I think one of the problems was the components used were so old in
design that the spec had altered by the time I managed to find examples
of them. The transistors used (can't remember the number at the mo) were
in glass domed cases with a black finish (about 3mm diameter by 7mm
tall). It also called up things like "postage stamp" type trimmers which
at the time were difficult to find (although they are available again now!).


OC71s.


..andy

To email, substitute .nospam with .gl

On Tue, 07 Sep 2004 17:39:45 +0100 (BST), "Dave Liquorice"
wrote:

On Tue, 07 Sep 2004 15:36:39 +0100, John Rumm wrote:

The transistors used (can't remember the number at the mo) were
in glass domed cases with a black finish (about 3mm diameter by 7mm
tall).

OC71 etc, though that was an audio type tranny. Nicely light sensitive
if you scrapped the paint off.

Until they started putting white opaque paste inside.

Then you had to carefully break the envelope, rinse out the gunk and
stick back together.


It also called up things like "postage stamp" type trimmers which
at the time were difficult to find (although they are available
again now!).

When I was at the "building my first radio stage" (late 60's early
70's) getting almost any electronic part was hard. RS, Farnell, etc
where way above the pocket money level. Tandy didn't do most of the
things required for UK designs and what they did do wasn't that cheap.
Maplin didn't exist...



..andy

To email, substitute .nospam with .gl

On Wed, 8 Sep 2004 00:37:01 +0100, tony sayer
wrote:

In article , Andy Wade
writes
Dave Plowman (News) wrote:

IIRC, OC82 was an output transistor in an ally can. OC71 was the common
general purpose type.

And the audio line-up in a good transistor radio of that era was an OC71
feeding an OC81D driver feeding a pair of OC81s in push-pull
(transformer coupled in and out). For the RF side you had an OC44
self-oscillating mixer and two unilateralised OC45 IF stages.

Nostalgia...


And the AF115 for the VHF or was it 114 ???


AF 116. Geranium.....


And the AF139 in yer TV amp

Them were the days...

..andy

To email, substitute .nospam with .gl

Dave Plowman (News) wrote:

Not always transformer output, though - high impedance speakers were
fairly common.

Those came later, surely, with complementary output stages - AC127s &
AC128s?

I've got a working 'Good Companion' I bought as a kit with my first pay
from the BBC. Micro alloy transistors and transfilters...

Popular kit that. A school friend of mine built one; he ended up
working for the Beeb too, at Pebble Mill. I remember being shown round
the CAR and studios there when it was all fairly new.

--
Andy

In article , Bob Eager
writes
On Tue, 7 Sep 2004 23:37:01 UTC, tony sayer wrote:

Nostalgia...

And the AF115 for the VHF or was it 114 ???

And the AF139 in yer TV amp

Them were the days...

So who remembers EF91s...EL91s...and I forget the others...


EF.* that was some sort of 6.3 volt heated triode wasn't it?.

Recall the EY51 the wire in EHT rectifier 'tho and the EB91 that double
diode thingy?...
--
Tony Sayer

In article ,
Andy Wade wrote:
Not always transformer output, though - high impedance speakers were
fairly common.

Those came later, surely, with complementary output stages - AC127s &
AC128s?

No - the previously mentioned Good Companion has it with a pair of OC82s.

--
*Why do we say something is out of whack? What is a whack? *

Dave Plowman London SW
To e-mail, change noise into sound.

Andy Wade wrote:
xenelk wrote:

Which was my point. I was just trying to explain it in simple
terms....

But you got it wrong. The need to use decent (i.e. well-screened)
coax cable for DTT is much more to do with keeping impulsive
interference at bay, than with the loss of the cable.

It made sense to me.

Signal degrades over any cable. The signal degrades more over low
quality cable compared to high quality cable. "xenelk" didn't lay claim
as to the reason for the degradation, it could mean signal strength
loss, susceptibility to interference or anything.

I'm not quite sure why you're arguing with someone who appears to agree
with you!

Buxnot wrote:

[...] "xenelk" didn't lay claim as to the reason for the degradation,
it could mean signal strength loss, susceptibility to interference or
anything.

I'm not quite sure why you're arguing with someone who appears to agree
with you!

"xenelk" said this:
All cables lose a bit of signal per metre. Higher quality cables have
less signal loss per metre than low quality cables. "Satellite quality"
cable tends to be higher quality.

If that's not about loss - in the sense of attenuation - then I don't
know what is.

--
Andy

Dave Plowman (News) wrote:

No - the previously mentioned Good Companion has it with a pair of OC82s.

Yes you're right - my memory must be getting a bit selective.

--
Andy

tony sayer wrote:
In article , Bob Eager
writes
On Tue, 7 Sep 2004 23:37:01 UTC, tony sayer wrote:

Nostalgia...

And the AF115 for the VHF or was it 114 ???

And the AF139 in yer TV amp

Them were the days...

So who remembers EF91s...EL91s...and I forget the others...


EF.* that was some sort of 6.3 volt heated triode wasn't it?.

Recall the EY51 the wire in EHT rectifier 'tho and the EB91 that double
diode thingy?...

No - correct about the E, 6.3 volt indirectly heated cathode, but the
F means pentode. It's C for triodes (e.g. ECC81, ECC82 and ECC83 the
ubiquitous double triodes)

--
Chris Green

tony sayer wrote:

EF.* that was some sort of 6.3 volt heated triode wasn't it?.

No, EF implies pentode (E = 6.3 V heater, F = pentode). Triodes are EC.

Recall the EY51 the wire in EHT rectifier 'tho

Only too well.

and the EB91 that double diode thingy?...

With the heater that lit up like a beacon when heater volts were first
applied. Yes, well.

How about the PD500 X-ray tube ^w^w sorry, EHT shunt stabiliser used in
early colour sets?
--
Andy

Bob Eager wrote:

So who remembers EF91s...EL91s...and I forget the others...

Pah, modern miniature valves, those. I started on octal valves: 6K8,
6K7, 6SN7GT, 6V6G, 5Z4 (classic post-war 4+1 superhet line-up...).

--
Andy

In article , writes
tony sayer wrote:
In article , Bob Eager
writes
On Tue, 7 Sep 2004 23:37:01 UTC, tony sayer wrote:

Nostalgia...

And the AF115 for the VHF or was it 114 ???

And the AF139 in yer TV amp

Them were the days...

So who remembers EF91s...EL91s...and I forget the others...


EF.* that was some sort of 6.3 volt heated triode wasn't it?.

Recall the EY51 the wire in EHT rectifier 'tho and the EB91 that double
diode thingy?...

No - correct about the E, 6.3 volt indirectly heated cathode, but the
F means pentode. It's C for triodes (e.g. ECC81, ECC82 and ECC83 the
ubiquitous double triodes)


I'm indebted to me 'learned friend....whos got a better memory than I!..

P was that series connected heather arrangement 100ma IIRC and

F was pentode and

Y was a 'wectifier

whatever was a tetrode?.....L or summatt!...
--
Tony Sayer

On Wed, 8 Sep 2004 10:49:39 UTC, Andy Wade
wrote:

Bob Eager wrote:

So who remembers EF91s...EL91s...and I forget the others...

Actually, I was thinking about the 1.4V filiaments.... DF series?

Pah, modern miniature valves, those. I started on octal valves: 6K8,
6K7, 6SN7GT, 6V6G, 5Z4 (classic post-war 4+1 superhet line-up...).

Oh, that too...I had access to a lot of ex-Army stuff!

--
Bob Eager
begin a new life...dump Windows!

In article om,
Dave Liquorice wrote:
When I was at the "building my first radio stage" (late 60's early
70's) getting almost any electronic part was hard. RS, Farnell,
etc where way above the pocket money level. Tandy didn't do most
of the things required for UK designs and what they did do wasn't
that cheap. Maplin didn't exist...

That was my electronic experimenting era too, but I don't remember
any problems. There were various mail order firms around (Henrys,
G.W.Smith) and Watts Radio in Kingston Apple Market (still there)
sold components as did a little shop in Hounslow just down the road
from the Coop: if I was quick I could go there and be back within my
tea-break time.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

On Wed, 8 Sep 2004 11:53:54 +0100, tony sayer
wrote:

I'm indebted to me 'learned friend....whos got a better memory than I!..

P was that series connected heather arrangement 100ma IIRC and

F was pentode and

Y was a 'wectifier

whatever was a tetrode?.....L or summatt!...

Any room in the old gits' shed? L was power pentode, F was its weaker
non-power sibling. Must be correct since I can't ever forget the PL36:
bug bastid power pentode thing to drive the line coils and EHT
transformer. Now the smallest of the small must have been the FM
demodulator of our telly:: EH80 rings a bell. It fell out once and
left all the other candles without any heater juice, since they were
all chained.

The fresh of face must have web kites covering this by now, all full
of flash and other essentials.

--
New anti-spam address cmylod at despammed dot com

tony sayer wrote:

In article , writes

tony sayer wrote:

In article , Bob Eager
writes

On Tue, 7 Sep 2004 23:37:01 UTC, tony sayer wrote:


Nostalgia...

And the AF115 for the VHF or was it 114 ???

And the AF139 in yer TV amp

Them were the days...

So who remembers EF91s...EL91s...and I forget the others...


EF.* that was some sort of 6.3 volt heated triode wasn't it?.

Recall the EY51 the wire in EHT rectifier 'tho and the EB91 that double
diode thingy?...

No - correct about the E, 6.3 volt indirectly heated cathode, but the
F means pentode. It's C for triodes (e.g. ECC81, ECC82 and ECC83 the
ubiquitous double triodes)



I'm indebted to me 'learned friend....whos got a better memory than I!..

P was that series connected heather arrangement 100ma IIRC and

F was pentode and

Y was a 'wectifier

whatever was a tetrode?.....L or summatt!...


No, EL 34/84 were power pentodes.
I think the L means 'power'


KT66 ws a beam terode, but thats yank speek.

"Dave Liquorice" wrote in message ill.com...
On Tue, 07 Sep 2004 15:36:39 +0100, John Rumm wrote:

The transistors used (can't remember the number at the mo) were
in glass domed cases with a black finish (about 3mm diameter by 7mm
tall).

OC71 etc, though that was an audio type tranny. Nicely light sensitive
if you scrapped the paint off.

It also called up things like "postage stamp" type trimmers which
at the time were difficult to find (although they are available
again now!).

When I was at the "building my first radio stage" (late 60's early
70's) getting almost any electronic part was hard. RS, Farnell, etc

That's just plain wrong. My father and later myself managed to obtain
everything he needed from the early 60s onwards. I can't remember who
all the suppliers were but any issue of Practical Wireless from the
time would be revealing. Electrovalue and Ambit were the ones we
mostly used.

where way above the pocket money level. Tandy didn't do most of the
things required for UK designs and what they did do wasn't that cheap.

If you mean getting things cheap was difficult then that's a different
matter. RS were trade only in those days but most large towns had a
shop that would order stuff for you.

Maplin didn't exist...

They certainly did exist by the early 70s.

MBQ

MBQ wrote:


Maplin didn't exist...


They certainly did exist by the early 70s.

About '74 ISTR. 1979 was the first time they produced what would be
recongnisable as "the maplin catalogue" today.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"John Rumm" wrote
| Maplin didn't exist...
| They certainly did exist by the early 70s.
| About '74 ISTR. 1979 was the first time they produced what
| would be recongnisable as "the maplin catalogue" today.

I still remember my old Maplin Customer Number - 100605. (Bit like an Army
Number for those old enough to do National Service, I suppose.) The last
time I tried to order using it, they wouldn't accept it as it was 'too
short'.

Someone'll probably pop up and say they were Maplin Customer 000031 now...

Owain

Someone'll probably pop up and say they were Maplin Customer 000031 now...


Well, I was no. 000054 (I jest)

and have still got all the Ambit International catalogues (true)
(and some OC71s, OC81s and AF117s ) (also true - sadly)

Must look them out to sell on E-Bay at some exhorbitant price

;-))


Nick

On Wed, 08 Sep 2004 12:14:06 GMT, Tony Bryer
wrote:

That was my electronic experimenting era too, but I don't remember
any problems. There were various mail order firms around (Henrys,
G.W.Smith) and Watts Radio in Kingston Apple Market (still there)
Hi,

There also used to be an electronics shop down the road in Hampton
Court.

cheers,
Pete.

On Wed, 8 Sep 2004 20:43:22 UTC, Pete C
wrote:

On Wed, 08 Sep 2004 12:14:06 GMT, Tony Bryer
wrote:

That was my electronic experimenting era too, but I don't remember
any problems. There were various mail order firms around (Henrys,
G.W.Smith) and Watts Radio in Kingston Apple Market (still there)
Hi,

There also used to be an electronics shop down the road in Hampton
Court.

Anybody remember Technical Trading in Brighton? Big ad on page 3 of some
magazine (Practical Wireless?). Long list of valves...
--
Bob Eager
begin a new life...dump Windows!

In article ,
nick smith wrote:
(and some OC71s, OC81s and AF117s ) (also true - sadly)

Must look them out to sell on E-Bay at some exhorbitant price

They come up quite often, but don't fetch that much.

--
*If at first you don't succeed, destroy all evidence that you tried *

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Pete C
writes
On Wed, 08 Sep 2004 12:14:06 GMT, Tony Bryer
wrote:

That was my electronic experimenting era too, but I don't remember
any problems. There were various mail order firms around (Henrys,
G.W.Smith) and Watts Radio in Kingston Apple Market (still there)
Hi,

There also used to be an electronics shop down the road in Hampton
Court.

There were two in Crowtree Road - the Red Radio Shop shop, run by the
late Bob Sharp G2HMI; and Pattison's, who refused to sell transistors
and went out of business in the mid 60s, although he was good for Denco
coils and aerial wire.

--
Frank Erskine

MBQ wrote:

"Dave Liquorice" wrote in message ill.com...

On Tue, 07 Sep 2004 15:36:39 +0100, John Rumm wrote:


The transistors used (can't remember the number at the mo) were
in glass domed cases with a black finish (about 3mm diameter by 7mm
tall).

OC71 etc, though that was an audio type tranny. Nicely light sensitive
if you scrapped the paint off.


It also called up things like "postage stamp" type trimmers which
at the time were difficult to find (although they are available
again now!).

When I was at the "building my first radio stage" (late 60's early
70's) getting almost any electronic part was hard. RS, Farnell, etc


That's just plain wrong. My father and later myself managed to obtain
everything he needed from the early 60s onwards. I can't remember who
all the suppliers were but any issue of Practical Wireless from the
time would be revealing. Electrovalue and Ambit were the ones we
mostly used.


Electrovalue started up in te late 60's, frtom a shed in surrey.

Prior to that it was Henry's radio mainly IIRC.


where way above the pocket money level. Tandy didn't do most of the
things required for UK designs and what they did do wasn't that cheap.


If you mean getting things cheap was difficult then that's a different
matter. RS were trade only in those days but most large towns had a
shop that would order stuff for you.


Yes.

Maplin didn't exist...


They certainly did exist by the early 70s.

Don't think so...mid 70's more like.


MBQ

Dave Liquorice wrote:

When I was at the "building my first radio stage" (late 60's early
70's) getting almost any electronic part was hard. RS, Farnell, etc
where way above the pocket money level. Tandy didn't do most of the
things required for UK designs and what they did do wasn't that cheap.
Maplin didn't exist...

(Joining the old farts natter late) So what us then-young-un's used to
do was get stripper boards by the pound - ee-lec-tron-ick Modules, PCBs,
and the occaisional bagfull of assorted nuttiness, either by mail order
(John Bull Electrical is still going, selling surplus items by type
these days - haven't noticed "parcels of surplus shold by weight" over
there any more, but maybe they're still there), or at your Local
Electronics Shop for Local People. At the revelant time (early 70s for
me), local was Manchester - there was a little place in Shude Hill (area
behind the Cathedral replaced in the late70s/early80s by the Armpit
Centre, shortly afterwards lovingly remodelled by Gerry Adams and the
Bombmakers ;-) which sold components and stripper boards.

Going through some of the boxes in the garage, I still come across the
odd three-legged tin can desoldered from such a board thirty years ago;
oddly enough I haven't used any of those components for ever such a long
time, though!

Ob d-i-y: yesterday's minor foray into ee-leck-tron-icks meets
ee-leck-triss-it-ee, using components no more than a year old, was to
make the kids iMac control the power on external hard drives/CD burner
using its own poweron/poweroff. Almost as simple as wiring the coil of a
mains-rated-contacts relay across the 12V supply for the hard drive;
politeness to the iMac power supply and internals meant a 250mA fuse,
followed by a diode, with another normally-reverse-biased diode and 2k
resistor in parallel with the relay coil, to give the back EMF somewhere
harmless to go when the power drops out. The iMac is a 2nd-gen CRT one -
quite easy to open up, unlike the 1st-gen - and with a standard IDE
drive and 4-pin power connector; I piggybacked a "power-stealer"
male-to-female-with-0V-and-12V-brought-out-on-extra-wired connector (as
supplied with many CPU fan kits, and therefore knocking around the
relevant spares box in Casa Zaba) into the back of the HD, and there was
room alongside the HD to hide away the little bit of circuitry, with the
12V (OK, 11.4V for the pedants ;-) output brought out on a 2way
Minifit-Junior wire-mounted Molex just next to the VGA-mirror socket on
the back of the iMac - a moment with the Dremel converting one of the
small holes at the edge of that connector's cover into a slot running to
the edge. Box at the bottom of the iMac trolley has incoming mains, one
unrelayed outgoing IEC320 to the iMac mains input, a couple of
relay-controlled leads (one IEC320, one calculator-style L&N-only, to
suit existing external periphs) and the inevitable 4-way mains block.

Ahh, sweet sweet bodging ;-)

"Stefek Zaba" wrote
| Ob d-i-y: yesterday's minor foray into ee-leck-tron-icks
| meets ee-leck-triss-it-ee, using components no more than
| a year old, was to make the kids iMac control the power
| on external hard drives/CD burner using its own poweron/
| poweroff. ....

If you'd wired it via a coin meter could have been a nice little earner:
"50p in the slot every time you want to use the hard drive, kiddies"

| Ahh, sweet sweet bodging ;-)

And for your next project ...
http://www.mini-itx.com/projects/mac-itx/

Owain