Hifi pre-history

[Jim Lesurf[_2_]]

Just to let people know I've added some examples to the 'valve era' page at

http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

[Brian Gaff]

As a matter of interest. I'm running an old Rogers Cadet at the moment and
it really does make the grille in the top hot. How did valve stuff ever pass
health and safety back in the old days I wonder?
Brian

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"Jim Lesurf" > wrote in message
...
> Just to let people know I've added some examples to the 'valve era' page
> at
>
> http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
>
> Jim
>
> --
> Please use the address on the audiomisc page if you wish to email me.
> Electronics
> http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
> Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
> Audio Misc http://www.audiomisc.co.uk/index.html
>

[Don Pearce[_3_]]

On Thu, 12 May 2016 12:58:01 +0100, Jim Lesurf >
wrote:

>Just to let people know I've added some examples to the 'valve era' page at
>
>http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
>
>Jim

Just had a quick skim. Did I read that right? You have to buy and fit
your own output transformer. If that is really so, I can see why there
is no overall NFB.

d

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[Jim Lesurf[_2_]]

In article >, Don Pearce
> wrote:
> On Thu, 12 May 2016 12:58:01 +0100, Jim Lesurf >
> wrote:

> >Just to let people know I've added some examples to the 'valve era'
> >page at
> >
> >http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
> >
> >Jim

> Just had a quick skim. Did I read that right? You have to buy and fit
> your own output transformer. If that is really so, I can see why there
> is no overall NFB.

Yes. A different age. You *could* choose to buy it with a speaker and
transformer from Armstrong, as some ads showed. But these were an 'optional
extra'. The chassis wasn't for someone who just wanted to buy and use a
mass produced radio/radiogram.

The approach at the time was that keen 'enthusiasts' put together their own
kit. Bear in mind that well within living memory at the time you could have
bought radios where each *valve* came in its own nicely made wooden
cabinet. These were essentially the 'high end separates' / DIY of their
day.

This was the background that lead the company into making hifi rather than
consumer radios and TVs.

FWIW I'm currently collating adverts for the period from 1932 to about 1946
to illustrate just how different to now it was back then. Different world
that people have forgotten about.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

[Don Pearce[_3_]]

On Thu, 12 May 2016 16:56:08 +0100, Jim Lesurf >
wrote:

>In article >, Don Pearce
> wrote:
>> On Thu, 12 May 2016 12:58:01 +0100, Jim Lesurf >
>> wrote:
>
>> >Just to let people know I've added some examples to the 'valve era'
>> >page at
>> >
>> >http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
>> >
>> >Jim
>
>> Just had a quick skim. Did I read that right? You have to buy and fit
>> your own output transformer. If that is really so, I can see why there
>> is no overall NFB.
>
>Yes. A different age. You *could* choose to buy it with a speaker and
>transformer from Armstrong, as some ads showed. But these were an 'optional
>extra'. The chassis wasn't for someone who just wanted to buy and use a
>mass produced radio/radiogram.
>
>The approach at the time was that keen 'enthusiasts' put together their own
>kit. Bear in mind that well within living memory at the time you could have
>bought radios where each *valve* came in its own nicely made wooden
>cabinet. These were essentially the 'high end separates' / DIY of their
>day.
>
>This was the background that lead the company into making hifi rather than
>consumer radios and TVs.
>
>FWIW I'm currently collating adverts for the period from 1932 to about 1946
>to illustrate just how different to now it was back then. Different world
>that people have forgotten about.
>
>Jim

My first ever amplifier was a single ended DIY kit from Radio and TV
Components (Acton) Ltd. The input valve was a double triode (ECC83, I
think) and the PA was a 6V6 GT. The feeling of triumph when it worked
was quite something.

d

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[Dave Plowman (News)]

In article >,
Don Pearce > wrote:
> My first ever amplifier was a single ended DIY kit from Radio and TV
> Components (Acton) Ltd. The input valve was a double triode (ECC83, I
> think) and the PA was a 6V6 GT. The feeling of triumph when it worked
> was quite something.

The first amp everyone built here was the Mullard 3-3. Unless you were
very rich - then the 5-10.

--
*My wife has a slight impediment in her speech. She stops to breathe.

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

[Don Pearce[_3_]]

On Fri, 13 May 2016 00:57:53 +0100, "Dave Plowman (News)"
> wrote:

>In article >,
> Don Pearce > wrote:
>> My first ever amplifier was a single ended DIY kit from Radio and TV
>> Components (Acton) Ltd. The input valve was a double triode (ECC83, I
>> think) and the PA was a 6V6 GT. The feeling of triumph when it worked
>> was quite something.
>
>The first amp everyone built here was the Mullard 3-3. Unless you were
>very rich - then the 5-10.

Pocket money definitely didn't stretch that far.

d

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[Phil Allison[_3_]]

Don Pearce wrote:

>Jim Lesurf >
> >
> >Just to let people know I've added some examples to the 'valve era' page at
> >
> >http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
> >
> >Jim
>
> Just had a quick skim. Did I read that right? You have to buy and fit
> your own output transformer. If that is really so, I can see why there
> is no overall NFB.
>
>

** The EXP48 output stage uses a pair of 6F6 pentodes operating essentially in class A, so has low distortion without NFB.

However the output impedance is high, providing current drive to the speaker.
The gain of such a stage follows the speaker's impedance, rising strongly at bass resonance and also at frequencies above 1kHz due to voice coil inductance.

With typical speakers of the time, mounted on an open baffle, this gave the resulting sound an automatic eq that was quite intentional.

Note the lack of any form of tone control.



..... Phil

[Don Pearce[_3_]]

On Thu, 12 May 2016 23:20:07 -0700 (PDT), Phil Allison
> wrote:

>Don Pearce wrote:
>
>>Jim Lesurf >
>> >
>> >Just to let people know I've added some examples to the 'valve era' page at
>> >
>> >http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
>> >
>> >Jim
>>
>> Just had a quick skim. Did I read that right? You have to buy and fit
>> your own output transformer. If that is really so, I can see why there
>> is no overall NFB.
>>
>>
>
>** The EXP48 output stage uses a pair of 6F6 pentodes operating essentially in class A, so has low distortion without NFB.
>
>However the output impedance is high, providing current drive to the speaker.
>The gain of such a stage follows the speaker's impedance, rising strongly at bass resonance and also at frequencies above 1kHz due to voice coil inductance.
>
>With typical speakers of the time, mounted on an open baffle, this gave the resulting sound an automatic eq that was quite intentional.
>
>Note the lack of any form of tone control.
>

Intentional or happy accident. I remember that sound - mellow was what
we would have called it.

d

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[Woody[_4_]]

"Phil Allison" > wrote in message
...
> Don Pearce wrote:
>
>>Jim Lesurf >
>> >
>> >Just to let people know I've added some examples to the 'valve
>> >era' page at
>> >
>> >http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
>> >
>> >Jim
>>
>> Just had a quick skim. Did I read that right? You have to buy and
>> fit
>> your own output transformer. If that is really so, I can see why
>> there
>> is no overall NFB.
>>
>>
>
> ** The EXP48 output stage uses a pair of 6F6 pentodes operating
> essentially in class A, so has low distortion without NFB.
>
> However the output impedance is high, providing current drive to the
> speaker.
> The gain of such a stage follows the speaker's impedance, rising
> strongly at bass resonance and also at frequencies above 1kHz due
> to voice coil inductance.
>
> With typical speakers of the time, mounted on an open baffle, this
> gave the resulting sound an automatic eq that was quite intentional.
>
> Note the lack of any form of tone control.
>
>

I remember that from the 60's. In the Music Room the teacher used to
play us records with an old E.A.R. record player with valve amp
feeding what I guess was maybe a 8inch or 10 inch loudspeaker mounted
in the centre of a (quite solid) baffle board about 4ft or so square.
I can still hear it in my minds eye (as it were) to this day - and it
makes me smile.


--
Woody

harrogate3 at ntlworld dot com

[Graeme Wall]

On 13/05/2016 08:19, Woody wrote:
> "Phil Allison" > wrote in message
> ...
>> Don Pearce wrote:
>>
>>> Jim Lesurf >
>>>>
>>>> Just to let people know I've added some examples to the 'valve
>>>> era' page at
>>>>
>>>> http://www.audiomisc.co.uk/Armstrong/reviews/valve/ValveEra.html
>>>>
>>>> Jim
>>>
>>> Just had a quick skim. Did I read that right? You have to buy and
>>> fit
>>> your own output transformer. If that is really so, I can see why
>>> there
>>> is no overall NFB.
>>>
>>>
>>
>> ** The EXP48 output stage uses a pair of 6F6 pentodes operating
>> essentially in class A, so has low distortion without NFB.
>>
>> However the output impedance is high, providing current drive to the
>> speaker.
>> The gain of such a stage follows the speaker's impedance, rising
>> strongly at bass resonance and also at frequencies above 1kHz due
>> to voice coil inductance.
>>
>> With typical speakers of the time, mounted on an open baffle, this
>> gave the resulting sound an automatic eq that was quite intentional.
>>
>> Note the lack of any form of tone control.
>>
>>
>
> I remember that from the 60's. In the Music Room the teacher used to
> play us records with an old E.A.R. record player with valve amp
> feeding what I guess was maybe a 8inch or 10 inch loudspeaker mounted
> in the centre of a (quite solid) baffle board about 4ft or so square.
> I can still hear it in my minds eye (as it were) to this day - and it
> makes me smile.
>
>

Used to listen to BBC schools programmes on a similar set up, don't
remember what the receiver was. Well I was only 5!

--
Graeme Wall
This account not read.

[Dave Plowman (News)]

In article >,
Graeme Wall > wrote:
> Used to listen to BBC schools programmes on a similar set up, don't
> remember what the receiver was. Well I was only 5!

At my school, it was a Truvox radio jack (crystal set) plugged into the
tape recorder. (Schools broadcasts were never at the correct time for the
appropriate period so always a recording.)

--
*And don't start a sentence with a conjunction *

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

[tony sayer]

In article >, Dave Plowman (News)
> scribeth thus
>In article >,
> Graeme Wall > wrote:
>> Used to listen to BBC schools programmes on a similar set up, don't
>> remember what the receiver was. Well I was only 5!
>
>At my school, it was a Truvox radio jack (crystal set) plugged into the
>tape recorder. (Schools broadcasts were never at the correct time for the
>appropriate period so always a recording.)
>

We used to have a valve Leak amp, can't remember which one now, but we
also had a Troughline tuner. Was a bit peeved that the science master
couldn't explain what one of they was;!...

--
Tony Sayer

[Dave Plowman (News)]

In article >,
tony sayer > wrote:
> In article >, Dave Plowman (News)
> > scribeth thus
> >In article >,
> > Graeme Wall > wrote:
> >> Used to listen to BBC schools programmes on a similar set up, don't
> >> remember what the receiver was. Well I was only 5!
> >
> >At my school, it was a Truvox radio jack (crystal set) plugged into the
> >tape recorder. (Schools broadcasts were never at the correct time for
> >the appropriate period so always a recording.)
> >

> We used to have a valve Leak amp, can't remember which one now, but we
> also had a Troughline tuner. Was a bit peeved that the science master
> couldn't explain what one of they was;!...

I don't think schools stuff was broadcast on FM in my area when I was a
kid. ;-)

But we did have Leak equipment in the main music room. And a Leak pickup -
mono of course. It was all just dumped on a domestic trolley (dumb waiter)
Gawd knows what H&S would make of that today. Speaker looked to be home
made. Think it was all supplied by a local place.

--
*If you lived in your car, you'd be home by now *

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