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Hifi pre-history
Just to let people know I've added some examples to the 'valve era' page at
http://www.audiomisc.co.uk/Armstrong.../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/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Hifi pre-history
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.../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 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
Hifi pre-history
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.../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/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Hifi pre-history
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.../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 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
Hifi pre-history
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. |
Hifi pre-history
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 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
Hifi pre-history
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.../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 |
Hifi pre-history
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.../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 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus |
Hifi pre-history
"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.../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 |
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