Hornby / Triang R253 Dock Shunter Question

[Il Grifone]

It's not so much the brushes bouncing on the commutator (eccentric and rough commutators don't help of course) as the breaking of an inductive circuit to cause the spark. Dublo motors are particularly sensitive to correct brush tension I find.

 

Neither of the following is really relevant to the original post, however....

 

Loudspeaker cross-over design is fairly simple (phase distortion caused by the reactive components is luckily inaudible*) and resolves to cross-over frequency and rate of roll-off.

My prized B & O speakers succumbed to the dreaded suspension break-up syndrome. Replacement suspensions were available on eBay and they now sing again. I doubt that the speaker characteristics now correspond to the original design, but never mind. They sound good to my ears despite their age. (I've had them nearly 25 years and they were quite venerable when i acquired them.)

 

The first radio (wireless telegraphy back then) communications used spark transmitters. Titanic had some quite advanced equipment.

 

https://www.rfcafe.com/miscellany/smorgasbord/titanic-marconi-wireless-telegraph-company.htm

 

I read somewhere that 1912 was also the year that radio operators were surprised to hear speech through their headphones instead of 'hash' and Morse code. The demise of spark transmitters followed this development quite quickly.

 

[kevinlms]

2 hours ago, Il Grifone said:

It's not so much the brushes bouncing on the commutator (eccentric and rough commutators don't help of course) as the breaking of an inductive circuit to cause the spark. Dublo motors are particularly sensitive to correct brush tension I find.

 

Neither of the following is really relevant to the original post, however....

 

Loudspeaker cross-over design is fairly simple (phase distortion caused by the reactive components is luckily inaudible*) and resolves to cross-over frequency and rate of roll-off.

My prized B & O speakers succumbed to the dreaded suspension break-up syndrome. Replacement suspensions were available on eBay and they now sing again. I doubt that the speaker characteristics now correspond to the original design, but never mind. They sound good to my ears despite their age. (I've had them nearly 25 years and they were quite venerable when i acquired them.)

 

The first radio (wireless telegraphy back then) communications used spark transmitters. Titanic had some quite advanced equipment.

 

https://www.rfcafe.com/miscellany/smorgasbord/titanic-marconi-wireless-telegraph-company.htm

 

I read somewhere that 1912 was also the year that radio operators were surprised to hear speech through their headphones instead of 'hash' and Morse code. The demise of spark transmitters followed this development quite quickly.

 

(I've had them nearly 25 years and they were quite venerable when i acquired them.)

 

What your ears? I thought you were a little older than that!

[Il Grifone]

 I am, but the ears were acquired at a very young age!  

 

The speakers are only thirty years younger than I am. IIRC their test data sheet states 1977.

[melmerby]

1 hour ago, Il Grifone said:

 I am, but the ears were acquired at a very young age!  

 

The speakers are only thirty years younger than I am. IIRC their test data sheet states 1977.

Still well off topic!

My Dalesford D100/200 8" bass units are about that age, the STC (now Coles) 4001G super tweeters and the Celestion HF1300 tweeters (both in store) are older than that, as the bass units were originally KEF B200 8" but I overdrove them!

[Il Grifone]

My B&O speakers have Celestion HF1300s IIRC they were a feature of BBC designs back in the day.*

 

* Back then the speakers were not good enough for the music; nowadays the music is not good enough for the speakers!

Luckily  the old music is still around, even if some of the digital formats don't have enough bits to do justice to it. Yes DAB I am thinking of you.... I won't go into the analogue/digital argument - I have a B&O deck and cartridge as well!

 

It was supposed to be spelt analog and (digital) disk. Yeah, right....

Edited May 3, 2021 by Il Grifone