Talk:EMS Synthi A

Advert
Re the linked advert with the line "every nun needs a Synthi": my secondary school had a Synthi A in the music dept, and there was a poster on the wall of the music room reading "Even Orpheus needs a Synthi". This was in September 1976. Possibly there were other variants? --Redrose64 (talk) 22:46, 9 August 2009 (UTC)
 * There were indeed. I went to an EMS presentation in Liverpool in about 1974 just before I bought my VCS3 and the walls were covered with an array of posters. I doubt many have survived, however. Rodhull  andemu  22:57, 9 August 2009 (UTC)

Patch pins
There were three types of patch pins: white, red and green. The proportions differed: I think that about 75% were white, the rest red or green in equal quantities. Each was essentially a jack plug, no larger than 2.5mm diameter - but may have been smaller, since they were easily bent, particularly near the tips. Red and green ones contained a resistor, whilst white ones were plain wire internally.

I was once told the circumstances for using each, something to do with "if you're routing the signal out of here or into here you should use a red pin, otherwise use white", but I was never told the actual reasoning, nor did I see an official description. Didn't find out what green were for, either. RTFM yes, I would have done, but I was under the instruction of one who believed in hands-on training, and I think the manual got filed under "recycling". --Redrose64 (talk) 10:46, 11 August 2009 (UTC)


 * Since you seem to know a bit about the patch pins, could you please help me with this part of the text that says "The 2700 ohm resistors soldered inside the pin vary in tolerance 5% variance and later 1%; the pins have different colours: the 'red' pins have 1% tolerance and the 'white' have 5% while the 'green' pins are attenuating pins having a resistance of 68,000 ohms."? I can't seem to understand exactly what it says, because it was hastily written. Thank you in advance. SentientContrarian (talk) 17:00, 1 April 2012 (UTC)
 * I'm not entirely sure what it's supposed to mean myself.
 * The thing is, it seems to give undue importance to the tolerance. The electronic component known as a "resistor" has a number of properties, the most important of which is the resistance, which is measured in ohms, symbol Ω. The value is never exact: manufacturers will specify the tolerance as a percentage. Thus, a resistor nominally of 2700Ω may actually have a value greater or less than 2700Ω, but the manufacturer will endeavour to ensure that it lies somewhere in a given range. Where the tolerance is 5%, this range is between Ω and Ω; and for tol. 1%, the range is Ω to Ω. So, since either one may produce a resistor of the same value as the other, I don't think that the tolerance is the significant factor for the Synthi A patch board.
 * I can try to find out: I've not seen my abovementioned instructor since about 1983, but I see his brother once a week. -- Red rose64 (talk) 20:24, 1 April 2012 (UTC)

I'm not aware of any patch pins, white or otherwise, that were a straight short-circuit inside. this would have made their delicate construction rather redundant, & in any case, the purpose of the resistors was to remove the need for the extra circuitry that would have been required to buffer multiple destinations from a single source, whether this be signal or control; if you patched using multiple "short circuit" pins, the sources would be overloaded.

my synthi has white, red, green, yellow & two shades of grey. I mix & match them with impunity, but will measure the resistances at least & report back.

& upon the matter of tolerance- in 1970, very accurate resistors of the small size necessary to fit inside the patch pin shells were expensive. remember that the EMS instruments were an attempt to make synthesis more affordable; it made sense for the pins to be offered in standard & deluxe variants. the higher accuracy of the more expensive pins has a practical advantage if one wishes to achieve a predictable & reliable result. one wonders what accuracy of component was installed in the prestopatch devices....

duncanrmi (talk) —Preceding undated comment added 14:57, 29 August 2012 (UTC)

[reporting back, after an unconscionable absence, for which many apologies...]

white- 2k7 red- 2k7 yellow- 2k7 grey- 2k7 purple- 3k1 green- 6k2

I can only presume- not wishing to take them apart, & with no way of measuring it- that the difference between the various 2k7 pins is the accuracy/tolerance of the value. plainly, though, there are no straight shorts amongst them.

duncanrmi (talk) 11:23, 3 December 2013 (UTC)

Grammar, Spelling & Syntax
I will try to correct some spelling, grammar and syntax errors. However, there are a few points where I don't exactly understand what one of the previous contributor meant. More on that later. SentientContrarian (talk) 07:36, 1 April 2012 (UTC)