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General Vintage Technology Discussions For general discussions about vintage radio and other vintage electronics etc. |
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23rd Sep 2019, 12:59 am | #21 | |
Heptode
Join Date: Jul 2006
Location: Winchester, Hampshire, UK.
Posts: 636
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Re: Mullard glass transistors
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I worked with a few Mullard apprentices some years later myself as part of an ond course. They said the first years output of the factory was underneath one of the factory perimeter roads as they tried to get to grips with mass production! They also said site security was very very tight as a whole weeks worth of production could be put in the back of a transit van and if the van got nicked well .. you can imagine the consequences. All bulldozed now of course. |
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27th Sep 2019, 7:54 pm | #22 |
Hexode
Join Date: May 2005
Location: London 90% , Northwest England 10%
Posts: 385
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Re: Mullard glass transistors
Question are the Russian made ones suitable for true replacement use ( can one tell the difference in use by scope or ear between Old Stock/NOS and modern equivalents in the same circuit. For Valves and Transistors generally I have an idea of replicating some of my Dads Equipment wholly in new components.
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28th Sep 2019, 5:54 am | #23 | |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
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Re: Mullard glass transistors
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Functional replacement is much easier. Early transistors had huge tolerances on their parameters. Well-designed circuits were made to handle this. Not-so-well-designed circuits might have a select-on-test resistor value to accommodate the spread in transistors. The worst circuits needed selected transistors. The question is in rather general terms so the answer would have to be along the lines of 'it depends', which isn't terribly helpful. If you have a tolerant circuit design, you can get away with murder. If you allow yourself to fiddle with bias resistors, you can do a lot and often even use current silicon devices. It gets more difficult if the supply voltage is low, though because the turn-on voltage of silicon becomes significant. Also, with low supply voltages, the things designers could have done to make the circuit tolerate device spreads are badly limited. David
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28th Sep 2019, 11:12 am | #24 | |
Dekatron
Join Date: Apr 2009
Location: Oxfordshire, UK.
Posts: 4,924
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Re: Mullard glass transistors
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Personally, I would not get too distracted by such issues; life's too short. If Russian devices work, just press on with them! B
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