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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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18th Nov 2022, 7:38 pm | #1 |
Triode
Join Date: Jan 2021
Location: Hove, East Sussex, UK.
Posts: 20
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Garrard 3000 pick up wiring
I am renovating an HMV 2340 and the amplifier has been finished. My next task is to renovate the Garrard 3000 turntable that is now on my bench. The pick up wiring is a bit of a mess and doesn't look standard. If I upload a photo please could one of you have a look and offer advice if those extra resistors - including one that is not even properly connected - should be left alone if they test in spec. Many thanks.
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19th Nov 2022, 1:16 am | #2 |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,225
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Re: Garrard 3000 pick up wiring
That believe it or not is correct. HMV which was part of Thorn, did some odd wiring around these decks.
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19th Nov 2022, 2:18 am | #3 |
Banned
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
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Re: Garrard 3000 pick up wiring
So that unmarked ceramic tubular capacitor, is actually the AM aerial ?. Well I never.
There is also what I think are two RF chokes, probably oscillator and antenna tuning coils. I must have missed the day they taught that at uni. Joe |
19th Nov 2022, 8:23 am | #4 |
Dekatron
Join Date: Jul 2008
Location: Kington, Herefordshire, UK.
Posts: 3,675
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Re: Garrard 3000 pick up wiring
Value engineering at its finest! Teak veneer above - underneath.
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19th Nov 2022, 11:13 am | #5 |
Triode
Join Date: Jan 2021
Location: Hove, East Sussex, UK.
Posts: 20
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Re: Garrard 3000 pick up wiring
Thank you all for your comments.
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19th Nov 2022, 12:03 pm | #6 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,866
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Re: Garrard 3000 pick up wiring
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19th Nov 2022, 2:10 pm | #7 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,340
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Re: Garrard 3000 pick up wiring
At the time of production this was top of HMV's Stereogram range. It looks as if it has been very badly "got at" by a previous owner. I would be inclined to remove all those added-in components and just run the 4 cartridge wires from the under-the-deck tagstrip straight into the amplifier's AF stage. And there is no need for mains-isolating caps on this model which, at first, is what I thought they were.
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Edward. |
19th Nov 2022, 3:12 pm | #8 |
Octode
Join Date: Feb 2007
Location: Harrow, London, UK.
Posts: 1,493
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Re: Garrard 3000 pick up wiring
Before you jump to conclusions, check out the schematic.
The schematic shows quite clearly a bass boost on the crystal/ceramic cartridge comprising of a 4K7pf in series with 2.2Kohms. The loose 2K2pf is a mystery as whilst it is also shown on the schematic, it is unclear where it goes. However, the text associated with the schematic refers to manufacture tests and it may be used for this function. Chris |
19th Nov 2022, 3:47 pm | #9 |
Dekatron
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,866
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Re: Garrard 3000 pick up wiring
I thought mains isolation initially too, interesting to hear it’s for tone correction. But what a mess!
I wonder whether early models weren’t so equipped, and this example has had a living room floor dealer mod? |
19th Nov 2022, 10:28 pm | #10 |
Heptode
Join Date: Jan 2009
Location: West Lothian, UK.
Posts: 762
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Re: Garrard 3000 pick up wiring
The unconnected capacitor is mentioned in the service sheet (from the DVD).
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George |
20th Nov 2022, 9:52 am | #11 |
Dekatron
Join Date: Sep 2015
Location: Southwold, Suffolk, UK.
Posts: 8,340
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Re: Garrard 3000 pick up wiring
That circuit above tells the story and explains all. It's just rather unusual (well, to me) to see tone compensation components wired onto a tag strip like that and ahead of the volume control.
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Edward. |
20th Nov 2022, 11:42 am | #12 |
Pentode
Join Date: Mar 2022
Location: Retford, Nottinghamshire, UK.
Posts: 196
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Re: Garrard 3000 pick up wiring
That capacitor with one leg stuck out in fresh air does look very odd!
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Paul |
20th Nov 2022, 8:54 pm | #13 |
Octode
Join Date: Feb 2007
Location: Harrow, London, UK.
Posts: 1,493
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Re: Garrard 3000 pick up wiring
The capacitor c103, sticking out with one leg, is there for a reason.
The schematic tells all, as buggies said. Answers to Derby DE21 7SS to arrive no later than April 1 2023. Chris |
20th Nov 2022, 11:26 pm | #14 |
Hexode
Join Date: Dec 2020
Location: Raunds, Northamptonshire, UK.
Posts: 359
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Re: Garrard 3000 pick up wiring
You have been watching too many episodes of the Gadget Show or Michael Portillo.
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Graham |
27th Nov 2022, 9:48 pm | #15 |
Octode
Join Date: Aug 2005
Location: Saltburn-East, Cleveland, UK.
Posts: 1,786
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Re: Garrard 3000 pick up wiring
Hi, the additional components attached to the pick-up wiring are a "matching pad" for the cartridge, more often used where a ceramic pickup is connected to a high gain RIAA corrected amplifier, it's not beyond possibility that the amplifier circuit was used in a number of Thorn/BRC designs at the time.
Alternatively, the radiogram may have been fitted with different models of autochanger, depending on the "manufacturer" badge (e.g. Ferguson, Ultra or HMV), where the associated cartridge was matched to the amplifier using a matching pad. Andrew |