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stainless steel pre-amp/main in jumpers


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Hi,

I just acquired an old Marantz 2230 receiver and it does not have the jumpers for the amp section. I have an 1/8 circular piece of stainless steel. If I cut this to size and form it, can I use this homemade jumper without any risk of damaging the unit? I'm just not sure if stainless steel would work well as a jumper. Thanks for your help!

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short jumper?

Just use copper:

Some typical electrical conductivities

Electrical Conductivity (S·m-1)

Temperature(°C)

Notes

Silver

63.01 × 106

20

Highest electrical conductivity of any metal

Copper

59.6 × 106

20

Annealed Copper

58.0 × 106

20

Referred to as 100 %IACS or International Annealed Copper Standard. The unit for expressing the conductivity of nonmagnetic materials by testing using the eddy-current method. Generally used for temper and alloy verification of Aluminium.

Aluminium

37.8 × 106

20

Seawater

5

Drinking water

0.0005 to 0.05

Deionized water

5.5 × 10-6

changes to 1.2 × 10-4 in degassed water; see J. Phys. Chem. B 2005, 109, 1231-1238
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Those old steel things, which basically connected only the "hot" part of the plugs together, weren't terribly good. Audioquest makes a pair of what are basically very short interconnects (?3"-4" long), that at $25/pr. seem a little pricey to me, but they sure improved things the one time I switched.

pre_amp_jumpers.jpg

Still, no reason you couldn't use a pair of interconnects of any length.

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I am assuming that there are two RCA jacks that are in effect shorted by the jumpers.

Deferring of course to the actual topology if this is different, these can each be replaced by 2 RCA plugs interconnects.

But to answer your question, no, they will not harm anything!

Sorry, I was delayed in noticing any posts since the "jumper? " post!. Yup, those jumpers are what I was referring to!![;)]

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short jumper?

Just use copper:

Some typical electrical conductivities

Electrical Conductivity (S·m-1)

Temperature(°C)

Notes

Silver

63.01 × 106

20

Highest electrical conductivity of any metal

Copper

59.6 × 106

20

Annealed Copper

58.0 × 106

20

Referred to as 100 %IACS or International Annealed Copper Standard. The unit for expressing the conductivity of nonmagnetic materials by testing using the eddy-current method. Generally used for temper and alloy verification of Aluminium.

Aluminium

37.8 × 106

20

Seawater

5

Drinking water

0.0005 to 0.05

Deionized water

5.5 × 10-6

changes to 1.2 × 10-4 in degassed water; see J. Phys. Chem. B 2005, 109, 1231-1238

It was always my belief that PLATINUM was the best metal conductor. No?

tc

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I don't have a Marantz but my old JVC has what I'm quite certain is similar to what you've got.

The receiver has a set of pre-amp outputs and power amp inputs at the back panel. These are RCA females. The jumper is a U-shaped piece of metal which serves an an electrical connection. It is essentially two RCA males with no shield. And of course Larry C is showing you a set of short RCA connectors which will do the same job (a good idea in my view).

I believe this jumper scheme is there just to give an extra level of flexibility. When removed you can directly feed the power amp and you have a pre-amp output. And you can add an equalizer, etc.

I would recommend you make some jumpers out of ordinary copper wire rather than stainless steel, or get the connectors which Larry suggests.

My caution about using stainless steel is because I think it might create a corrosion problem. A connection of dissimilar metals can set up a little electrolydic (sp) cell. I don't know if that is the case here but it is something to think about. I've never seen electrical connections made of stainless steel, at all. Something is up with this. and I think it is not just resistance.

Also, it is my understanding that there are many compositions of what we know as stainless steel. Some have very high amounts of chromium, and others not. My copy of Mark's Handbook of Mechanical Engineering is at the office, but such is what I recall. In my experience, some stainless will attract a magnet, others not at all. This is just a demonstration of the different compositions.

Gil

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