PDA

View Full Version : Preamp out-led on a Marantz 2252B, how to ?



Viking
01-26-2009, 12:05 AM
Hi,

Recently baught a turntable. Im looking in to connecting a KAB subsonic rumbel filter, however this has to be connected after the preamp.

On the backplate on the Marantz 2252B there are four phono plugs for preamp out and amp inn, they are not connected - I red that they are connected internally.

How to intercept ? Is there an internal physical switch, or will the unit itself switch when external equipment is connected/intercepted ?

This preamp out, is it only for the phono inputs, or also fed from the radio, the aux etc ?

SMKSoundPro
01-26-2009, 12:16 AM
Dear Viking,

I am not familiar with that exact model number, and can only offer that generally, there would be a jumper from the preamp output to the power amp input. Sometimes it is a piece of U shape metal that inserts into the center "tip" of the RCA jack.

If this is the case, then the Marantz pre out goes into the rumble filter input. The rumble filter output goes to the power amp input.

See link: http://images.google.com/imgres?imgurl=http://www.classic-audio.com/marantz/pics/2252b_br.jpg&imgrefurl=http://www.classic-audio.com/marantz/2252b.html&usg=__hSmOQgEbBDEoq7DMlcwk7nupUaE=&h=301&w=852&sz=74&hl=en&start=8&um=1&tbnid=xvvQOA8tqjOy3M:&tbnh=51&tbnw=145&prev=/images%3Fq%3Dmarantz%2B2252b%26um%3D1%26hl%3Den%26 safe%3Doff%26sa%3DN

I see the pre out power in rca's, but no external jumpers. Maybe it is some kind of automatic switching as soon as you plug an rca into these jacks, it senses a broken internal signal path.



Good Luck!
Scotty.

Viking
01-26-2009, 12:40 AM
There are no external jumpers, its connected internally. Service manual diagrams shows the internal switch, but not how it works.

Most probably, as you suggest, its a mechanical functionality, disconnecting when plugging in ? I will try your suggestion. Thanks.

Hofmannhp
01-26-2009, 03:58 AM
There are no external jumpers, its connected internally. Service manual diagrams shows the internal switch, but not how it works.

Most probably, as you suggest, its a mechanical functionality, disconnecting when plugging in ? I will try your suggestion. Thanks.

Hi Viking,

last week I made some restoration work on two Marantz Receivers. One was the 2325 and the other a 2275.
They work similar to the 2252 with their pre-out and main in connectors.
These connectors are switched automaticaly.....when no cable is plugged in, the pre out and main in are connected. When you plug in a cable with a RCA plug, the connection is switched off.
In cause of frequently existing contact problems with this "switching" jacks, I prefer to change them to non switching jacks and plug a bridge from outside the cabinet.

HP