Switch in C-2301

[Pilsern]

Hi,

I am looking at the schematics and inside pictures of the Sansui C-2301 preamp and I notice that on the Riaa-eq printcard (4471) there is a switch (sw1)

Anyone here tried different settings on it or know what it does ?

Switch is visible on the right side here;
http://amp8.com/sansui/etc/jpeg2/c2301-325.jpg


Thanks,

 

[scottrt]

I restored an un-molested original unit last month. All the SM says is the switch is for RIAA DC zero volts adjust. No mention of where to measure those figures on the RIAA board. The two main output boards each have their own pair of 4.7K trimpots for setting DC zero (measure at the balanced output rear connector...one is for + pin to ground pin, one is for - pin to ground pin)... top board is left channel, bottom board is right channel.

To actually answer your question, one my unit only toggle 3 was in the closed position, so that's how i left it. Looks like all of yours all in the closed position, indication that all of those resistors nearby are 'in use' for DC zero purposes.

These preamps are simply stunning sounding with the quietest background and smoothest sound yet incredibly detailed and easy sounding. Makes you wanna listen all day....

The fellow that owns it has been looking for years for the matching amp. Still looking....

Let me know if you need any help on modern transistor substitutions. I replaced every transistor and spent alot of time in the archives and downloading Data Sheets to be sure the replacements were considered appropriate and an improvement if anything.

Here is a link to my restoration pics. That Sansui Glue was just terrible in this preamp. Worst case of it I have ever seen.

http://s694.photobucket.com/albums/vv306/scottrt/Sansui C-2301 restoration/
Scott T.

P.s.: I also had to replace the two bulbs that illuminate the volume numbering, AND the AUX lamp on the input selector switch... probably because these lamps had so many hours on them...probably as many as the amp itself has had the power turned on.

 

[Pilsern]

I restored an un-molested original unit last month. All the SM says is the switch is for RIAA DC zero volts adjust. No mention of where to measure those figures on the RIAA board. The two main output boards each have their own pair of 4.7K trimpots for setting DC zero (measure at the balanced output rear connector...one is for + pin to ground pin, one is for - pin to ground pin)... top board is left channel, bottom board is right channel.

To actually answer your question, one my unit only toggle 3 was in the closed position, so that's how i left it. Looks like all of yours all in the closed position, indication that all of those resistors nearby are 'in use' for DC zero purposes.

These preamps are simply stunning sounding with the quietest background and smoothest sound yet incredibly detailed and easy sounding. Makes you wanna listen all day....

The fellow that owns it has been looking for years for the matching amp. Still looking....

Let me know if you need any help on modern transistor substitutions. I replaced every transistor and spent alot of time in the archives and downloading Data Sheets to be sure the replacements were considered appropriate and an improvement if anything.

Scott T.

Hi Scott & thank you for your feedback,
The picture in the link are not of mine amp, just to show what I meant.

You are right these units are amazing both in looks and sound.
Interesting that you have restored a unit, I read your member profile and will e-mail you if that is ok.

Thanks again,

 

[Pilsern]

Scottrt,

I must thank you for you information regarding the C2301 preamp - As you stated it needed a thorough cleaning of switches and pots - After that all "issues" with the amp is gone

Thanks alot!!

 

[DCinDC]

The matching 2301 amp was on ebay last month for 1500 with no takers. If you step down to the 2102 or 2101, then can be had for 250 to 500.