Wilfred,
 
Does it include the 20K mixing resistors? Just shorting the two outputs together would not be a good idea.
 
Loch

No it doesn't, but I'm pretty sure it will work. I've used a mono guitar cable before on which one of the jacks was replaced with a stereo jack, and it worked fine. But I'll let you know as soon as it's here and I've tried it!
 
Wilfred

Update: the 6,3 mm mono female > 6,3 mm stereo male jack works like a charm! The biggest difference is that you have to use batteries. My Series I has the the pickup selector permanently on both (it's removed from the lower horn and hidden in the body cavity) so for pup-selection I'm already used to use the volume controls. I've found that if I want to use one pickup only , I have to add a tiny bit of volume for the other. I'm not technical at all, but there seems to be some kind of threshold. All in all a very easy and great solution!
 
Wilfred

You're hearing what's expected if you don't have the mixing resistors. When you turn the volume of one pickup down, you're shorting it, and the over all sound has this in it too. With the mixing resistors, you can turn one pickup completely off with the volume control.  
 
You can add the resistors inside the connector you purchased if there is room. We usually use 1/4 watt but you can use 1/8 watt if the space is really tight inside.

 
Well, it's this one, no room inside I'm afraid. It works for me, as a plan B option so to speak, or to use at low volume in the living room with the little practise amp I've got hidden behind the couch... ;-)
 
Wilfred

Wilfred,
 
If you're very careful, there is room inside that jack to wire in the resistors. You will need to use 1/8 watt or smaller resistors instead of the usual larger 1/4 watt ones.
 
Loch
 
(Message edited by lmiwa on April 16, 2010)