crossfader design

hi

i was looking on the net to find a simple crossfader (dry/wet) stereo circuit and i came up with this.

since i am total noob and copying other peoples designs, can someone tell me is this going to work and if it will,
witch one is better, version 1 or 2

Version 1 has unbuffered inputs, effectively short-circuiting the source.

Depends on what the source is if that'll work. Might even damage the source circuit.

I don't think either one of those are really elegant design.

Ok, version 2 is better, 

I am not looking for audiophile crossfader just something that will work wihout frying something on the other end.

cyrano said:

Version 1 has unbuffered inputs, effectively short-circuiting the source.

Depends on what the source is if that'll work. Might even damage the source circuit.

Click to expand...

A 15k load is a short circuit?? 

kike said:

hi

i was looking on the net to find a simple crossfader (dry/wet) stereo circuit and i came up with this.

since i am total noob and copying other peoples designs, can someone tell me is this going to work and if it will,
witch one is better, version 1 or 2

Click to expand...

Is this for a DJ mixer application? I recall when I managed a mixer design group and we had a couple DJ mixers in our stable. There is more than one popular DJ mixer crossfade law...  As I recall, but this was decades ago. One crossfade would bring up and overlap both inputs at roughly full volume until muting one or the other at full extremes of travel. Another law was more like fading one up while bringing the other down at same time (more like pan controls).

JR

It is for a dj mixer but for cue mix.

This mixer doesnt have the option to mix between cue and master

kike said:

It is for a dj mixer but for cue mix.

This mixer doesnt have the option to mix between cue and master

Click to expand...

This is going way back so let me scrape off some cobwebs.  ;D

Back in 1978 I published a kit DJ mixer. I designed in an automatic cue circuit that first summed the two sources together, then subtracted the active output from the sum. What remains in the cue output is the unselected input audio.  8)

I had several customers back in the 70s that bought these kits as a cheap way to get a club system up and running, then decided to keep using them. I used rotary mix controls coincidentally and not as a nod to the Bozak 10-2DL.

Also coincidentally I did some consulting work for Rudy Bozak back around then (designed a consumer delay product). 

JR

Walrus said:

A 15k load is a short circuit?? 

Click to expand...

You're right, of course, missed that resistor. Sorry.

i want to be able to blend between cue signal that i selected and master signal,
I will try with the version 2 and see what will happen.

Just want to sum up for OP the discussion in the thread:

Version 1 has minimum 15 kOhm input resistance, version 2 has 10 kOhm input resistance. The talk about short circuiting the source was a mistake.


I can't see any upside to version 2 personally, but I may be missing something.

Also wanna add that I would use coupling capacitors to avoid DC on the pot, which would cause rumble and scratch. These would go in series with the resistors in the input arm of the cross-fade circuit.

In the same vein it may be nice to use FET input opamps after the cross-fade to avoid input bias current in the pot for the same reasons. You can then use 5532 to drive the output.
Best of luck!

Thank you so much for the advice, I will change it