3D imaging pre-amp

[aragorn723]

Bonzo,

Do you notice a difference by putting the speakers further apart?  Sounds like this gizmo is pretty handy for less than optimal setups.

Dave

[Bonzo]

No, I didn't!
This is a bedroom setup, I cannot change speaker setup due to small space 

But this circuit is really surprising! Bass seems to have increased a bit after 20 hours of use.

Ciao!

[aragorn723]

cool!  Looking for some Russian caps now, gonna build one of these babies to play with

Dave

[aragorn723]

Hi,

Would it be possible to switch the output on this 3d preamp box?  One side of the switch would be for rca outputs, and the other would be to a 1/4" headphone output (this would allow you plug an ipod's output to the 3d preamp input, then connect headphones to its output).  Thanks,

Dave

[Karl5150]

So I built one following the drawings and the shopping list. (The shopping list has 240k and the drawings show 249k) I notice 2 things on first play:
 1- while it doesn't give the illusion that the music is coming from somewhere out in front of me, it definitely gives a fuller depth presentation to the music playing in my head.
 2- the potentiometer works backwards, what would normally be all the way down gives the most effect, turning it "up" lessens the effect.
I checked several times and my build wiring matches the drawings and photos.
Similar/different experiences?
Thanks for any input.
Karl

[Bonzo]

So I built one following the drawings and the shopping list. (The shopping list has 240k and the drawings show 249k) I notice 2 things on first play:
 1- while it doesn't give the illusion that the music is coming from somewhere out in front of me, it definitely gives a fuller depth presentation to the music playing in my head.
 2- the potentiometer works backwards, what would normally be all the way down gives the most effect, turning it "up" lessens the effect.
I checked several times and my build wiring matches the drawings and photos.
Similar/different experiences?
Thanks for any input.
Karl

Karl, it mirrors my experience exactly.
My first thought were the sound was slightly "above" the center of my head...

I forgot: the pot works backwards too!

[aragorn723]

Is there any way to make the pot go the right way?

Dave

[2wo]

I would need to check the schematic to be sure, but I would think that you could reveres the 2 end connections at the pot...John   

[Bonzo]

Is there any way to make the pot go the right way?

Dave

For me it's not a real problem: it's a bit counterintuitive, I admit, but it's not "plain wrong"...we're dealing with an "effect", not with a volume control 
Ciao!

[Karl5150]

This does have quite an insertion loss. Using my SEX 2.1 at work to burn it in, it is taking a significant twist of the volume pots to get it up to normal listening levels. On the plus side, I notice the "fuller" effect it has on the sound, albeit with a little loss of the laser sharp imaging the system usually has.

Karl

[Bonzo]

This does have quite an insertion loss. Using my SEX 2.1 at work to burn it in, it is taking a significant twist of the volume pots to get it up to normal listening levels. On the plus side, I notice the "fuller" effect it has on the sound, albeit with a little loss of the laser sharp imaging the system usually has.

Karl

You'd better buy a quickie... 

[aragorn723]

Funny, I have the reverse problem, way too much gain (with a solid state amp)  The Quickie is pretty nice though, it beats the NAD and Cary ones I used to have (with pjccs).

Dave

[aragorn723]

Got a newbee question on the parts list from the first page.  The part number listed for the switch doesn't look like the right one ( i pulled it up on parts express and a SPST switch came up).  Can someone help me find the right one?  Searching by DPST at PE gives me a switch with spade connectors, or one with screw connectors (I would prefer solder tab).  Thanks in advance!

Dave

[aragorn723]

Has anyone tried to bypass this pre-amp?  I built one and it is definitely nice.  Like others, i definitely agree that it has a LOT of insertion loss.  There is an on/off switch for the circuit which turns off the 3d part, but the insertion loss is still there regardless of switch position.  Is there a way to add a bypass/defeat switch into the circuit that would eliminate the effect of the insertion loss?  Sometimes I just want more volume, and would definitely be a fun toy to play with! (and nice not to have to disconnect everything to do that).

Dave