3D imaging pre-amp

[aragorn723]

Hi Bonzo,

Have you put a lot of time on the components?  To me that sounds like they aren't burned in yet (I had a similar experience with the Quickie before burn-in).

Dave

 

[jake111]

Thanks, Bonzo
I think I'll build one.
Jess

 

[Bonzo]

Have you put a lot of time on the components?  To me that sounds like they aren't burned in yet (I had a similar experience with the Quickie before burn-in).

Not at all aragorn...maybe is too early to judge...

I'll give it a burn-in period connected to my tv, thank you for the suggestion!

 

[aragorn723]

Please let us know your thoughts when it's burned in!

Dave

 

[Bonzo]

ATM it's still hooked to my bedroom tv setup.
Speakers are close to each other (no stereo image needed), but this preamp in some way made the sound more "open", it seems it's acting like this software: http://www.ambiophonics.org/index.html

 

[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...  ;D ;D ;D

 

[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