Passive Preamp

[Bgt]

just ordered some here:
http://www.diyfidelity.com.au/product_info.php?cPath=0_33&products_id=32

Whats the price?

 

[Bgt]

just tried them, cannot get the full output voltage How come? input is 10k, output is max 7,2k so there is a loss at putting !v in and getting 0.72V out. Anyone? See this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=42703&pagenumber=4

 

[philipbarrett]

So here's mine - sort of a badly needed panic volume control between my DAW and monitors. Parts are RS 100K stereo pot, 2 14.75K resistors (closest I had), 2 RS Mini-Jack connectors and courtesy of Hobby Lobby, a 50 cent box & a 99 cent knob. No silver wiring so I don't think I broke $10 on this project.

 

[philipbarrett]

...and the guts

 

[Bgt]

just tried them, cannot get the full output voltage How come? input is 10k, output is max 7,2k so there is a loss at putting !v in and getting 0.72V out. Anyone? See this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=42703&pagenumber=4

23 steps instead of 24. But how to calculate a 10k 23 step att.?

 

[Bgt]

just tried them, cannot get the full output voltage How come? input is 10k, output is max 7,2k so there is a loss at putting !v in and getting 0.72V out. Anyone? See this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=42703&pagenumber=4

23 steps instead of 24. But how to calculate a 10k 23 step att.?

 

[Bgt]

still puzzled how to make it 23 steps

 

[detex]

Quick question

I just built this setup using the 100K audio taper Alphas from Radio Shack with 22K resistors running in parallel. everything works great but I am not getting much in the way of volume... There is no sounds through he amp up until around 3/4 turn of the pot... Any ideas?

thanks.

D

 

[Nordic]

Wrong impendance (too high, I think) to match the next stage....

 

[detex]

Will try it with the 10K pots and see how it goes.

Ok, off to the shack. Thanks.

 

[justpoor]

Can someone please post or email me a close up picture of the radshack passive preamp. I want to build one but can't read schematics. Some close up pictures would really help. Thanks.

 

[Mindcrime]

I'm in the same boat Justpoor, I really like the one FBJ did!! I would love some more details about it

 

[justpoor]

No one is willing to share,,,, hic hic hic

 

[spacemen12]

Hi,
I talk to someone about my passive preamp and he starts talking about phase difference between frequency. I don't really understand. Is this a real problem or iit is just some electric concern?

I built my passive preamp based on this schema:
http://www.diyaudio.com/forums/showthread.php?postid=20694#post20694

The preamp sit between monica (from diyparadise) (without the gain stage) and a gainclone

Thanks

 

[gunonme2]

what about this way

any good?

 

[Speedskater]

Almost 5 years later, a thread returns to the top of the list.

 

[kriss777]

passive pre

hi

just built a passive pre haller design using 100k alps pot sounding very good, i would now like to introduce a 6 way 2 pole rotary switch could anyone give me a step by step guide on how to do this
thanks

 

[mikesp1]

Output impedance of my source is 75ohm, input impedance of my power amps is 100K. What Alps pot, 10K, 50K, 100K and wich resistor should i use? Thanks a lot!

 

[mikesp1]

Output impedance of my source is 75ohm, input impedance of my power amps is 100K. What Alps pot, 10K, 50K, 100K and wich resistor should i use? Thanks a lot!

Today i tried a 10k log alps with 10k resistor (shunt mode) sound is realy nice but almost no bass🙁

Next experiment was a 10k linear alps in normal mode, no series resistor, know i have realy nice bass.

I am confused now what i should do. Come on guys lead me in the right direction.

 

[DF96]

What is the value of the output coupling capacitor in your source? How low do you want your bass to go?