how to attenuate aleph p 1.7

[elviukai]

hi, I am using kristijans board, and I have laying arround few dact 10kohm atenuators, how ever it way too high for p 1.7. at 10kohm sound is very loud. it should be 1-2kohm I think

what parts I should change do use this 10kohm dact in p 1.7?

thanks in advance

 

[Nisbeth]

You can use a 10k attenuator on the input instead.


/U.

 

[wuffwaff]

Hi,

are you shure you connected it the right way? The only difference between a 2k and a 10k pot is the output and input impedance. The attenuation should be the same.

William

 

[elviukai]

hi wuffwaff if I use on input I will need balanced atenuator(double price)

I am using in in the same place as in kristijan schematic. just instead 2kohm I use 10kohm. the sound is very loud with 10kohm even in mimimum position(10kohm)

 

[apassgear]

1K where the pot is runs fine according to NP

 

[barryblue]

Too loud

Hi,

If you have the DACT connected as the 2K potentiometer in your schematic you effectively do are not attenuating the signal. The 2K potentiometer sets the Master gain for one channel as per the original P1.7. You do not require a DACT for this just s simple multiturn pot.

You need to move the DACT to the input or output (preferably) to reduce the volume......

Hope this helps!

 

[elviukai]

 

[elviukai]

I found thread
http://www.diyaudio.com/forums/showthread.php?s=&threadid=67926&goto=nextoldest

where Mr. Nelson said that there is possible to use 1kohm single pot to adjust volume.(place a single potentiometer between the Source
pins of the Mosfets, where a good value is about 1 Kohm.)


anybody tried that?

 

[harryeng]

Hi Elviukai,

I tried, and gave up.... I have the same PCB as you have, but wanted to use large capacitors meaning I had all sort of problems with space.

You can use the 2K potmeter to play with the gain, but normally you also need to attentuate so that would be a no-go.
I had a pot I tried to put in front, but as my CD player had no bufferstage (don't ask) that ended into very strange effects.

I ended up using a 2K resistor bank on the output, using a board by Mikkel.

Now I have a great sounding P1.7!



Greetings, Harry.

 

[Johnwkkwan]

Hi Harry,

Your preamp lokk very nice.

Notice you have a display on front panel and relay volumn control.

Is it remote control ?

I like to have one like this for my BZLS.


Do you mind post a link where to buy this one, how much is this ?

Thanks !

John

 

[analog_sa]

The pot at the input may produce too much noise in case of high sensitivity speakers or power amp.

Between the sources didn't work for me well.

After a lot of trials a 600ohm 34-position Daven stepped attenuator (with 100uF output cap) at output sounds best so far.

 

[Nisbeth]

Hi Harry,

Your preamp lokk very nice.

Notice you have a display on front panel and relay volumn control.

Is it remote control ?

I like to have one like this for my BZLS.


Do you mind post a link where to buy this one, how much is this ?

Thanks !

John

Not sure, but it looks like it's from here: electronics.dantimax.dk


/U.

 

[harryeng]

Correct!

I got the complete set from Dantimax.com

I made some small changes, but these were just to be able to start/stop my power amps, CD player etc. with voltage outputs from my pre-amp.

I also made a new input board for the buttons. This was a partial copy from Mikkels design which I changed just to solve some mechanical problems.

Greetings, Harry.

 

[Johnwkkwan]

Hi both,

Thanks for your advice.

Shall check with dantimax.


Harry,

By the way, could you describe sound from P 1.7 you made.

Is it clean, sweet, transparent, good seperation and with wide sound stage and also a good dynamic range ?

As I heard from most diyer.

Besides, any hum problem ?

Thanks !

John