[sdiy] REDUCING pt2399 delay noise??

[Tom Wiltshire]

Hi Dan,

The datasheet for the PT2399 offers a maximum delay of 342mS with a  
27.6K resistance, so it may be that you're just trying to push the  
chip too far. It is sampling the signal, so the usual rules of "no  
frequency components above the nyquist frequency" apply. It's not at  
all clear how the internal sampling rate is related to the clock  
frequency though. Unhelpfully.

On a more positive note, you could have a look at Scott Schwartz'  
PT-80 delay, which uses a SA571 for noise reduction. He did this  
originally becuase he was wanting an accurate modern clone of the  
Ibanez AD80, but it was in that device as a compander for noise  
reduction.

http://www.generalguitargadgets.com/index.php? 
option=com_content&task=view&id=125&Itemid=26

HTH,
Tom


On 16 Jan 2009, at 15:15, Dan Snazelle wrote:

>
>
> Building another pt2399 delay (with cv control) and i am using  
> pretty much stock values from the
>  REBOTE 2 delay
>  (though i have looked at the echobase and the bernardi delay also)
>
> my question is this:
>
> at LONG delay times ( longest with say a 50k or even 100k pot) i  
> start hearing bubbling noises, static, and what almost sounds like  
> oscillations.
>
> is there a way to reduce this? heaver input or output filtering?  
> more bypassing?
> supply voltages?
>
> i don't need  the delay to be TOO long but these sounds start to  
> happen at around 80% on the 50k pot.
>
> thanks
>
>
>
>
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