Active Baxandall causes noise

Shatronics · 12th June 2011, 11:57 PM

Hello DIY'ers.

I've made a preamp for my amplifiers. It has volume, gain and tone control.
Everything works excellent except I have trouble with the tone control. It's based on an active Baxandall tone control. When I haven't connected the pots it doesn't make any noise at all, but as soon as they are connected the distortion gets very high.

Here is the reference: Audio Designs With Opamps -2

I use TL072 as opamp. The values are:

10 K pot (only value I could get with dual slide pot)

2K resistors across the bass.
2K7 resistors acroos the treble.
0.47µF capacitor at bass.
4.7nF capacitor at treble.

Any ideas of what might cause the trouble? I have to use 10K pots, because I have some nice dual slide pots.

Regards,

Simon H.A.

Shatronics · 13th June 2011, 12:55 AM

Found the problem. Short between the outputs (It's stereo).

Regards,

Simon H.A.

Nelson Pass · 13th June 2011, 01:01 AM

It's always something.

12th June 2011, 11:57 PM	#1
Shatronics diyAudio Member Join Date: May 2011 Location: Gentofte	Active Baxandall causes noise Hello DIY'ers. I've made a preamp for my amplifiers. It has volume, gain and tone control. Everything works excellent except I have trouble with the tone control. It's based on an active Baxandall tone control. When I haven't connected the pots it doesn't make any noise at all, but as soon as they are connected the distortion gets very high. Here is the reference: Audio Designs With Opamps -2 I use TL072 as opamp. The values are: 10 K pot (only value I could get with dual slide pot) 2K resistors across the bass. 2K7 resistors acroos the treble. 0.47µF capacitor at bass. 4.7nF capacitor at treble. Any ideas of what might cause the trouble? I have to use 10K pots, because I have some nice dual slide pots. Regards, Simon H.A.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Baxandall active tone control	jenks	Solid State	3	18th April 2008 09:18 PM
Active noise cancellation for a computer?	MikeHunt79	Everything Else	0	3rd April 2008 10:54 PM
Active Noise Cancellation	gcladis	Pass Labs	4	27th June 2006 11:36 PM
active crossover + noise	Calebay	Solid State	5	20th April 2005 04:20 PM
Active Noise Cancellation	manse	Everything Else	7	31st March 2003 04:57 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

13th June 2011, 12:55 AM	#2
Shatronics diyAudio Member Join Date: May 2011 Location: Gentofte	Found the problem. Short between the outputs (It's stereo). Regards, Simon H.A.

13th June 2011, 01:01 AM	#3
Nelson Pass The one and only Join Date: Mar 2001	It's always something.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)