Gainclone help plz!!

TedPolzin · 11th April 2003, 05:01 AM

Hi I am having some problems with my attempt to build gainclones. I have sucessfully built 4 clones. I am also having trouble with others. I get full voltage on the output. This has happend with 5 chips. I an getting frustrated since they may be cheap but not that cheap. I have looked at the chips and have no idea why this happens. The bad ones are identical to the good ones. I take my time and it still does it.

Please do you have any ideas??

thanks

Ted

RAYSIMMONS · 11th April 2003, 05:51 AM

can you post a schematic or a photo of your wiring?

Cradle22 · 11th April 2003, 06:53 AM

Hi!

I had the same prob on my first attempt because I was using a LM3876 instead of a LM3875, but wired it exactly the same way like a LM3875, so I also got full voltage at my (supposed) output pin... but the pins are all aligned in another way than with the LM3875.

Don't use the "standard" schematics with anything else than a LM3875. You will have to adapt the schematics ton anything else.

Bye,

Arndt

Olle Bard · 11th April 2003, 01:21 PM

how about the lm3886. does it have the same pinout as the LM3875?

if it doesn´t ive got some unsoldering to do

UrSv · 11th April 2003, 01:31 PM

Quote:

Originally posted by Olle Bard
how about the lm3886. does it have the same pinout as the LM3875?

if it doesn´t ive got some unsoldering to do

So you didn't check the datasheet before building it...

Olle Bard · 11th April 2003, 01:35 PM

you can timagine how silly i feel when im saying this: no

i thought national had some standard they used on all their cihps(would be quite good).

which pins should i connect to?
the +, -, gnd, mute(to gnd via resistor), in+, in- and the output?

UrSv · 11th April 2003, 02:44 PM

Quote:

Originally posted by Olle Bard
you can timagine how silly i feel when im saying this: no

i thought national had some standard they used on all their cihps(would be quite good).

which pins should i connect to?
the +, -, gnd, mute(to gnd via resistor), in+, in- and the output?

The answer is in the scriptures:

http://www.national.com/ds.cgi/LM/LM388.pdf

TedPolzin · 11th April 2003, 02:50 PM

Quote:

Originally posted by RAYSIMMONS
can you post a schematic or a photo of your wiring?

I can post a pic when the digital camera gets back from Germany tomorrow. It is a 3875 using Peter Danials schematic

Thanks

Ted

UrSv · 11th April 2003, 03:11 PM

Quote:

Originally posted by TedPolzin

I can post a pic when the digital camera gets back from Germany tomorrow. It is a 3875 using Peter Danials schematic

Thanks

Ted

So that means that oscillations might very well be the reason for the sound...

Olle Bard · 11th April 2003, 04:42 PM

does anyone have a product sheet for the lm3875?

11th April 2003, 05:01 AM	#1
TedPolzin diyAudio Member Join Date: Oct 2002 Location: Drayton Valley, AB	Gainclone help plz!! Hi I am having some problems with my attempt to build gainclones. I have sucessfully built 4 clones. I am also having trouble with others. I get full voltage on the output. This has happend with 5 chips. I an getting frustrated since they may be cheap but not that cheap. I have looked at the chips and have no idea why this happens. The bad ones are identical to the good ones. I take my time and it still does it. Please do you have any ideas?? thanks Ted

11th April 2003, 06:53 AM	#3
Cradle22 diyAudio Member Join Date: Jan 2003 Location: Dortmund, Germany	Hi! I had the same prob on my first attempt because I was using a LM3876 instead of a LM3875, but wired it exactly the same way like a LM3875, so I also got full voltage at my (supposed) output pin... but the pins are all aligned in another way than with the LM3875. Don't use the "standard" schematics with anything else than a LM3875. You will have to adapt the schematics ton anything else. Bye, Arndt __________________ ************************ A Sacrifice For Freedom

11th April 2003, 01:21 PM	#4
Olle Bard diyAudio Member Join Date: Mar 2003 Location: Stockholm	how about the lm3886. does it have the same pinout as the LM3875? if it doesn´t ive got some unsoldering to do __________________ I like turning knobs clockwise

11th April 2003, 01:35 PM	#6
Olle Bard diyAudio Member Join Date: Mar 2003 Location: Stockholm	you can timagine how silly i feel when im saying this: no i thought national had some standard they used on all their cihps(would be quite good). which pins should i connect to? the +, -, gnd, mute(to gnd via resistor), in+, in- and the output? __________________ I like turning knobs clockwise

11th April 2003, 04:42 PM	#10
Olle Bard diyAudio Member Join Date: Mar 2003 Location: Stockholm	does anyone have a product sheet for the lm3875? __________________ I like turning knobs clockwise


	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

11th April 2003, 05:51 AM	#2
RAYSIMMONS diyAudio Member Join Date: Feb 2002 Location: CLEVELAND OHIO	can you post a schematic or a photo of your wiring?

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
Freebird + Gainclone = "integrated" gainclone?	bikehorn	Chip Amps	9	5th January 2006 03:07 PM
JLH v Gainclone?	Jezz-the-Fezz	Solid State	5	12th December 2005 12:08 PM
Big gainclone	steven344	Chip Amps	10	23rd November 2005 07:58 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