Message	Date	From	Subject
957	2007-08-16 10:15:47	Sam Morgan	'corrected' LTSpice and ELR audio amp circuit help needed.
forgive the repeat, had a bad link in there to my ltspice .asc file I am trying to analyze a circuit in LTSpice. Sad part is I have no clue what I'm doing. The circuit is the audio amp used in the electroluminescent receiver. Circuit can be found here: http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm <http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm> I am focusing on area from the input at C95 to the output of C98. I wanted to get a visual of the circuit with the 2.2Uf cap at C99 and then play with the value of C99 and see the results. I spoke with WN5Y and he said to replaced the 2.2Uf with a 10uf and it did increase the gain, I did, but it was to large an signal increase. Now my speaker distorts when volume is over 10-15%. So I thought I might could learn Spice using this simple 1 transistor circuit, and be able to find a value I needed for C99. Here you can find my attempt on doing this: http://pages.suddenlink.net/ka5oai/ltspice/elr-audioamp.asc <http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm> I just guessed that the output resistor would be mid range between the 70k and 150k input listed in the TDA2003 specs. http://home.eunet.cz/rysanek/pdf/tda2003.pdf <http://home.eunet.cz/rysanek/pdf/tda2003.pdf> Any and all help would be appreciated. Maybe even a meeting on echolink later this evening? -- GB & 73's KA5OAI Sam Morgan -- GB & 73's KA5OAI Sam Morgan
962	2007-08-16 11:39:55	Sam Morgan	Re: 'corrected' LTSpice and ELR audio amp circuit help needed.
Nick Kennedy wrote: > Sam, I tried your circuit and made a few changes. Got a decent > frequency response and transient response output. Also, my earlier > statement that your circuit ends up "hi pass" was wrong -- it's > "lowpass" instead. > > Notes are included in the file. > thanks again Nick, that will help lots with my learning. along with reading your tutorial: http://pages.suddenlink.net/wa5bdu/ reading in the elr pages I saw that the circuit: http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm was based on: http://www.rason.org/Projects/bipolamp/bipolamp.htm -- GB & 73's KA5OAI Sam Morgan

forgive the repeat, had a bad link in there to my ltspice .asc file

I am trying to analyze a circuit in LTSpice.
Sad part is I have no clue what I'm doing.
The circuit is the audio amp used in the electroluminescent receiver.
Circuit can be found here:

http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm
<http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm>

I am focusing on area from the input at C95 to the output of C98.
I wanted to get a visual of the circuit with the 2.2Uf cap at C99
and then play with the value of C99 and see the results.

I spoke with WN5Y and he said to replaced the 2.2Uf with a 10uf and it did
increase the gain, I did, but it was to large an signal increase.
Now my speaker distorts when volume is over 10-15%.
So I thought I might could learn Spice using this simple 1 transistor
circuit,
and be able to find a value I needed for C99.

Here you can find my attempt on doing this:
http://pages.suddenlink.net/ka5oai/ltspice/elr-audioamp.asc
<http://www.pan-tex.net/usr/r/receivers/elraudioamps.htm>

I just guessed that the output resistor would be mid range
between the 70k and 150k input listed in the TDA2003 specs.
http://home.eunet.cz/rysanek/pdf/tda2003.pdf
<http://home.eunet.cz/rysanek/pdf/tda2003.pdf>

Any and all help would be appreciated.
Maybe even a meeting on echolink later this evening?
--
GB & 73's
KA5OAI
Sam Morgan

--
GB & 73's
KA5OAI
Sam Morgan