Simple Symetrical Amplifier - Page 390

PauloPT · 09:07 PM

I was reading some old - and other not so old - threads about servos and I'm having second thoughts. Seems to be the servos always add something to the audio signal. The question is - is it audible? I don't have the experience to know this. I fell in love with the SSA and I don't want anything to spoil it's beautifull sound! But again, my speaker protection circuit is only trigered if the amp outputs more than 0.7V of dc. Perhaps not today or tomorrow or next week but what if in a few months the output goes 0.5V dc? There goes woofers... So, to servo or not to servo?

PauloPT · 3rd February 2013, 09:04 PM

Quote:

Originally Posted by Esperado

can-you bring me a link to the schematic ?

I'm afraid I can't... The schematics weren't published only the pcb layout here:
Simple Symetrical Amplifier

Esperado · 3rd February 2013, 09:40 PM

Quote:

Originally Posted by PauloPT

I'm afraid I can't... The schematics weren't published only the pcb layout here:
Simple Symetrical Amplifier

Ok, just to change the implantation for single OPA.
Don't worry about signal degradation, just audiophile stupidity, it works outside from the audio bandwitch. Just use film cap and good OPA. You take no risk, as you can remove-it any time.

If you use double OPA, please use this schematic.
Simple Symetrical Amplifier

If you'll use a single OPA, i can try to modify the layout for it.

PauloPT · 3rd February 2013, 09:48 PM

Quote:

Ok, just to change the implantation for single OPA.
Don't worry about signal degradation, just audiophile stupidity, it works outside from the audio bandwitch. Just use film cap and good OPA. You take no risk, as you can remove-it any time.

Great!

Thanks!

Quote:

If you'll use a single OPA, i can try to modify the layout for it.

That would be great too!

I have some single opamps opa132 and opa267 in my parts bin

Thank you

Esperado · 02:43 AM

here it is:

PauloPT · 4th February 2013, 08:37 AM

Many thanks, Esperado!

One more thing: Should I parallel small capacitors with the amp feedback resistors and use decoupling caps at the opamp pins? I'll be using OPA132.

Thanks.

PauloPT · 4th February 2013, 09:52 AM

Hi shaan,

The pcb layout says rails are 45V. I have two transformers with me, one gives me 35V dc rails after rectification and the other 50V dc. Can I use any of these?

Thank you.

Jay · 4th February 2013, 11:55 AM

Better sound with lower voltage.

sofianirawan · 4th February 2013, 01:07 PM

that true mr jay..I have transformers toroid 18v 0v18v to build amplifier SSA by shaan and lazy cat..and sound quality is very good

PauloPT · 5th February 2013, 09:34 AM

I'm just asking because I see +-45V on the pcb. So +-35V would be OK?

3rd February 2013, 09:01 PM	#3891
PauloPT diyAudio Member Join Date: Jan 2010 Location: Lisboa, Portugal	To servo or not to servo? I was reading some old - and other not so old - threads about servos and I'm having second thoughts. Seems to be the servos always add something to the audio signal. The question is - is it audible? I don't have the experience to know this. I fell in love with the SSA and I don't want anything to spoil it's beautifull sound! But again, my speaker protection circuit is only trigered if the amp outputs more than 0.7V of dc. Perhaps not today or tomorrow or next week but what if in a few months the output goes 0.5V dc? There goes woofers... So, to servo or not to servo? __________________ Kind Regards, Paulo. Last edited by PauloPT; 3rd February 2013 at 09:07 PM.

4th February 2013, 08:37 AM	#3896
PauloPT diyAudio Member Join Date: Jan 2010 Location: Lisboa, Portugal	Many thanks, Esperado! One more thing: Should I parallel small capacitors with the amp feedback resistors and use decoupling caps at the opamp pins? I'll be using OPA132. Thanks. __________________ Kind Regards, Paulo.

4th February 2013, 09:52 AM	#3897
PauloPT diyAudio Member Join Date: Jan 2010 Location: Lisboa, Portugal	transformer question Hi shaan, The pcb layout says rails are 45V. I have two transformers with me, one gives me 35V dc rails after rectification and the other 50V dc. Can I use any of these? Thank you. __________________ Kind Regards, Paulo.

5th February 2013, 09:34 AM	#3900
PauloPT diyAudio Member Join Date: Jan 2010 Location: Lisboa, Portugal	I'm just asking because I see +-45V on the pcb. So +-35V would be OK? __________________ Kind Regards, Paulo.

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4th February 2013, 11:55 AM	#3898
Jay diyAudio Member Join Date: Feb 2003 Location: Jakarta	Better sound with lower voltage.

4th February 2013, 01:07 PM	#3899
sofianirawan diyAudio Member Join Date: Jul 2011	that true mr jay..I have transformers toroid 18v 0v18v to build amplifier SSA by shaan and lazy cat..and sound quality is very good

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