Transformer smoked

Aidan135711 · 1st August 2008, 08:03 PM

Hello everyone
I need schematics for a guitar practice amp.It is a Sound City SC10.I think it is a 10W amp.
When it came to me the TDA2030 power amp IC was smoked and the power transformer too.It was a center tapped thing with 2 diodes as full wave rect.
IC was replaced with TDA2030A(I think it can handle higher supplies) but I don't know what the secondary voltage of transformer should be.I have tried several but bad distortion sets in after volume level 2.This with a sine wave test tone @200mV p-p.Even worse with guitar plugged in.
I have tried several starting from about 12V and now the transformer I have in gives smoothed supply of 25VDC ripple 200mV p-p(maybe this ripple is too high?),the maximum I can give it,but the problem persists.
I have searched a lot for drawings but can't find any.
Has anybody out there got them?

dnsey · 1st August 2008, 08:17 PM

The datasheet is here

Your amp will probably closely follow the application circuits.

Aidan135711 · 1st August 2008, 09:33 PM

Hey dnsey
I already have that datasheet but I just noticed that max supply is +44V.
I lookd at this recently but thought this meant +22 and -22 for a dual rail supply.
The typical circuit of figure 12 shows a max supply of +44V for a single supply amp.
Seems like I have'nt enough volts!Silly me.
Thanks.

Aidan135711 · 1st August 2008, 09:34 PM

Although I would still like drawings for this amp.

1st August 2008, 08:03 PM	#1
Aidan135711 diyAudio Member Join Date: Feb 2008	Transformer smoked Hello everyone I need schematics for a guitar practice amp.It is a Sound City SC10.I think it is a 10W amp. When it came to me the TDA2030 power amp IC was smoked and the power transformer too.It was a center tapped thing with 2 diodes as full wave rect. IC was replaced with TDA2030A(I think it can handle higher supplies) but I don't know what the secondary voltage of transformer should be.I have tried several but bad distortion sets in after volume level 2.This with a sine wave test tone @200mV p-p.Even worse with guitar plugged in. I have tried several starting from about 12V and now the transformer I have in gives smoothed supply of 25VDC ripple 200mV p-p(maybe this ripple is too high?),the maximum I can give it,but the problem persists. I have searched a lot for drawings but can't find any. Has anybody out there got them?

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1st August 2008, 08:17 PM	#2
dnsey diyAudio Member Join Date: Mar 2004 Location: Shropshire, England	The datasheet is here Your amp will probably closely follow the application circuits.

1st August 2008, 09:33 PM	#3
Aidan135711 diyAudio Member Join Date: Feb 2008	Hey dnsey I already have that datasheet but I just noticed that max supply is +44V. I lookd at this recently but thought this meant +22 and -22 for a dual rail supply. The typical circuit of figure 12 shows a max supply of +44V for a single supply amp. Seems like I have'nt enough volts!Silly me. Thanks.

1st August 2008, 09:34 PM	#4
Aidan135711 diyAudio Member Join Date: Feb 2008	Although I would still like drawings for this amp.

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