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Hoffman Amps Forum image Author Topic: Amp distorting problem  (Read 6877 times)

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Offline john121

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Amp distorting problem
« on: April 28, 2021, 11:06:30 am »
Hi and thanks for reading.
I have built the amp seen in the attached circuit diagram. The midrange and treble are reproduced fine but the amp distorts the bass.
Do you know how this problem may be addressed, what changes need to be made or components added / removed.
Q3 seems to be driven wrong. The lower output transistor appears to have no bias. The top transistor may not receiving enough voltage (possibly needs a bootstrap) .
Can you please advise how these problems or any other problems you have noticed may be addressed. This is a cheap and cheerful build, so am not intrested in a high performance amp, just want to get this one to work.
Thanks.

Offline shooter

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Re: Amp distorting problem
« Reply #1 on: April 28, 2021, 11:59:30 am »
Quote
midrange and treble are reproduced fine but the amp distorts the bass.
at all volumes?
it take more ump to drive bass, also speakers, some are to cheap to give good bass response.
got a scope?
Went Class C for efficiency

Offline PRR

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Re: Amp distorting problem
« Reply #2 on: April 28, 2021, 03:29:54 pm »
There are better plans than this.

You have posted this on at least one other forum.

Offline john121

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Re: Amp distorting problem
« Reply #3 on: April 29, 2021, 12:04:27 am »
Thanks for the replies, much appreciated.

Sorry I do not have a scope, was hoping for advice from examining the attachment.

I have included an attachment with a recent mod just applied

Thanks
« Last Edit: April 29, 2021, 12:20:28 am by john121 »

 


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