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Class D Bass amplifier

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New Member
Hey guys!

I recently finished my first larger project (in a long time!)
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As Hero will probably remember, I was considering building a Class D Bass amplifier! Well I have done so and completed it now.

240v Input, Dual laptop supply-age!
170w Output (Theoretical)
+/- 24v PSU
Based around the TDA8920BTH in BTL mode
4Ohm 12" speaker
Laney Bassman 40 Preamplifier

I had intended to convert my Laney Bassman 40 into a much better amplifier because to put it bluntly... It sounded like utter cr*p due to the lame-ass power stage!
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Luckily with this amplifier, the power amplifier and preamplifier stage were two separate PCB's meaning I could hopefully savage it and use the preamp stage with a new power stage (I diagnosed the problem of which stage sounded so bad by testing the line-out section of the preamplifier on my Marshall Bass 20 amplifier (a lovely amplifier!) and the preamp stage sounded very sweet.

So! I ripped out the horrible power stage along with the bulky transformer (this reduced the weight a lot! And prepped the Preamplifier stage for use with my new power supply (the transformer was a 30v-30v non-torroidal one). After testing the preamplifier stage at +/- 24v, I concluded that it worked fine.
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I bought the power supply and power amplifier board off eBay for a total of:
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Well-Known Member
Most Helpful Member
good bass amps are mostly power supply.... i used to have a Traynor 100W head when i was in high school, and i kept thinking it sounded awful when playing with a band. a few years later i got an Earth 100W head, and it weighed a lot more, because of the power transformer being about twice as big, even though the output transformer was about the same size. that Earth amp sounded much better than the Traynor, even through the same speakers.

if i were to build a bass amp today, i would probably not use a class D amp, but a good class AB design, but that's my druthers... the power supply would definitely be where i would give the most attention to detail
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