Originally bought this TDA8920BTH for a ghettoblaster, thinking I could run it off +24V DC from 2x SLA - wrong! Decided to put it in a box with a cheap RS toroid & Chinese filter board rather than let it go to waste. The datasheet claims 215W 'typical' into 6R bridge at 10% THD, so >200W into 4R bridge seems not entirely impossible. I have no use for such an amp, but it was fun to build & I'm sure I'll be asked to provide a small soundsystem for a house party at some point in the future! Maybe even a sub amp if I ever decide to build a sub.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Really Old Class D Amp
I built this thing around 20 years ago. It still works. I just thought maybe somebody would be interested in an Old School design. FETs at the time I couldn't get to work right, so all is bipolar transistors and J-Fet Op Amps. Power supply does have 2 of those TO-3 BUZ things driven by a transformer. It is for Bass at cutoff of 500 Cy, but is actually good to 3 Kc. 60 watts a channel. I use it to drive a pair of Eminence 18 inch woofers in my 57 Chevy.
I built this thing around 20 years ago. It still works. I just thought maybe somebody would be interested in an Old School design. FETs at the time I couldn't get to work right, so all is bipolar transistors and J-Fet Op Amps. Power supply does have 2 of those TO-3 BUZ things driven by a transformer. It is for Bass at cutoff of 500 Cy, but is actually good to 3 Kc. 60 watts a channel. I use it to drive a pair of Eminence 18 inch woofers in my 57 Chevy.
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fooeywuffle - love your 57 Chev. My parents bought an identical one new when I was in high school. Yours looks quite cherry!
Sorry for going off topic. Oh yeah, your amps are cool too!
Rod
Sorry for going off topic. Oh yeah, your amps are cool too!
Rod
My grandmother bought the 57 Chevy for me in 1967. I refurbished the whole thing myself except for the seats. painted it in my back yard. Had to add AC when I moved here to Palm Springs CA. That was a job.
hifimediy T3 mono blocks
Just finished these and they sound wonderful. Connexelectronic SMPS500Rs for power supply.
Just finished these and they sound wonderful. Connexelectronic SMPS500Rs for power supply.
Excuse my ignorance Chris, but is the massive capacitance between the PSU and amplifier board really needed? I was under the belief that SMPS onboard supplies were normally sufficient at supplying large amounts of power when required?
Cheers,
Cheers,
They look massive, but only in size. I removed the 10000uF electrolytic caps and replaced with 35uF film and oil ASC caps. I experimented with different caps on a Hifimediy T2 and liked the sound with the film caps. And you are correct, caps not needed with the SMPS but I wanted to keep the relay in place so I used this option.
I found that increasing the amount of capacitance on the D class that I built helped the performance significantly, in fact the manufacture suggested it.
Another just finished brick.
A Hifimediy T2 (stock), a SMPS300R from Connexelectronic, a Pesante enclosure from HIFI2000 and a lot of patience. Sounds very good, an very rich and detailled soundstage.
And yes, 220 V kills.
Statistics : Electrical Safety Council
and for more in-depth view
OSHA Construction eTool: Electrical Incidents - How Electrical Current Affects the Human Body
So, be careful and responsible (and forgive-me for going off-topic).
A Hifimediy T2 (stock), a SMPS300R from Connexelectronic, a Pesante enclosure from HIFI2000 and a lot of patience. Sounds very good, an very rich and detailled soundstage.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
And yes, 220 V kills.
Statistics : Electrical Safety Council
and for more in-depth view
OSHA Construction eTool: Electrical Incidents - How Electrical Current Affects the Human Body
So, be careful and responsible (and forgive-me for going off-topic).
Very nice work, mravlca! Beautiful!
Also: you are someone of great taste. The Prodigy are amazing. I wish they'd come to North America some time. We didn't even get to see a screening of World on Fire at our movie theaters. Amazing band, very underrated.
Jim
Great design. I think you achieved the goal of every DIYer: not to hide in a black opaque box all the work invested in the construction (like me).
Thank you all for great compliments!
@J.R. Freeman: The Prodigy are amazing group. BTW I also didn't see the movie World on Fire, but I am thinking to buy a DVD.
Best Regards,
Ales
@J.R. Freeman: The Prodigy are amazing group. BTW I also didn't see the movie World on Fire, but I am thinking to buy a DVD.
Best Regards,
Ales
my woofer amplifer:
2 x L15D (irs2092)
balanced input ,with one speaker terminal inverted ( to help with buss pumping issues)
40 0 40 V AC 800VA toroidal
3 x 10000uf 80V capacitors per rail.
30ohm slow start for around 150ms with seperate transformer.
Own designed chassis (1.6mild steel black powder coated ,with anodized faceplate)
tested for just over 300W rms per channel into 4 ohm resistive.
My woofer EQ (technically not for this thread)
Took the Marchand bassis circuit diagram and added a 2 channel parametric filter and designed my own board. For use with my twin 12" sealed woofer I built.
2 x L15D (irs2092)
balanced input ,with one speaker terminal inverted ( to help with buss pumping issues)
40 0 40 V AC 800VA toroidal
3 x 10000uf 80V capacitors per rail.
30ohm slow start for around 150ms with seperate transformer.
Own designed chassis (1.6mild steel black powder coated ,with anodized faceplate)
tested for just over 300W rms per channel into 4 ohm resistive.
My woofer EQ (technically not for this thread)
Took the Marchand bassis circuit diagram and added a 2 channel parametric filter and designed my own board. For use with my twin 12" sealed woofer I built.
