Hi,
Actually I'm currently building chip amp (TDA2050) but since they don't take much effort to design, I'm looking for discrete designs and try to learn basics of them. Anyways, I found a website called "eleccircuits" and soon realized most of designs there are terrible english translations of documents provided by a Thai company "Prakito". Here's 100W ocl design by them, it seemed quite standard to me but since I'm only starting to learn these, I want to take your opinion on them.
http://www.prakito.com/docs/audio/100W. OCL.pdf
Note: I posted this link at r/diyaudio and a few helpful people showed up, but tbh no one uses that subreddit for serious stuff.
Actually I'm currently building chip amp (TDA2050) but since they don't take much effort to design, I'm looking for discrete designs and try to learn basics of them. Anyways, I found a website called "eleccircuits" and soon realized most of designs there are terrible english translations of documents provided by a Thai company "Prakito". Here's 100W ocl design by them, it seemed quite standard to me but since I'm only starting to learn these, I want to take your opinion on them.
http://www.prakito.com/docs/audio/100W. OCL.pdf
Note: I posted this link at r/diyaudio and a few helpful people showed up, but tbh no one uses that subreddit for serious stuff.
Very standard indeed ! But 100W is not realistic, 75W on 8Ω perhaps.With 4Ω could be more but with only 1 set of power transistors a bit risky.
Input is about 1V.
Mona
Input is about 1V.
Mona
Thanks. What do you think about the pcb design? Btw if I'm not terribly wrong, names of components don't match between layout and schematic but it seems just about it. Also, do you think it's comparable to p3 or power amp section of p27 from ESP? Shipment + board is expensive and takes a long time, so I wanna etch my own board. Any idea is welcome 🙂
The transformer voltages are too low for 38VDC rails and there are some details which won't make the amp sound particularly good either. The PCB is not too bad but I wouldn't waste time on such an amplifier unless it was for some utility purpose.
I think you would do much better with one of Apexaudio's designs here on the forum. There are many of them, from small amps like this one up to huge PA amps and there are some recent threads cataloguing all his designs for forum users. All will have PCB designs by builders and you can learn alongside other constructors. Search patiently, join the build threads before deciding what you want. Have fun.
I think you would do much better with one of Apexaudio's designs here on the forum. There are many of them, from small amps like this one up to huge PA amps and there are some recent threads cataloguing all his designs for forum users. All will have PCB designs by builders and you can learn alongside other constructors. Search patiently, join the build threads before deciding what you want. Have fun.
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I second Ian Finch's recommendation to try an Apex Audio amp. One that has been thoroughly tested and praised in the same power class would be the FX8 Bimo mod. PCBs, spice models and many constructors have made it. Another good easy one to try is the FH9. Low cost parts and easy to make and sounds great. More recently, the CFH7 has also shown itself to be easy to build and low cost while sounding great. You can listen to sound clips of all these amps in this thread and decide which you like. A little more tricky to get working but excellent sounding is the Ranchu quasi MOSFET.
http://www.diyaudio.com/forums/solid-state/295286-virtual-audition-very-simple-quasi-mosfet-amp.html
http://www.diyaudio.com/forums/solid-state/295286-virtual-audition-very-simple-quasi-mosfet-amp.html
Thank you. I wanna build this power amp for my guitar amp, I'll build a home system later on. Do you think hifi designs you mentioned are applicable in this scenerio? I guess I could try and run spice and simulate distortion characteristics but I currently don't have access to a computer.
Distortion should be applied via distortion boxes or guitar speaker drivers with characteristic distortion sound. These amps are all "high fidelity" low distortion and clean flat frequency response. If 50w into 8ohms is enough the FX8 or FH9 or CFH7 is fine with 35v rail supply. Need more? Go with FH11/12 with 50v rails for 150w amp. For a guitar amp a linear supply is very heavy. Look into lightweight SMPS.
Then you should really be reading the instruments and amplifiers forum because this one is for hi-fi and stereo amplifiers etc. Guitars need sound effects and controls to suit which hi -just can't match. Instruments and Amps - diyAudio
Hi Guys
There is no problem having 100W output with a single pair of BJTs and there are thousands of amps built exactly that way that are reliable. When the load is known, there is no issue.
As a guitar amp, most solid state PAs just need to have reasonable overload protection, as the example circuit has. The distortion characteristic for musical instrument use is that the amp is basically clean until it clips. At that point, the output becomes a square wave and has a buzzy character.
I built a stereo 100W/ch amp in 1U for a player. I installed clip LEDs. He liked it best when the clip LEDs were on solid. Fortunately his speaker cabinets had sufficient power rating toi handle the clipped output without burning up.
The distorted signal in the preamp is also often squared off. The EQ after will make this spikey so it will sound crisp and bright. This spikey signal going into the power amp will be sent to the speaker with exactly the same shape until the power limit of the amp is reach. First, the spikes are cut off and the tone becomes rounder. Then if you drive the amp further, the whole signal is squared and the sound becomes brighter again but in a different way than before. Once hard clipping is achieved, all amps sound about the same.
The example circuit is the most common type built over the past 50+ years and is entirely reasonable to use as a learning tool.
Have fun
There is no problem having 100W output with a single pair of BJTs and there are thousands of amps built exactly that way that are reliable. When the load is known, there is no issue.
As a guitar amp, most solid state PAs just need to have reasonable overload protection, as the example circuit has. The distortion characteristic for musical instrument use is that the amp is basically clean until it clips. At that point, the output becomes a square wave and has a buzzy character.
I built a stereo 100W/ch amp in 1U for a player. I installed clip LEDs. He liked it best when the clip LEDs were on solid. Fortunately his speaker cabinets had sufficient power rating toi handle the clipped output without burning up.
The distorted signal in the preamp is also often squared off. The EQ after will make this spikey so it will sound crisp and bright. This spikey signal going into the power amp will be sent to the speaker with exactly the same shape until the power limit of the amp is reach. First, the spikes are cut off and the tone becomes rounder. Then if you drive the amp further, the whole signal is squared and the sound becomes brighter again but in a different way than before. Once hard clipping is achieved, all amps sound about the same.
The example circuit is the most common type built over the past 50+ years and is entirely reasonable to use as a learning tool.
Have fun
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I have an extra pair of those transistors, so I guess I could parallel those with ballast resistors. Would I need to change amp topology or can I just parallel the output transistors?
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Hi Guys
If you use the same value of emitter resistor for the existing pair of outputs, then the new pair will idle at the same current and stability will remain about the same. No more power will be delivered except to lower-impedance loads. However, to get the most benefit possible there, the EF2 should be changed to an EF3 and that entails recompensating the amp among other things.
Have fun
If you use the same value of emitter resistor for the existing pair of outputs, then the new pair will idle at the same current and stability will remain about the same. No more power will be delivered except to lower-impedance loads. However, to get the most benefit possible there, the EF2 should be changed to an EF3 and that entails recompensating the amp among other things.
Have fun
To be honest I'm hesitang to make major changes. Could you eleborate a bit? Also how does this circuit compare to Elliott's p27 or p3a amp? I'm asking because I'd like to try and build something robust and built by others, I wouldnt wonder if it was the circuit or my build that led to a problem and support threads out there would make debugging easier.
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