If you really need to get rid of noise, try a CLC or CLCLC filter, but make sure you simulate it in spice first to tune the values and get rid of resonance/ringing. Cap ESR matters a lot here, you might need to choose some high ESR caps to increase the damping factor of the system.
Yes, it does not hurt I think.
And I do not hear anyone about a switch on/off 'thump' noise but if there is hopefully this resistor helps.
I have not made this amp yet, but I think a 10k resistor (or an even higher value) will help to reduce the thump noise.
Turn on/off-thump is minimal without the resistor but yeah include one if you feel better with it.
According to that linked thread, I will say that connecting a 10k-resistor won´t help much charging the cap, cause the heaphones are a short in comparison.
On my PCB it´s easy enough to take 2x standard 0.6W resistor and solder them from cap to GND@ the output connector (botton layer).
According to that linked thread, I will say that connecting a 10k-resistor won´t help much charging the cap, cause the heaphones are a short in comparison.
On my PCB it´s easy enough to take 2x standard 0.6W resistor and solder them from cap to GND@ the output connector (botton layer).
I will use 1k.
I did not make the amp yet. I am pretty sure it sounds so good it qualifies building it in a small aluminium enclosure. But that requires careful planning to fit everything in, it's like a puzzle. And I was waiting for the necessary components.
Finally I have everything and I can start, when I have time. Can't wait.
I did not make the amp yet. I am pretty sure it sounds so good it qualifies building it in a small aluminium enclosure. But that requires careful planning to fit everything in, it's like a puzzle. And I was waiting for the necessary components.
Finally I have everything and I can start, when I have time. Can't wait.
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Easy enough to solder a pair of resistors across the 1/4" jack socket, which is what I tend to do (when I remember!).
The thump on this one is nowhere near as brutal as other amps, such as my T2 (or Noir), but can't hurt to tame it.
Look forward to hearing how you get on with your build Widea.
The thump on this one is nowhere near as brutal as other amps, such as my T2 (or Noir), but can't hurt to tame it.
Look forward to hearing how you get on with your build Widea.
By the way, just want to double check but each output transistor dissipates around 300mW right?
Yes, it simmed at around 300mW, which was well within specs for the BD139
I've not measured it directly though.
I've not measured it directly though.
Would higher voltages for the PSU work? Asking for a friend 😛
Edit: Also, is gain set by changing R7 and R8? Excuse my inexperience
Edit: Also, is gain set by changing R7 and R8? Excuse my inexperience
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See post #5.
The question about the power dissipation is also answered in this thread at least twice (incl. the schematic from lineup with static DC values) but avtech23 was kind enough repeating it.
Better to read the thread once slowly than 3 times too quick😉
Set it up in LTspice for yourself. See attachment for quick work.
The question about the power dissipation is also answered in this thread at least twice (incl. the schematic from lineup with static DC values) but avtech23 was kind enough repeating it.
Better to read the thread once slowly than 3 times too quick😉
Set it up in LTspice for yourself. See attachment for quick work.
I want to make sure I get everything right which is why I always double check to ask 😛 I think it's more polite than getting it wrong and then wondering why it doesn't work, personally
(Good to know I was right though)
Edit: Also, I have already simmed the model in LTspice but again, want to confirm if it's the right idea or not 🙂
(Good to know I was right though)
Edit: Also, I have already simmed the model in LTspice but again, want to confirm if it's the right idea or not 🙂
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Yeah, don´t worry, I know that feeling.
Let us know of your progress.
Are you using Kicad? And don´t forget to post your P113-project and comparisons with this one.
Let us know of your progress.
Are you using Kicad? And don´t forget to post your P113-project and comparisons with this one.
Yeah, kicad. I have a lot of experience laying out circuits just...not much with the design phase, hence I still feel very much out of my depth here.
Will be interesting to compare the very different topologies!
Will be interesting to compare the very different topologies!
What I've been working on 🙂
It's a weird shape because it's meant to slide into this case, the cutouts are for the IEC socket and RCA jacks.
It's a weird shape because it's meant to slide into this case, the cutouts are for the IEC socket and RCA jacks.
Ikr? It's so cute! I can't wait to build in it.
Decided to stick with 12V in the end btw, increasing voltage also increased distortion by quite a bit and I'm not a fan.
Decided to stick with 12V in the end btw, increasing voltage also increased distortion by quite a bit and I'm not a fan.
I bought a pile of these a while back:
3.7V 5V Mono Stereo Output Bluetooth Audio Module Universal Bluetooth Receiver Module 7 PIN Output Interface Speaker Amplifier|Integrated Circuits| - AliExpress
They are dirt cheap and I thought it might be a good way to add simple BT capability to some of the older amps that I've refurbished.