Well, my current amp is running on an unregulated psu consisiting of a 12v 3a radioshack power transformer, a full wave rectifier with .1uf subbing ceramics on it, and 3x4700uF caps, not snubbed. all this runs into a 3300uF smoothing cap. input caps are polarized elecrtolitics, I think either 1 or 10uf. Sounds decent, but I want to rip it apart and go to point 2 point, so this would be an opportune time to upgrade it. As i am already ordering from Mauser, I can use the caps i have right now to make this thing sing better.
Well sounds to me then that you could just improve your setup without playing with the active bits at first. I'd recommend building a multistage CLCLC power supply to filter out the ripple , rather than lumping all your caps into one bundle.
Buy some toroidal metal powder cores and wind your own inductors for the L part. Or if you have an aversion to inductors, use low value Rs (say 0.22R).
When I did such a mod on my desktop active speakers (which are powered with TDA7265s) I was surprised how much improvement I got in soundstage depth from this.
Buy some toroidal metal powder cores and wind your own inductors for the L part. Or if you have an aversion to inductors, use low value Rs (say 0.22R).
When I did such a mod on my desktop active speakers (which are powered with TDA7265s) I was surprised how much improvement I got in soundstage depth from this.
I will take a look at your schematic. I think I have enough components to upgrade the system.
when you say .22R you mean .22 ohm right?
Feel free to send PM to ask more questions. With an SMPSU you need to take fairly stiff measures in filtering both common-mode and differential mode noise to get the best performance.I use my own hand-wound common-mode chokes because I've yet to find an off-the-shelf one which comes up to snuff. On the differential mode noise, ferrite beads are your friend in a CLCLC style filter where the L elements are wires passed through ferrite beads.
Thank you Andrew, did you have any suggestions as to what lm3886 schematic i should use for my amp and power supply?
Is this ok?
This is sort of what I was hoping for, as "not all caps sound the same", or sometimes a noob might not know where to use ESR caps and where not to, what type of resistors. There are so many variables and i really want to learn how to make the RIGHT one, the first time.
AndrewT, thanks for the helpful words. Is there anything I should change on the Nat-Sem schematic? Any tweaks worth mentioning? Advice on the specific brands of components and what should be purchased? Whatever schematic I end up building, I will build it point to point. This was what made Mick's amp such an attractive starting point, i was mostly interested in the building style rather than the schematic.
Point to point building is lot harder than it looks.
You have to design it well before starting to solder, changing anything is pain in the ***.
After making 2 point to point builds, I never want to make another, but try one and you will see if you like it or not. I didn't really make a plan where goes what, more like started and placed everything where I had space. Don't do it like me
You have to design it well before starting to solder, changing anything is pain in the ***.
After making 2 point to point builds, I never want to make another, but try one and you will see if you like it or not. I didn't really make a plan where goes what, more like started and placed everything where I had space. Don't do it like me
Point to point building is lot harder than it looks.
You have to design it well before starting to solder, changing anything is pain in the ***.
After making 2 point to point builds, I never want to make another, but try one and you will see if you like it or not. I didn't really make a plan where goes what, more like started and placed everything where I had space. Don't do it like me
Trust me, I know. I have built 3 amps in point to point so far, and I really enjoy the planning and execution. This thread is part of the planning...
After this chip amp I will build a high voltage class A tube amp. That might end up being a turret board build.
Forget about branding.
Use up to spec commercial grade components that suit the locations in the amplifier.
Include DC blocking at the input and in the NFB. Inverting has both via just one capacitor.
Include RF filtering at the input.
Include both MF and HF decoupling.
Include a Zobel on the output and preferably use the full Thiele Network on the output.
Ensure the source impedance is reasonable, probably from 100r to 1000r.
Ensure the speaker does not draw currents that the chipamp cannot deliver.
Ensure the chip remains cool for all normal replay conditions.
Get your prototype chipamp working properly.
Learn what it can do.
Learn what it cannot do.
Learn what can be changed and still remain stable.
Learn what components can be omitted and what other constructions must be added to allow those omissions.
Then, when you understand ALL of that, you can start looking at what changes to topology and branding can bring to improve performance.
Use up to spec commercial grade components that suit the locations in the amplifier.
Include DC blocking at the input and in the NFB. Inverting has both via just one capacitor.
Include RF filtering at the input.
Include both MF and HF decoupling.
Include a Zobel on the output and preferably use the full Thiele Network on the output.
Ensure the source impedance is reasonable, probably from 100r to 1000r.
Ensure the speaker does not draw currents that the chipamp cannot deliver.
Ensure the chip remains cool for all normal replay conditions.
Get your prototype chipamp working properly.
Learn what it can do.
Learn what it cannot do.
Learn what can be changed and still remain stable.
Learn what components can be omitted and what other constructions must be added to allow those omissions.
Then, when you understand ALL of that, you can start looking at what changes to topology and branding can bring to improve performance.
Ok, this is sound advice. I will try to follow it as best i can.
Regardless of experience and sound though, i would still like to know if there is such a thing as recommended components. I'm not made of money and I want my amp to play well from the start, thus I'd like to buy "once and right" regardless of what schematic i use. When i decide to experiment on another build this amp will most likely be given to a friend, as most of my projects end up getting gifted to make space for more projects. Makes shopping for friends birthdays really easy. ^_^
To simplify, is there an accepted brand and type of caps and resistors? Is there a thread someone can point me to that would shed some light on these specifics? I will figure out cooling and Power supply stuff myself, but I'd really like to avoid buying and assembling something with sub par components, as the price difference is so minimal when considered "per amp" that id rather buy the nice stuff straight away.
I made my first np100v12 amp out of just radioshack components, the second i made using brand name components sourced locally and the difference in sound is astounding. This is what stopped me from just going ahead with building this amp and ask you guys for advice.
Quick question, as I already own two transformers that i believe have no center tap ( marked 0-13-27 ) i would have to connect the two together to get + and - rails and a zero volt line, correct?
Also, would the transformers give out 13 and 26 volts independently? I ask this because i am interested in using that secondary 13v for something else...
Also, would the transformers give out 13 and 26 volts independently? I ask this because i am interested in using that secondary 13v for something else...
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