MiniRef Schematic and PCB layout

[linuxguru]

Originally Posted by quadtech

For a multi-channel HT amp setup, it might aid the layout in the chassis
if you could move the LM1875s to the width side of the PCB, kinda
where the LM3886 was located in the MyRef monoblock PCB.

I thought about it initially, but what I've done is better for small form-factor 2-channel setups, where the chipamps can be bolted to the rear wall of the cabinet. It will even work with the Projekt X cabinets on EBay, where the largest dimension is the depth - in this case it could bolt to the side wall(s).

The other advantage of this form-factor is that the power trace lengths from the main filter caps to the chipamps is shorter and encloses less EMI radiating area for the circulating currents.

[madisonears]

I don't understand the purpose of a redesign, and I really don't understand copping Mauro's designation. The amp, as originally designed and subsequently built by hundreds of DIY'ers, was Mauro's best personal effort, after much experimentation, at building a compact, simple, economical, reasonably powerful amplifier with excellent sound. He succeeded on every count, as many will testify. It was, indeed, his own personal reference amplifier. That's why it was called "MyRef".

Now you want to shrink it, economize it, reconfigure it, "improve" the circuitry. What is left to call it "MyRef" other than your own desire to take advantage of Mauro's considerable efforts and ingenuity and the notoriety it afforded him?

It's fine that you want to tinker with it, but then it's your baby and it should be called something else entirely. Perhaps your design will sound even better, and it will deserve its own unique designation. It is not MyRef, mini or otherwise.

Peace,
Tom E

[skodaboy]

redesign!!
thats what most people do on this forum.evenif its just a capacitor!
i think your being quite unfair to linuxguru.hes been very helpful on this forum and never shows any attitude in his posts. ibelieve he's an honest guy who wants to credit where credit due and not hanging on coat tails.
thats how things move forward , some take a leap in design (mauro rev) and that may become the new standed.take the whole gainclone scene!!

[madisonears]

I, too, believe he's an honest guy. I also value his posts. It's precisely for those reasons that I think he should use another name for his design. He is not merely changing a capacitor (we already did plenty of that and didn't change the name!); he is changing the basic form of the amp. The only thing it still has in common with Mauro's design is the embedded opamp.

I'm not being unfair to Linuxguru at all. He can redesign anything he wants, but when it no longer resembles the original it should have its own name. I'm being fair to Mauro.

Peace,
Tom E

[Luke]

Originally Posted by madisonears

I, too, believe he's an honest guy. I also value his posts. It's precisely for those reasons that I think he should use another name for his design. He is not merely changing a capacitor (we already did plenty of that and didn't change the name!); he is changing the basic form of the amp. The only thing it still has in common with Mauro's design is the embedded opamp.

I'm not being unfair to Linuxguru at all. He can redesign anything he wants, but when it no longer resembles the original it should have its own name. I'm being fair to Mauro.

Peace,
Tom E

Hi Tom,

I'm not sure I agree. The title of the thread is what caught my attention, and I like the design. If he called it my gainclone x, I wouldn't be here discussing it
with you
It is after all a mini myref isn't it? Should the mini aleph be called Greys mini se class A?

[linuxguru]

OK, I see the point being made by Tom, and I'll concede it to him. The main issue seems to be the use of the "MyRef" name for a circuit which isn't actually the same as Mauro's original MyRef design.

I hereby change the name of this design to "MiniRef", which more accurately reflects the fact that it is not the MyRef, although it derives/borrows numerous ideas from Mauro's MyRef design (it also uses ideas due to Brad Howland, Walt Jung, DeBoo and numerous earlier designers) . I will also make the change on the schematic and the silkscreen of the PCB, as soon as it is practical to do so and before it is fabricated (if that ever happens).

[pinkmouse]

Thread title updated.

[madisonears]

You just went on my hero list. The new name is a clever idea, and it should please everyone.

Good luck with this project.

Peace,
Tom E

[linuxguru]

Here is the current MiniRef schematic and board layout (initial prototype version) with some layout and component changes:

1) The main PSU filter caps are now of 30mm diameter (from 35mm earlier).
2) The smaller PSU caps, along with placement optimizations, allow the board to be shrunk to 100 sq.cm. (about 15% lower than the previous version).
3) Some component values have been changed after simulation runs.
4) Slightly improved signal ground planes and shielding.
5) Drill optimizations - only 5 different drill sizes.

I have taped out the Gerbers and Excellon files, and they've been sent for fabrication of the initial prototype run - maybe 10 to 20 boards at most. There are still some unrouted airwires visible on the board layout, but they're Eagle artifacts which are not required to be routed. There may still be errors in the schematic and layout which may be discovered only after building prototypes - we'll see how it goes when the boards are delivered in ~2 weeks.

[undefinedza]

Hi linuxguru,

This looks like a fantastic design, thank you for contributing it

Seeing your name reminds me that I've been craving a LCDuino build!

Has this design been tested? I'd like to build one to replace a gainclone that has been giving me trouble...

Thanks,
Chris