Super Gainclone With Klever Klipper Based on Cordell Design

I considered suggesting turning the clipper into a subsection as well. In fact, you could make a layout for just the clipper and connect it to one of the known good LM3886 boards (or even my Modulus-86 if you'd like to up the performance).

A line-level circuit is a much better candidate for a first "hello world" layout.

Tom
 
Many thanks to all for the great input.
Clearly I've got a long way to go!


Just one point Tom. The data sheet states "AM Mute Attenuation Pin 8 Open or at 0V, Mute: On
Current out of Pin 8 > 0.5 mA, 115 80 dB (min)
Mute: Off"


Am I missing something here?


Cheers once again.
Mike
 
Thanks for that Tom, et al,


I've already purchased a couple of basic vanilla LM3886's in parallel Mono boards and power supplies (transformer on the way) to cobble something together for 4 ohms, that should already hopefully work and I'll have some music again.


The reason for the SGC with Buffer ,Servo, Klipper and all kinds of perhaps over the top bits and Bob's (get the pun) is pure self indulgence. The enjoyment will be the same if I fail or succeed! Well almost. If I fail, all the stray cats will disappear and the Salsa class right across the road from my house will get some payback on Sunday mornings!


I once took my Fender Champ apart, copied the single sided board into Protel99, etched a board, bought a reverb, Got all the metal corners, jewels, Fabric, wood and blah blah! Took months and months but at the end it worked. I didn't design it but it was my baby and I had a great time doing it. I tried the famous AX84 hi octane (tubes from a great guy at Sovtek). Boy did that oscillate and it was so much fun trying not to electrocute myself. I never did get it work at high volume and almost died trying ha ha ha!!!


Maybe you can see where I'm coming from, you know "Its the journey etc"
Back on point, I really like the double sided board with copper on one side and countersunk holes! No problem with silk screen alignment. Very interesting article! I may give that a bash to try follow your entire train of vey kind advice!


Take care,


Mike
 
If you're into making your own PCBs, I suggest looking into toner transfer. I bought a cheap laminator and some brochure paper, which I use in my "garage fab". With some practice I'm able to get down to about 0.25 mm registration error between the top and bottom layers, which is good enough for a basic two-layer board.

Here's a good writeup on the method: Creating PCBs with the toner transfer method

Tom
 
Another option for smallish boards is to use the classic UV method, using a nail paint UV lamp. Those are dirt cheap on ebay and it works quite well. It might require a bit of trial and error the first time to find the correct exposure time given your materials and setup but then it's very repeatable, without any trouble up to tssop pitch. See here for more details.

Dual sided can work but honestly... I've come to appreciate having true plated through holes boards. Main problem wasn't the etching but the drilling. 0.8mm bits are awfully fragile. ;)
 
I'm fortunate, in as much as the cost of making a silkscreen in my town, is quite cheap, so I usually go down that route.
Tom, using the 2 sided board you discussed earlier and leaving copper all on one side makes that entire side the ground plane then?
I've also looked into the package sizes you mentioned and noticed that the 1uF input cap, if I were to use a EVO-120 is a wopping 16x25mm. Is that the usual size for this type of cap?


Thanks,


Mike
 
Regarding the cap size: yes it's quite usual. Still, you don't need an audiophile approved cap. A good mkp from a reliable brand will be smaller and good enough not to be the weakest link in any system.

A 1uF/63Vdc wima mkp2 is 11mm*7.2mm. A 1uF/100Vdc wima mkp4 is 7mm*26.5mm.

For myself, I'm not quite certain I can hear the difference with a MKT such as the wima mks2... 3.5mm*7.2mm for 1uF.
 
An MLCC (multi-layer ceramic cap) will fit within 5.08 x 2.54 mm. Example: 1.0 uF, X7R from TDK: P/N: FG26X7R2A105KNT06

Just make sure you get X7R dielectric as the other types have really horrid voltage coefficient. Not that the voltage coefficient of X7R is pretty, but at least it's not horrid. :)

If you insist on using film caps, you'll be paying for it in terms of area.

Yes. If you leave the top copper as a solid plane and drill out (countersink) the copper around the pins where you don't want it, I suggest connecting the plane to ground. I would draw it in the layout tool as a copper pour.
The only drawback of home made two-layer boards is that you don't get the thru-plating as 00940 mentioned. You can buy rivet kits that allow you to make your own thru-plated holes, but at that point you may as well send your layout to China and get a couple of boards made. Outfits like Seeed Studio are dirt cheap. I haven't personally used them, but many here seem to have. Alternatively, OSH Park in Oregon is good. They handle their production in the US.

Tom
 
Sorry, I wasn't very clear in my last post. It all depends on what you're using the cap for.

I'd suggest mkp (or possibly mkt) for coupling/signal filter caps of relatively small values. Once you go above a few uF, you're stuck with electrolytic. For anything requiring small values, np0 ceramic is fine.

For supply bypassing, x7r ceramic is good, providing you're checking the datasheet for the capacitance vs working voltage dependency. Mkt can be an alternative.
 
Hi Tom and all contributors to my Cordell SGC layout project.

I’ve had another go at the layout using two layers as recommended. I went for the bottom layer as ground though Tom!. Yes, I’m still a beginner!

I couldn’t figure out how to solder under the components that had the pins underneath them (never used vias before!). If I DIY the board, then they’ll have to be solid wire vias next to the offending items, I believe?

I’m really not sure about the power planes! I imagine they are in the wrong places, wrong size, missing etc. Hopefully you’ll be able to set me on the right track.

I’ve separated the ground plane into two halves with one track at the bottom joining the two halves, trying to keep the lower power signals on the right hand side of the ground.

I’m confused regarding the quiet ground connection from R1 to main ground next to the Speaker Ground, which is on the higher voltage/ current side of the board. Is that in the right place? It looks like my quiet ground net is all over the place!

Please have a look and let me know if I’ve made any progress regarding your input.

If I can get the thing to work, then I’ll probably get the board fabricated by the pro’s using normal vias at the component leads.

Thanks again.

Mike
 

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Different design objective

excuse me,
the Klever Klipper is really worth to realize it?
another way
Audio Amp Power Limiter
These circuits have different objectives. Rod's limiter is for speaker protection. The Klipper is a soft-limiter to improve audio quality and overcome the issues with overdriving the LM3886. There is a chapter in Cordell about this and the title says it all; "Clipping Control and Civilised Amplifier Behaviour".
 
I got some feedback from Bob regarding the Klipper.

"I'm glad you like the Klever Klipper. Quite awhile back I auditioned the SGC against a 35 W tube amp I built. People preferred the sound of the SGC with the Klever Klipper turned on, and frequently confused the SGC in that mode with the tube amplifier when they did not know which amplifier was playing".

That's why I am trying to get this design to work. I love the sound of tubes!