The Kuartlotron - All in one layout conception

[Project16]

Hello everyone!

I am newbie in layout design but after making two single cards of this assembly to the superb sound, I decided to design a stereo layout.
This layout will include a power supply and volume potentiometer to the minimum but already proposed suggestions are already planned.
All help will be welcome!

Kuartlotron thread:
The Kuartlotron - keantoken's simple error-correction superbuffer

[Project16]

@Jean Paul

Before continuing with the implementation of a supply, tell me if the positioning of the inputs and outputs is better like that?

Regard's!

[jean-paul]

Yeah that is better but still either one of the sets (inputs/outputs or both) could be at the backside of the board. I mean the side that is closest to the RCA plugs. that way wiring will be easy and it will look better. I see you implemented a motorized potentiometer. Nice. Add the pads for RK27 also. Pads cost nothing and they give the builder the opportunity to choose between RK27 and a motorized potentiometer. Just use two footprints over each other.

[Project16]

Like this?

[jean-paul]

YES ! Excellent. This way mounting it in a case will be easy just like wiring the RCA's. Always think of how it will look and feel when in a case and how you are going to install a board. For world peace please include M3 mounting holes too (one at every edge). The potentiometer must be aligned to the upper side of the board to be able to mount it flush with the front cover of your case and to be able to tighten it with its nut....i.e. lower side of the bushing must be on the green line. It will free board pace so that you can add CLC filtering of the power supply + and -. Coils are our friends.

Pads for optional input/output caps ? Muting relay (can be just above the output connectors, a very small relay is enough) ? A few more hours and I'll be buying a board from you

[Project16]

For RK27 I must draw the footprint because at first I did not plan a motorized potentiometer but it is a good idea.
It's not very well arranged and not to scale but I propose this provision and when it will be good to you after I put the other components.

[AndrewT]

make sure the motor has at least a capacitor across it's input and maybe provision for a snubber as well.

I did one a couple of years ago powered from a separate transformer and I can hear the motor interference (while adjusting volume) in the audio channels

[keantoken]

The motor case should be grounded. A PCB in my junk pile has a motorized pot bypassed by a 22nF ceramic and driven by a TA7291:

http://www.toshiba.com/taec/componen...DE_EN_3604.pdf

I think the ceramic cap would be damped nicely by the saturated junctions of the bridge driver.

[Project16]

AndrewT:
It is noted, thank you!

Kentoken:
Yes, it's expected and all will be well used when I have designed the footprint RK27 for positioning components.

@Jean Paul
Here is my investment proposal on the card. For the power part I adopted a circuit with conventional LM 317/337 preceded by a pre-regulation, which gives an excellent result.

Regard's!

[jean-paul]

Hi I would place the PSU next to the rectifier diodes (keep PSU parts grouped together).

- Try to keep a sound distance between AC input and the buffers inputs and outputs just in case.
- Move rectifier and diodes 10 mm closer to the corner but leave enough space for 3 mm mounting holes with clearance for your screw driver
- Inputs and outputs can go to the right section.
- You could add pads for smaller input caps too. Just put the footprint over the existing one. Smaller caps pick up garbage less easy.
- Output caps will be possibly somewhat larger when you choose MKP caps due to their value. Still 10 µF MKT/MKS caps exist in 5 mm and 10 mm pitch.

I use Wima MKS 2-XL and ERO green MKT a lot and they sound just good. Of course we could discuss for pages that MKP is better etc. but in this case I think smaller caps will perform better certainly with the motorized potentiometer in the vicinity. A ground plane might be a wise idea too.

Placing the potentiometer like you did now will be way better when mounting the board against the front cover. Thanks. I sent you a PM.