Soft Start and Standby Functions for your Aleph Amplifier

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Ok, I've had a look at the pcb, and here are my first thoughts:

1) Mains traces have nowhere near enough clearance from each other and from the LV traces for 240V usage.

2) A-E suggested to the Doc that a bigger traffo might be useful. We can implement this with a bigger board, but it is already quite large. Do we want to go for an offboard traffo, so you can use whatever you can easily get? For example, I have many suitable transformers in my junk box, none of which would fit this PCB, and I am loath to spend another £10 on a suitable one.

3) I can't find matching relays to those that A-E used. Can we decide on a suitable replacement that's easy to get all over the world, or maybe include relays with the PCB?

However my main difficulty is with the size of the board. I'm only using the demo version of Eagle currently, as I can't afford to upgrade. So, if Jason is willing, and I believe he has a full version of Eagle, I suggest we work together, if he can edit the boards, I can help out where I can, and keep an eye on the project. You up for that Jason? :)
 
pinkmouse said:
Ok, I've had a look at the pcb, and here are my first thoughts:

1) Mains traces have nowhere near enough clearance from each other and from the LV traces for 240V usage.

2) A-E suggested to the Doc that a bigger traffo might be useful. We can implement this with a bigger board, but it is already quite large. Do we want to go for an offboard traffo, so you can use whatever you can easily get? For example, I have many suitable transformers in my junk box, none of which would fit this PCB, and I am loath to spend another £10 on a suitable one.

3) I can't find matching relays to those that A-E used. Can we decide on a suitable replacement that's easy to get all over the world, or maybe include relays with the PCB?

However my main difficulty is with the size of the board. I'm only using the demo version of Eagle currently, as I can't afford to upgrade. So, if Jason is willing, and I believe he has a full version of Eagle, I suggest we work together, if he can edit the boards, I can help out where I can, and keep an eye on the project. You up for that Jason? :)


I think the parts that are hard to get for others such as caps relays and transistors ic's stuff that could be hard to get should be included in the kit with board.

and i have eagle too :D

j'
 
Here are all the optimasations Algar_emi recommended:

There is no real errors but things that can be improve before you go on
production.
One of my goal was to have a one side PCB, 4X6 inches lenght max because
I wanted to use a 9X6 one side PCB.

So, the things to improve are:
-The transfo on the PCB VA rating is a little to low to supply directly
outboard fans. I recommend to use a slightly bigger transfo, such as the
MT2228-ND, 18V, 0.7VA instead of the 0.34VA I used. You'll need to
increase slightly the dimension od the PCB to accept the bigger transfo
and chnage the transfo pins location, or as I taught to do, make
provision on the PCB to accept both transfo. You may be able to fit the
bigger traansfo by rearrange this section of the PCB.

-J1 & J2 are connectors that I got from a surplus store. You are better
to replace them from connectors that you can get from digikey, such as
nice little Molex connectors such as the Digikey WM5824-nd (this is a 3
pins conn, you need a 4 pins and maybe a little bigger, but you got the
idea.

-J2 is not well located, the others parts around are too close, so J2 is
kind of difficult to plug in, get some more room around it.

-U2 is too close to D1. You need to install a DIP socket to plugin U2.
Bring U2 more to the right of the PCB
-RLY4 is a little to close to the screen mounting hole. You may move the
PCB right side of the PCB to get some more air on the right section of
the PCB.
-U3 is really close to Q1, again move the right side a little bit to the
right.
-Add an other piin hole for maybe an smaller dimension and or type of
capacitor for C35, as I did with C34 (optional)

-You may add 0.1uF, decoupling cap for U2 and U3 on the supply pins. I
was planning to add them from under the PCB if needed.

-A last request, if you get a silkscreen option, would you right my name
in full on the PCB along with the copyright?
 
Here the final version of the schematic that match my ver 1.0 PCB.
It is very flexible.
This version of DC filter confuses me, especially the 10.000uF capacitor with such low voltage (16VDC).
I use this topology for a Pass Labs X250
http://scintilla-buizenversterkers....erkers/zelfbouw/zelfbouw sites/DC-Blocker.htm
but with four pcs 47.000uF/63V to enhance the reliability and reduce of dynamic loss go for looking the associated toroidal transformer to the pictures in post #19 under
Pass X250 repair
but maybe there are still better dc filter options.
 
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