Sorry, i have another PSU design question!

[MidnightArrakis]

they all can provide max 300/400mA, which isnt enough for me.

>> How about a power transformer with dual-secondaries rated at:

1) 16VCT @ 700MA

2) 20VCT @ 600MA

And.....they look like this:


Or.....then, there are these:

1) 16VCT @ 1.25A

2) 20VCT @ 1.00A

And.....they look like this:


Would these work for you???

Cost is around USD $15.00 +/- "some change" each!!!

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[f.aiseur]

I have reviewed your schematic. A few observations.
I now see the need for a 40 V supply... as the majority of the circuitry is discrete components and of an older "style" designed to run on a single supply. Nowadays it would of course be (and is) built using Opamps using split supplies.... which is how you are going to configure the additional circuitry (VU meters and drivers, etc.) I assume?
Speaking of your +/- supply. I would change your rectifier system... it will only provide half-wave rectification which produces a lot more ripple (hum). Use an 18-0-18 transformer... and configure as per my schematic.
+/- 16 or even 18 volt power would not be critical in your app... so 15 volt (fixed) regulators could be used. No need for extra circuitry and adjustment.
I can't see a simple way to be able to use one transformer. A commercial product might (and often do) use a dual secondary transformer. You may be able to find one through Digikey or similar... but likely to be expensive! The only ones that I am aware of are large units for PA's which need separate high and low voltages for the PA and preamp stages.
I have looked at your PCB layout which seems fine thus far... and has the rats-nest... but does not yet include the actual tracking. That's the hard bit!

 

[f.aiseur]

Hi GJB,

Thanks for the advice, will then change the rectifier system ( this is the kind of very useful tip to me, like where the noise can come from, etc..)
Actually, ont this same topic and as you mentioned it, i've read somewhere that the adjustable regulators, like lm317, are less noisy than the fixed ones... is it an urban legend?

Thanks also for taking time to check my projects and uups! yes i realized i didnt clean the folders and included some things that were just abandoned sketches, sorry for this...


@MidnightArrakis

Well.... those seems like perfect thing yes!

Can you give me a bit more than those pictures/ maybe a link or reference? That would be very nice!

You having some experience with pcb designs, how do you feel about have this kind of transformer on the same PCB as the PSU?
I like it for practical reason but i've read some comments about also noise increasing, stability problem etc...

Cheers!

 

[DarkSky]

A single secondary (or +/- pair of secondaries) can supply more than one rectifier/regulator circuit. Regulators such as the LM317 and its neg counterpart the LM337 will sit on supply rails of up to 40v and can be dialled to output regulated rails ranging from 1.2V to 37V per side at 1.5A.

That means with a transformer that has a single pair of secondary windings for +40V, 0V, -40V can feed multiple regulator circuits outputting dual rail supplies from 2.4V (+1.2V, 0V, -1.2V) to 74V (+17V, 0V, -37V). It may not (?!) be as power efficient as using a trafo with multiple +/- secondary pairs, but it's simpler and almost certainly cheaper.

 

[GJB17]

Hi... just quickly. The transformer you need should ideally two separate windings... one of around 35 volts (for the 40V supply)... and 18-0-18 volts (for the +/-). To be safe each winding should be able to deliver around 1.5 times your ultimate (dc) current draw.
The spec you have given is unclear. Does 18 volts CT mean 18-0-18 or 9-0-9 ???
Please send me a link to them so as I can have a look myself.
Cheers,
PS... from my experience fixed regulators are not less noisy... both the same... if used (by-passed) correctly. Actually I had noticed that you had a cap bridging the In and Out of regulators. Loose it... it will just transfer any HF noise straight past the regulator.

 

[MidnightArrakis]

@MidnightArrakis

Well.... those seems like perfect thing yes!

Can you give me a bit more than those pictures/ maybe a link or reference? That would be very nice!

You having some experience with pcb designs, how do you feel about have this kind of transformer on the same PCB as the PSU?
I like it for practical reason but i've read some comments about also noise increasing, stability problem etc...

Cheers!

>> Here are some links:

https://powervoltgroup.com/ProductDetails.aspx?ProductID=147&InputID=131

https://powervoltgroup.com/ProductDetails.aspx?ProductID=137&InputID=62



-----------------------------------------------Secondary RMS----Secondary RMS-----Secondary RMS
-------------------------------------------------(Individual)----------(Series)--------------(Parallel)
DSZ6-36 Dual-Primary: 115/230V 8 Pin-----18V @ 0.55A-----36VCT @ 0.55A-------18V @ 1.10A

SZ7-36 Single-Primary: 115V 6 Pin----------18V @ 1.00A-----36VCT @ 1.00A-------18V @ 2.00A

[The transformer you need should ideally two separate windings] -- Or, two separate transformers, right???

Can anybody/somebody please provide some more concise and/or precise information as to what is needed here? I am confused as to what exactly the OP is looking for as far as what are the end-result voltage and current requirements.

/

 

[MidnightArrakis]

My PCB's are way simpler than the ones you have posted... i.e. small double sided PCB's.
Nonetheless I am happy to share them with you. What would be the best way to get the files to you. Email would probably be easiest... or Dropbox... if you don't mind giving me that info.

[using Kicad (since you mentioned it!] -- I guess my "Old Eyes" must be blind.....as I have been all through this thread and I haven't seen where anyone has mentioned "KiCAD". Where have I missed this comment?

[What would be the best way to get the files to you. Email would probably be easiest] -- Just ZIP -- ALL -- of the files up and e-mail them to me at: -- [email protected] -- and I will give them a once over, OK??

And, if you have any GERBER and N/C Drill files, include them both as well and I can import them into my "GERBER Analyzing & Editing" program and check them over for any fabrication issues. Also, let me know if you have used either Imperial (Inch) or Metric (millimeter) units for both types of files. The importing routine wants to know that first.

Since you're in Australia, I would assume that everything is in Metric units, right???

I have been reviewing the GERBER and N/C Drill file data of this -- popular -- "NetEQ" PCB using my "GERBER Analyzing & Editing" program and.....>> YOU WOULD NOT BELIEVE << how many issues I have found within these data files!!! And, what I find to be so surprising is.....so many of the members on this forum just blindly and happily buy these files from other members on here without having -- ANY IDEA!!! -- of what it is that they are actually spending their money on!!! In other words.....it's one thing to bring up some GERBER files in a "GERBER Viewer" and take a look at them. BUT!!!.....it's a whole other story to import those SAME files into a program that is capable of performing an analysis of the files and run PCB-fabrication "Design Rule Checks" on them to expose and uncover WHAT IS WRONG with those files!!! That's what my program does.

Bottomline.....I certainly wouldn't send these GERBER and N/C Drill files out to a PCB-fabrication shop to be made. These files would give the PCB-shop far too much -- grief and heartburn -- to have to work on in order for them to provide a customer with a good and workable board!!!

But.....that's just me.

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