GC Preamp Suggestions

[n00beR]

There is all ready a design like this available, but it doesn't use smd components.
The design is by Alcaid discussed here and the eagle files can be found here

Hope this helps

Craig

 

[n00beR]

Here's mine

layout

The two wires are missing Vias

Tobias it has been suggsted it would be benificial to keep the power and signal grounds seperated.

Keep up the good work

 

[n00beR]

Updated my design; It now has indpendant power/signal grounds, individual power traces for each chip and indipenant ground plane for left and right channels

Im not happy with this design as there is a lot of wasted board real estate at the output end 😱

more revisions to come 😛

edit:
Might go the full hog and seperate the boards for true dual mono on this one 😀

 

[filholder]

Hi Guys

This preamp design looks really interesting. It is exactlly what i have been looking.

If, when the design is finalised, someone makes some boards i will defintely be up for some.

If not looks like i might have to have a got at etching for the first time.

Fil

Keep up the good work guys

 

[Gcollier]

These are all very nice designs. I would very much like to hear the consensus on independant versus a single groundplane. Personally I am not so sure this is a better approach...however given that my original plan was for a HT preamp single channels might be best, I could just add as manny as needed. If we do come up with a design that satisfies the masses I would love to see a group buy on it.

 

[maxw]

I would very much like to hear the consensus on independant versus a single groundplane.

Likewise considering how common it is to have the same ground for everything

 

[n00beR]

Regarding ground planes I dont think it matters if you have the one or two. It may help in initial testing if you are having problems with one channel.

As regards shared grounds, I think the general idea is to keep the power and the signal ground seperate to avoid hum produced by the power supply, if any is present.

If a board was put forward for a group buy, I think most people would impliment there own power supply DIY, or otherwise.
All power supplies are not created equal, so it removes the possibility of people being dissapointed in the design due to incompatability with their choice of power supply.

Although you will find a lot of commercial stuff has shared grounds. I don't know about high end stuff, I've never had the money to buy any hence the DIY 😀

I know its proably a 100:1 shot of having power supply problems, but it increases the chances of keeping more people happy.

Also having both preamp sections on a board or only one is down to preference. It depends on how you plan to mount it, or what case you choose to put it in, I have not quite decided yet.

Thanks for all the input, keep it comming.

 

[BrianDonegan]

Knew there had to something out there for this:

http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp?SKU=57F991&N=4

One for volume, one for balance.

Next to the jog dial on my DVD player, there is a small button that changes function. Got me thinking of something like this:

 

[tobias_svensk]

Good morning

jleaman: sure, I can send you the files in a couple of days if you want.

motherone: I'm thinking of sending the files to www.olimex.com
I think i can fit in three of this boards on that "PCB PROTO PANEL DSS - $33,00 USD" they are 100x160mm and the boards are about 75x52mm.

If they looks ok when they come I would keep two myself and then I could always send you the third 😉

 

[n00beR]

I have heard good reports about olimex. Lots of diyers use them.
I think guzzler over at head-fi.org used them in a group buy to get his USB DAC.

 

[tobias_svensk]

Hello noober, sounds nice!

Some pics
Top [210kb]
Bottom [117kb]
"Assembled" [154kb]

 

[steenoe]

Some pics

And those pictures are very nice. Great renderings.

Also having both preamp sections on a board or only one is down to preference.

If the boards end up beeing made professionally, they could be scored like BrianGT's boards. Then you could choose whatever config you want to.
Are you guys considering a PSU board to go with this preamp?

Steen🙂

 

[n00beR]

Here is the latest itteration

 

[carlosfm]

Here is the latest itteration

😱
At last, something quite decent around here.😎

 

[tobias_svensk]

So you think it's a big difference in having separate GP for power and signal ?

I'm asking because I don't know myself.

 

[carlosfm]

I was talking about the PSU bypass arrangement.
It's not so common to see the caps where they should be, as I've been insisting for years.
Some more tuning and they can be even closer, avoiding corners.😉

 

[maxw]

I was talking about the PSU bypass arrangement.
It's not so common to see the caps where they should be, as I've been insisting for years.
Some more tuning and they can be even closer, avoiding corners.😉

But in that last layout they cant get any closer?!?

 

[carlosfm]

But in that last layout they cant get any closer?!?

Really, I can't see the difficulty in understanding what I'm saying.
Look at my previous post, look at the board and think.
How to avoid unnecessary corners and how to get the caps as close as possible to the PSU pins?

One hint:

 

[jleaman]

Hello noober, sounds nice!

Some pics
Top [210kb]
Bottom [117kb]
"Assembled" [154kb]

Are you wanting to do up some board's ? maybe a parts Group Buy ?

 

[tobias_svensk]

Ok, i thought you ment the other thing.

So... if I was to choose between a 120uF 6.3mm/2.5mm and a 330uF 8mm/3.5mm el.cap what would you choose? as the 330uF comes more away from the pin.

Or two 120uF, one very close and the other just beside?