Alembic F2B FET Version with Balanced Output

DarkRain · Post by **DarkRain** » 17 Dec 2013, 14:20

Had a little time for a friend request (he is a bass player and wanted a little preamp for small / medium gigs). I've used a FET version of the Alembic F2B bass preamp and attached an balanced output - for maximum headroom the pedal will use AC power supply (9V AC) - the OA is using +/- power supply.

This is the last version of the schematic and the first version of board. Build it ... put it on oscilloscope, everything looks good (i don't have a bass guitar right now for some tests but already spoked to a friend of mine to come and give it a try).

SCH: https://dl.dropboxusercontent.com/u/152 ... 2b_fet.sch
BRD: https://dl.dropboxusercontent.com/u/152 ... 2b_fet.brd

If you would like to build it you are more then welcomed.

Best regards,
Gabriel Tudoran
Analog Sound

PS: It works wonderful with guitar also.

Godebut · Post by **Godebut** » 27 Dec 2013, 20:00

I just get a shedload of text when hitting the schematic?

DarkRain · Post by **DarkRain** » 27 Dec 2013, 20:10

Hhihiih

just right-click and save link as (or save file as) - that is what is inside an eagle file. That is correct, just save them as files and should be OK (web browsers doesn't recognize the MIME Type)

Best regards,
Gabriel Tudoran
Analog Sound

Godebut wrote:I just get a shedload of text when hitting the schematic?

Godebut · Post by **Godebut** » 28 Dec 2013, 12:47

Thanx

DarkRain · Post by **DarkRain** » 28 Dec 2013, 13:19

No problem,

If you will build it drop me an opinion about it.

Best regards,
Gabriel Tudoran
Analog Sound

DarkRain · Post by **DarkRain** » 30 Dec 2013, 15:21

Tow pictures with the prototype and ... a sound sample with various settings directly into sound card.

Please don't throw with tomatoes .... i'm just a guitar player

Best regards,
Gabriel Tudoran
Analog Sound

DarkRain · Post by **DarkRain** » 05 Jan 2014, 10:19

Hey guys, some recordings made by a friend of mine who is a bass player (not like me

). The EQ was at 12 o'clock and in the name of the clips you will find the Gain and Volume settings (ex G9 V8 is Gain at 9 o'clock and Volume at 8 o'clock).

There are also 3 clips recorded with the bass directly into sound card and one with Sansamp BDDI and one with M80 from Mxr. The clips ware recorded for comparison.

Enjoy and any comments are greatly appreciated.

Best regards,
Gabriel Tudoran
Analog Sound

deltafred · Post by **deltafred** » 05 Jan 2014, 20:59

Sounds pretty good.

I have saved the .sch and .brd files but Eagle won't open either, it gives an errors of "Invalid data in file /home/...." I have no experience of using Eagle so maybe it is something I am doing wrong.

Any chance of putting up a schematic as a jpg, gif or png file?

Post by **The G** » 06 Jan 2014, 07:26

It opens all right in Eagle 6.4.0.

: f2b_fet_sch.png (4.48 KiB) Viewed 3796 times

This PCB image has 300dpi.

: f2b_fet_pcb.png (8.91 KiB) Viewed 3796 times

deltafred · Post by **deltafred** » 06 Jan 2014, 10:40

Thanks for the pictures ggedamed.

I was trying to use Version 5.12.0 for Linux from the Ubuntu Software Centre, which is probably well out of date.

I should get the latest version from the Eagle website, but I really don't need another application to learn.

DarkRain · Post by **DarkRain** » 06 Jan 2014, 10:54

The schematic is not full, i will post it ASAP (the supply and xlr output is not in there).

Best regards,
Gabriel Tudoran
Analog Sound

PS: This is the link with PDF with full schematic https://dl.dropboxusercontent.com/u/152 ... t_full.pdf

deltafred wrote:Thanks for the pictures ggedamed.

I was trying to use Version 5.12.0 for Linux from the Ubuntu Software Centre, which is probably well out of date.

I should get the latest version from the Eagle website, but I really don't need another application to learn.

deltafred · Post by **deltafred** » 06 Jan 2014, 12:58

I deleted my old version of Eagle and downloaded the latest, 6.5.0 (Light), and it works fine now. Thanks guys.

What voltage AC are you using DarkRain?

DarkRain · Post by **DarkRain** » 06 Jan 2014, 13:18

Anything between 6 and 10v would do ... is not critical.
I would recommend not to exceed 10v as it will exceed opamp voltage (30v - +/- 15v)

Best regards,
Gabriel Tudoran
Analog Sound

deltafred wrote:I deleted my old version of Eagle and downloaded the latest, 6.5.0 (Light), and it works fine now. Thanks guys.

What voltage AC are you using DarkRain?

Duckman · Post by **Duckman** » 09 Jan 2015, 13:25

Dropbox links are dead

Please, can somebody share a new valid link, or pdf of the complete project?
Thanks!

DarkRain · Post by **DarkRain** » 09 Jan 2015, 13:39

Duckman wrote:Dropbox links are dead
Please, can somebody share a new valid link, or pdf of the complete project?
Thanks!

@Duckman - There you go bro, both BRD and SCH eagle files

https://dl.dropboxusercontent.com/u/152 ... 2b_fet.brd
https://dl.dropboxusercontent.com/u/152 ... 2b_fet.sch

Duckman · Post by **Duckman** » 09 Jan 2015, 17:38

Thanks a lot!
This is a little embarrassing

but I don't use eagle.
If you have the pdf, you save me from install eagle just to see one schemo

If you don't, I downloaded the codes, any way and I'll wait a little more and then... reinstall eagle!

DarkRain · Post by **DarkRain** » 09 Jan 2015, 19:08

that is not a problem. I will make you a pdf doc tomorow with the schematic and a ready to print pcb

Duckman · Post by **Duckman** » 09 Jan 2015, 23:59

Tanks!!

I just need the schematics, but a verified PCB always help to check and debug.

Thanks again!

WarrenPease · Post by **WarrenPease** » 14 Jan 2015, 02:36

Hi, Gabriel.

Thanks for all the cool stuff you have posted for our benefit.

What value resistor do you use in between the caps in the power supply, (R6, R7, R8, R9)?

Something like 120R?

Thanks

DarkRain · Post by **DarkRain** » 14 Jan 2015, 08:31

@WarrenPease: anything between 100 and 150 ohm will do just fine

Regards,
Gabriel