Boss - FA-1 Fet Amplifier

Duckman · Post by **Duckman** » 15 Jul 2009, 02:29

Hi, guys!
After my search for options, here's the problem:
reading some reviews about the FA-1, I became interested in build it, so I breadbord it first, but for some reason got less volume than I expected. To make it short, I checked, double and triple checked, change parts, change breadboard and... nothing... still a kind of 1:1 volume. I never got the oportunity to try one of this, but I see reviews that claim it as a louder device. I also read here that some factory schems have "mistakeks" included.

Maybe the problem it's obvious for someone with a little more knowledge than me

If someone used this schem without a problem, I accept any help.

Tkx!

Duckman · Post by **Duckman** » 16 Jul 2009, 17:35

Nobody?

Duckman · Post by **Duckman** » 06 Aug 2009, 01:58

Ok, got it.
Maybe somebody got the schems or some gut shots of the Analog Man version to see diferences by my self?
Tkx!

roseblood11 · Post by **roseblood11** » 06 Aug 2009, 06:06

Hi,

I think the schematic is correct. And as far as I know, it IS a very loud unit...
The same schematic is published on ustomp: http://ustomp.com/?p=6,
but he uses a different opamp in his layout.
He claims that C2 is a "non-polar 47F cap", but he must have misread the schematic, I´m sure that it says "0.47µF np"...

Did you use the HA1457W opamp?

regards, Immo

Duckman · Post by **Duckman** » 09 Aug 2009, 00:20

Thanks for your post, Immo!

I noticed that C2 value is a little unclear, so I tried both values, and I don't ear a big difference. Also, I buyed the two HA1457W and the 2SK246GR at Small Bear, trying to keep the original configuration, but no "loudest" at all.
What about R5? Is the only value not printed, just handwritten. Maybe...?
In order to reach some satisfaction, I'll try the 4558/J201 version, just in case... and I tell you when I'm done.
Thanks for your time!!
I found this too:

Dimitree · Post by **Dimitree** » 11 Mar 2011, 20:47

so I want to confirm that the original schematic is 100% correct and that cap is a 0,47uF, not a 47uF. I have the original pedal at home and compared with the clone I can't tell any difference.

the pedal shown in the attached pic is not mine, it's another version of the FA1 based around another IC, but the rest is identical (except the ceramic caps, different values and different connection with the IC), and you can see C2 0,47uf. I will add some pics of mine too.

Dimitree · Post by **Dimitree** » 11 Mar 2011, 20:54

pics of mine:

ps. I confirm 15K for the handwritten resistor

Dimitree · Post by **Dimitree** » 11 Mar 2011, 21:00

this is the other version
it's easy to spot the differences: different IC, 2 more resistors, different values for the 2 ceramic caps. you can notices that those differences are only to adapt this different IC on the circuit

Duckman · Post by **Duckman** » 11 Mar 2011, 23:01

Awesome!!

You're a very kind person

iq01221 · Post by **iq01221** » 21 Jun 2011, 03:19

Y just did a improved version, sounds great!!!!
Layout:
http://ustomp.com/files/fa1buildetch.pdf

Rockhound252 · Post by **Rockhound252** » 12 Nov 2011, 19:37

Have you got any othe layout¿ In a springboard i think

Duckman · Post by **Duckman** » 12 Nov 2011, 23:35

Springboard? You mean stripboard, right?

iq01221 · Post by **iq01221** » 13 Nov 2011, 04:39

I've made the ustomp version, with 4,7uF, like the schem says, j201 and TLC2272 SMD dual-opamp. And it's a very loud stomp.
I've tried with 47uF cap too, but it don't affect the out volume anyway...

It's a great sounding pedal. I hope you can solve it.
Regards!!

Duckman · Post by **Duckman** » 13 Nov 2011, 11:23

Well done. In one of the photos posted above by Dimitree, you can see clearly a 0.47uF in the original board, but, as I said before, not a big difference in sound.
Mine, I finally gave it to a friend because I do not settle for the sound.

RnFR · Post by **RnFR** » 13 Nov 2011, 12:09

with all these gutshots, ive decided to turn this into the official FA-1 thread, since we don't have one yet.

guycapuano · Post by **guycapuano** » 03 Dec 2011, 18:23

Anyone have a vero for this one? I had an original here yesterday and am FLOORED!

guycapuano · Post by **guycapuano** » 05 Dec 2011, 21:43

bump anyone?

roseblood11 · Post by **roseblood11** » 05 Dec 2011, 21:47

download the "do it yourself layout creator" and make a vero...

guycapuano · Post by **guycapuano** » 05 Dec 2011, 21:48

roseblood11 wrote:download the "do it yourself layout creator" and make a vero...

I dont know how yet, I'm a noob remember?

Duckman · Post by **Duckman** » 06 Dec 2011, 02:40

C'mon guycapuano! Give it a chance! The DIYLC program it's not hard at all and you'll be satisfied doing it by yourself

Boss - FA-1 Fet Amplifier [schematic]