Alembic F2-B

phil mailloux · 7th April 2008, 12:32 PM

Hey guys,

I want to build a clone of the Alembic F2-B starting from the schematic on this site. http://moosapotamus.net/IDEAS/F2B/alembic.htm

The only difference being that I only want one channel. I should mention I'm a newbie in electronics, not totally though, I've done some soldering of PCB kits before and such. A friend of mine who's an engineer will also help.

So here's my questions

I've drawn up an eyelet board for the placing of the components, can one of you guys be so kind as to check out this next to the schem and telll me if I did it ok? I'm not sure I got all the switches and pots with the right lugs. Look at the drawing of my pots like you would be directly looking at the back of the pot. Also, I had no idea how to draw a switch and for that matter what sort of switch to use.

This is only the drawing of the channel. My friend and I still need to figure out the power section.

Brett · 7th April 2008, 04:36 PM

If no one else has got back to you by next week, I'll scope it out for you. I have exams and a major project to complete this week.

You'll probably neeed to bump the thread back up to the top to remind me though.

makinson1 · 8th April 2008, 09:23 PM

Hint, Hint. Look at the schematic of the Black Face Fender Twin-Reverb. That's the one Garcia gave to Turner to build the prototype. Somebody out there is making good quality G10 glass boards with brass turrets for the old fender amps. Save yourself a ton of work and buy one.

phil mailloux · 9th April 2008, 12:21 AM

Thanks very much for the hint. I had read the circuit was based on a blackface dual showman so I went and checked out a bunch of Fender circuits. The F-2B's channels are obviously Fender tone stacks, no doubt about that and it is indeed almost identical to the vibrato channel of the blackface twin reverb besides one or two cap values.

I doubt I'll find a pre-built layout exactly like that but at least now I can compare my layout to the Fender ones available.

makinson1 · 9th April 2008, 12:50 AM

Check these out:
http://www.hoffmanamps.com/index.html
http://www.turretboards.com/

phil mailloux · 12th April 2008, 08:18 AM

Thanks very much for the links, I won't find something pre-made since I'm only building a preamp but now I know where you find the glass boards and the turrets for when I build it.

I like to do it all myself anyway, I feel like I'm cheating if I buy a turret board or populated board from someone else

So does anyone have a second to see if my layout will work or if I screwed up? I'd be eternaly grateful to anyone who does

scottnixon · 16th April 2008, 02:58 AM

The schematic referenced has an error in the tone stack. There is a node on the 100k and 250pf at top. The 680pf is paralleled with the 250 to shift the treble point. There are several photos of the F-2B on the net showing controls and switches. While your basic eyelet layout (with the above correction) would work, it looks potentially noisey and very messy with too many runs from the controls to the board and the treble boost and shift caps should be close to controls and not on the board. Again find photos of the alembic's internals as well as other guitar heads and emulate the layout and ground paths. There are turrent board versions of Princetons that can easily fit your needs. I have fun building preamps for myself all the time, one or two different each year. It's easy, but tricky and if you're a rookie with tubes, read up on safety or build a fet version

GRollins · 16th April 2008, 03:04 AM

I have it directly from Mica Wickersham that the F2-B is a straight derivative of the old Fender front end. There's no debate there. The "F" in the name is a hint if you want to think along those lines. Add an effects loop and a simple crossover and you're done.
I own one, myself. It makes a nifty front end for a Hafler P-500.

Grey

Nordskov · 18th April 2008, 09:18 PM

So scottnixon what you are saying is that where the line from R4 to C3 crosses the line from C2 to R5 there should be a connection between the two?!

I have just finished my layout and are about to order the electronic parts so this is vital information.

I plan only to make a single channel preamp but with the same circuit as Phill found on moosapotamus.
He has a good power supply compared to the original.

I just can't wait to finish this project!

Thanks

scottnixon · 19th April 2008, 03:16 AM

Yes, there should be a 'dot' or node at intersection of C2, C3 and R5. Phil's eyelet-layout was missing that connection.

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7th April 2008, 04:36 PM	#2
Brett diyAudio Member Join Date: Jan 2002	If no one else has got back to you by next week, I'll scope it out for you. I have exams and a major project to complete this week. You'll probably neeed to bump the thread back up to the top to remind me though.

8th April 2008, 09:23 PM	#3
makinson1 diyAudio Member Join Date: Aug 2004 Location: Tallahassee, FL	Hint, Hint. Look at the schematic of the Black Face Fender Twin-Reverb. That's the one Garcia gave to Turner to build the prototype. Somebody out there is making good quality G10 glass boards with brass turrets for the old fender amps. Save yourself a ton of work and buy one.

9th April 2008, 12:21 AM	#4
phil mailloux diyAudio Member Join Date: Mar 2006 Location: Canadian in Australia	Thanks very much for the hint. I had read the circuit was based on a blackface dual showman so I went and checked out a bunch of Fender circuits. The F-2B's channels are obviously Fender tone stacks, no doubt about that and it is indeed almost identical to the vibrato channel of the blackface twin reverb besides one or two cap values. I doubt I'll find a pre-built layout exactly like that but at least now I can compare my layout to the Fender ones available.

9th April 2008, 12:50 AM	#5
makinson1 diyAudio Member Join Date: Aug 2004 Location: Tallahassee, FL	Check these out: http://www.hoffmanamps.com/index.html http://www.turretboards.com/

12th April 2008, 08:18 AM	#6
phil mailloux diyAudio Member Join Date: Mar 2006 Location: Canadian in Australia	Thanks very much for the links, I won't find something pre-made since I'm only building a preamp but now I know where you find the glass boards and the turrets for when I build it. I like to do it all myself anyway, I feel like I'm cheating if I buy a turret board or populated board from someone else So does anyone have a second to see if my layout will work or if I screwed up? I'd be eternaly grateful to anyone who does

16th April 2008, 02:58 AM	#7
scottnixon diyAudio Member Join Date: Mar 2001 Location: High Point, NC	The schematic referenced has an error in the tone stack. There is a node on the 100k and 250pf at top. The 680pf is paralleled with the 250 to shift the treble point. There are several photos of the F-2B on the net showing controls and switches. While your basic eyelet layout (with the above correction) would work, it looks potentially noisey and very messy with too many runs from the controls to the board and the treble boost and shift caps should be close to controls and not on the board. Again find photos of the alembic's internals as well as other guitar heads and emulate the layout and ground paths. There are turrent board versions of Princetons that can easily fit your needs. I have fun building preamps for myself all the time, one or two different each year. It's easy, but tricky and if you're a rookie with tubes, read up on safety or build a fet version

16th April 2008, 03:04 AM	#8
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	I have it directly from Mica Wickersham that the F2-B is a straight derivative of the old Fender front end. There's no debate there. The "F" in the name is a hint if you want to think along those lines. Add an effects loop and a simple crossover and you're done. I own one, myself. It makes a nifty front end for a Hafler P-500. Grey

18th April 2008, 09:18 PM	#9
Nordskov diyAudio Member Join Date: Jun 2007	So scottnixon what you are saying is that where the line from R4 to C3 crosses the line from C2 to R5 there should be a connection between the two?! I have just finished my layout and are about to order the electronic parts so this is vital information. I plan only to make a single channel preamp but with the same circuit as Phill found on moosapotamus. He has a good power supply compared to the original. I just can't wait to finish this project! Thanks

19th April 2008, 03:16 AM	#10
scottnixon diyAudio Member Join Date: Mar 2001 Location: High Point, NC	Yes, there should be a 'dot' or node at intersection of C2, C3 and R5. Phil's eyelet-layout was missing that connection.