Alembic F2B! (PCB and Layout)
Hello Everyone!
Started this project about a month ago, started doing some research before designing the PCB and stuff.
Used moosapotamus' schems (for both preamp and PSU with slight mods)
Just did the first tests and it sounds really really good. I'm testing it straight to my Ampeg SVT's Poweramp and I'd even dare to say that I like it better than the Ampeg's tube preamp.
This baby is really soft, warm and tubey, but it's also got lots of punch, ideal for every style basically.
So, here is the %&+*!:
PCB: http://rapidshare.com/files/201834589/A ... B.pdf.html
Some instructions:
-Pads labeled with numbers correspond to the 12AX7's pins.
-Both stages cathode bypass caps (C3, C5, C10, C11) are 50uF as appears in the schem, but had some troubles finding some quality caps for that value here in chile so I designed the PCB for using 2 Axial 25u Sprague Atom in parallel, also elft the pads for using normal radial 47uF Caps.
-Bright Switch wired as shown, Low pot must be wired upside down!
-Use Shielded cable for input.
-I left the grounds separated according to each "stage" of the preamp following RG's instructions in his great Star grounding article. All the ground must be indeed wired to the chassis using a single node (or "star"), which should be as close as possible to the input (it shouldn't be so far away from the PSU either)
-I used a 250V AC for High Voltage and 6,3V AC for heaters.
Values:
Resistors:
-R1, R2, R3: 1.5k 2W
-R4, R5: 100R 1/2W
-R6: 470k/2W
-R7: 68k 1/4W
-R8, R14: 1M 1/4W
-R9, R12: 1.5K 1/4W
-R10, R13: 100k 1W
-R11: 100k 1/2W
Caps:
-C1, C2, C4: 47uF/450V
-C3,C5 / C10, C11 : 25uF (Can be replaced by 47uF)
-C6 250pF 300V(?) (I used a Silver Mica with high voltage tolerance, 500V I think)
-C7, C12: 100nF
-C8: 47nF
-C9: 100pF
Some useful Links:
http://www.moosapotamus.net/IDEAS/F2B/alembic.htm
http://www.geofex.com/article_folders/s ... targnd.htm
Warning: Project as this preamp have voltages than can be lethal, please be careful and don't do it if you don't have enough experience with this kind of circuits!
Enjoy!
Greetings from Chile!
Douglas
Started this project about a month ago, started doing some research before designing the PCB and stuff.
Used moosapotamus' schems (for both preamp and PSU with slight mods)
Just did the first tests and it sounds really really good. I'm testing it straight to my Ampeg SVT's Poweramp and I'd even dare to say that I like it better than the Ampeg's tube preamp.
This baby is really soft, warm and tubey, but it's also got lots of punch, ideal for every style basically.
So, here is the %&+*!:
PCB: http://rapidshare.com/files/201834589/A ... B.pdf.html
Some instructions:
-Pads labeled with numbers correspond to the 12AX7's pins.
-Both stages cathode bypass caps (C3, C5, C10, C11) are 50uF as appears in the schem, but had some troubles finding some quality caps for that value here in chile so I designed the PCB for using 2 Axial 25u Sprague Atom in parallel, also elft the pads for using normal radial 47uF Caps.
-Bright Switch wired as shown, Low pot must be wired upside down!
-Use Shielded cable for input.
-I left the grounds separated according to each "stage" of the preamp following RG's instructions in his great Star grounding article. All the ground must be indeed wired to the chassis using a single node (or "star"), which should be as close as possible to the input (it shouldn't be so far away from the PSU either)
-I used a 250V AC for High Voltage and 6,3V AC for heaters.
Values:
Resistors:
-R1, R2, R3: 1.5k 2W
-R4, R5: 100R 1/2W
-R6: 470k/2W
-R7: 68k 1/4W
-R8, R14: 1M 1/4W
-R9, R12: 1.5K 1/4W
-R10, R13: 100k 1W
-R11: 100k 1/2W
Caps:
-C1, C2, C4: 47uF/450V
-C3,C5 / C10, C11 : 25uF (Can be replaced by 47uF)
-C6 250pF 300V(?) (I used a Silver Mica with high voltage tolerance, 500V I think)
-C7, C12: 100nF
-C8: 47nF
-C9: 100pF
Some useful Links:
http://www.moosapotamus.net/IDEAS/F2B/alembic.htm
http://www.geofex.com/article_folders/s ... targnd.htm
Warning: Project as this preamp have voltages than can be lethal, please be careful and don't do it if you don't have enough experience with this kind of circuits!
Enjoy!
Greetings from Chile!
Douglas
- fosnal1950
- Breadboard Brother
Hi Darkglass,
Great work there, I've always wanted to try one but never got to it.
Could post me the pdf file ; it could only be downloaded 10 times and I was too late.
Could I pm you with my e-mail address ?
Alf
Great work there, I've always wanted to try one but never got to it.
Could post me the pdf file ; it could only be downloaded 10 times and I was too late.
Could I pm you with my e-mail address ?
Alf
- moltenmetalburn
- Resistor Ronker
PCB pdf hosted here for all to download, enjoy!
http://www.redhillmetal.com/uploads/Alembic%20PCB.pdf
thanks again douglas!
http://www.redhillmetal.com/uploads/Alembic%20PCB.pdf
thanks again douglas!
"The Humans Will Never Destroy Us"
- fosnal1950
- Breadboard Brother
Thanks guys !
Regards, Alf
Regards, Alf
- premiumplus
- Breadboard Brother
Very cool, darkglass, good work.
Are you playing bass or guitar through this? I've read that David Gilmour used to use Alembic preamps, and I'm guessing that this is the one? And what / where do you get the stepup transformer, T2?
Thanks!
Are you playing bass or guitar through this? I've read that David Gilmour used to use Alembic preamps, and I'm guessing that this is the one? And what / where do you get the stepup transformer, T2?
Thanks!
Vinyl rules.
I built it for a Bass Player... I'm a bassist as well, it's unbelievable on bass. Really really great sound...I own a Mesa and an Ampeg bass hybrid heads and this was as good as the preamps on those 2 amps!
Really nifty having in mind that this uses just 1 12ax7.
And yes, David Gilmour uses this preamp with Hiwatt poweramps . It sounds amazing on guitar as well!
I used just one custom made transformer. And it's inside the same chassis.
With 250V, and 6.3V taps.
Regards
D.
Really nifty having in mind that this uses just 1 12ax7.
And yes, David Gilmour uses this preamp with Hiwatt poweramps . It sounds amazing on guitar as well!
I used just one custom made transformer. And it's inside the same chassis.
With 250V, and 6.3V taps.
Regards
D.
- moltenmetalburn
- Resistor Ronker
Beautiful work Douglas!
"The Humans Will Never Destroy Us"
- briggs
- Tube Twister
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- borislavgajic
- Opamp Operator
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- Posts: 1542
- Joined: 27 Feb 2008, 14:23
- Completed builds: ...script phase90,ETI phaser,Ross phaser,mutronC200,vox wah,WH10,FW-3,mutronIII,DrQuack,Penfoldautowah,Tubezipper,
Dipthonizer,seekwah,Talkingpedal,morleywha
...soulpreacher,dynacomp,compulator
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EHX bassmicrosynth,EHX EnglishMuffin,Tube Phaser,springtubereverb ,greyDOD,FulldriveII mosfet,OCD,VOX repeat percussion,RingStinger,Meatball,12stage phaser.... - Location: Sombor , Serbia
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Wow that rocks boris!!!
Thanks a lot!!
Thanks a lot!!
- borislavgajic
- Opamp Operator
Information
- Posts: 1542
- Joined: 27 Feb 2008, 14:23
- Completed builds: ...script phase90,ETI phaser,Ross phaser,mutronC200,vox wah,WH10,FW-3,mutronIII,DrQuack,Penfoldautowah,Tubezipper,
Dipthonizer,seekwah,Talkingpedal,morleywha
...soulpreacher,dynacomp,compulator
...buzzaround,fuzzfactory,screwdriver,sho,superdouper,St-9,RogerMayer octavia,Tychobrahe octavia,paralelluniverse,string damper,slowgear
...CE-2,ibanez fL301,EH theCloneTheory
EHX bassmicrosynth,EHX EnglishMuffin,Tube Phaser,springtubereverb ,greyDOD,FulldriveII mosfet,OCD,VOX repeat percussion,RingStinger,Meatball,12stage phaser.... - Location: Sombor , Serbia
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you are welcome
boris
boris