The return of the BSIABII. 2N3819 or BF245C?

Started by Xavier, December 12, 2005, 11:12:04 AM

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Xavier

After a few succesful builds now I will attempt both the Colorsound Overdriver and (again) the BSIABII.

Now that I have the original vero I did for the BSIABII, it's no wonder it didn't work at all. All the transistors were wrong placed, at least 2 resistors were wrong (K instead of R :icon_eek:), and I even forgot a capacitor. Why did I use a 2N3904?.....well.....

Now that I have some J201, Q3 and Q4 is no problem, but what about Q1, Q2 and Q5? I know from reading the archives that all-j201 Bsiabs sound gainy and compressed, but I don't have any 2N5457 at hand. I only have 2N3819 and BF245C. Which should I use?. I have downloaded both datasheets but looks like chinese language to me.

Also, I'm attempting my first vero layout, the Shaka Express. Will post as soon as it's done....

Steben

#1
Phew.... don't know: 2N5457 are quite cheap you know  ::). BF245"A" should work...

EDIT: 2N5457 has a huge specification tolerance! Some could even sound the same as J201.
Yet your BF245C should do it I guess. Definitely less gain than a J201. Mind the different pin placements with fet's!
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Marcos - Munky

Use the J201s. I built mine using them, and it sound great. A friend build one using BF245s, and it didn't worked, but I don't know if he uses BF245C (the one with most gain), or another one with less gain.

Xavier

Quote from: Marcos - Munky on December 12, 2005, 11:54:54 AM
Use the J201s. I built mine using them, and it sound great. A friend build one using BF245s, and it didn't worked, but I don't know if he uses BF245C (the one with most gain), or another one with less gain.

I have enough J201's to build it. It's just that I've read some opinions about them having too much gain. Originally the designer (Ed Guidry?) thought that the 2n5457 on the first stage made the pedal sound more open and not so compressed

The thing about the pinouts is crazy. 2n5457, 2n3819 and bf245c ALL HAVE DIFFERENT PINOUTS.

Marcos - Munky

Mine have J201 for everything and it doesn't sound compressed. It reminds me Van Halen's "Ain't Talking About Love" sound.

Jered

  Why not put TO-92 sockets on your board and then try all the different FET's you have until you find the combination you like. Then solder them in.
  You don't even have to use TO-92 sockets. Any sockets will do.
  Jered

Xavier

Quote from: Jered on December 12, 2005, 09:04:22 PM
  Why not put TO-92 sockets on your board and then try all the different FET's you have until you find the combination you like. Then solder them in.
  You don't even have to use TO-92 sockets. Any sockets will do.
  Jered

Transistor sockets are very hard to find in Spain. Maybe I could use opamp sockets for that purpose ..

Jered


didier

Quote from: Xavier on December 13, 2005, 03:40:07 AM
Transistor sockets are very hard to find in Spain. Maybe I could use opamp sockets for that purpose ..

or use a one-line socket and just clip off 3 holes (your pcb must be arranged for in-line transistors this way)
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