MPF102 OD?

[Alpha579]

Hey evry1,
Are there any nice MPF102 OD's that can also be used as a clean boost ala Tubescreamer? Because i want to make a simple but effective od to get some SRV sounds out of my wee valve amp. Any suggestions?
Alex

[Brian Marshall]

my next original design is a 3 fet overdrive. uses mpf102's.  I dont want to give it away, but it really isnt all the ground breaking.

it can go from clean boost to all out fuzz, but gets a very nice TS sound with a more natural pick attack.

the first fet is just a buffer.  Then two drain follower amplifiers with a feedback loop....

[Gringo]

You can try the Odie at RunOffGroove, they say it's been tested with both j201 and mpf102. You can also try the peppermill (ROG again), just sub the 1k source resistor with a 2.2k and the 1uf source cap with a 2.2 or 4.7uF to replace the j201.

Good luck!

[Alpha579]

Brian, sounds cool! Cant wait till youve finished!
The Odie is quite high gain isnt it?

[Brian Marshall]

never built an odie, but they compare it to a tubescreamer.

[brett]

Hi.  I've fooled with the Odie and learned a few things.
First I built it with 2N5485s (I think) and found that I needed largish caps to bypass the source resistor to get the gain up to a good level (1 used 2 x 4.7uF, which might be what the V1 schematic called for).  Later I substituted J201 fets and found that the gain was a bit too wild.  I virtually stopped using it (it had almost as much gain as a Blackfire).  Recently, I reduced the bypass caps down to 1uF (each) and it is really singing again.  A bit like a tubescreamer with the drive way up, but much smoother distortion.  A really good sound.  So the result you get depends a lot on the gain you are dialling in via different jfets and different bypass caps.

have fun.