YA Simple OD/Boost....

[ExpAnonColin]

Someone from the HC boards commissioned me to build then a light overdrive, this is what I came up with.  Since I'm at work, and love being off task, I thought I'd draw a schematic up quick...  It actually doesn't sound bad at all, especially for the amount of thought I put into it.  It *does* have some very very light mis-bias crackle at the decay... but it really does overdrive quite nicely, it's sort of a treble boost with some nice light clipping capabilities.

Thought I'd post it for the OD addicts/newbies looking for a simple project.  The perf layout is realyl straightforward, so I didn't think I'd post what I ended up doing (it only took me maybe an hour, and I got it right the first try...)

Any schem mistakes/bad design recommendations are appreciated of course...  The 100? value  I can't remember from work, so play around with it either way.

Cheers!

-Colin

[petemoore]

Signal path> Base tied to ground, that's a small amount of resistance.
 I think I'd start somewhere like 470k or twixxed 100k -  1meg

[travissk]

It *does* have some very very light mis-bias crackle at the decay...

Crackle OK!  

[ExpAnonColin]

Signal path> Base tied to ground, that's a small amount of resistance.
 I think I'd start somewhere like 470k or twixxed 100k -  1meg

Run that through me again?  What exactly are you referring to?  The initial 690 ohms to ground on the first base?

-Colin

[puretube]

being aware of the risk of being misunderstood ( :wink: ) :
the 10µF el. cap after 1st transistor should be replaced by a link
(=dead short, omit, direct connection...);
it doesn`t do anything
but reducing the effective value of the following 0.2µF cap
by about 2%.....

[ExpAnonColin]

being aware of the risk of being misunderstood ( :wink: ) :
the 10µF el. cap after 1st transistor should be replaced by a link
(=dead short, omit, direct connection...);
it doesn`t do anything
but reducing the effective value of the following 0.2µF cap
by about 2%.....

Thanks... wouldn't have seen that myself.

-Colin

[ExpAnonColin]

Fixed...

-Colin

[puretube]

at the risk....
837k is very close to 820k in series with 18k...

[ExpAnonColin]

at the risk....
837k is very close to 820k in series with 18k...

I only buy/use 10, 47, and 22 values.

-Colin

[petemoore]

I'm sorry to have interjected like that, [fishing for feedback on resistor values from base to ground?...could be], ...I should have used the trusty '?'.

[puretube]

me too would insert a "k" for the "?"
0.1µF/690R is s.th like a low-impedance ~2khz hi-pass,
which in turn doesn`t require a big 10µF afterwards,
supposed there`s s.th. left to amplify at all, when gain pot
is maxed, loading the pickup with the series 0.1/690...

[ExpAnonColin]

I was using that resistance to ground to decrease the amplitude of the oncoming signal, basically as a fixed pot at a very low setting...  not realizing of course that I was creating a HP filter, which explains the hotter sound of the box.

-Colin