Maxon OD808

[nonoxxx]

Hello ,
I was taking a look at the Maxon Od 808 schematic  and noticed that the filter in  the feedback loop is reversed in comparison with the ts9 /ts808.v ( for what I know the 4.7k and the 50 nf forms a low pass instead of  an high pass).
Is this an error on this schematic ?
(on the vero board layout from tagboardeffects it's the same)

thanks

[Fender3D]

It does not matter which comes first, when you have 2 passives in series

[antonis]

Nothing wrong on schematic.. 

The only difference between TubeScreamer & OD808 in that filter is connection to GND vs Vbias..

Despite components order, R+C (or C+R) in series form the same kind of filter..
(which here is a High Pass one in the mean of: the higher the frequency -> the lower the capacitor reactance -> the more the current flowing through 4k7 resistor - the more the gain...)

edit: Federico is faster..!!

[nonoxxx]

Nothing wrong on schematic.. 

(which here is a High Pass one in the mean of: the higher the frequency -> the lower the capacitor reactance -> the more the current flowing through 4k7 resistor - the more the gain...)

edit: Federico is faster..!!

Thanks a lot, so the maxon at the end have less gain ?

[antonis]

so the maxon at the end have less gain ?

At the end of what..??

OD808 & TS have the same NFB loop arrangement with same cap/pot/resistor values..
Considering both 1458 & 4558 behave in the same manner, it shouldn't be any difference in gain..

Even the HPFs at both OD808 & TS non-inverting inputs are the same (1μF cap, 10k bias resistor & 2 X10k voltage divider resistors) although we shouldn't deal with signal input when dealing with gain as a measure of Vout/Vin..

[nonoxxx]

Ok ,it was the phrase i quoted that confused me ( i am french and my English is not really good )

[antonis]

No problem..

I'm Greek and my French are by far worse than your English..

To make things clear: You can consider both OD808 & TSsomething almost identical..
(at least, about the distortion stage..)

[Mark Hammer]

Le sequence des deux composantes fait aucun difference.

[Fender3D]

^^
...now I must say parbleu!

[POTL]

Hi
A few months ago I was assembling a screamer, and also asked this question)
How to connect VB or GND correctly?
If there is a possibility worth trying, the level of overdrive will be different
If my memory does not lie to me, then when connected to ground overdrive was more powerful, and when connected to VB less tangible.

[nonoxxx]

theorically, you can use both , with no modifications in sound. I have tested it and don't find any differences

[duck_arse]

ahh, I spotted tantalum. that might be the difference in who puts to V/2 and who to ground. to ground, the tant can never be reverse, whereas if it is taken to V/2 bias, the (+) lead might go less than (-) lead, which tantalums don't tolerate. IF it were a poly cap instead, it would not matter where it was referenced, an electro might not like it, but wouldn't up and dies because of a little reverse polarity.

[nonoxxx]

ahh, I spotted tantalum. that might be the difference in who puts to V/2 and who to ground. to ground, the tant can never be reverse, whereas if it is taken to V/2 bias, the (+) lead might go less than (-) lead, which tantalums don't tolerate. IF it were a poly cap instead, it would not matter where it was referenced, an electro might not like it, but wouldn't up and dies because of a little reverse polarity.

Personnaly for these kind of values (0.220uf) , I use film caps  

[nonoxxx]

So what is the hype about this pedal over a ts9 or TS808 ? a lot of guy's tell that i'ts better for hign gains than regular TS (ibanez)

the only differences I see is the Opamps buffers (I don't  think itchange the sound) , I will try  to calculate the output impedance

[Mark Hammer]

The difference between the TS9 and TS808 lies entirely in the output impedance, which can be good in some contexts, and make no difference in others.

[nonoxxx]

yes I know, the two output resistor, my interrogation was for the Maxon OD808, I heard a lot of people said that the maxon is better

[Fender3D]

^^
a lot of people believe electronics is a miracle too...

[edy_wheazel]

 As it was already said above, nothing wrong there. I build it from this exact schematic and it works fine.