Maxon OD-808 for OD-820 what the one changed?

[ANDYEFFECT]

Maxon OD-808 for OD-820 what the one changed? 
 
What did change among the two pedals? which the differences? 
is it just the placement of a circuit to increase the voltage it interns from 9v to 18v? 
abraços
hugh

André

[ANDYEFFECT]

Maxon OD-808 for OD-820 what the one changed? 
 
What did change among the two pedals? which the differences? 
is it just the placement of a circuit to increase the voltage it interns from 9v to 18v? 
abraços
hugh

André

maxon uses two 1458 op-amp?

[JHS]

The OD-820 is a stock TS-808 with Chargepump and a slightly different gain adjustment (double pot - FB-Loop and RC-network alà Dist+).
Furthermore there is a passiv mid-filter with a recovery stage after the clip-stage.

JHS

[ANDYEFFECT]

The OD-820 is a stock TS-808 with Chargepump and a slightly different gain adjustment (double pot - FB-Loop and RC-network alà Dist+).
Furthermore there is a passiv mid-filter with a recovery stage after the clip-stage.

JHS

is there some way of transforming the od-808 in od-820?

[JHS]

Short answer: IMHO No !!!

Of cause you can mod the 808 to 820 specs, but afterwards you might be disappointed with the sound.
Compared to the 808 the 820 is a thin, artificial sounding OD with only a bit more headroom (the I-buffer in the 820 operates only with 9V) and a little more output. IMHO the 820 can't beat a good 808.

You can change the ICs in the 808 to LF 353, JRC TL072 or OPA 2132 for a clearer, less middy sound.

JHS