power sag in a stupid DS-1 stompbox

Started by Steben, May 04, 2011, 06:00:13 AM

Previous topic - Next topic

Steben

Think about this: an opamp draws more current as signal increases, most of them are class AB.
If one puts a sag resistor in series with the power/battery line, the supply voltage drops at higher current draw.
Since the clipping treshold is set by silicon diodes, headroom change is nihil. However, if one uses for example zeners at higher treshold (+/-3V) the fall in supply voltage crosses the clipping treshold. This means at higher draw the clipping can get harsher. just my 50 cents.
But another big change is the following: the single transistor stage in front of the opamp has a very fragile bias setup. The base voltage is set by a feedback divider circuit. This means that the base voltage drops as well as the power drops. Knowing the log characteristics of the base-emitter junction, this means a drop in gain (response curve gets flat). Compression gets involved!!!
  • SUPPORTER
Rules apply only for those who are not allowed to break them

ayayay!

Are you just kind of "thinking out loud" here?  I thought this was all common knowledge about the DS-1. 
The people who work for a living are now outnumbered by those who vote for a living.

Steben

Quote from: ayayay! on May 04, 2011, 09:31:18 AM
Are you just kind of "thinking out loud" here?  I thought this was all common knowledge about the DS-1.  

power sag in a DS-1?  :o common knowledge?
Talking about adding resistor in power line?
  • SUPPORTER
Rules apply only for those who are not allowed to break them

Steben

I mean: no dying battery stuff please .... that's a bit rubbish
  • SUPPORTER
Rules apply only for those who are not allowed to break them