Tube bass overdrive
- Bernardduur
- Transistor Tuner
Hey all!
I found this picture a while ago on the internet by searching on "bass overdrive" in google. Right now I can't seem to find it anymore.
Can anybody tell me something about it? I can't find if it is an idea, an already exsisting pedal or something completely different. The 6E5 tube is awesome (magic Eye)......... although I don't know it's function there then to determine the overdrive.
I'm asking as I am designing a new bass amp for myself (ultra lin 6550 amp) and I know it'll lack OD. This circuit is maybe quite nice in it
I found this picture a while ago on the internet by searching on "bass overdrive" in google. Right now I can't seem to find it anymore.
Can anybody tell me something about it? I can't find if it is an idea, an already exsisting pedal or something completely different. The 6E5 tube is awesome (magic Eye)......... although I don't know it's function there then to determine the overdrive.
I'm asking as I am designing a new bass amp for myself (ultra lin 6550 amp) and I know it'll lack OD. This circuit is maybe quite nice in it
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1
- Dirk_Hendrik
- Old Solderhand
Information
right. DC coupling to the first tube's grid.. that's going to work... Use your volume control to bias your tube...
- Bernardduur
- Transistor Tuner
????Dirk_Hendrik wrote:right. DC coupling to the first tube's grid.. that's going to work... Use your volume control to bias your tube...
Looks like a normal tube input without any grid resistors.
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1
- Dirk_Hendrik
- Old Solderhand
Information
your grid is negative biased toward the cathode through a 1M resistor. Of you turn down your bass volumecontrol to 0 what's the voltage on the grid? Yep. Zero volts as well. What you miss here is an input cap.
- Bernardduur
- Transistor Tuner
Ehm, usually I am not that quick on this, but all amps I build have the same input stage (usually w/ grid resistor).
We're talking about the input, right?
We're talking about the input, right?
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1
- Dirk_Hendrik
- Old Solderhand
Information
jep
admittedly, unbuffered non-ac decopled stages seem normal in fx count. Especially outputs. brrr
admittedly, unbuffered non-ac decopled stages seem normal in fx count. Especially outputs. brrr
- analogguru
- Old Solderhand
Information
tube technology...... thats an own matter.....Dirk_Hendrik wrote:your grid is negative biased toward the cathode through a 1M resistor.
The grid is biased at 0 volts with the 1M resistor.
The cathode is biased between + 1,2V and + 1,8 V with the cathode resistor. Therefore the grid appears negative to the cathode.
It stays at zero volt and the cathode between + 1,2 V and + 1,8 V...... BUT:Of you turn down your bass volumecontrol to 0 what's the voltage on the grid? Yep. Zero volts as well. What you miss here is an input cap.
There is a (small) DC-current flowing from the grid to ground. If the 1M resistor is replaced by the pot (or a pot in parallel) then this DC-current will flow over the pot. DC current flowing over a pot causes: CRACKLE !!!
Therefore the wiper of the potentiometer should never be connected directly to the grid. Better use a fixed 1M to ground and a cap between it.
Now lets assume you have an old pedal in front of the amp and the output cap has become leaky and there is a DC of lets say 2 volts at the output of the pedal. What will happen ?
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.