DIY marshall preamp quesstion
I'm building a sort of jcm800 type tube preamp with a master volume right after the cathode follower/tone stack stage. Nothing unusual. My question is do I need a coupling cap after the master volume? This will be the output. I know this is obvious to most of you, but I'm not sure. Any help is appreciated.
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plush
- Cap Cooler
If there's a gain stage or phase inverter after master volume, then yes, you need a coupling cap after it.
Also, it should be useful to add a series resistor to protect the tube from shorts to ground.
Also, it should be useful to add a series resistor to protect the tube from shorts to ground.
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phatt
- Transistor Tuner
If this is a stand alone preamp then YES you need a cap to decouple the stage.
Be aware the output of your preamp is the tone stack Volume pot which relies on the High Z of the PI (assuming the classic Marshall circuit topography).
The classic Valve tone stacks are Hi Z output and if the next stage is not hi Z input then it loads down the effect and so your tone controls won't work as effectively. The result may be rather disappointing.
Adding a HiZ buffer stage will guarantee the tone stack will work into most anything.
Phil.
Be aware the output of your preamp is the tone stack Volume pot which relies on the High Z of the PI (assuming the classic Marshall circuit topography).
The classic Valve tone stacks are Hi Z output and if the next stage is not hi Z input then it loads down the effect and so your tone controls won't work as effectively. The result may be rather disappointing.
Adding a HiZ buffer stage will guarantee the tone stack will work into most anything.
Phil.