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Help with Hybrid Design

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SerpentRuss:
That's interesting.  I really didn't want to build a pedal.   I'm wondering if there will be enough power in the 7 volt AC side to make a 9 volt supply.  I imagine the load is very small for this.

phatt:
Yes my tone circuit draw little current.
Well you need to research another Fet stage to run a tone section.
Sorry but beyond my scope to design something from scratch like that but you can always just add another stage in front with enough gain to pickup the loss from a tone circuit. I assume it's doable,, outcome unknown??
My thoughts ,, not worth it for such a tiny amp. xP
Phil.

SerpentRuss:
Rather than screw with this design, since it's my first project, I've decided to build this as drawn as a small combo amp using a switched output jack that will allow me to use another cabinet if I want to experiment.  I will include some build photos as I go.   Wish my luck.

phatt:
Hang on I just reread the 1st post and as this is your first build,, I'll assume you don't have a lot of teck skill.

Warning!!! RE this;
"The power supply for the amp I'm trying to build features an inexpensive 7-volt Antec Toroid transformer with the 120-volt coils split, making it a small isolation transformer.  The 7-volt side is used for the tube filament."

Unless I've missed something in translation,,,that tells me it is a 120/120 split *Primary* so something sounds wrong :loco

Also the way in which the power Tx is drawn up in that schematic seems strange.
Others here may know more but meantime be careful cause if I'm right as it could kill you. :police: :police:

Normally when a Tx states 120/120 split primary that means it can be wired up to either 120 mains ans 240 mains. It is most likely NOT an isolation Tx :-\
Maybe post a picture of the Tx you wish to use ideally showing the label.
Phil.

SerpentRuss:
This is my first amp build, but I have about 40 years of experience working with electricity all the way up to medium voltage circuits like 4160-volt motors.   I know how to work safely.

You're right, it's not an isolation transformer, but it's being used as one.   This design has a very low current draw because it is a sub-1-watt amp.  The guy who builds these has used this exact transformer in this way on several small amp builds. One primary set of leads on the transformer gets driven by the mains inducing about 120 volts on the other set.  The 7-volt secondary is dropped to 6.3 volts to run the filament on the tube.  The 6CL6 power amp doesn't require a lot of DC voltage.  I think this supply will put out about 135 volts DC.  The OT is wired using the 1/2 watt tap.

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