My challenge was to build a Valve Guitar amplifier for under $150. As power transformers for even a small Valve amplifier cost around $80 (In Australia) and a 'cheap' Single ended output Transformer costs a similar amount, this was potentially going to blow the budget before I had even started.
to get around the high cost of Transformers a pair of back to back off the shelf power transformers are used to provide firstly power for the heaters and then 250 Volts for the valves, while being slightly more complex this cost about $30 - a saving of $50.
for the output Transformer 100 volt PA transformers are readily available and the 2.5 Watt tap should provide the required 4.5Kohm load for an EL84 and a 5 Watt line Transformer costs less than $10 saving another $70.
Circuit
The design is
based on a 12AX7 providing gain, a simple (inexpensive) single knob EQ and
a single ended output stage using an EL84.
test
Kit costs $xx (Australian) and
includes:
PCB
Valve Sockets
Assembly
instructions
Email
for more details or Paypal instructions (to order) - note at this stage I
will have to work out mail costs on a case by case
basis...
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