Hello, I'm putting together a amp using some cheap L20 amplifier boards from E-bay. The amp sounded great, but didn't have enough gain so I picked up a pre-amp for it that was recommended to use with the L20 amplifier and wired it up today. When I turned it on the bridge rectifier burnt up on my speaker protector which is hooked up to the same transformer output. The speaker protector gets 15 Volts AC single and the pre amplifier gets 15-0-15 volts AC and this comes from a tap on my main transformer.
I pulled the power from the speaker protector and tested the voltage and everything looks good, but there seems to be DC voltage running through the pre amp which could have been the cause for the damage to the speaker protector, but I thought the relays would have clicked off if there was an issue.
I measure 15-0-15 volts AC going into the preamp, but there is 18 volts DC coming out of the outputs and when I have a pot switch hooked up I can measure around 6 volts DC coming out of the input. This can't be right? Can any one shed some light on what is going wrong?
Here is a picture of the amp and pre amp. I have a lot of the wires pulled so I could just test the pre amp so I'm sorry if it's hard to see how it was all wired up.
Thanks for the help!
Dale P.
I pulled the power from the speaker protector and tested the voltage and everything looks good, but there seems to be DC voltage running through the pre amp which could have been the cause for the damage to the speaker protector, but I thought the relays would have clicked off if there was an issue.
I measure 15-0-15 volts AC going into the preamp, but there is 18 volts DC coming out of the outputs and when I have a pot switch hooked up I can measure around 6 volts DC coming out of the input. This can't be right? Can any one shed some light on what is going wrong?
Here is a picture of the amp and pre amp. I have a lot of the wires pulled so I could just test the pre amp so I'm sorry if it's hard to see how it was all wired up.
Thanks for the help!
Dale P.