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Hey Friends...
I just picked up a Fender Stage 100 Guitar Amp Head from eBay. It was reported to have a loud buzz when the reverb tank was connected. As with many amps these days, the stock, tank could be the small, 2 spring tank. So for a $100 plus shipping, I thought, what the heck. The only annoying thing is that someone hacked the back of the case (as you can see in the photo) but that is not the end of the world. I already own a Stage 100 Combo Amp- one that I like. Anyhow....
Step 1 - Listen.... Yes, there was a loud buzz when I connected the reverb tank.
Step 2 - Remove chassis from case and give it a good cleaning.
Step 3 - Deoxit on all pots and jacks
Step 4 - Inspect RCA cables going to tank - they felt flimsy at the connectors going into the reverb tank, so replace cables.
Step 5 - Clean leads at reverb tank with Deoxit. The RCA jacks get dirty and corroded. Make sure they are clean.
Step 6 - Measure resistance on reverb tank RCA jacks to make sure there are no opens circuits. The input and output will have different readings- Remember - DC resistance readings are not the same as "Impedance" specs. Also, some reverb tanks are grounded from one side of the RCA connectors. Other tanks are grounded on both sides. I see that in reading specs for difference tanks. You might have a ground loop here. There are a handful of YouTube videos that show you how to test a tank. This particular tank seemed to be ok.
Step 7 - Check to make sure the Input and Output is connected CORRECTLY. You never know, someone might have swapped the Red and White on the PC board. For the Fender, "typically", the Red RCA goes to the Reverb "Input" side of the pan. That is what I see and read.
Step 8 - Make sure the reverb tank is NOT touching the metal amp chassis - Ground loop potentials - could be a reason why the buzz occurs.
Step 9 - Reconnect and test - Success!!
Step 10 - Go for a better tank !!! I had a full size tank from an old Peavey project amp. It's an Accutronics 4eb2c1b, Input Impedance 600 Ohms, Output Impedance 2,250 Ohms. The DC resistance at the RCA jacks will be measured at around 50 ohms and 200 ohms. It's a tad under 17". So I mounted this inside the Fender case. Since you have space in this case, you can move the reverb tank forward a bit. And just to be safe (even though you have the space), I put some blue masking tape on the top of the tank. No reason to do that... I just did to make sure nothing touches the pan. I also mounted the tank on a single layer of cardboard. That helps with isolation and shock absorption.
Step 11- Connect - Success!!! The larger tank offers a much deeper reverb sound- very nice.
You might have to experiment with reverb tanks to make sure they will work with the circuitry. But for a quick mod, this worked nicely. And yes, I did the same thing with the Stage 100 combo. Big difference in the Reverb sound.
I just picked up a Fender Stage 100 Guitar Amp Head from eBay. It was reported to have a loud buzz when the reverb tank was connected. As with many amps these days, the stock, tank could be the small, 2 spring tank. So for a $100 plus shipping, I thought, what the heck. The only annoying thing is that someone hacked the back of the case (as you can see in the photo) but that is not the end of the world. I already own a Stage 100 Combo Amp- one that I like. Anyhow....
Step 1 - Listen.... Yes, there was a loud buzz when I connected the reverb tank.
Step 2 - Remove chassis from case and give it a good cleaning.
Step 3 - Deoxit on all pots and jacks
Step 4 - Inspect RCA cables going to tank - they felt flimsy at the connectors going into the reverb tank, so replace cables.
Step 5 - Clean leads at reverb tank with Deoxit. The RCA jacks get dirty and corroded. Make sure they are clean.
Step 6 - Measure resistance on reverb tank RCA jacks to make sure there are no opens circuits. The input and output will have different readings- Remember - DC resistance readings are not the same as "Impedance" specs. Also, some reverb tanks are grounded from one side of the RCA connectors. Other tanks are grounded on both sides. I see that in reading specs for difference tanks. You might have a ground loop here. There are a handful of YouTube videos that show you how to test a tank. This particular tank seemed to be ok.
Step 7 - Check to make sure the Input and Output is connected CORRECTLY. You never know, someone might have swapped the Red and White on the PC board. For the Fender, "typically", the Red RCA goes to the Reverb "Input" side of the pan. That is what I see and read.
Step 8 - Make sure the reverb tank is NOT touching the metal amp chassis - Ground loop potentials - could be a reason why the buzz occurs.
Step 9 - Reconnect and test - Success!!
Step 10 - Go for a better tank !!! I had a full size tank from an old Peavey project amp. It's an Accutronics 4eb2c1b, Input Impedance 600 Ohms, Output Impedance 2,250 Ohms. The DC resistance at the RCA jacks will be measured at around 50 ohms and 200 ohms. It's a tad under 17". So I mounted this inside the Fender case. Since you have space in this case, you can move the reverb tank forward a bit. And just to be safe (even though you have the space), I put some blue masking tape on the top of the tank. No reason to do that... I just did to make sure nothing touches the pan. I also mounted the tank on a single layer of cardboard. That helps with isolation and shock absorption.
Step 11- Connect - Success!!! The larger tank offers a much deeper reverb sound- very nice.
You might have to experiment with reverb tanks to make sure they will work with the circuitry. But for a quick mod, this worked nicely. And yes, I did the same thing with the Stage 100 combo. Big difference in the Reverb sound.
Attached Files