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SurfGuitar101 Forums » Gear »

Permalink G Spring - Bad hum

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Hey Techies,

Connected my G-Spring for the first time in about 3 months and got a very loud hum when turning on the amp. There is also very little reverb happening under the very loud hum. Everything tight inside, cables, tubes. I tried it several times on three different amps, and changed guitar cables to no avail. Turn it off, the hum goes away. I did a search on the Gear forum and didn't see this problem. Any ideas?



Shoot the Pier
Shoot The Pier on Facebook
We are on Instagram under "@shootthepiersurfband"
My Art

Hey Bill! Great to hear you're getting back around to reverb oriented art, sorry to hear about the G-Spring drama.

Sounds like you've effectively ruled out the Amp and the Guitar cables.

Next tests in the process of elimination, from least expensive to most expensive:

  1. disconnect foot switch if connected. (free, takes seconds). Different? Better?

  2. stabilize the transducers at both ends of the springs in the pan. (price: 15-30 min of your time to open/re-assemble and a toothpick). Different? Better?

  3. replace the RCA cables inside the unit. (price: $10'ish bucks and up if you don't have one from some old TV/VCR'ish kit laying around to test with.) Different? Better?

  4. ::::: The options (brands, new vs. nos/anos, etc) from this point on become very subjective and personal in preference and taste. I've merely made price references of commonly available stuff :::::
    6K6GT tube replacement. ($7-9'ish bucks a pop and up.) Different? Better?

  5. 12AX7 and/or 12AT7 tube replacement. (price: $13-$15'ish bucks a pop and up.) Different? Better?

  6. Replace the pan. (price: $25'ish and up)

  7. From there, you're likely talking about bench time and internal components needing soldering etc. ranging from pots (bandmate had a potentiometer go bad on a G-Spring causing it to more or less stop working, IIRC), to transformers (I had an output transformer that created a crunchy sizzle on various note frequencies on my G-Spring.) (price: parts + labor, likely $100-$150 ante/minimum in most places I'd imagine, unless you find a tech with a spare comparable used part laying around.)

Hope that helps!


El Mirage @ ReverbNation


Thanks much! Incredible detail... like you've been in this box before haha. I will begin the process this week and let you know. As for music, you may not know we released a new EP in June called Longboard Mornings. And, we are already working on a new psychedelic surf record (I got the Ric 360/12 into the mix) to be released next year. The first two of those tunes, Mad Summer and Surf Trip, are up on our page Thanks again for responding! Cheers.

Shoot the Pier
Shoot The Pier on Facebook
We are on Instagram under "@shootthepiersurfband"
My Art

Last edited: Sep 11, 2019 07:41:33

Agree with all the suggestions made - just a couple of other cheap things you might try:

  1. Before you replace RCA cables or tubes, consider the possibility of oxidation in RCA male/female connectors, tube pins, and tube socket pins. Spray these with a good cleaner like DeOxit D5 or Radio Shack electronic cleaner/lub and then insert/remove male parts (RCA jacks and tubes) a few times to remove potential oxidation via friction after being loosened up by cleaner. This is usually a bigger issue on old amps and reverb units, but I have had newer tube equipment that needed oxidation cleaned up from contacts.

  2. You should be able to verify continuity of RCA cables using an Ohmmeter. Center-pin to center-pin should show close to 0 Ohms, and same with the ground tabs. While testing, bend the leads near the jack - sometimes a fault may be intermittent due to varying pressure on the cable. I have changed cables only to ultimately find the replacement also defective, so I almost always check to make sure they're good.

  3. As a general service measure, I also occasionally tighten the tube socket pins a bit with a jeweler's screwdriver, but only after unplugging the amp and draining the filter capacitors. If you don't know how to do that, skip this as there may be high voltages on the tube pins. An alternative is to let it sit for a day or two after unplugging, but I have occasionally been surprised how long the filter capacitors will store a high voltage charge.

  4. Make absolutely sure your reverb pan is not connected backwards. This may sound stupid, but it happens. If you or anybody else ever had it out, it is definitely easy to install backwards and that can produce symptoms like you describe. I've seen experienced techs make this mistake occasionally when they were in a rush.

Beyond both these sets of suggestions, you're probably dealing with circuit internals, as stated earlier.

The Delverados - Surf, punk, trash, twang -
Kristi Jean and the Ne'er Do Wells - Country/Rockabilly Collision: and
Chicken Tractor Deluxe - Rural Americana Music: and

Fady and Dave,

Thank you so much for all the good info. I printed it all for future reference. I plugged it back in this evening and still had the loud bad hum. I disconnected the foot switch, but no better. I turned it off, and before I was about to begin the surgery, I remembered something. Somewhere I read to pick up the G Spring and gently and slowly rotate it 360 degrees then back again. I did that, set it down, turned it on, then the amp... NO HUM, and just the deepest prettiest reverb anywhere. Now, I know you both immediately know what was going on in there... spring related obviously (?) Straightening them out or something? So, although it sounds as it is supposed to now, does this problem indicate the need to replace a component (pan maybe) in the near future? Again, thank you both for responding. Surf on...

Shoot the Pier
Shoot The Pier on Facebook
We are on Instagram under "@shootthepiersurfband"
My Art

That almost sounds like good ol RFI (radio frequency interference). I say almost because that would explain the change in hum, but the faint/near nonexistent reverb before and now it’s back... not so much.

Could be a connection being loose or going bad somewhere inside; warmed up or a slight jostling restored it just enough. Perhaps other gremlins. Hard to say for sure.

If it comes back, I’d say consider the same steps from before - they are all checks dealing with physical connections and or potentially parts that are failing.

In the meantime, enjoy it while ya got it!


El Mirage @ ReverbNation

Bill, do you mean you spun it on its long axis like grilling on a spit? I can see how that could untangle the springs.

Redfeather wrote:

Bill, do you mean you spun it on its long axis like grilling on a spit? I can see how that could untangle the springs.


Yes. Just rolling it over upside down on its long axis.

I'm sure it wasn't radio interference based on how loud the hum was before... and it completely disappeared after rolling it over. It's as if a couple of the springs got tangled up in the pan then straightened out... if that would cause a hum. All good now. Thanks.

Shoot the Pier
Shoot The Pier on Facebook
We are on Instagram under "@shootthepiersurfband"
My Art

It could be a bad filter cap (especially if it was working fine 3 months ago but suddenly hummed when you turned it on after 3 months for no particular reason)

He who dies with the most tubes... wins

Surf Daddies

It could be a bad filter cap.

... or the filter cap(s) could have a bad connection. I recently had an amp with a cold solder joint at one end of the filter caps that came apart, it hummed like crazy. Touched up solder joint, completely fixed.

But if it's internal circuitry, it could be a lot of things.

The Delverados - Surf, punk, trash, twang -
Kristi Jean and the Ne'er Do Wells - Country/Rockabilly Collision: and
Chicken Tractor Deluxe - Rural Americana Music: and

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