My tube amp has developed an annoying high frequency ringing that is coming from the bell end on the left side of the Hammond power transformer. The link below is a photo of the amp and the power transformer is in the middle. If I touch the bell end very lightly the ringing stops. It is quite annoying and can be heard across the room. Has anybody experienced this and what would you suggest I do to stop it?
kuroguy said:My tube amp has developed an annoying high frequency ringing that is coming from the bell end on the left side of the Hammond power transformer. The link below is a photo of the amp and the power transformer is in the middle. If I touch the bell end very lightly the ringing stops. It is quite annoying and can be heard across the room. Has anybody experienced this and what would you suggest I do to stop it?
Screws are all tight?
BTW, that is BEAUTIFUL!!
Checked earlier today and the screws are all tight, and thanks for the compliment. I really do love the sound of this amp (minus the new ringing). I'm thinking removing the bell end and adding some sort of damping material to the inside of the bell end. Any thoughts from anyone on what material or even doing that?
Agreed.... very nice looking amp. When you say high-frequency ringing, any idea what frequency it is? Did it just start suddenly? Does it stop instantly when the power is turned off or die out as B+ drops?
Regards, KM
Regards, KM
Noisy PT seem to be common with Hammond brand. I had that with mine (not as loud) and I solved it by using auto body repair kit. I happened to have some fiberglass resin and sheet leftover from other project so I used that on the inside surface of bell. I sanded it a bit so that it will cling onto metal surface and applied it with the sheet cut to size. The overall thickness is about 1/8" and it reduced the ringing to almost none. The PT still buzzes though. You can also use Bondo but make sure it's not too thick or the bell won't close.
The other option is to go with different brand as it is what I'm planning on doing. I don't think Hammond PTs are what they used to be anymore. 🙄
The other option is to go with different brand as it is what I'm planning on doing. I don't think Hammond PTs are what they used to be anymore. 🙄
I was thinking about mixing some 2 part epoxy and pouring a layer of about 3/32" thick on the inside of the offending bell end. My other option is to complain to Hammond about the ringing. I expected more from a $50 transformer. I guess I'll give Hammond an opportunity to make this right before resorting to the other option.
kmaier said:
B+ is on a time delay and the ringing starts as soon as the B+ comes on. It stops as soon as the power is turned off. Definately coming from the power transformer and only the one side. Sounds like it is in the 10-12KC range.
freq is just an estimate. I could be way off. I placed a piece of steel between the output transformer and the power transformer and the ringing didn't change. It only comes from one side and the amp is symmetrical, so I doubt it is picking up stray magnetic field from the output transformers.
I'll wait to see what Hammond says and then I think I'll try the epoxy on the inside of the bell end. Should be a real pain in the *** removing the transformer.
I'll wait to see what Hammond says and then I think I'll try the epoxy on the inside of the bell end. Should be a real pain in the *** removing the transformer.
Odd.... if it's induced from load, one would expect the ringing to be 60Hz or a harmonic thereof. Is the PT running hotter than before? Rectifiers and filter caps are okay? Be very interesting to see what you eventually find out.
Don't expect too much from Hammond... my brother had problems with extreme magnetic fields from 300 series PTs, only on one side... so bad that it would hold a screwdriver in place (buzzing of course) and disturbed the OPT from a good distance. Despite repeated emails to Hammond, they offered no advice, just typical marketing info saying everything is fine. He eventually swapped them out for Dynaclones, problems solved.
Regards, KM
Don't expect too much from Hammond... my brother had problems with extreme magnetic fields from 300 series PTs, only on one side... so bad that it would hold a screwdriver in place (buzzing of course) and disturbed the OPT from a good distance. Despite repeated emails to Hammond, they offered no advice, just typical marketing info saying everything is fine. He eventually swapped them out for Dynaclones, problems solved.
Regards, KM
What a pain in the *** this was. As I recall, when I built this amp I set the power transformer on my bench and started attaching parts to it (not really), so I was forced to remove a significant amount of the amp in order to get to the screws and remove the bell end. Once the bell end was off I mixed up enough 2 part epoxy to coat the inside of the bell end with about a 1/16" thick layer. I reassembled the amp and the ringing is gone. My amp is not as quiet as can be.
Thanks for the suggestions.
By the way, Hammond wanted me to send the transformer back to them for evaluation before saying if they would replace it or not. Not worth the expense for the risk.
Thanks for the suggestions.
By the way, Hammond wanted me to send the transformer back to them for evaluation before saying if they would replace it or not. Not worth the expense for the risk.
At least your effort wasn't wasted.
I've bought my last Hammond transformer. That's it for me. 😡
I've bought my last Hammond transformer. That's it for me. 😡
The new Hammond
Perhaps this is what that butt ugly knockout plug is for on the new series Hammond xfmers. You remove it to let the annoying noise spill out.
The older X-series end bells were IMO far more attractive. How many requests did they get from electricians that wanted to install BX cable or conduit on their tube utput xfmers anyhow to make such an across the board change????? Doofus's and ijits!
Fred, why did you have to grow old, relax supervision of the company and then die? You are missed!
Perhaps this is what that butt ugly knockout plug is for on the new series Hammond xfmers. You remove it to let the annoying noise spill out.
The older X-series end bells were IMO far more attractive. How many requests did they get from electricians that wanted to install BX cable or conduit on their tube utput xfmers anyhow to make such an across the board change????? Doofus's and ijits!
Fred, why did you have to grow old, relax supervision of the company and then die? You are missed!
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