I have not used a Hammond Power Transformer for awhile... I came across a old 272JX and it has a nice buzz to it while running.
do they all have a buzz to them when running? Just curious
Thanks
do they all have a buzz to them when running? Just curious
Thanks
I've had some models that have a good buzz to them. You may have a defective one. If not there are two things that can cause it. Either it's overloaded. Or you may have some DC on your mains supply.
I have only purchased two Hammond power transformers, both 278CXs that I was drawing just over half of the rated current. Both put out a pretty good buzz.
No accounting for tastes...
Well, let's see, Guiness says it's a "nice" buzz, Jeb-D says it's a "good" buzz, and SpreadSpectrum says it's a "pretty good" buzz. Sounds like everybody likes it. 😀
Well, let's see, Guiness says it's a "nice" buzz, Jeb-D says it's a "good" buzz, and SpreadSpectrum says it's a "pretty good" buzz. Sounds like everybody likes it. 😀
Used a number of Hammond transformers. Mine typically put out a "hefty" buzz. All without any help from cannabis.
Chokes seem to be quieter than their transformers.
Chokes seem to be quieter than their transformers.
I have two Hammond 272JX and they both buzz slightly. But there are two members on this forum told me that their 272JX run silent. May be those two are defective. 😉
Someone told me that PT can buzz when distorted AC line voltage is fed.
Someone told me that PT can buzz when distorted AC line voltage is fed.
SpreadSpectrum,
I see you live in SoCal, at my place the mains has some DC which causes mechanical hum. Also, Hammod transformers are spec'd at 115V Vin but at my place the mains is about 122V. I use a power resistor in series with the primary to drop the extra 7V. It also adds DCR to the primary which brings the Hum level down quite a bit. Though I would only recommend that if your amps are on the lower powered side.
There are some "DC trap" and "DC blocker" circuits made up of a couple capacitors and diodes you can build. You can also run a search on mechanical hum and it brings up useful info. This is a common problem for people using toroids. EI core transformers are less prone to this problem, but they are not immune.
I see you live in SoCal, at my place the mains has some DC which causes mechanical hum. Also, Hammod transformers are spec'd at 115V Vin but at my place the mains is about 122V. I use a power resistor in series with the primary to drop the extra 7V. It also adds DCR to the primary which brings the Hum level down quite a bit. Though I would only recommend that if your amps are on the lower powered side.
There are some "DC trap" and "DC blocker" circuits made up of a couple capacitors and diodes you can build. You can also run a search on mechanical hum and it brings up useful info. This is a common problem for people using toroids. EI core transformers are less prone to this problem, but they are not immune.
This is good to know... I just tested a small Hammond 190-0-190 transformer... no hum.
The 272JX is spec'ed at 300-0-300.... but is putting out 337-0-337... go figure.
Thanks for the info guys.
The 272JX is spec'ed at 300-0-300.... but is putting out 337-0-337... go figure.
Thanks for the info guys.
The 272JX that is currently connected to a TubelabSE on my bench runs anywhere from 320-0-320 to 343-0-343 volts depending on the line voltage, the load, and the phase of the moon. It does not hum though. I may not have the best hearing on the planet, but I have put my ear right on the transformer. no buzz. Maybe I just got lucky and got a good one.
Another question: are the 300 series transformers better than the 200 series? It appears that the only difference is that the 300 series are more expensive and use something called "concentric wound"? What is it?
The 300 series have "universal primary windings". This means that they can be operated from several different power line voltages. This allows some flexibility in the output voltage by choosing a different primary tap.
The 300 series is also specified for 50 Hz operation. This means that a 300 series transformer will have more iron in it than a 200 series transformer of equal ratings. This will allow it to run cooler than a 200 series transformer, or it will allow you to run it a bit over the specs if you are running it on 60 Hz.
The 300 series is also specified for 50 Hz operation. This means that a 300 series transformer will have more iron in it than a 200 series transformer of equal ratings. This will allow it to run cooler than a 200 series transformer, or it will allow you to run it a bit over the specs if you are running it on 60 Hz.
zigzagflux said:
That might be a useful clue. I hesitated to mention it earlier, but mains quality can be a factor. Flat-topped mains can cause all sorts of problems, as can DC (as others have noted).
I have used a couple of 200 series power transformers. They all buzzed and ran hot. BUT the 300 series is totally different----very quiet, very cool running. I don't know if it's the extra iron or something else, but the 300 transformers are much better in my opinion.
Dave
Dave
I had one that buzzed, I think it ended up being loose laminations. Try tightening up your end bells and see if it goes away. You can do a quick test by squeezing the edges of the bells right by the stack to see if the buzz goes away. Also, rubber insulators are a nice thing to have between the x-frmr and chassis. Don't tighten too tight, you want some absorbtion.
I also noted that when fed with 124v line voltage, the power transformers buzz louder than with 110v or 117v, and the heating could be a saturation issue due to the higher voltages.
The fact that some buzz and some don't would give a little more validity to the probability of loose laminations or end bells. Hope this helps 😉
I also noted that when fed with 124v line voltage, the power transformers buzz louder than with 110v or 117v, and the heating could be a saturation issue due to the higher voltages.
The fact that some buzz and some don't would give a little more validity to the probability of loose laminations or end bells. Hope this helps 😉
The ones I've used buzzed a great deal... annoying, but they are very economical compared to some... I have had much better luck with the output voltage being on target than some others... it's simply a choice of price... if you are worried about it.. then get a more expensive transformer...
I've used many Hammonds - 269EX's which run cool with no buzz. 272HX's which run warm, no buzz either. I typically use Hammond black steel chassis ... maybe the steel chassis calms them down ?
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