Hammond Power Transformer Buzz...

Guiness · 12th April 2008, 02:28 AM

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

Jeb-D. · 12th April 2008, 03:11 AM

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.

SpreadSpectrum · 12th April 2008, 05:25 PM

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.

EC8010 · 12th April 2008, 06:15 PM

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.

Jeb-D. · 12th April 2008, 06:58 PM

Quote:

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.

Yeah, it really helps the sound quality, like a veil has been lifted

zigzagflux · 12th April 2008, 06:59 PM

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.

Evenharmonics · 12th April 2008, 07:05 PM

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.

Jeb-D. · 12th April 2008, 07:14 PM

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.

agent.5 · 12th April 2008, 07:16 PM

Has anyone used the 700 series of Hammond transformers? Any buzz?

http://www.hammondmfg.com/700.htm

Guiness · 12th April 2008, 08:12 PM

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.

12th April 2008, 02:28 AM	#1
Guiness diyAudio Member Join Date: Dec 2002 Location: USA	Hammond Power Transformer Buzz... 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 __________________ Guiness

12th April 2008, 06:15 PM	#4
EC8010 diyAudio Moderator Emeritus Join Date: Jan 2003 Location: Near London. UK	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. __________________ The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...

12th April 2008, 08:12 PM	#10
Guiness diyAudio Member Join Date: Dec 2002 Location: USA	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. __________________ Guiness

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12th April 2008, 03:11 AM	#2
Jeb-D. diyAudio Member Join Date: Nov 2005 Location: SoCal	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.

12th April 2008, 05:25 PM	#3
SpreadSpectrum diyAudio Member Join Date: Nov 2007	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.

12th April 2008, 06:59 PM	#6
zigzagflux diyAudio Member Join Date: Oct 2006	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.

12th April 2008, 07:05 PM	#7
Evenharmonics diyAudio Member Join Date: Apr 2007	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.

12th April 2008, 07:14 PM	#8
Jeb-D. diyAudio Member Join Date: Nov 2005 Location: SoCal	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.

12th April 2008, 07:16 PM	#9
agent.5 diyAudio Member Join Date: Aug 2003 Location: San Francisco, CA	Has anyone used the 700 series of Hammond transformers? Any buzz? http://www.hammondmfg.com/700.htm

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