Aleph 30 transformer hum

[Heiney9]

I have a commercial (as opposed to DIY) Aleph 30. Recently I've noticed a transformer hum at both the speaker level and now I can hear it inside the chassis. Inside the chassis it seems to come and go in "waves" as it will get louder and softer as if it's cycling.

I recently had the amp plugged into a power conditioner which also regulates voltage and now I have it plugged directly into the wall and no change. I do use a tube pre-amp and thought that could possibly be the issue but even with the pre-amp off and outputs unplugged I still get the hum.

A very slight hum has been there since I bought it (used) but as the amp warmed up it used to go away almost completely, now it's constant and I can hear it through the speakers when sitting approximately 6-7' away. In addition to the actual transformer hum inside the chassis.

Any ideas? Is this a known issue? Do I need to send it into Pass Labs for a check up?

Thanks In Advance for any input

-Brock

 

[tiefbassuebertr]

check out this:
http://www.diyaudio.com/forums/soli...buzzing-toroid-transformers-what-right-5.html
and
PLITRON - audio transformers - toroidal transformers - toroids - output transformers - current transformers - power transformers - medical isolation transformers - power toroids
also this article is very interesting:
Measuring Acoustic Noise Emitted by Power Transformers
Menno van der Veen, Consultant, Zwolle, The Netherlands; and Francisco de Leon, Brian Gladstone, and Valeriu Tatu, Plitron Manufacturing Inc., Toronto, Ontario
you can order it about
Audio Engineering Society (AES)
or about
http://www.plitron.com

 

[roscoeiii]

I had some toroid hum in my FirstWatt F1 which was due to DC on my crappy AC lines. To the best of my knowledge, most power conditioners do not remove this (and mine certainly didn't!). But there are 2 commercially available products that can take care of the problem of toroid hum if it is DC causing this. One is the PS Audio Humbuster (which I use now). The other is the Channel Islands XDC-2. I believe both companies also have 30 day trial periods, so if that's not the problem no big loss (except shipping).

Best of luck. I know the toroid hum drove me nuts (well nutsier)

 

[h_a]

Uh?

If a power conditioner does not remove DC, it is not worth the name...

Transformers age and mechanical humm becomes louder. The humm from the speakers is a different story and may be related to aged caps. A hint for that would also be that the humm went away after some time previously. Anyway, it would not hurt to replace the caps after 10 years of use.

Have fun, Hannes

 

[roscoeiii]

Hannes,

From my understanding, and from talking to folks at both PS Audio, Channel Islands and makers and sellers of other power conditioner, most power conditioners do not remove DC. I haven't had a stream of power conditioners through my system, but consensus among the folks I have talked to and inquired if their power conditioner treated the problem was that this is not a feature of power conditioners more generally.

 

[h_a]

Then what it's good for?

 

[roscoeiii]

There are many other ways that cleaning up power that will improve the sound of a system. And by the small number of products available that remove DC, it (and the associated toroid hum) may be a fairly uncommon problem. Numerous reviews of power conditioners can attest to how they may affect the sound (usually positively, though there are some downsides as well for certain types of conditioners with certain types of components).

 

[tiefbassuebertr]

I had some toroid hum in my FirstWatt F1 which was due to DC on my crappy AC lines. To the best of my knowledge, most power conditioners do not remove this (and mine certainly didn't!). But there are 2 commercially available products that can take care of the problem of toroid hum if it is DC causing this. One is the PS Audio Humbuster (which I use now). The other is the Channel Islands XDC-2. I believe both companies also have 30 day trial periods, so if that's not the problem no big loss (except shipping).
Best of luck. I know the toroid hum drove me nuts (well nutsier)

I don't understand this term because I am not an english man: "well nutsier"
also not after read this:
Nutsier

In the attachement you will find some informations concerning the reasons for toroid hum

 

[roscoeiii]

Ah, sorry. "nutsier" meant that it drove me more nuts (meaning crazier than I already am)

 

[Heiney9]

Thanks for the help so far..............and I don't know of a single std power conditioner until you get into power regenerators that filter DC from the line. PS Audio makes a UPC200HB that is their standard power cond. w/their humbuster product built in the same unit.

My concern is why the hum/buzz through the speakers........that leads me to believe it's an equipment issue not line issue.

 

[Bill Fuss]

If it hums with the inputs shorted or even with no input cables I would send it to Pass Labs.

 

[tiefbassuebertr]

Thanks for the help so far..............and I don't know of a single std power conditioner until you get into power regenerators that filter DC from the line. PS Audio makes a UPC200HB that is their standard power cond. w/their humbuster product built in the same unit.

My concern is why the hum/buzz through the speakers........that leads me to believe it's an equipment issue not line issue.

...or an mass (GND) management issue. I guess, at least one component has an unwanted transition resistance to mass, especially if the hum does not disappear, when you make a shorted input. If the hum no longer present by shorted input, check out the acoustical behaviour at open input. Now there could be two different observations:
1) hum also no longer present or very low level hum: then the failure comes from outside (pre amp cable or pre amp itself)
2) hum still present: unwanted transition resistance between metal enclosure (cabinet, envelope, case) and GND too large through oxidised or loose screw; this means not present screening effect of the amplifier PCB against electrical fields.
An other possibility is an unwanted ground loop. In such cases are isolation transformers for the low power devices such pre amps and compact disc players helpful, if there are three pole mains connectors present. Actually in such cases the hum don't goes away by input shorting.