Months ago I've bought this great amp and got it serviced completely.
Very happy with the sound and although everything is working fine there is still one thing left and hope you guys can help to find a solution.
When the amp is switched on there is an annoying hum, we think it is originating from the giant transformer but don't know what to do to tackle/let the hum stop.
Any ideas and/or solutions to disable the humming?
Very happy with the sound and although everything is working fine there is still one thing left and hope you guys can help to find a solution.
When the amp is switched on there is an annoying hum, we think it is originating from the giant transformer but don't know what to do to tackle/let the hum stop.
Any ideas and/or solutions to disable the humming?
Take it back to whoever did the work and tell them they aren't finished.
Make sure other amps substituted in the system lack the hum first.
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Bad capacitors, so take it back to the service shop, they did a poor job.
You cannot fix it yourself, it takes an experienced technician.
This one might be hard to track down. Do a Google search on causes of transformer hum, and there are a lot of possibilities. First thing to do is what Rayma said, take it back to the technician and see what he can do. In particular, plug it in at the technician's shop and listen to it there. If it does not hum at the shop, that's a powerful clue, and points to the mains quality at home, or wherever you're trying to use it.
I am not an expert on the subject, but one of the best audio resources on the internet is Rod Elliott's site at Elliott Sound Products. He has an article on the topic: http://sound.whsites.net/articles/xfmr-dc.htm
This forum also has numerous threads on the subject. A search for threads on "mains filter" turns up 33.
Here's one:
Variations of DC Main Filter against buzzing Toroid Transformers - what is the right?
And another:
DC Mains filter to remove buzzing trafos
Again, this may not be your problem at all, but I wouldn't give up without looking at it.
Regards,
Mike
This forum also has numerous threads on the subject. A search for threads on "mains filter" turns up 33.
Here's one:
Variations of DC Main Filter against buzzing Toroid Transformers - what is the right?
And another:
DC Mains filter to remove buzzing trafos
Again, this may not be your problem at all, but I wouldn't give up without looking at it.
Regards,
Mike
Thank you guys, will forward the info to my friend, the technician.
Let's see were the end will be.
BTW: here are some technical info of the amp.
Circuitry designed by John Curl
THX Ultra-certified
Direct Coupled -- no capacitors or inductors in signal path
DC Servo and relay protection circuits
High bias Class A/AB operation
2 kVA Toroid power transformer with independent secondary windings for each channel, 150,000 µF power supply filter capacitance
Independent power supplies for each channel
Hand matched complementary JFET input stages and MOSFET driver stages
40 beta-matched 15 amp, 60 MHz bipolar output transistors
AC present, standby/normal, current overload, temperature indicators
Rear mounted gain controls and rear handles
12 volt DC automatic turn-on circuitry; ground lift switch
Tiffany-style RCA input jacks
Gold-plated 5 way speaker binding posts
Color coded, gold plated brass banana plugs included
4 rack space height front panel
Let's see were the end will be.
BTW: here are some technical info of the amp.
Circuitry designed by John Curl
THX Ultra-certified
Direct Coupled -- no capacitors or inductors in signal path
DC Servo and relay protection circuits
High bias Class A/AB operation
2 kVA Toroid power transformer with independent secondary windings for each channel, 150,000 µF power supply filter capacitance
Independent power supplies for each channel
Hand matched complementary JFET input stages and MOSFET driver stages
40 beta-matched 15 amp, 60 MHz bipolar output transistors
AC present, standby/normal, current overload, temperature indicators
Rear mounted gain controls and rear handles
12 volt DC automatic turn-on circuitry; ground lift switch
Tiffany-style RCA input jacks
Gold-plated 5 way speaker binding posts
Color coded, gold plated brass banana plugs included
4 rack space height front panel
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