Question about Audio Players & Recorders
Kustom Profile One 100w PA
Shortly after unit is switched on a loud bang can be heard through the speakers. Turning the master volume down/off does not alter this.
Alternatively there is often a continuous screeching noise but this does not persist. At other times the unit works normally for hours and at other times there is nothing at all from the speakers.
I am not too technially minded but I have been told this may indicate a ''relay fault'' (whatever that is! )
Is this reasonably easy to fix or am I looking at buying a new amplifier?
Thanks for looking.
I have three of these in my amp repair shop. one of them does exactly this. as well, the other two are suspect to the same issue. i believe it is low quality leaky or shorting caps. are you using the xlr inputs or 1/4 inch inputs? so far, these are working good thru the 1/4 inch jacks, but the xlr inputs are squeely with feedback and i get that loud bang/pop from one of them. kustom wants me (my shop) to be an authorized repair station for them. i want to be able to resolve these three amps before i accept. if they are a nightmare to deal with, then i will tell them no way.
i will post back with in the next week with more results and hopefully i will have precise solution with parts and procedures.
yost amplifier repair
Posted on Jan 21, 2010
Thebrother, thanks for helping with this issue. I also have a sick Profile One head; symptoms are a variant on what sympbrili described. I get also get a screeching noise coming through both outputs; it was intermittent at first (would appear when amp was turned on and slowly fade in volume and eventually disappear). That recenty changed: now the amp operates properly when first turned on, but after a few minutes the screeching appears and now doesn't go away. Even before seeing this Fixya discussion I suspected a leaky cap due to the symptoms, but have no clue as to where in the signal chain to look. Any insight you come up with willbe greatly appreciated!
Posted on Jan 27, 2010
I have learned quite a bit about this PA.
First, understand that the power amp is always on and always at full output (100W) to the speakers. What you adjust for volume is really a sub fader that has the 5 individual inputs assigned (hardwired) to it. You also can control the Playback volume but this is simply another source that has been summed to the output of the "Master" sub AFTER the EQ and internal FX are applied. Since the amp is always on and at max, any interruption/drift to the power supply will result in noise regardless of the input levels.
The addition of 2 caps (47uF 50V) across the input side of each of the +/- 15V regulators will take care of the squealing noise. Add one cap to each regulator across pins 1 + 2 (cap’s neg to pin 2 on each).
There are also 2 current limiting resistors that are undersized and fail. While I have not experienced the "popping" in my unit I believe it is one or both of these resistors opening, or drifting enough to open the power flow enough to cycle the amp off and on, hence the "pop". They are R34 and 40. Originally 100 ohm 1W they should be replaced with 130 ohm 2W metal oxide resistors. When I checked my original 100 ohm ones both showed the signs of excess heat and one was down to 57 ohms. I suggest you mount the replacement resistors on end so that they have better air flow around them to help with the heat dissipation.
If you need to replace components in the speaker cabinets you should look at Goldwood GW-6024 woofers and GT-1016 tweeters. I believe these will fit without needing to modify of the cabinets and their specs are very similar to the originals.
I have no affiliation with Kustom so what I say is not authorized by the people who designed this thing. I am just a guy who can read a circuit and has a brain. Hope this helps.
Posted on Jul 02, 2010
I've had the same problem with a kustom one amp that came in to my shop. The -15v 100ohm resistor was fried and took out the .01uf film cap next to it (nice burn mark on the side). After replacing both, the unit runs fine for a few minutes, but a shorted load from the front control panel is causing the resistor to burn up again. (when i disconnect the 5pin plug to the front it runs fine and plugged in the -v drops considerably) Without a schematic I'm scrapping it, but would be nice to hear if anyone has dealt with that additional issue.
Posted on Jul 16, 2013
The problem I've had was a static noise over powering the audio output. Bruce Collins of Mission Amps replaced the two resistors as recommended for the pop sound and touched up the solder connections. It seemed to work for awhile until two weeks ago and it completely static out. Having no schematic for this amp,
Bruce replaced the chip nearest to the main volume knob. He replaced the chip with a higher grade. ( you would to contact him at missionamps.com for the specific chip) Anyway, we used the Kustom last Friday without any problems. I'm keeping my fingers crossed, lol. Also Bruce put a dummy load on the amp to make sure nothing was weak on the board. Other than that, its working so far with no static sound.
Posted on Feb 20, 2013
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Sep 11, 2017 | Kustom Music
Sep 27, 2014 | Kustom KPM7250T PA Amplifier/Mixer
Aug 16, 2011 | Kustom KSC215H PA Cabinet
Aug 11, 2011 | Kustom KPM7250T PA Amplifier/Mixer
Apr 16, 2011 | Kustom KSC10ML PA Monitor
Jul 21, 2017 | Kustom KPC10MP Powered Speaker Pair
Mar 06, 2011 | GE Profile 21.6 cu. ft. Side-by-Side...
Dec 10, 2010 | Kustom Profile 2 PA Speaker / Mixer Stand
Dec 10, 2010 | Kustom Profile 2 PA Speaker / Mixer Stand
Oct 21, 2017 | LG Audio Players & Recorders
2,787 people viewed this question
Usually answered in minutes!