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Author Topic: Eros is humming  (Read 1087 times)

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Offline Why1504

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Eros is humming
« on: February 01, 2017, 11:36:16 pm »
I have a new build.  probably has 100 hours of burn in.  I noticed a yesterday that I had a hum.  It is coming from the Eros.  There is a minor hum when it is powered off and is more pronounced when powered up.

I have no idea how to proceed here.  Please help.

Offline Caucasian Blackplate

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Re: Eros is humming
« Reply #1 on: February 02, 2017, 08:44:36 am »
I would start with a check of the voltages.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Why1504

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Re: Eros is humming
« Reply #2 on: February 04, 2017, 12:50:04 am »
got to the bench this morning.  on the A side the of the chassis,  A side of the C4S card, when powered up, the A side LEDs light, B side  LEDs do not light.  After about 4 seconds the A side LEDs go out.

Offline Why1504

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Re: Eros is humming
« Reply #3 on: February 04, 2017, 10:12:00 am »
I would add, that all of this was operating normally when I did the testing at the conclusion of the build.  Eros has about 100 hours on it.

Offline Doc B.

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Re: Eros is humming
« Reply #4 on: February 06, 2017, 09:29:18 am »
Why don't you post your voltages, noting the ones that are not to spec. That is always the place to start. It could be that you have a bad connection that has shown itself after a few heat cycles, and voltages might help us isolate where the problem lies.
Dan "Doc B." Schmalle
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Bottlehead Corp.

Offline Why1504

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Re: Eros is humming
« Reply #5 on: February 11, 2017, 04:43:21 am »
Finally got a chance to catch my breath this morning ( I run a company and the last two weeks have been insane.  Today I leave on travel for a week, back Friday and Sat of next week then gone for two more weeks)  Here are my voltages:

                  A                       B
KREG         .6                      1.77
BREG        7.42                   96.8
OB            221.4                 95.1
OA            220.8                169.7
bA                  0                     0
IA             223.0                 223.9


Thanks for any assistance!!

Offline Caucasian Blackplate

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Re: Eros is humming
« Reply #6 on: February 14, 2017, 02:56:26 pm »
KREG         .6                      1.77
BREG        7.42                   96.8
OB            221.4                 95.1
OA            220.8                169.7
bA                  0                     0
IA             223.0                 223.9
I would suspect you have a broken wire or very loose solder joint in your build somewhere.  It could be the ground connection for the board with all the out of whack voltages. 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Sugar Man

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Re: Eros is humming
« Reply #7 on: February 15, 2017, 04:37:35 am »
I added the MourQuiet to my Stereomour and wasn't totally happy with the sound.  When I turned it back over to investigate, I had totally forgotten to solder a terminal tab with a bunch of resistor leads.  I could have sworn I double- and triple-checked everything.  Sounded much better after I applied a bit of solder to the oversight.  Good luck finding your problem.
Mike "Stein" Ayotte

Current Gear:

Stereomour II w/ Jupiters and JJs
Rega RP6 w/ Audio Note IQ3 (MM)
Eros w/ Mundorf Silver Oils
Blumenstein Orcas and Subs

Paraglows (retired)
Quicksand
Quickie w/ PJCCS

Offline Why1504

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Re: Eros is humming
« Reply #8 on: February 15, 2017, 10:56:33 pm »
Thanks. I plan to work on her this Saturday.

Offline Why1504

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Re: Eros is humming
« Reply #9 on: March 25, 2017, 04:23:28 am »
After 4 weeks of travel followed by 3 weeks of sickness I finally got in this morning and began doing some serious investigation.  Almost immediately I found a wire that wasn't connected.  Fixed that.

All of the voltages are now in spec.

But, the preamp has now developed a white noise with some thumps that sound much like a dirty album.  the noise is coming out of both channels.  I get it with the turntable disconnected.

HELP!!

Offline Why1504

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Re: Eros is humming
« Reply #10 on: March 26, 2017, 06:08:21 am »
I cleaned up a couple of solder bridges. I know I have a bad joint somewhere.  When I tap on the chassis the noise will come and go.

All of the LEDs are glowing.  I have requested one of my engineers to help me with this next week.

Offline Caucasian Blackplate

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Re: Eros is humming
« Reply #11 on: April 14, 2017, 10:35:57 am »
I cleaned up a couple of solder bridges. I know I have a bad joint somewhere.  When I tap on the chassis the noise will come and go.

You can get in there and poke around with a wooden chopstick to find the joint that is aggravated by tapping on the chassis.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Why1504

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Re: Eros is humming
« Reply #12 on: April 28, 2017, 05:28:08 am »
I found the bad Joint!! Fixed it!!

The rattle is gone.  However, I still have a hum but it only becomes audible at about 1/2 volume which is a significant improvement.

Any suggestions on the hum??

Offline Why1504

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Re: Eros is humming
« Reply #13 on: April 28, 2017, 07:38:16 am »
The hum is still there but with music the sound is fantastic.

I ma guessing the signal is way overpowering the hum.

Offline Doc B.

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Re: Eros is humming
« Reply #14 on: April 28, 2017, 08:23:45 am »
Is the music too loud to listen to at 1/2 volume? If the cartridge has a relatively low nominal output level, the hum can just start to be audible with no signal playing at very high volume settings. That hum would be a soft, sine wave type of hum. If the hum is buzzy that would be a grounding issue, most likely between the turntable and the Eros.
Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.