Aleph 5 low level buzzing at output both channels - Page 2 - diyAudio
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Old 30th July 2012, 08:02 PM   #11
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Quote:
Originally Posted by KatieandDad View Post
At low volume it should take a good few seconds to quieten down and die.

Unless you have a DIY amp with PSU monitoring to prevent turn-off thumps.
that depends on the bleeder resistors. jenk them out and it will play for a looong time
put in a 500ohm 20W and it will go silent very fast.
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Old 30th July 2012, 08:05 PM   #12
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Originally Posted by jefromson View Post
In that case I would hear some nasty audio output, don't you think? Sounds glorious and perfectly balanced L/R.

The amp is not DIY but its output dies almost instantly at turn-off. Do you know for sure that an Aleph 5 should hold a charge and output something for a few seconds?
my aleph2's played for about 2 sec after power down.
but they were DIY with with 408.000uF and 1K bleeder resistors.
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Old 31st July 2012, 03:21 PM   #13
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Smile SOLVED! - Aleph 5 Low Level Buzzing in Output - Radiation from UPS

I'm pleased to say the buzz was caused by too close proximity to a CyberPower UPS. The amp must have been picking up radiation from the UPS' switching power supply. I separated them by about three feet and no more buzz.

Problem solved. Thanks to everyone who offered help! I love my Aleph 5!!!
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Old 31st July 2012, 03:35 PM   #14
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Originally Posted by AudioSan View Post
that depends on the bleeder resistors. jenk them out and it will play for a looong time
put in a 500ohm 20W and it will go silent very fast.
Who? in the real World would use 500R 20W Bleeders ?

As a minimum I would use 1K as you did, but 10K will do the job without loading the PSU.

Last edited by KatieandDad; 31st July 2012 at 03:37 PM.
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Old 31st July 2012, 04:57 PM   #15
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Originally Posted by KatieandDad View Post
Who? in the real World would use 500R 20W Bleeders ?

As a minimum I would use 1K as you did, but 10K will do the job without loading the PSU.
one that dont care about power draw and want a fast PSU bleed
10K will take a very long time to bleed out. for my F5 i use 2.2K.
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Old 19th August 2012, 05:43 PM   #16
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Default Update! True cause of low level Aleph 5 buzzing - Loose capacitor screws

I feel a bit silly but at the same time very relieved to report this. After I thought I had determined the buzz was external interference from a nearby UPS, I moved the amp into another room to test it with some new speakers, the buzz returned and would not go away.

I then opened the amp, scoped the rails and found the minus rail to have 4 times the ripple as on the plus rail. On a whim, I tightened the screws which connect each PS capacitor to the main PCB, the minus rail ripple dropped to match the plus rail, and the buzz at the outputs disappeared, this time for real.

Apologies to The Cyberpower UPS people whose product is NOT broadcasting interference into the Aleph.

And thanks to Mr. Nelson Pass for designing such a wonderful-sounding, beautifully built piece of classic machinery that thankfullly only needed some screws tightened to sound its best after many, many years of service.

This time I can say with certainty: Problem solved!
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Old 19th August 2012, 06:35 PM   #17
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Should not have needed the screws tightened - they should have lock
washers on them.

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Old 19th August 2012, 06:57 PM   #18
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Thanks, Mr. Pass. It doesn't have lockwashers now but I will add next time I open it (which may be a long time from now).

Your Aleph 5 makes my Gallo Reference 3.1's sing like no other amp, and added what sounds like almost a full, solid, slammin' octave to the bottom end compared to some other highly regarded amps. My wife heard the improvements across the entire range instantly the moment we turned Mr. Aleph on. I now drive it with a Primare SP31 in balanced mode and it all sounds AMAZING!!!
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