bencat

Main system problems

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Super Wammer

I have had an issue with my main system which i thought I had identified abut it would seem that I have not .

System

Allo Digione , Shanti Power Supply , MiniDSP DDRC22D , Denafrips Pro 8 Dac , Concordant Exhiliarant Pre , Krell KSA 50 Amp , Quad ESL 57 Speakers .

Now it developed a loud hum on the left channel and I thought that i had narrowed this down to the Krell and sent it away to be looked at as I have seen what one of these can do when they go down. I recently got the amp back and the engineer said he could not find a fault on the amp and that it sounded fine.

So yesterday did a full dismantle and then put the system together again worked for about thirty seconds to a minute then the humming on the left channel started again . Tried a quick change of pre but still there . I intend over the weekend to bring in a small pair of speakers and hook them up to see if they show the same hum , which if they do means it is a problem with something in the equipment . If they sound fine then it points to an issue with the Quad ESL 57 and that is not only not good but probably very costly as well .

Has anyone come across this issue with Quads before as the hum is quite loud and continuous I would think it is the mains input and crossover that would be the issue and not the panels which tend to buzz and pop but then again I am just not sure .

Any suggestions ot help would be appreciated .

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Super Wammer

Rather obvious I know but have you tried changing the speaker cables around to see if the hum follows the cable or stays on the left channel?

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Super Wammer
3 minutes ago, Speedracer said:

Rather obvious I know but have you tried changing the speaker cables around to see if the hum follows the cable or stays on the left channel?

I have considered this but if the amp is still a possible cuase then there is a chance that I can damage two speakers instead of one . So going to use some small speakers that cost wise i can easily replace and this not only enables me to do as you say if the hum is there and not chance the Quads but will also identify if the probelm is with the Quads or the equipment connected to it .

Thanks for the advice though much appreciated .

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Posted (edited)

I would suggest taking things right back to basics and revert temporarily to a simple system format with a bare minimum of boxes.

Borrow a  valve power amplifier known to be in g.w.o. and a cd player with variable output from some friendly local wammer.  Connect these up with the 'stats and see what transpires. 

P.S. Before doing this it may be worth swapping the power cables over on the ESL57s  just in case there is a poor connection somewhere in the chain.   

Edited by TECUMSEH VALLEY
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With all those components could it be a ground loop or some interference between the wires?

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Posted (edited)

+1 for stripping it back to basics. The number of times I’ve been asked to try and troubleshoot a sound system only to be told I’m mad for wanting to disconnect it all and start again. 

Cue numerous other people fiddling around and faffing and getting nowhere before they come back to me. I strip it down, put it back bit by bit and hey presto-it works. 

At the moment you don’t *know* it’s the amp so strip back and rebuild until you do one way or the other. 

Edited by dannybgoode

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It’s frustrating.

I don’t have the answer but as already mentioned starting from scratch and adding a component at a time makes sense.

I did this trying to trace a distortion in one channel. After hours of moving heavy kit around and trying different amps, speakers cables etc etc etc I definitely, absolutely pinned it down to one monoblock amp and/or the shared PSU. Dragged it down to a dealer who soak tested for 10hours a day for 5days - no fault. Within 10minites of getting it home the fault reappears. Pissed off I need to get 150Kg of amps and PSUs to Oxford from the NE - I’ve put it off and put it off, bought replacement temp. amps (system working perfectly with the replacement) and now need to wait till this virus passes.

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Super Wammer

I have admit that I have been avoiding this but finally today put cheap speaker on the left channel . First off no sound then after a bit of faffing got sound no hum. 

Well that lets the equipment off the hook but points to a problem with one of the ESL57 not something I want to think about given the possible costs. So just to see what happens put the Quads back in and no hum and no sound. Another bit of faffing and music emerges .

Playing as it should no hum except from me along to the melody. Bit of a dance round to celebrate. Then leave the system playing at low level for half an hour go back still playing nicely now been listening at more problem causing levels for about another hour still no issues.

I have not really done anything no idea what the problem was but just going to quit while I am ahead and enjoy.

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Hi Andrew.

Had a 57 in recently where the owner claimed hum issues.

Plugged it in and immediately took the trip out.

A bit of investigation and it turned out the earth and neutral leads were swapped around in the round Bulgin end of the mains cable.

Fixed it and now back with owner and no hum. Presumably his is an old installation without a trip in the consumer unit.

I'm not saying that is the problem here, but it's worth checking in said plug that all wires are in correct and securely. An intermittent earth or neutral connection might just give the same symptoms.

H.

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Super Wammer

Hey, a win is a win! :^

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Super Wammer
Posted (edited)
21 minutes ago, toprepairman said:

Hi Andrew.

Had a 57 in recently where the owner claimed hum issues.

Plugged it in and immediately took the trip out.

A bit of investigation and it turned out the earth and neutral leads were swapped around in the round Bulgin end of the mains cable.

Fixed it and now back with owner and no hum. Presumably his is an old installation without a trip in the consumer unit.

I'm not saying that is the problem here, but it's worth checking in said plug that all wires are in correct and securely. An intermittent earth or neutral connection might just give the same symptoms.

H.

That is an excellent idea and once this session finishes as the music is still playing I will get the screwdrivers out and have a good look at both the main plug and the bulgin plug end and make sure they are all fully tightened and connected correctly . As I have spare time I might well order and make up a new set myself with good quality Bulgin and UK Mains plugs . I f anyone has a couple of decent bulgin plugs packed away not doing anyhting PM me quite happy to pay a sensible price .

Sorry something prompted me to have a look and I forgot these Quads have been converted to the One Thing mains supply input so it is not Bulgin plugs at all but a three pin kettle plug so it is these I would need .

Edited by bencat

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Super Wammer

Okay too good to last the hum is back and it moves speaker when I move the speaker cables over . So it is the equipment . Changed the pre and the dac and still there so it is either the DDRC 22D or the Krell . Just too depressed to continue today as the system working before the hum was as good as I have come across . Will take the DDRC out of the system tomorrow but as this seems to only start after warm up the Krell is my guess. Sod,s law that I have no power amps spare at the moment so not able to swap  out that .  May have to just bite the bullet and send the Krell off again. 

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Posted (edited)

Have you tried changing interconnect cables? I remember having a hum that was down to a faulty interconnect. 

Edited by wHIZZY
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Super Wammer

Okay tested every inter connect in the system and all of them are fine no issues . Thanks to the superb kindness of another Wammer I now have a Croft 4S power amp to substitute for the Krell .

Today has been the day i got brave enough to do a full swap over (my own equipment is no problem but always very nervous of other peoples) . System is playing now no issues at all very quiet considering this is a Valve power .

Music is good but it is just getting warmed up and getting better all the time . Quads as I expected seem to love Valve amps very surprising how loud this goes I think the Croft is a  65 Watt push pull amp but loads of head room . Nice wide soundstage and quite tight bass , then the vocals all types just sound like real voices from real people .

Huge sign of relief from me as this is the one system i have at the moment that does not exite my tinitus so I can hope fully now relax and listen and read and view this site in a decent amount of peace . In this current climate I am sure there are arguments about waht is and is not vital and i do understand them . For me to have a music system that I can listen to for long periods without any stress is a vital thing for me , it calms the pain I constantly have and allows me to drift in and out of the music . Thanks to all those that have helped it does now seem as if the Krell left channel is the issue and when things get a little more calm it is going to have to go to be looked at and repaired . For the moment Croft is king and long may it reign .

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