Who Would Have Guessed This Was The Problem or Man This Stuff Is Weird Part 2 (apologies to Jud)

[TubeLover]

The other night, I sat down happily anticipating a lengthy listening session on my system. I was barely starting to enjoy things when I was best with a popping, crackling sound every ten seconds, and a low level, but discernible hum. There are a LOT of tubes in my system, the preamplifier, DAC and power amp are all tube based. It seemed that it had to be a failing tube somewhere in the system.  While aggravating, but I really didn't feel like troubleshooting that night. The next day, I checked, and re-seated every tube in the system and found nothing. I turned everything on, and let it warm up for the required period, and the same problems occurred, but this time, in checking further I discovered that the pops, crackling and hum were happening in BOTH speakers! That would seem to clearly point to something failing in one of the electronic components. 

 

At that point, in reviewing circumstances to see what else could possibly be the issue, I finally remembered that I had swapped in a new pair of cables between the preamp and the power amp about a week earlier, but was interrupted from listening to the system, as planned that night. Do to other circumstances, a couple of dinners out with friends that ran late into the night, the Stanley Cup Playoffs, etc. I had gone over a week without listening to music on that system at all. 

 

Just as a starting point, I pulled the new cables out, and reinserted the ones previously in use. I again let the system warm up as needed, and sat back for further troubleshooting, and nothing, no problems at all, just pure uninterrupted music. I've been in audio a  long time, and I have no idea whatsoever as to how cables could cause all of those problems and exactly the same in both speakers? Later in the day, I put the new cables back into use, and boom, the same exact problems returned. After swapping the original cables back in, again, all the problems disappeared, no pops, no crackling, no hum. 

 

I can come up with no answer that would explain this. I just wrote the company that I purchased the cables directly from, on an introduction special. I am, however, still mystified. And please don't ask what brand these cables were. This is a relatively small company and exposing this might cause them some substantial harm, given the number of searches done on the internet every day by people purchasing things. We all know the rule of thumb on the internet, 99% of the people who are happy with things do not comment online, 90% of those who are unhappy do, which hopelessly skews things. I will not be "that guy". Some years back, I had purchased a pair of their cables and found them to be an outstanding value. Something clearly isn't right here, but I am not going to use their name, given that this is one, single instance, and also one that I can find no one I know of in audio who has been able to explain.Oh, and by the way, the connectors were top notch, and very well installed, and they had quite a bit better connectivity to the jacks on my amp and preamp, than my original cables do.

 

It's just baffling. 

 

JC 

[fas42]

A long shot, but there could be a buildup of static because of the material used in the cables, and how the materials are reacting to what they are touching. Normally this type of behaviour has far more subtle impact on the audio, but in your case the type of gear you're using may be particularly sensitive to such factors.

 

I would do some experiments. Organise the new cables so that when connected to the components, that all along the length of the cable they don't touch each other or anything else; they are surrounded by air at all points - this may take some fiddling with how the components on sitting on their stands; but could tell you something important. If the nature of that interference noise changes, then you're on to it. Also, depending upon what you find then try securing the cable along its length in some way that it can't move, easily - a form of clamping so that it effectively becomes rigid, won't move from an idle touch.

 

 

[mansr]

5 hours ago, TubeLover said:

Just as a starting point, I pulled the new cables out, and reinserted the ones previously in use. I again let the system warm up as needed, and sat back for further troubleshooting, and nothing, no problems at all, just pure uninterrupted music. I've been in audio a  long time, and I have no idea whatsoever as to how cables could cause all of those problems and exactly the same in both speakers? Later in the day, I put the new cables back into use, and boom, the same exact problems returned. After swapping the original cables back in, again, all the problems disappeared, no pops, no crackling, no hum.  

 

[...] Something clearly isn't right here, but I am not going to use their name, given that this is one, single instance, and also one that I can find no one I know of in audio who has been able to explain.

If you don't want to reveal the brand, can you at least tell us if there's something unusual about the "bad" cables? Things like high capacitance or odd/no shielding.

[One and a half]

XLR or RCA?

 

May also be an intermittent fault in the connectors on the pre/power amp.

[asdf1000]

1 hour ago, mansr said:

Things like high capacitance or odd/no shielding.

 

In addition to this, would also like to know the brand/model of the 'good cable' - so we can look at it's capacitance/shielding also.

 

[TubeLover]

4 hours ago, One and a half said:

XLR or RCA?

 

May also be an intermittent fault in the connectors on the pre/power amp.

RCA. And over the past two years that I've owned the preamp and power amp, I've tried four different cables without any issue prior to this.

 

JC

[fas42]

What makes me suspicious is the "beset with a popping, crackling sound every ten seconds" comment - there's a cycling of the behaviour, which is classic slow charge, and then rapid discharge, of a voltage characteristic ... I have never had it so severe, but I have come across far more subtle versions of that - altering grounding arrangements is one of the possible solutions.

[esldude]

You could try one new cable on one channel only.  See if it stays in that channel, and if the severity is less.  My guess is barring some very odd interaction, you'll have one channel acting up as before.  

 

Also if you are trying these say feeding a power amp from pre-amp, try them between DAC and pre-amp to see if they cause the same issue. 

 

Sounds to me like a poor connection or not a good ground.  If you have a multi-meter check to see if you get a good zero or very near 0 ohms between the center pins on each end and between the outer shells on each end. 

[TubeLover]

17 hours ago, Em2016 said:

 

In addition to this, would also like to know the brand/model of the 'good cable' - so we can look at it's capacitance/shielding also.

 

the company who made the cables does not note the capacitance, but does point out that they are specifically unshielded .

 

JC

[TubeLover]

5 hours ago, esldude said:

You could try one new cable on one channel only.  See if it stays in that channel, and if the severity is less.  My guess is barring some very odd interaction, you'll have one channel acting up as before.  

 

Also if you are trying these say feeding a power amp from pre-amp, try them between DAC and pre-amp to see if they cause the same issue. 

 

Sounds to me like a poor connection or not a good ground.  If you have a multi-meter check to see if you get a good zero or very near 0 ohms between the center pins on each end and between the outer shells on each end. 

Tried your first recommendation, and, again, I can't explain it, but both channels act the same when tried individually. My multi meter is temporarily loaned out so I am not able to check anything with it. 

 

I also wanted to try your recommendation initially, of connecting the cable between the DAC and and preamp. However, because of how they are positioned (the DAC is on a lower shelf, and quite difficult to get to as far as connections) and being beset with a very painful case of bursitis in my hip, I just am not able to currently make that happen, physically. 

 

JC

[esldude]

36 minutes ago, TubeLover said:

Tried your first recommendation, and, again, I can't explain it, but both channels act the same when tried individually. My multi meter is temporarily loaned out so I am not able to check anything with it. 

 

I also wanted to try your recommendation initially, of connecting the cable between the DAC and and preamp. However, because of how they are positioned (the DAC is on a lower shelf, and quite difficult to get to as far as connections) and being beset with a very painful case of bursitis in my hip, I just am not able to currently make that happen, physically. 

 

JC

So are saying that putting the noisy cable on one channel makes both channels act up with popping noise?

 

Tube gear has higher impedances floating around which makes it easier to get high frequency garbage in over unshielded cable. So I'd suggest returning the cable 

[mansr]

4 hours ago, TubeLover said:

the company who made the cables does not note the capacitance, but does point out that they are specifically unshielded .

Well, there's your answer.

[motberg]

2 hours ago, mansr said:

Well, there's your answer.

agree that is a good possibility - I have found a certain (fairly popular) brand of non-shielded cables in my system when using any type of tube preamp can result in an intermittent 7.5 khz squeal of about +6db.. crazy stuff.. pop in a shielded set and AOK .

These were RCA also..

[TubeLover]

22 hours ago, esldude said:

So are saying that putting the noisy cable on one channel makes both channels act up with popping noise?

 

Tube gear has higher impedances floating around which makes it easier to get high frequency garbage in over unshielded cable. So I'd suggest returning the cable 

Sorry if my earlier statements did not make it understandable but both cables perform exactly the same. There is no "one" bad cable.

 

I've contacted the manufacturer and they are having me return the cables and will refund me the cost.

 

JC

[TubeLover]

16 hours ago, motberg said:

agree that is a good possibility - I have found a certain (fairly popular) brand of non-shielded cables in my system when using any type of tube preamp can result in an intermittent 7.5 khz squeal of about +6db.. crazy stuff.. pop in a shielded set and AOK .

These were RCA also..

Sounds like you've nailed it on the head, apparently unshielded cables and tube components should not be mixed.

 

JC