Help me Identify Electrical Noise/Distortion in my System

You may have a noisy attenuator on the R channel, except you say streaming is distortion-free. When streaming do you attenuate at the digital device or do you use the Sim attenuator?

Volume control is at the integrated Simaudio for my analog and digital sources. I do have a home theater processor connected to the HTB input on the Simaudio but I doubt that's related. 

On the issue of mistracking, I assume you’ve checked VTF. What VTF gauge do you use and where are you with respect to the recommended VTF range of values? 

I have a Neoteck digital scale that measures to .01g. I have the tracking weight at 2.6g which is the high end for the cartridge. Ortofon manual states to set VTA between 2.4-2.6g. I've also messed with antiskate values from the maximum to the minimum for the tonearm (pg 3 of manual). I noticed some improvements to the distortion by increasing the antiskate. I even added a small magnetic weight to the antiskate weight to increase the value even more but I didn't hear an improvement and removed the additional weight.

https://www.pplaudio.com/documents/mofi-ultradeck-manual.pdf

ajnackman

My second issue ... In some cable positions, the right channel actually audibly cuts out until I adjust the cable ...Once the cable is in the right position, I have no issues apart from the distortion I described above.

I consider that connection your primary problem and it could be responsible for your other issues.

I plan on inspecting the cable connection and swapping the cable from right to left channels to see if the issued follows - but the connection wouldn't cause the mistracking I encountered. That is due to another issue.

ajnackman 

... the connection wouldn’t cause the mistracking I encountered. That is due to another issue.

How can you be so certain? A binding cable in your wiring could absolutely cause mistracking. 

Its not something that I knew was even possible, how does the phenomenon work?

Tiny tonearm wires have to make a right angle turn at the pivot. Check there’s no binding there. Also if the lift mechanism is set very close to the arm tube, it can interfere with travel across the LP. That’s easy to detect once you know to look for it.

The pickup arm has to be able to move freely, as close to friction-free as possible. Any physical resistance in the wiring - even slight - could limit that. Given that you know there's an issue (one channel intermittent), it makes sense to resolve that issue first.

So I definitely have something going on with my DH Labs phono cable. Amp on, cartridge up - when I move the cable near the phonostage RCA jack my right woofer pumps and an audible scratching noise is evident. Swapped the right and left cables and the same behavior swaps to the left channel. I opened up the cable connectors to make sure everything still looked okay. Upon visual inspection the solder connections look fine. If I put my ear right up to where the RCA connector and cable meet and bend the cable I can hear an audible crinkly noise. I hear this at both connectors but its far more apparent on the problematic end.

Link to photos: https://imgpile.com/p/cMkYs03

I'm going to reach out to DH labs next but does anyone have an idea of what might cause the woofer pumping without any input? Is there some RF signal or a ground issue that is somehow making its way through the cable?

I would just buy a cheap phono cable and see if that fixes the problem.

If so you can then replace or have your DH Labs phono cable repaired.

Either have the cable repaired, or just replace it. Not worth putting all this time and effort into something you know is bad.

After speaking to DH labs, they will repair the cable under warranty. Going to try my setup with another cable later tonight and will report back.

I'm still really interested in what actually causes the woofer pumping and noise associated with a bad connection.

Welp - tried with a new phono cable and the right channel fuzz is still present. Back to square 1. Realigned my cartridge from start to finish and I’m still experiencing a slight amount of “fuzz” in the right channel on some records. I would say it’s somewhat improved but not entirely. Not sure where to go from here. 

When you swapped L and R cables in the first experiment, did you swap at both ends or only at one end?

I swapped only at the phono pre end. So right output from TT went to left input phono pre and the buzz and woofer pumping swapped channels with the cable.

So you proved now that the problem is upstream from the distal end of the DHL cable. Not the cable itself.

ajnackman 

I swapped only at the phono pre end. So right output from TT went to left input phono pre and the buzz and woofer pumping swapped channels with the cable.

That sounds like a faulty phono cable, or faulty wiring between it and the phono cartridge (such as in the pickup arm) or a faulty phono cartridge.

I do think I have two issues that the DHL cable may be highlighting. I think the RCA to cable connection is definitely problematic. Bending the cable results in the signal dropping out completely. But I also agree that there is another issue upstream of the phono cable resulting in some "fuzz" that also swapped channels with a new phono cable. I heard almost the same sound that I'm hearing from my setup while riding to work this morning in a tunnel listening to the radio with some poor signal.

I'm not sure how or if I could rewire or even check the wiring in the tonearm. The tonearm does have adjustable azimuth at the headshell and it appears as if the headshell could actually be remove to service the wiring but the turntable has RCA jacks on the back of it. Would I need to remove the tonearm to inspect the wiring connection to the RCA jack in the back of the tonearm or potentially run new wiring?

I tested the continuity of the tonearms leads with my multimeter. White, blue, and green leads fluctuated between 0.5 and 0.6 ohms. The red lead fluctuated between 0.5 and 1.0 ohms. It would eventually settle on 0.5 but had a tendency to shift around more than the others. Are these poor enough values to suggest a continuity issue?

No. Where did you place the leads? In other words, these resistances were measured between where and where?

Between the lead connector inside the heat shrink and either the center RCA pin or the sleeve depending on the signal cable.

A place to look for a possible problem regarding the dropout you get when you wiggle the R channel input is inside the chassis where there should be a wire soldered to the RCA jack or actually two wires, one to the hot and one to the ground pin on the jack itself.  It’s worth a look inside, even though in my experience it’s never that simple.  Also wiggle the wire externally to mimic the situation where you get a dropout, while observing what goes on inside at the jack.

But the resistances you measured are typical and include the resistance per foot of the wire plus the lowest resistance that your meter is capable of registering.  Most meters will not show zero ohms even when you touch the two probes directly together.  My very high quality meter measures 0.2 ohms in that case. You could also try placing one probe of your meter on the internal wire that goes to the jack hot side, before the solder joint, and the other probe up at the cartridge pin while also wiggling the wire in the way that produces the dropout.  That way you are measuring across the possible trouble spot. But don't expect a miracle.

I've done a good amount of testing on my system and some additional research and wanted to provide an update here for the community. I am still looking for advice and am by no means an expert here. I'm still learning. I recently installed a new pair of speakers that I have been waiting on for a long time - a pair of Ascend Acoustics ELX towers which are a three way design. This has isolated the woofer pumping to the low frequency drivers. The overall excursion is significantly reduced compared to my old LS50s to an acceptable amount. As a parallel issue, I have been doing some research on ground loop and EMI/RFI which I believe to be another problem in my system. 

Steps that I've taken:

1. Measured continuity in my tonearm wiring from the cartridge leads to the RCA connections on the phono preamp side of the cables and confirmed good continuity.
2. Visually confirmed the lifting mechanism of my tonearm isn't interfering with playback
3. I confirmed that my tonearm wiring isn't binding or preventing my tonearm from creating a full physical sweep across my records. There is slack in the exposed wiring between the tonearm base and the plinth. I have been thinking that the issue is then electrical in nature and not mechanical although I cannot completely rule out some sort of degradation to my tonearm wiring or connections.
4. The repair of my DH labs phono cable helped reduce the high frequency "hiss" during playback but did not eliminate it at all.
5. I have a spare TVC passive preamp from Prometheus audio that I installed into the audio chain between my Sutherland and Simaudio. This resulted in no elimination of the "hiss". My understanding is that a TVC can break a ground loop between devices due to the air gap in the TVC. I have since removed this device.
6. Installed a separate grounding cable between my Sutherland Little Loco and my Simaudio. I discovered that my Simaudio has a small chassis ground screw on the back. Now my Sutherland is the center of my chassis grounding scheme. This has greatly improved but not completely solved the issue. So adding this grounding cable reduced the Voltage potential between my equipment which must have been exacerbating the cause of the high frequency hiss during phono playback.

So the question remains what the main cause is. After some research I think its possible that the combination of my Cadenza Bronze, tonearm wiring, and Sutherland is acting like an antenna for EMI/RF. Moving the phono cables around doesn't appear to change the nature of the sound so it appears to be originating upstream. To be clear, the undesired "hiss" is now fairly minor in nature and I can certainly live with it, however the question remains how to eliminate it completely. I honestly really love the sound of my system now but there is part of me that wants to optimize what I have.

I really don't want to move my turntable but the only other thing I can think of is trying to add some shielding to my tonearm wiring. I also wonder if I could somehow run a pair of shielded ground cables directly from the ground connections on my cartridge to the ground post of my TT external to the tonearm as a test to try and bypass the internal ground wiring and determine if the turntable wiring is indeed the culprit. I may be way off base here.

Any additional thoughts here are appreciated!

The other thought I had is that "hiss" could be entirely related to a ground loop. I found an old post by Almarg which could be what I am experiencing:

"In addition to producing hum, ground loops can also result in high frequency noise and buzz, by coupling harmonic distortion components and/or noise that is typically present on the ac lines into signal return paths. However, if you don't hear that when no music is playing, or if any low level buzz or noise that you do hear is the same whether or not the equipment is temporarily floated with a cheater plug, I doubt that it would have any effect on sound quality. I suppose it is slightly conceivable that inaudible ultrasonic noise that is introduced by a ground loop could somehow intermodulate with the music and have audible effects, but it's easy enough to rule out that possibility -- just compare the sonics with and without the ac safety ground temporarily lifted via a cheater plug."

https://forum.audiogon.com/discussions/more-grounding-questions?highlight=system%2Bgrounding

I have my entire system plugged into a Furman Elite 15pfi. I don't exactly want to plug the entire thing into a cheater plug as a test...