#233

wanted to circle back on this with a discovery I made today. i was getting a ground loop on a balanced cable from my DSI Prophet 08 Rev 2. Tried an unbalanced cable and the loop went away which perplexed me. Checked the manual on the synth, unbalanced outputs…

I wouldnt think that connecting balanced cables to unbalanced ports would cause a problem but i guess they can.

#234

AFAIK there are very few synths with balanced outputs (although I think my old A4K may have had them), and it’s nearly always better to use unbalanced cables. On some synths using balanced cables with its unbalanced outs will result in a severe volume drop due to out of phase signals. This came up recently with people trying to use balanced cables with their Super 6’s.

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#235

Oh I thought most keyboard gear was balanced. The prophet 08 is the only synth I have that’s unbalanced. The rest are balanced. I could see older synths being unbalanced too. Good to know unbalanced synths is probably more common than I assumed.

I still don’t understand why the loop though. You wouldn’t think that the ring would still be common to ground same as plugging in unbalanced cable to balanced in/out. In my case I was even still going into a xfmr DI box which I thought would surely isolate the loop but nope.

If you plug unbalanced output -> balanced cable -> balanced input, I could see phase issues arising from that setup depending on the input balancing circuit. There could be a difference between cold and ground that the input would cancel.

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#236

Yeah, I am not sure of the numbers but in 30 years of owning probably around 30 synths, the only balanced one I’ve owned is the A4K. I wish it was more common. I think the Wavestation A/D rack maybe had balanced outs back in the day too, but I only had the keyboard EX version.

Anyway, hope you get the ground loop hum sorted!

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#237

I actually just went through this same thing concerning my old Teac reel to reel. It’s unbalanced RCA ins and outs and I have it connected to my balanced patchbay. I mostly send audio from Ableton to and from it. I found that it was distorting on the way in and needed a lot of gain on the way out. So my results were often distorted and noisy. I bought the ART Cleanbox Pro to deal with this. Now I have Balanced TRS out of my patchbay going into the XLR inputs of the Cleanbox. Then the unbalanced RCA’s from the Cleanbox to the RCA inputs of the Reel to Reel. Totally solved my problems. Got it for just 40 bucks on eBay too!

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#238

I also have a Rev2 and didnt even realize it was unbalanced outs. I have it connected to my balanced patchbay using balanced TRS cables and everything seems perfectly fine.

#239

Well that is the frustration of ground loops. They are actually very complicated and highly dependent on the electrical environment of your studio.

If you are ever down for some light reading: https://web.mit.edu/jhawk/tmp/p/EST016_Ground_Loops_handout.pdf

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#240

Me after an evening of looking for ground loop when I just wants-ta jam.

image

But in all seriousness, I have a noise problem that comes and goes. I suspect it is the heating element in my dishwasher. But when that noise is present, recording is just off the table.

13 Likes
#241

How do you guys deal with low signal like sounds from kalimba? Today I tried mic with it by using Rode NT4 and Mixpre-6. My Mixpre set to 38dB gain, but it the volume didn’t get to -20dB even I put my kalimba close.

#242

Here’s something huge I learned recently. I process external audio through my modular all of the time and I’ve always struggled with getting proper gain staging. I have some Ladik modules for sending line level audio in and out of the modular. I also have a send/return for guitar pedals. I would frequently have distortion and noise problems so I emailed Ladik and this is what they had to say:

“Eurorack standards defines quite low headroom, “normal” level is ±5V(peak-peak) and power supply allows max. level around ±10V, this is only 6dB headroom.
So if your sound source is not quite perfectly steady (say within 3dB) it will be tough to establish a reasonable level with any of pre-amplifiers…”

I’m not really sure I full understand how the power effects the headroom but the fact that Eurorack does have very little headroom explains a lot of my gain staging issues.

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#243

Have you tried any other mics? Are you sure you have the mixpre channel set to mic and not line level? I don’t have any issues recording my kalimba with a dynamic mic, so the signal should be hot enough with a stereo condenser.

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#244

My latest personal insights:

  1. audio converter from same year&price dont differ too much in terms of sound. I have made a blind test with bbface/axe2/er301 and sent samples to my friends. No difference except some noise that 301 gets being patched from different case.
    Some $$$-interface with transformers can add some difference but I can do it myself with rack/500 gear before interfaces. To be honest I thought that different will be bigger for my ears.

  2. unwanted noise is evil. From some bad designed euro modules, ground loop. Even if s/n is big, noise is very unwanted in pauses between sound. This noise is very hard to transparently remove even with pro-plugins like RX and need a time. Try to fix most of the causes of noise.

Think again about switching from portable euro case to 1 big studio case with linear psus.

#245

Yes, this sounds maybe weird. With highly dynamic percussion sources like kalimba or shakers, around 30-40dB of gain would be perfect to achieve a good digital level without clipping. But it will totally depend on the sensitivity of the mics. KM84s into TG2 pre here.

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#246

would the NT4 be running on a dying battery instead of 48V from the Mixpre ?
In many condenser mics, insufficient phantom power results in very low levels.

#247

Thanks for doing this! it was really instructive for me to get a sense of the way these pieces can color a mix. Also, cool track. Is the final somewhere?

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#248

Thanks for all your words.

The NT4 is powered by 48V on Mixpre-6 and set to Mic In and linking 1 & 2. Gain set to 38dB. Also I applied 80Hz low cut to eliminate potential unwanted room noise. I use Pro Tools.

Perhaps I will provide a sound clip to see what I got.

May I ask (newbie question), how you guys place your mic for kalimba? I tried with a very close distance (2 inches) but the sound isn’t natural at all. If 4 inches far the body resonance sound didn’t get in, and the recorded signal is weak too.

Thanks again.

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#249

For Kalimba I’d start at least a foot back, maybe two, but it’s really all about experimenting. Every room/kalimba/mic/pre combination is gonna act and sound differently.

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#250

Thanks! It’s on here:

Have learned sense I posted this that all these coloring agents really start to show when you push them (heavy input…actually guess I did know that at the time), or by running through a lot of times/running individual tracks through them so there’s a cumulative build up of the vibe they bring. It’s all so subtle, it’s really hard to do solid, very definitive a/b’ing.

I think another thing I’ve learned is what to listen to…a lot of these things are most about thickening low/low-mids and glueing them in to the track.

2 Likes
#251

Regarding the topic, lately I’ve been learning the basic/ fundamental on recording, mixing and mastering. Before that I shared my works on Soundcloud but do not care much about the quality, all clips are raw and DIY-ish. I’ve been collecting vinyl for about 10 years for genres included ambient, noise/ drone and experimental. This year my studio is all set, with some decent turntables and such, I realized how good an experimental record would sounds like, it is the things I’d never come up with before. It makes me want to do more on the sound quality (which before I thought is not important in such genres).

Few weeks ago I randomly watched a YouTube clips about re-amping Fairfield Circuitry Shallow Water and amazed by the sound he got by use of re-amp DI box. I have this pedal since day one it releases, love it for sure but I can never get it right and capture the beauty from DAW. This clips convinced me (even he’s not intended to) to get my very first DI box RNDI. At first glance, the sound improvement seems no difference, but soon realized the sound ‘density’ is way better, and not to mention the hi is more airy now.

Update on signal level on Mixpre with NT4:
:relaxed: Problem solved! It is because I only set 48V Phantom on Input 1, in fact I need to set it on both Input 1 and 2. However with this setting the red LED on the mic is unlit. Anyway the level is work as normal now.

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#252

Though I am not sure about what you said (I am so weak on those dBV, dBu stuffs, confused to apply these into real world application) I kinda feel the same thing. Lately I realized that something like Mannequins RIP (or other output modules) does help to level matching, i.e.

Modular signal > Mannequins RIP > Line level > Pre amp

compare with-

Modular signal > Pre amp with signal attenuated by fader/ gain trim

At first glance both have the same result, but I found the former one can have a better control for dynamic range, besides you can route the signal to other outboard gears (for example pedals) ‘properly’.

I am still experimenting the way to do it right, please feel free to share! Thanks.