1073 clone high pass filter hum

easlern

Boredom artist
I just got a 1073mpf, works great but turning on the high pass filter causes a big hum around 60Hz to appear. I'm guessing it's a ground loop but when the filter's off the hum is gone so I'm not too sure. Anyone had a similar issue, could it be proximity to power supply, em interference, something else?
 
Well that was silly- I moved the unit a few slots down from the furman and now it's fine. Guess that part's sensitive. . .
 
Yeah I'm kind of in a big gear change (heh pun), I got rid of some stuff, got some new stuff, rearranged the room. I don't know yet if I'll get better recordings but it sure is fun!
 
dude thats interesting to me because awhile back Id had a fairly overbuilt strip with huge transformers etc....and turns out it was making a bunch of noise! and I grabbed a $5 plastic strip laying here and the noise buzz shit was gone....immediately and I was thinking "that was easy".

i mean, ffs... the unit like a Fruman does one thing? and it cant even shield that? I tossed my pos power strip and the $5 plastic one thats noisless won...I dont care what marketing says. ha

1073mpf.... two channel preamp ....what did you have before that you're trading out?
 
Yeah you'd think they had that stuff figured out regarding interference. But I did get the glorified power strip version not a "nice" furman.

I actually got the single channel mpf, I couldn't commit to the dual one money wise. I had an la-610, sold that on ebay which covered most of the mpf. I was deep in the 610 (I still have a 6176) but for the stuff I'm doing lately it hasn't been a good fit. Very wooly with some shrill mids that are hard to shape. I'm not blaming the pre though, I may have used the wrong tubes or mikes with it. I was notching 1k on just about every source, I finally admitted maybe it's time to try something different. Real glad I did because I've been using the mpf for a few days and all those problems I had are gone.
 
6176 is one I'd like to try out. the 1073 out to be a different flavor.

haa the noise makers in the studio....it does seem simple but isnt always so simple. I took a LDC turned it up and went around the room and captured a few noise makers and removed them, kind of like a noise-detector! mic. my transformer powerstrip was actually humming pretty damn loud per the mic and headphones, of course without that normal people sitting you didnt hear it much, similar to a computer fan only being noisy as hell with the mics on and headphones.
 
That's a good idea about looking for noises with the mic, never thought of that heh. I'm not too picky about noises really though, I have recordings with floor creaks and room noise and stuff, my son yelling in the background. I just leave it in if I can't comp it out. But that hum was *really* not good, I'd have to high pass the high pass filter to get anything usable.
 
Having heard just a little bit your singing in the new pre, it's going to be a good fit. Was it the La-610 you had been using in the recent stuff? If so, that piece of kit had been sounding pretty good too.

I think we assume what we want is a "warm" sound with "tube character" and the like, but at the end of the day what those adjectives mean is low-mid buildup. So for vocals, the critical question is: Does this voice need help in the low-mids? Your voice is powerful in those frequencies and really doesn't.
 
Yeah for the past few months I've been using the la-610, but I bypassed the compressor. It was very good at what it did but seemed to add to the darker tone. I might want another opto eventually but the 6176 compressor is useful enough and has enough character I'm happy.
 
Yeah you'd think they had that stuff figured out regarding interference.

It's the nature of most preamps, there's nothing wrong or any poor design.
You don't want them near anything that can affect the delicate mic signal...things like amps, computers, large power supplies, or anything with large transformers, which is what you have in most of the Furman power units.
For that matter, I keep all my Furman power units in their own small rack, with no audio gear.

All my preamps are also in their own rack...far away from all my other gear.
I even have an input XLR patch bay in the same preamp rack for the pre's inputs...and the pre's outputs I run to another rack, where my other patch bays are that the rest of my gear is hooked up to.
 
That's a good idea keeping power on a separate rack, my only fear is that if I get another rack I'm gonna end up going to reverb and filling it with other stuff lol
 
Hmm... Have noticed a bit of hum from my headphone amp which sits right above the Furman PL-8. Think I'll try moving that...
 
That's a good idea keeping power on a separate rack, my only fear is that if I get another rack I'm gonna end up going to reverb and filling it with other stuff lol

I made my own rack for the power units...it's only an 8-space rack...but you can get 'em ready made in all sizes, though if you only have 1-2 single space Furman units...then you're going to be stuck with the empty space begging for more gear. :D

If you have a power amp or any other "power" type units, you can group them all in with the Furman stuff.
 
Going round with a 'probe' mic is a good idea.
Even better, record the proceedings and stuff the result through Right Mark analyser. This will show up very low level and VLF noise sources.

You can also save the graphs as a reference.

Dave.
 
I had 3 Chameleon 7602's stacked with their power supplies I don't know how long. Finally- for the same reason got off my lazy ass and got them mounted down under the table. Yes!
 
"I had 3 Chameleon 7602's stacked with their power supplies I don't know how long. Finally- for the same reason got off my lazy ass and got them mounted down under the table. Yes! "

Mixit: Wall rat and line lump PSUs are NOTORIUOS for spewing out hum. Do not 'tidy them up' inside a rack!

Dave.
 
"I had 3 Chameleon 7602's stacked with their power supplies I don't know how long. Finally- for the same reason got off my lazy ass and got them mounted down under the table. Yes! "

Mixit: Wall rat and line lump PSUs are NOTORIUOS for spewing out hum. Do not 'tidy them up' inside a rack!

Dave.
Nope, this is a pair of their half rack PS in my 'stack' :>) Still IIRC I could hear the dif pulling them away from the pres.
 
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