Balanced output to unbalanced Input, to Float pin 3 or short pin 3 to Grd?

[CoolCat]

I had to come back to this thread due to my having buzzing and horrific sound issues on this ISA430 to the Line 6 UX8 unbalanced Line In.
Tried the Pin 1 to 3 and the float 3 and it was still distorting and buzzing a lot. I wondered why is this so hit and miss and it works then it doesn't and its noisy or anemically thin?

Feeling like a dull tool...I just realized (read online) this UX8 interface is not just a cheaper Unbalanced Line In....its a cheaper -10 signal Line Input Unbalanced designed for -10 consumer stuff and drum machines and keyboards. ...not +4 outboard preamps etc...

It gets financially expensive this "technical rabbit hole".
To buy a Pro ISO Radial is too expensive for 8 channels...for a $100 interface from 2009. No go...

To buy a new interface that workins in +4 and has Balanced LINE IN is pretty expensive.

To just use the Outboard Preamp into Interface Mic Preamp XLR balanced is FREE. (and last I looked I wasn't making any money on this gear. lol)

so appreciated all the inputs and help before, but apologize because I left out it was a "unbalanced Line In but also -10 consumer, line in, 10k impedance.
and the ISA430 has +4 only with transformer out balanced....

Doubt anyone is interested in a Line 6 UX8 interface but the Balanced to Unbalanced discussion was informative!

 

[LazerBeakShiek]

It outputs -10. Not the end of the world really.

+4 is where it is at.

A Focusrite6i6 USB gen2 interface is about $50.
a Presonus MP-20 microphone preamplifier, Discrete, has Jensen transformers. Mono output bus and stereo output busing. About $100 on reverb.
I rarely lose money when I sell my gear. Keep your shit clean. Keep it nice.

 

[ecc83]

CoolCat, +4dBu down to neg ten is, near as Behringer is to swearing, a 12dB loss. Very close is the series combination of 8k2 and 2k7, -10dBV across the 2k7. That gives a load on the source of 10.9k not going to bother anything remotely decent. Those resistor values do not take into account source resistance nor input resistance but should be near enough. If the signal is a bit low, swap 2k7 for 3k3, if high swap 8k2 for 9k1 or 10k. A box of dinky Metal Film resistors is peanuts from Zon.

A transformer output should be on XLR 2 and 3 (tip and ring for jack) I doubt it will have a centre tapped ground to pin 1. You may or may not need to connect pin one (jack sleeve) to the destination ground depending on whether or not you get a ground hum.

Jusfort! Balanced -10dBV inputs are as rare as rocking horse dropping but should you need one, split the 8k2 into 2X 3k9 "either side" of the 2k7 and take the signal again across the 2k7. Rin drops a bit to 10.5k, still nay bother.
Dave.

 

[CoolCat]

the Focusrite 6i6 allows software switching to +4 or -10....wish this had that.

what's weird is I swear it was working for this, but it was really buzzing and thin/distorting sounding.
the old Aphex 207 here... allows unbalanced Output with a -10 or +4 switch, nice little feature for consumer-gearheads.
none of my other preamps do that. UX8 Line 6 state the units have good headroom of 18.5? whatever that means.

rocking horse droppings? lol

 

[Steenamaroo]

I had to come back to this thread due to my having buzzing and horrific sound issues on this ISA430 to the Line 6 UX8 unbalanced Line In.

Might be stating the obvious here but if you're using an unbalanced connection between preamp and interface, you're at the mercy of whatever noise is in the environment so are you
1: Using the shortest cable possible
and
2: Keeping your cable away from obvious sources of noise, like transformers, power supplies, etc?

UX8 interface is not just a cheaper Unbalanced Line In....its a cheaper -10 signal Line Input Unbalanced

Unbalanced inputs generally are.
It's not a guarantee but a reasonable expectation.

Not seeing why running both devices from the same power socket and using your shortest TRS patch cables shouldn't be fine.
If your patch cables run by a big ass transformer or something, you might need to do some rearranging.

 

[ecc83]

"UX8 Line 6 state the units have good headroom of 18.5? whatever that means."
Headroom is usually referring to an input and means how many dBs over the Operating Level the device can handle before distortion sets in. Sometimes (but rarely!) they will state the distortion level at the dB level, e.g. "+20dBu at 0.1%THD" For comparison, these days you would expects distortion to be lower than 0.01% at all levels below that.

But! These specifications are nightmare for the non-technical. First we have two (at least) op levels, +4dBu about 1.2V rms* and -10dBV 0.316 V rms. Now, is that headroom figure stated ref "dBu" that is referred to 0.775V rms or is it reffed one volt? Matters coz the first is 6.5V and the latter 8.4! Manufacturers are bloody terrible at giving good, rational specifications. Often a frequency response of a mic is given as a bare "50Hz to 16kHz" is that ref 1kHz and how many dBs up or down at the extremes?

This did not matter or happen so much 50 years ago. The studio and hi fi magazines (when the latter were run by engineers and not beardy tweaks!) would review perhaps 3 or 4 items per issue and woe betide any firm who failed to supply a properly written specification! They would be castigated by the experts and the firms knew that would lose them sales. Today the market is flooded with kit and there is no time nor enough technicians to sort the buggers out.

*rms? Don't sweat it, it is the "normal" way to specify an alternating voltage and the suffix is rarely shown.


Dave.

 

[LazerBeakShiek]

the Focusrite 6i6 allows software switching to +4 or -10....wish this had that.

oh wait...hhhuh. It has outputs for line level +4 , and instrument. So I think it does. It has been a while. Lemme look at tit.

 

[CoolCat]

Line 6 UX8 states 18.5 dbu for incoming 20-20khz. Mentions 10k ohm and the consumer -10 dbv....but claims due to high headroom it doesn't distort.

yes all units are on the same house voltage strip,
but interesting seems to be picking up noise, sometimes worse than others. ..maybe too close to the 430's transformers...somethings noisy with these two playing together.

it is odd the 430 + UX8 has always been random problems and being its such an old unit I often jump to conclusions 430 is failing.
I did rummage through old notes and there are three Line Outputs can do +28 dbu.
always had a love hate with this 430 due to the noise and distortion..basically horrific crap sound randomly, but now !! knowing the -10 unbalanced will help resolve the distortion surprises and be aware of level.

The "test" cables with Pin 1+3, or Float Pin 3... is still a bit unknown why one seemed to work then other times is noisy.
This 430 is soooo frkn loud, like the ISA One....just so much gain, easy to overdrive the -10 Line In....now I see!

I feel really a dum*ss on this -10 thing, after all these years...wow..Im just now finding this out?
Hindsight it was then just "dumb luck" it would sound great sometimes and other times noisy, anemic distorted etc.. cables and bad gain staging/overdriving.

I looked up the old Aphex 207 units, they used to be had $70, $110...thought Id buy one for $100....now people are asking $500 or $400!! what's going on with this price gouging? I paid $650 for a very used scratched up 430...now its too much and old as the hills.

About the time I get really knowing it and leaving it on all the time, it will probably fail in old age, needing caps etc...lol

 

[LazerBeakShiek]

Wait and look around. Those Aphex tubeescence preamps will be found for less than $100.

Is/are there other hardware you have that inputs -10/+4 and switches the input line/instru level up or down?

The 'used market' is only getting worse.

 

[CoolCat]

I have a 207 and it was cheap but really nice sound and now the "-10" option works for this weird UX8 Line In issue.

like always it gets priced out.....

1. get a PRO ISO $105 used and beaten up box
2. J ISO...Jensens $242 outlet new
3. get another 207...$250-$450 with fees and shipping and taxes...reverb stuff (and no known shape of item...very old)
4. say hell with the UX8 and get a new 8channel interface with +4 Line In Balanced that works with everything I have....but this is $$$$ (and I do have years and enjoy the UX8 for free Platinum Pod Farm, best headphone amp, and doesn't need logged into Internet like the Antelope Audio, and has been great....except for the Line In design...ok the preamps aren't that great either....
5. Sell everything....start over.......but with wisdom! like getting married a 2nd or 4th time...wisdom!

 

[ecc83]

I have a 207 and it was cheap but really nice sound and now the "-10" option works for this weird UX8 Line In issue.

like always it gets priced out.....

1. get a PRO ISO $105 used and beaten up box
2. J ISO...Jensens $242 outlet new
3. get another 207...$250-$450 with fees and shipping and taxes...reverb stuff (and no known shape of item...very old)
4. say hell with the UX8 and get a new 8channel interface with +4 Line In Balanced that works with everything I have....but this is $$$$ (and I do have years and enjoy the UX8 for free Platinum Pod Farm, best headphone amp, and doesn't need logged into Internet like the Antelope Audio, and has been great....except for the Line In design...ok the preamps aren't that great either....
5. Sell everything....start over.......but with wisdom! like getting married a 2nd or 4th time...wisdom!

Do you have a link to the UX8's user manual? I tried to hind it to no avail. Don't give up on it yet. I remember Line 6 products being very popular in the magazines some years ago and folks didn't seem to have much bother with them. Go nut and buy this...
I have had a few, even put one in a posh tin for a chap to use inline with his active monitors he was chuffed to bits. Cheap enough that you can butcher the wires as you need to (I hope you can solder?) OK...NOT the finest transformers extant but I found them pretty good and should be fine at -10dBV levels.

People don't usually have much in the way of noise issues at line levels, even neg ten and unbalanced. Fork! The hi fi industry has exchanged signals, cassette decks e.g. at even less than that, most run at 100-150mV That's -20dBV territory and unbalanced at that.

Ground loop problems need a very systematic approach. As has been said, keep mains connections as compact as possible but then introduce just one piece of kit at a time. If that cheapo isolator fixes things you can then look at something of higher quality. The Art isolators are well thought of.

Dave.

 

[CoolCat]

This shows the UX8. Not much there as in "old school" schematics and engineering info.

2-6 Toneport UX8

https://line6.com/data/6/0a060b316ac34f0593bf82135/application/pdf/GearBox%203.7%20User%20Manual%20%20-%20English%20(%20Rev%20C%20).pdf

Specs

Line 6 | Legacy Products

Create, record and perform with guitar in new ways.

line6.com

I can solder "ok". A friend just gave me a really nice gun, and with large magnifier, I did the AKG P420 mod = capacitor on a SMC part.
Also recently did a bunch of cheap crap cables, installed heavy Switchcraft XLR.... so Im novice. Its not assembly line perfection.

I had bought two XLR to 1/4 cables, one is pin 1+3, 2 tip. and the other is 2 tip, 1 and 3 is floating. This all the gear stacked on a desktop, no long runs.
Actually next time I get the solder gun out Im going to shorten a bunch of these cables to 24 inch or so... get some Guiness Stout going, for a steady hand...lay off the coffee.

 

[LazerBeakShiek]

Kind off topic..but it fits a few posts.

Why would you want a preamp that has no transformers to track a input a microphone? Sometimes that tube on a starved plate doesn't seem to be helping.

The transformerless aphex 107, 207, etc is clean. Another Super clear that sounds like nothing. You paid money for that fancy microphone. So whats the point? Thats why 'elders' get Neve1073's, and Focsrite ISA with Lundahl's, or Warm's with Cinemag, Presoni with Jensens? The transformer designs have tone and character or color.. whatever 'word' you like. 'distortion' even?

 

[ecc83]

Kind off topic..but it fits a few posts.

Why would you want a preamp that has no transformers to track a input a microphone? Sometimes that tube on a starved plate doesn't seem to be helping.

The transformerless aphex 107, 207, etc is clean. Another Super clear that sounds like nothing. You paid money for that fancy microphone. So whats the point? Thats why 'elders' get Neve1073's, and Focsrite ISA with Lundahl's, or Warm's with Cinemag, Presoni with Jensens? The transformer designs have tone and character or color.. whatever 'word' you like. 'distortion' even?

I have always been suspicious of claims of "mojo" or "colour" from pre amps with front end transformers?
There just does not seem to me to likely be enough level from a microphone to cause audible distortion in a decent mic traff? The Lundahl LL1538* for instance hits 0.2%THD for 0dBu at 50 Hz. 775mV is a heck of a mic signal! There is also next to bugger all in the spectrum of most instruments at 50Hz, certainly not in a voice. Transformers distort more progressively as frequency decreases so at 100Hz and 0dBu THD is likely better than 0.1% (a very good valve hi fi amp!) and gets better and better as F increases.

Of course, not every pre amp uses Lundies! But transformers from Sowter and Jensen et al are still very good and will, IMHO produce naff all distortion at regular mic levels, e.g. around -30dBu.

The single ended output stage Neve used will give distortion but for those looking for "attitude" from many transformer pre amps, caveat bloody emptor.

*I recall a journalist's visit to Lundahl's works and the boss said "we design transformers to be a clean as possible."

Dave.

 

[Steenamaroo]

Not seeing why running both devices from the same power socket and using your shortest TRS patch cables shouldn't be fine.
If your patch cables run by a big ass transformer or something, you might need to do some rearranging.

Didn't realise the ISA430 is XLR output only.
Same applies, though.
I'd be testing with the shortest possible XRL to TRS cable.
1-2-3 connected to S-T-R.

I realise R is left open at the interface but still... I'd start there.

Actually next time I get the solder gun out Im going to shorten a bunch of these cables to 24 inch or so

So we're have nondescript noise issues, but aren't keeping our cable runs short yet.

I had bought two XLR to 1/4 cables, one is pin 1+3, 2 tip. and the other is 2 tip, 1 and 3 is floating

Sounds messy.
Get a cable and confirm with multimeter that the pinout is 1-2-3 to S-T-R, and also confirm that no combinations of pins is shorted internally.
Do a short recording, keep gain modest, cable short, and pinout standard.


Idk, the description of the fault isn't really clear to me from this thread,
so I'm thinking establish exactly what happens when you do what you're meant to do, and share a recording here?

 

[LazerBeakShiek]

I have always been suspicious of claims of "mojo" or "colour" from pre amps with front end transformers?
There just does not seem to me to likely be enough level from a microphone to cause audible distortion in a decent mic traff? The Lundahl LL1538* for instance hits 0.2%THD for 0dBu at 50 Hz. 775mV is a heck of a mic signal! There is also next to bugger all in the spectrum of most instruments at 50Hz, certainly not in a voice. Transformers distort more progressively as frequency decreases so at 100Hz and 0dBu THD is likely better than 0.1% (a very good valve hi fi amp!) and gets better and better as F increases.

Of course, not every pre amp uses Lundies! But transformers from Sowter and Jensen et al are still very good and will, IMHO produce naff all distortion at regular mic levels, e.g. around -30dBu.

The single ended output stage Neve used will give distortion but for those looking for "attitude" from many transformer pre amps, caveat bloody emptor.

*I recall a journalist's visit to Lundahl's works and the boss said "we design transformers to be a clean as possible."

Dave.

a transformerless would be for bouncing copying, like on a 8 track. Where you want superior clarity in duplication. Also 'live' playing.

A transformed descrete preamp is for tracking/recording musical sources, where you turn up the gain against turning down the output. Called coloration. (Common term.)

TRUE or FALSE?

 

[ecc83]

a transformerless would be for bouncing copying, like on a 8 track. Where you want superior clarity in duplication. Also 'live' playing.

A transformed descrete preamp is for tracking/recording musical sources, where you turn up the gain against turning down the output. Called coloration. (Common term.)

TRUE or FALSE?

Well, if you mean a mic at medium to high levels into decent transformer? False IMHO for the reasons I have already set out. "Discrete" preamp? Do you mean one made with individual transistors caps and Rs? If so then they are largely snake oil to me and inferior to say an NE5532/4 in almost every way.
I can see they were quite advanced when the best op amp we had was the 741! But the world has moved on.

Dave.

 

[LazerBeakShiek]

then i have no idea what youre talking about or any of that advertisement bullshit

Decent in relation to what, THD? nevermind

 

[ecc83]

then i have no idea what youre talking about or any of that advertisement bullshit

Decent in relation to what, THD? nevermind

Calm down. "decent"? A sowter, Cinemag, Jensen. "Advertisement"? lost me there. "THD"? very little. Rather the point.

Dave.

 

[LazerBeakShiek]

ahaha both speaking English, and we cannot even come close to understanding each other...hahhah

I thought I was clear. Apparently so did you. yall be good!