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Is this feasible?
Old 5 days ago
  #1
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Is this feasible?

Apologies in advance if this is a stupid question. Does this signal path make sense and is it feasible?

SIGNAL PATH:

(L) AUDIO FROM AT-1240>CH 1 PREAMP>CH 1 EQ>CH 1 COMPRESSOR>INPUT 1 INTERFACE/DAW

(R) AUDIO FROM AT-1240>CH 2 PREAMP>CH 2 EQ>CH 2 COMPRESSOR>INPUT 2 INTERFACE/DAW


I make sample-based music and often sample from vinyl. I want to have as much control over my signal before it hits my DAW (both L and R audio signal).

I'm looking to run my signal through a PREAMP, an EQ and a COMPRESSOR. The purpose of the PREAMP is simply to add some warmth/color to the signal.

My initial concern is that the PREAMP will be looking for a balanced signal and what I'll be sending out from the turntable is unbalanced.





Thanks in advance for any help!
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Old 5 days ago
  #2
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Sweetwater sells a very affordable adaptor cable in three different lengths. Other retailers may offer the same. Enter “RCA to XLR male unbalanced interconnect cable”. It should do exactly what you want.
A word of advice. Do not connect to the (very tempting) 1/4” DI input. It is unbalanced, and it will seem to work, but the impedance of one MILLION ohms is way, way higher than your turntable outputs are expecting.
Old 4 days ago
  #3
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??

I'm curious about this.

The turntable outputs either a 'phono' level for feeding to an external RIAA preamp, or line level using its own built-in phono stage.

How does either of those options work for connecting to a mic preamp?

The Art tube preamp he has doesn't have a line in.

Surely you can't just connect it using an rca to xlr cable.
Old 4 days ago
  #4
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Quote:
Originally Posted by dnouse View Post
My initial concern is that the PREAMP will be looking for a balanced signal and what I'll be sending out from the turntable is unbalanced.
It's not a question of unbalanced vs balanced, it's that the preamp's inputs are looking for a microphone level output from the source.

Even if using the non-line out option on the 1240, the Art preamp doesn't have an RIAA stage so I really don't see how that can work at all.

Happy to be corrected though, as always.
Old 4 days ago
  #5
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Quote:
Originally Posted by dnouse View Post
... Does this signal path make sense and is it feasible?
....
My initial concern is that the PREAMP will be looking for a balanced signal and what I'll be sending out from the turntable is unbalanced.
...
Out of curiosity regarding turntable progress, I looked up the specs on the AT-LP1240-USB. Is that the one you have?

If so, I was pleasantly surprised to see it has a normal 'phono' output, a class- compliant 16-bit 44.1k/48k USB output, and a ~150mV 'Line' output. The 'Line' out is a switch selection for the RCA outputs on the back.

That 150mV corresponds to about -14dBu, so just a little (~20dB or so) of preamp gain (or accumulated via the EQ and compressor series) is needed to get you in a sweet spot in your DAW inputs. If the unbalanced cable is short enough from the turntable's RCA 'Line' out to the preamp, you'll be able to get away with a simple RCA-to-TS cable. The instrument input on the ART MPA II is an 800k input impedance and tolerates up to +17dBu input level, so it's probably going to behave just fine with a TS cable input on the front.

I did all sorts of fiddling around with my MPA II when I had it, and it seemed to gracefully accommodate everything I tried.

Last edited by MediaGary; 4 days ago at 03:49 PM.. Reason: added MPA II comment
Old 4 days ago
  #6
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Ah, well there you go, all curiosities and questions answered, mine included!

I'm kind of embarrassed that I know so little about voltage & resistance etc.

I mean, I shouldn't be, I've never studied it or needed it as part of any job, but it's starting to become clearer.

So in a case like this, you basically just look at output source voltage, destination input resistance and how much input gain is available and then you see whether you can match or not, correct?

I don't know what the relationship is between ohms and voltage but I'm sure it's an equation I won't have to look too hard for!
Old 4 days ago
  #7
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Quote:
Originally Posted by Quetz View Post
...
So in a case like this, you basically just look at output source voltage, destination input resistance and how much input gain is available and then you see whether you can match or not, correct?

I don't know what the relationship is between ohms and voltage but I'm sure it's an equation I won't have to look too hard for!
Well, in the context of the OP's question, the only reason to mention the high 800k-ohm input impedance of the front TS jack of the ART preamp is to assert that it's 'really high' relative to a normal 'line' input which would be in the 10k to 40k range. Nevertheless, the only potential downside of using the high input impedance is that it could be noisier than a value that's closer to normal.

Passive electric guitars and passive bass that are the intended/preferred source devices for the 'instrument' inputs of interfaces and active DI boxes. BTW, impedance is sort of like resistance for alternating signals and is generally frequency-dependent.

The relationship between voltage and dBu (or dBV) units is a pain in the neck to keep track of, so I made a spreadsheet of values and posted it in an article on my website a few years ago. The article is called 'Stacking the Tracks'.

As a matter of Ohm's Law (yeah, in physics, you're cool if you get a unit of measure named after your surname ... Hertz, Maxwell, Volta, Joule, Coulomb...I digress) the equation is E=IR, meaning volts(E) is current(I) multiplied by resistance(R), and all the other combinations are true... I=E/R, R=E/I.

That should get you going into the dark arts of electricity.
Old 4 days ago
  #8
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Thanks for the info Gary.

I do not have time to study yet another discipline!!

Although, I already know I will find the time somewhere
Old 4 days ago
  #9
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Quote:
Originally Posted by Quetz View Post
Thanks for the info Gary.

I do not have time to study yet another discipline!!

Although, I already know I will find the time somewhere
Please bias your "spare" time to continuing your fabulous work on the Mackie Control enhancements you've been building. I'm hoping that some of that work can be beneficial to my Midas M32 Mackie Control implementation. Hint: there are a lot of Behringer X32's out there...
Old 4 days ago
  #10
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Thank you for the encouragement Gary!

The map and functionality/features are all finished/consolidated/tested, it's just the marketing videos and website part that are going slowly - too damn slowly.
I'm going to extend the discount period because I won't have given people enough time to see everything in action.

Too many other life dramas getting in the way but it will get there soon.

X32/M32... Hmm.

Because this is Studio One only for the time being, I would of course like to implement it on as many different devices as possible within that ecosystem.

Am I correct in thinking that when you press the 'DAW Remote' button on the X32 that it becomes a Mackie Control device?

Edit: Yes..
I just looked at the Behringer product page and there is an asterisk next to the phrase 'Mackie Control', but when you scroll down to look at what the note is it just mentions Apple trademarks

I'm going to read through the manual.
Are you using Studio One?
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