Signal levels too hot!

[Xrod]

Greetings! This is my first post here.

I recently added a new mic and channel strip and am having problems taming the volume levels. I have an AT 2035 with db cut engaged, into an ART TPSII preamp with output virtually off, into a Focusrite 2i4 interface, also virtually off in order to get a reasonable recording level.

It seems like using a channel strip/preamp into my interface is basically ganging two preamps in series. The super hot signal makes adjusting the gain level super sensitive. Is this normal? Am I getting the full benefit of the channel strip sound this way?

I have similar problems when recording guitar and bass, active or otherwise, and have to turn the output of the instrument way down when I prefer to drive the pickups at a higher level.

Thanks in advance for any insight you all may be able to provide.

 

[Steenamaroo]

It seems like using a channel strip/preamp into my interface is basically ganging two preamps in series.

You may well be, depending what input connections you're using.
It's important to understand gain staging and the several points at which a signal can be tapped.
Google line level, instrument level and mic level if this is greek to you.


On modern interfaces the XLR input is generally in front of a microphone preamp, and 1/4" inputs generally expect an instrument or line level signal (usually switchable).
In the ideal world you'd run your preamp into a dedicated line level input on the back of the unit, but your particular focusrite doesn't have any so the front line input will do.

The path should be Mic -> Xlr to xlr cable -> preamp -> Xlr to 1/4" jack cable* -> focusrite.
If you find that the gain knob on the focusrite still affects the signal level, refer to your focusrite manual to find out where to set it for optimal performance.

Set the focusrite front switch to line rather than inst.
*You can use 1/4" to 1/4" but it'll be unbalanced so you'll be more susceptible to stray hums and noises.

On a separate note, I'm not sure how much of an improvement, if any, you'll get over the stock preamp but do let us know.

Hope that helps.

 

[Xrod]

Thank you! Makes perfect sense....

I have a basic knowledge of gain staging, but will study it some more......

I think that the focusrite engages the preamp automatically when an XLR is connected...the mic/line switch has no effect.

When you say "preamp -> Xlr to 1/4" jack cable* -> focusrite", does that need to be a TRS connector or standard 1/4 TS, or does it matter?

I need to study balanced vs unbalanced as well!

Your last comment suggests that the quality of the ART preamp is probably not much better than the built in pre's in the Focusrite. I have heard over and over that a "channel strip" is key to quality recording, but it seems like there's the $300-$500 range, then into the thousands. The ART's a cheapie, as is my budget, but I want to really learn it so that I have something to compare it with for the future. I have also heard that replacing the stock tube with a better one, Groove tube or Mesa, gives an improvement.

Thanks again for the help!

 

[Steenamaroo]

Thank you! Makes perfect sense....

I have a basic knowledge of gain staging, but will study it some more......

I think that the focusrite engages the preamp automatically when an XLR is connected...the mic/line switch has no effect.

When you say "preamp -> Xlr to 1/4" jack cable* -> focusrite", does that need to be a TRS connector or standard 1/4 TS, or does it matter?

I need to study balanced vs unbalanced as well!

You've sort of got it....
The XLR socket is physically connected to a mic pre.
The jack connectors aren't. They (should) bypass the mic preamp and expect line or instrument level. The switch for line/inst only has effect when you've plugged in a 1/4" cable.

TRS connectors are for balanced audio and TS are for unbalanced in these circumstances, at least.
You want XLR to TRS for balanced audio between channel strip and interface, or just TS to TS (guitar lead) for unbalanced.
If you try the latter and hear a hum or buzz, you'll know to try a balanced cable instead.

Your last comment suggests that the quality of the ART preamp is probably not much better than the built in pre's in the Focusrite. I have heard over and over that a "channel strip" is key to quality recording, but it seems like there's the $300-$500 range, then into the thousands. The ART's a cheapie, as is my budget, but I want to really learn it so that I have something to compare it with for the future. I have also heard that replacing the stock tube with a better one, Groove tube or Mesa, gives an improvement.

Thanks again for the help!

Part of the reason I'm saying that is because I'm not sure your unit has a dedicated line input.
By that I mean the line input might actually go through the mic pre but with a pad in front of it to tame the signal.
If the gain knob still has effect on a 1/4" line input, that's not a great sign. Normally you wouldn't have a gain control with a line input.
In the ideal world you'd have a completely separate line input that just goes straight to the converters with nothing in between.


I don't know the art unit well and stand to be proven wrong, of course. It might be amazing.
None the less, it's good to try things and hear the difference for yourself.
It's also good to get hands-on and learn the gain stages, connection types etc. Does no harm.

The 'key' to quality recording, if there is one, is making a great sound. Everything else is secondary.
I doubt anyone on here would disagree. A good sound is a combination of playing ability, instruments, amps, the environment etc.
As long as your recording path isn't doing anything awful to the signal, all of ^ that stuff will shine through.

Of course great gear never hurts, but I'd rather record a great kit in a great room with 57s and behringer preamps than a bad kit in a bad room with neumanns and neves.

 

[Xrod]

Thanks again! I should have said "ONE of the keys to quality recording"! I know there are many, not least of which is the quality of the source!

For the benefit of any others that may read this post, the following quote is from the Focusrite 2i4 manual;

"Note the Scarlett 2i4 has no “Mic/line” switch – the Focusrite preamplifier stage is automatically configured for a microphone when you plug an XLR into the input, and for a line or instrument when you connect a jack plug. Set the LINE/INST switch next to the socket to INST if you are connecting musical instrument (a guitar in the example) via an ordinary 2-pole guitar jack, or to LINE if you are connecting a line level source such as the balanced output of an external audio mixer via a 3-pole (TRS) jack."

I'm off to purchase an XLR to TRS cable! I'll followup with my results.

Cheers!

 

[Steenamaroo]

Nice quote! lol. Thanks for the that.

Let us know how you get on. Best of luck, and welcome to HR.

 

[ecc83]

It is virtually certain that the 2i4 line inputs are simply the mic amps padded down, usually by some 20dB, even so, a lot of "prosumer" still has too much gain when used with equipment designed to operate at "pro" +4dBu levels.

The problem is that the Art pre amp has it own meters that you are surely going to want to use and in any case the whole point of a pre amp with a valve in it* is that levels are cranked a bit to get the valve "cooking"!

The solution is very simple, an attenuator. Two 10k Ohm resistors as series arms and a 1k shunt resistor will give you a 20dB attenuation. This should allow the Art to run as hot as it likes but keep levels within the capability of the AI. In addition to all the other stuff you are trying to learn, being handy with a solder iron is, A Very Good Thing!

*As against a "proper" valve pre amp which uses a high grade input transformer and a valve as the first stage......I would also view the use of exotic, expensive replacement valves as a waste of money.

Dave.

 

[MrWrenchey]

*You can use 1/4" to 1/4" but it'll be unbalanced so you'll be more susceptible to stray hums and noises.

That's not true, TRS cables are balanced. TS and Y cables are unbalanced, but the TRS outputs of preamps are balanced connections.

Everything else is spot on though. Steen's got you covered.

 

[ecc83]

That's not true, TRS cables are balanced. TS and Y cables are unbalanced, but the TRS outputs of preamps are balanced connections.

Everything else is spot on though. Steen's got you covered.

Not in the case of the Art pre amp discussed here. The XLR is certainly balanced but not the jack output. However, although not actually specified in the manual, it seems the unbalanced jack has an output impedance (Z) of just 150 Ohms and such a low source Z means that even an unbalanced connection is going to be very resistant to induced electrical noise, especially at line levels.

The OP could of course convert the output quite easily to "impedance" balanced for the princely cost of one 150 Ohm resistor!

Dave.

 

[Steenamaroo]

That's not true, TRS cables are balanced. TS and Y cables are unbalanced, but the TRS outputs of preamps are balanced connections.

Everything else is spot on though. Steen's got you covered.

There are no TRS outputs on his preamp.
It's balanced XLR or unbalanced jack output only on that one.

edit: Oops...I see Dave's got my back.

 

[Xrod]

A big thanks to all of you....that did the trick. Still experimenting with the ART pre, but I like it.... it has a nice, um, well, warm tube amp sound. This forum is going to be a life saver.... I'm formulating my next newbie question!

 

[Steenamaroo]

Glad to hear you're getting on better.
Good luck.

 

[MrWrenchey]

Not in the case of the Art pre amp discussed here. The XLR is certainly balanced but not the jack output. However, although not actually specified in the manual, it seems the unbalanced jack has an output impedance (Z) of just 150 Ohms and such a low source Z means that even an unbalanced connection is going to be very resistant to induced electrical noise, especially at line levels.

The OP could of course convert the output quite easily to "impedance" balanced for the princely cost of one 150 Ohm resistor!

Dave.

Oops! My bad! Thanks for the clarification.

 

[TimN]

I own a TPS II, and the outputs are sent to a Behringer ADA 8000--balanced XLR to balanced TRS into the Behringer, the level on the Behringer set to +4dBu. That goes into the E-mu soundcard via ADAT lightpipe. The OP is on the right track if he's getting XLR to TRS cables for the hook up . . . and I see he did just that.
The TPS II is a nice preamp--ART makes a lot of good gear.

 

[rob aylestone]

I'm always a firm believer of learning in stages, so mic into the interface, forgetting the preamp totally until you are very comfortable with the sound, the impact the controls have and how it all works. Then any improvement in quality by using a dedicated preamp can be appreciated, or not. Think how annoying it would be to discover that you personally liked the sound of the mic direct to the DA, rather than the pre-amp tone? It's a bit like guitarists who have been told how much better replacement pickups sound, who never listen to their new purchase with the originals. In most cases, these changes are 'nicer' to the listener, but without comparison, how do you know (or learn?).