ULN-2 preamps

[Yiannis]

Hi guys!

I have a ULN-2 and I think I get a lot of noise from the preamps.
would you please tell me what do you think abouts its preamps and at what gain there is no noise?
I have try to record a classic guitar with about 40 db gain and I have that noise.
Is this normal?
also i have that noise when i use the line in with about the same gain

I have also put 2 (1 m) xlr cables to the inputs so I dont have to look at the rear panel to connect my mics!
what if want to connect a bass guitar to the unit?
Do i have to use a di box?
...or should I connect an unbalance signal to the balance input?

thank you all

[James Lehmann]

The ULN-2 is a very clean pre-amp - if you're getting lots of noise on your recordings I'd look elsewhere in your recording chain, although like anything else it's of course possible it's developed a fault in which case send it back to Metric Halo.

Answers to the rest of your questions are in the manual which explains clearly how to connect all sorts of signals to the ULN-2 and the pros and cons of each respective input method!

[santacore]

I owned the ULN-2 for a short time. In my experience the pre's were a bit noise. Then again I was using it to record foley which is a lot different than music. I think they are good boxes for the money but they didn't live up to the hype.

[Yiannis]

thank you guys.

I did some...let's say tests and here are the results.

I have unplug everything from the ULN-2.

line in mode:
`preamp gain +48 db and the output meter shows signal at -54 db (noise)
gain +60 db output -42db
gain +72db output -30 db

Mic mode
preamp gain +60 db and the output meter shows signal at -54 db (noise)
gain +72db output -42

Here are some screen shots with waves PAZ.

forgive my ignorance guys but I want to be sure that this is normal

[RickCording]

Are you talking about METRIC HALO ULN2 Preamps having a noise problem?? I don't know about your 'tests' or the foley techniques mentioned, but I would agree with James that somethings wrong in your recording chain somewhere or your box needs repaired. I think the ULN2's are fantastic---clean and quiet and they live up to their specs in every way. You should hear the results while recording a Steinway, a Fazioli or a chamber ensemble!

[AdamJay]

do you have another preamp you can run the same tests on?

ANY preamp will produce noticable noise beyond 70dB

[Jimbo]

Originally Posted by Yiannis

I have unplug everything from the ULN-2.

I think this might be your problem.

I don't know why the electronics work this way, but when there's nothing plugged into a preamp, there's going to be static/noise coming out of the preamp.

Try plugging in a dynamic (ribbon, or moving-coil) mic, then wrap a pillow around the mic, or put it in a dead-quiet room. Now, measure the noise levels, and subtract the mic's self-noise (should be published by the manufacturer).

Let us know if this works.

- Jim

[Yiannis]

Originally Posted by RickCording

Are you talking about METRIC HALO ULN2 Preamps having a noise problem?? I don't know about your 'tests' or the foley techniques mentioned, but I would agree with James that somethings wrong in your recording chain somewhere or your box needs repaired. I think the ULN2's are fantastic---clean and quiet and they live up to their specs in every way. You should hear the results while recording a Steinway, a Fazioli or a chamber ensemble!

i agree with you that it is a fantastic box!thats why I bought it!
My nightmare is that if it is broken I have to sent it back....and that will take long!!
I haven't heard the results of a Steinway,Fiazioli or a chamber ensemble recording...but this could be loud enought to cover the noise I am talking about.
recording a quite classic guitar...results a noisy sound!
But thats my opinion and maby my ULN has a problem
One more time I think that it is a fantastic piece of gear

Originally Posted by AdamJay

do you have another preamp you can run the same tests on?

ANY preamp will produce noticable noise beyond 70dB

Yes Adam,I will give it a try.

Originally Posted by Jimbo

I think this might be your problem.

I don't know why the electronics work this way, but when there's nothing plugged into a preamp, there's going to be static/noise coming out of the preamp.

Try plugging in a dynamic (ribbon, or moving-coil) mic, then wrap a pillow around the mic, or put it in a dead-quiet room. Now, measure the noise levels, and subtract the mic's self-noise (should be published by the manufacturer).

Let us know if this works.

- Jim

I will try that too Jim!

thank you all guys

[James Lehmann]

Originally Posted by Yiannis

I have unplug everything from the ULN-2.

A largely meaningless test - a pre-amp needs to 'see' a load before you can make measurements that have any bearing on realworld performance.

Also - as pointed out, no pre-amp will remain completely silent at +72dB of gain! Most pre-amps don't even offer this much gain - the fact that a working ULN-2 gives you this much at all and cleanly is reason to be cheerful already.

None of which is to say that it's not possible your ULN-2 has developed a fault, but have you tried recording with:

Different cables?
Different Microphones?
Different Pre-amps?
Different A-D convertor?
Different D-A convertor?
Different monitors?
Different recording levels?
Different mic positions?
Different location?
Different computer?

to eliminate other possible causes?

[liuto]

Which microphones did you use for your recordings and at which distance? It is possible that you hear the microphone's noise with a source like a guitar at a distance of let's say 1,5m. With this kind of source a self noise of 20dBA can already be audible. With a lute at about 1m (softer than guitar) I can clearly hear the difference in noise floor between a Neumann KM84 (17dBA, 10mV/pasc) and a Schoeps CMC54 (15dBA, 13mV/pasc) with any decent preamp although both noise floors are no problem for a professional recording IMHO.
regards Hermann