Where to get the perfect in-line attenuator?

ullanta

ullanta

Veteran
Does anyone know where to get a 20dB in-line attenuator, ideally XLR-F to TRS-M or TRS-F to TRS-M? This is, of course, to feed a MicroTrack from a +4dB source...

An attenuating CABLE would be even better...

Thanks!
 
Thanks! Those sescom's are both a little more and a little less than I need... nothing seems to attenuate more than 14dB (and less than 40db), and I don't reall need a transformer (proicey!). The beachtek is not what I'm looking for in terms of elegance... but I have an old SignVideo beacktek knockoff that you just inspired me to try as a temp solution (set the unit for line-level, and use a 1/8 stereo to 2 TRS adapter to feed the MT...)

There are plenty of XLR barrel attenuators ot there, but I'd like to avoid 1) using an extra cable or 2) having long rigid adapters sticking directly into the XLR ports of the MixPre (since with their leverage they could potentially do some damage)...
 
ullanta said:
Thanks! Those sescom's are both a little more and a little less than I need... nothing seems to attenuate more than 14dB (and less than 40db), and I don't reall need a transformer (proicey!). The beachtek is not what I'm looking for in terms of elegance... but I have an old SignVideo beacktek knockoff that you just inspired me to try as a temp solution (set the unit for line-level, and use a 1/8 stereo to 2 TRS adapter to feed the MT...)

There are plenty of XLR barrel attenuators ot there, but I'd like to avoid 1) using an extra cable or 2) having long rigid adapters sticking directly into the XLR ports of the MixPre (since with their leverage they could potentially do some damage)...
Click to expand...

I use a pair of barrel adapters for this. I've got a set with a switch for 15/25/35 db pads, so I can use it with as much or as little pad as needed. I know you said you didn't want that, but it works. BTW, I use a pair of shorty interconnects, one side is right angle XLR even, so I don't have to attach them directly to the mixer.
 
Yeah, I guess that looks like the best solution until I find a chance to build an attenuator cable myself... I didn't think of the right-angle adapters, that might just do the trick...

Are you indeed using a similar setup with the MicroTrack? How's the noise level on the line-ins with this setup?

Thanks,
Barry
 
ullanta said:
Yeah, I guess that looks like the best solution until I find a chance to build an attenuator cable myself... I didn't think of the right-angle adapters, that might just do the trick...

Are you indeed using a similar setup with the MicroTrack? How's the noise level on the line-ins with this setup?

Thanks,
Barry
Click to expand...

No microcrapper for me, sorry... Heh...

I use them when connecting my R4 to really hot sources, or to otherwise fine tune the level of my inputs. The R4 only has a line-in/mic-in switch which is basically a 30db pad or so. Using the switchable attenuators let me choose a pad in between. Too bad I don't have an R4 Pro, cause that model has trim knobs.
 
Use the mix pre tape out?

Use the mix pre tape out?

Couldn't you use the tape output for feeding the Microtrack? That's what its for I believe. You would need to make up an appropriate cable but it would work well I think.
Regards,
Bernie
 
Well, I haven't thested the MixPre yet (it should be arriving tomorrow) but from what I hear, the tape output may still be too hot. Anyway, in general I'd prefer to use solid XLR connections rather than minijack... this is specifically for guerilla/run'n'gun/uncontrolled environment style work, where the unexpected is expected to happen and I want the unit as robust as possible.
 
Tape out from Mixpre would indeed be the correct way to hook it up.
Line level XLR way too hot for microtrack.
 
Barry you can run the consumer level out without any problem
about the right attenuator , call OR EMAIL SD( Jon Tattooles especially )and they will give you correct numbers of the resistors place inside the cable if you need go 14 db down or ask Matt stl , i ones sent him the values but cant find it on my computer
 
Well, I got the MixPre in the mail today, and for an update - the tape out is indeed a little too hot for the MicroTrack. It's not terrible in terms of metering, but the MixPre limiter isn't preventing peaks on the MicroTrack (haven't done extensive testing with the limiter threshold to see how well this can be made to work)... but in general, there is certainly clipping going on in the MicroTrack where the MixPre doesn't yet indicate it. It's a small amount of difference, it seems - maybe 3dB - so I can use the last meter LED as a peak indicator with good safety and not much over-caution.


I don't yet have the pads for the XLR output... when I get 'em, I'll report back.
 
You can adjust the limiters pretty low. The mini out of the MixPre is -10 so I'm kind of surprised that it's too hot for the Micro track but??? If your good with soldering you should be able to build the pad into the cable.
I like the Mixpre but I got into an argument with them about having so much "head room" above the top of the meter.
 
Well, the MicroTrack has this problem in general - the included mini-mic is too hot, and M-Audio released a pad for that... I had read reports on even -10 being too hot, which is why I started this thread even before my testing.

Anyway, the main desired effect is great - recordings are coming out quiet and clean!
 
Make an attenuator cable to suit your exact needs. I've done it before with excellent results. It's very easy, just follow this:

+Line level input -----R1----+-- +Mic level output
|
+----R2----+
|
Ground (input)----+--------------- Ground (output)
The attenuation of the circuit is determined by equation:
attenuation (in dB) = 20 * log10 ( (R1 + R2) / R2 )
This equation is quite accurate when the impedance of the Mic input where this circuit is connected has much higher impedance than the resistance of R2. Typical microphone inputs in equipments have input impedance of 1.5 Kohm or higher (which is much higher than 100 ohms).
Component selection tips:
  • R2 should preferably be something between 10 ohms and one kilo-ohms
  • R1 should be from few kilo-ohms to few hundred kilo-ohms..
Those value ranges generally works bets for audio applications.
 
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