Topic: Lunatec V3 > Mod-SBM1 Attenuator Question

[F.O.Bean]

how are the attenuators integrated into the gear chain?  are they plugged directly into the v3 analog outs? 
the reason I ask is b/c I run my v3 vertical (I think bean uses a cage) and plugging them directly into the back just isn't going to work for me since it is currently resting on my right angle xlr's. 

can't custom cables be made with 30 dB attenuators built into them?

FWIW, with the 480>v3>modsbm1 combo, i am running -30db attenuators on the v3 output>sbm1 so it doesnt get ridiculously overloaded levels from running the v3 near 0db for the straight v3 source

BUT, if you wanna just use the v3 as an ad rather than as an all-in-one, the -30db attenuators arent needed and also, you can shut the a>d section of the v3 off and conserve battery power as well

I ran the V3 > SBM last week for the first time and didn't have any overload problems.  Ran the V3 smoking HOT like I like to and ran the SBM line in around 2 I think.  Didn't have any overloaded levels.   

Am I doing something wrong or different Bean?  When I used to run the 316 > SBM i'd do the same thing.  Run the 316 hotter than hell and throttle back the SBM.

i just always heard that its better to run the modsbm1 at a higher level, so i run my v3>-30db attenuators>modsbm1 and run the modsbm1 at 8 out of ten, that way the v3 is run at 30-35db of gain and the sbm1 at 8 to both get at or near 0db

so it's better to attenuate the signal (and run the sbm1 almost wide open, ~8) than run the sbm1 low (~2, with no attenuators)?  isn't it simply two different ways to achieve the same output level?  isn't the sbm1 simply "attenuating" the signal when run at a lower level? 

I guess I don't understand how running external attenuators is going to sound better than using the attenuation of the bit mapper.

mine are plugged directly into the v3

as far as why to run attenuators, , i dont know, just did what a few folks suggested including toddr and the tapes have sounded fantastic so...........

if youre happy w/ the way the v3>modsbm1 levels/sound is w/ out the attenuators, then so be it, i may mess around and see if i like the sound w/ out the attenuators

also, i heard that running the modsbm1 more wide open like i do at 8 will yield more modsbm1 sound, which was what i was looking for, a more fatter/rounded sound compared to the v3, and i always figured that could be achieved by running more on the modsbm1 end, ala me running it at 8 compared to 2-3

[Todd R]

I guess I don't understand how running external attenuators is going to sound better than using the attenuation of the bit mapper.

It'll sound better since the output of the V3 is way too hot for the SBM1.  

Really, I don't understand how people say they run this combo without attenuators.  A local taper here swore he'd do that without issue (I think he has since recanted), so I tried with my gear back when I had an SBM1.  The recording came out totally fuct.  But he kept swearing he did it with no problems, which made me wonder if my SBM1 was bad.

Then I started modding SBM1's, and would always test each one before working on it, to make sure it was working properly.  As part of this testing, I decided to also test out the V3>SBM1 issue, with the V3 running at -2dbFS to 0dbFS (ie, hot).  Not a single one of the SBM1's I tested could handle this signal coming out of the V3.  Always clipped/distorted.

Then of course, I tried the more obvious -- rather than experimenting, I just read the manuals.  At 0dbFS output, the V3 puts out a +24dbu signal on its analog outs, +21dbu if run unbalanced.  The SBM1 manual says the SBM1 can take a maximum signal level of -3.8dbV (about -1.5dbu).  So the V3 run hot puts out a signal that is 22dbu higher than be accepted by the SBM1.  Give it this level of signal and the SBM1 will totally clip/distort/brickwall.  The level attenuator on the SBM1 is post-gain, so using this will not help at all -- you're still feeding it far too hot a signal.

I got some resistors to make attenuator cables for the MT, but never got around to doing it.  I'll have to check the values, but I should be able to make attenuator cables for use with the SBM1.  No problem building them into regular XLR connectors, but I'm not sure about building them into right-angle XLRs.

[Craig T]

I ran V3>sbm1 many times for 16bit backup/patchers and it definitely needs attenuators if you're maximizing your levels on the V3 for the 24bit output.

[F.O.Bean]

I guess I don't understand how running external attenuators is going to sound better than using the attenuation of the bit mapper.

It'll sound better since the output of the V3 is way too hot for the SBM1.  

Really, I don't understand how people say they run this combo without attenuators.  A local taper here swore he'd do that without issue (I think he has since recanted), so I tried with my gear back when I had an SBM1.  The recording came out totally fuct.  But he kept swearing he did it with no problems, which made me wonder if my SBM1 was bad.

Then I started modding SBM1's, and would always test each one before working on it, to make sure it was working properly.  As part of this testing, I decided to also test out the V3>SBM1 issue, with the V3 running at -2dbFS to 0dbFS (ie, hot).  Not a single one of the SBM1's I tested could handle this signal coming out of the V3.  Always clipped/distorted.

Then of course, I tried the more obvious -- rather than experimenting, I just read the manuals.  At 0dbFS output, the V3 puts out a +24dbu signal on its analog outs, +21dbu if run unbalanced.  The SBM1 manual says the SBM1 can take a maximum signal level of -3.8dbV (about -1.5dbu).  So the V3 run hot puts out a signal that is 22dbu higher than be accepted by the SBM1.  Give it this level of signal and the SBM1 will totally clip/distort/brickwall.  The level attenuator on the SBM1 is post-gain, so using this will not help at all -- you're still feeding it far too hot a signal.

I got some resistors to make attenuator cables for the MT, but never got around to doing it.  I'll have to check the values, but I should be able to make attenuator cables for use with the SBM1.  No problem building them into regular XLR connectors, but I'm not sure about building them into right-angle XLRs.

thanks for the more technical answer todd

[stober]

I guess I don't understand how running external attenuators is going to sound better than using the attenuation of the bit mapper.

It'll sound better since the output of the V3 is way too hot for the SBM1.  

Really, I don't understand how people say they run this combo without attenuators.  A local taper here swore he'd do that without issue (I think he has since recanted), so I tried with my gear back when I had an SBM1.  The recording came out totally fuct.  But he kept swearing he did it with no problems, which made me wonder if my SBM1 was bad.

Then I started modding SBM1's, and would always test each one before working on it, to make sure it was working properly.  As part of this testing, I decided to also test out the V3>SBM1 issue, with the V3 running at -2dbFS to 0dbFS (ie, hot).  Not a single one of the SBM1's I tested could handle this signal coming out of the V3.  Always clipped/distorted.

Then of course, I tried the more obvious -- rather than experimenting, I just read the manuals.  At 0dbFS output, the V3 puts out a +24dbu signal on its analog outs, +21dbu if run unbalanced.  The SBM1 manual says the SBM1 can take a maximum signal level of -3.8dbV (about -1.5dbu).  So the V3 run hot puts out a signal that is 22dbu higher than be accepted by the SBM1.  Give it this level of signal and the SBM1 will totally clip/distort/brickwall.  The level attenuator on the SBM1 is post-gain, so using this will not help at all -- you're still feeding it far too hot a signal.

I got some resistors to make attenuator cables for the MT, but never got around to doing it.  I'll have to check the values, but I should be able to make attenuator cables for use with the SBM1.  No problem building them into regular XLR connectors, but I'm not sure about building them into right-angle XLRs.

So does a v2 run just as hot?

[Brian Skalinder]

So does a v2 run just as hot?

Max V2 output, per the specs in the manual on Grace's website, is +27 dBu.  The issue ToddR outlined really only comes into play if one is using the digital -and- analog outputs of the V3 simultaneously.  If running only digi-out, doesn't matter what's coming out of the analog outputs, just disregard it.  If running only analog-out, simply set the levels accordingly for whatever device is next in the chain.

[mbgrace]

Looks like a 25dB pad would scale the V3 output level to the proper SBM-1 input level.  I have attached a schematic of a simple pad network that can be installed inside the female xlr connector.  These resistor values should work as long as the input impedance of the SBM-1 is not much below 10k Ohms.
I hope this helps!
Michael

[OFOTD]

Looks like a 25dB pad would scale the V3 output level to the proper SBM-1 input level.  I have attached a schematic of a simple pad network that can be installed inside the female xlr connector.  These resistor values should work as long as the input impedance of the SBM-1 is not much below 10k Ohms.
I hope this helps!
Michael

Thanks Mike.  Another reason why you have a LOYAL fan base.

[F.O.Bean]

Looks like a 25dB pad would scale the V3 output level to the proper SBM-1 input level.  I have attached a schematic of a simple pad network that can be installed inside the female xlr connector.  These resistor values should work as long as the input impedance of the SBM-1 is not much below 10k Ohms.
I hope this helps!
Michael

Thanks Mike.  Another reason why you have a LOYAL fan base.

Mike is the man

Like i stated earlier, if running digi and analog outs, a 30db pad works great for 480>v3>modsbm1