# Anti mode 8033 question



## roddey99 (May 5, 2009)

I have a tube preamp with 2 main outputs that main output #1 I can send to the tube amplifier and main output #2 I can send to the subwoofer with anti-modes RCA LFE summing cable. Anyone use there cable listed on there website?
Also I have a Denon 3808CI that I need to use sub out also to the same subwoofer. The question I have is pertaining to integrating the 2 systems with the anti-mode sub EQ. Besides hooking and unhooking them is there an easier way? Can a y- cable be used either before our after the anti-mode without hurting anything upstream our downstream of the Y cable so I can hook both the Denon and preamp to the same sub? The sub has no crossover internally but is amplified.
Or should I disconnect the unused preamp or subwoofer output of the Denon when not in use and only use 1 at a time.?
Whats the best way to do this?:scratchhead:


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## thewire (Jun 28, 2007)

Welcome to the Shack roddey99.

Even if the different subwoofer outputs used the same voltage there are minor variances and it will basicly short out eachother. What you could use is device to split them to select which one is in use but a simple Y-connection will not work. Using one at a time is what I do if I'm using something else. A device to split them can often degrade the quality of the signal but it depends on the device. If it is intended for subwoofer switching you would be in good shape or you could just move the cable being careful.


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## roddey99 (May 5, 2009)

thewire said:


> Welcome to the Shack roddey99.
> 
> Even if the different subwoofer outputs used the same voltage there are minor variances and it will basicly short out eachother. What you could use is device to split them to select which one is in use but a simple Y-connection will not work. Using one at a time is what I do if I'm using something else. A device to split them can often degrade the quality of the signal but it depends on the device. If it is intended for subwoofer switching you would be in good shape or you could just move the cable being careful.


Thanks for the welcome and reply. Its what I thought. There are mike on/off switches, but I wonder about loosing S.Q. using them.
Anti-mode does sell a cable that uses resistors to sum the LFE frequency for pre-amps. I cant post a link yet, but it is on anti-modes web shop for sale.
Does anyone know if this summing cable would be transparent or effect S.Q. to a hearable level? I am learning for sure. 
Also after the anti-mode I would have to use a RCA to XLR adapter to go to the sub. By going RCA to XLR would I loose the advantages of using XLR by not being able to have long runs of wire with noise reduction?
If it isnt advised to do the RCA to XLR adapter, would the Valodyne sms-1 be better since it has RCA input for the pre-amp, XLR LFE and RCA LFE input for the Denon AVR, and XLR LFE output going to the sub. Would that maintain the long runs of XLR cable if the anti-mode wont. I have about a 60 feet cable run to the sub. Thanks


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## roddey99 (May 5, 2009)

I know its a lot of questions, but I have about 2 weeks to figure it out. This is a new home theatre room and music room. My first.:gah:


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## thewire (Jun 28, 2007)

I think sometimes car audio will use more than one subwoofer output to reduce noise sometimes and they have summing done but that is done during the amplification stage. Some subwoofers will also have left and right inputs for doing that but I have not heard of any non passive devices capable of doing such a thing except for an external crossover such as the Outlaw Audio ICBM. I think that the summing cable is different name for a Y-cable. In which case if that is true my above statements still apply. It's use for summing signals would be useful for two subwoofer outputs with the identical signal I believe. There really would be no advantage to summing two identical outputs eather for any situation that I can think of. Perhaps someone else could suggest otherwise and I may stand corrected.


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## brucek (Apr 11, 2006)

> Does anyone know if this summing cable would be transparent or effect S.Q. to a hearable level?


The summing cable will be a simple resistive passive mixer. No, it won't be transparent, but for a subwoofer it will be fine.

A mixer has two problems

The first is that the mixer would result in a much higher output impedance than your preamp offers, and as such would degrade high frequencies if long runs of capacitive cable were used. You're not concerned about high frequencies with a sub, and your cable would be short, since it's feeding the anti-mode close to the preamp. So, no problems there.

The second problem with the mixer would be one of crosstalk. As long as the output that you use the mixer on is a buffered output and isn't simply a hard wire connection to the mains #1 output, then you're fine.



> By going RCA to XLR would I loose the advantages of using XLR by not being able to have long runs of wire with noise reduction?


The adaption of XLR to RCA (and vise-versa) removes the advantage of the balanced cabling. Often this isn't a problem, even in long runs. It's quite easy to test it though to find out if you're experiencing any additional noise as a result.

brucek


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## roddey99 (May 5, 2009)

Thanks it answered my questions. Now for output #1 and #2 of the preamp. From a picture of the internals of the preamp it looks like main output #2 is hardwired to output #1. Doesnt look like any electronics back at the RCA plugs. Just 2 wires running to the RCA outputs and wires running in between the RCA output plugs. What to do now? Anyway to add a buffer?
I have heard of tube buffers but I thought that was to give solid state a tubish sound. But would that work for buffering output #2 also for eliminating crosstalk? Or would a device like the Valodyne SMS-1 do the buffering?


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## roddey99 (May 5, 2009)

Or what should I use to do the buffering for output #2? Now I have my 5 post:whistling:
I see also the Valodyne SMS-1 has high level inputs. I am guessing that to use that I would hook a second pair of speakers wires from the tube amplifiers speaker binding post and run them to the SMS-1 then to the sub. I only see high level input on the sms-1, not high level input in AND output. Is this correct? Is it a better way than using the main out #2 on the preamp if it is unbuffered? I did email the manufacturer but I think unbuffered is the reply I am going to get from looking at it. Thanks


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## brucek (Apr 11, 2006)

> Or what should I use to do the buffering for output #2


You either need an active combiner or a transformer combiner. Both will preserve the crosstalk of your preamps main output.

You're easiest solution is to use a BFD as your sub equalizer. This provides stereo input, then you could combine the stereo output of the BFD with a passive combiner (since you don't care about crossover at that point).



> I see also the Velodyne SMS-1 has high level inputs. I am guessing that to use that I would hook a second pair of speakers wires to the tube amplifiers speaker binding post and run them to the SMS-1 then to the sub. Is this correct. Maybe a better way to do the sub management?


It's a solution.



> Or should I disconnect the unused preamp or subwoofer output of the Denon when not in use and only use 1 at a time.?
> Whats the best way to do this?


With regard to this question, you certainly don't want them both connected at the same time. I would manually connect and disconnect each time, or get a switch.

brucek


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## roddey99 (May 5, 2009)

brucek said:


> You either need an active combiner or a transformer combiner. Both will preserve the crosstalk of your preamps main output.
> 
> You're easiest solution is to use a BFD as your sub equalizer. This provides stereo input, then you could combine the stereo output of the BFD with a passive combiner (since you don't care about crossover at that point).
> 
> ...


 Thank you,sir, for your answers. Rod


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## roddey99 (May 5, 2009)

This is just an observation,but,it is nice to retire to a small farming town away from the cities, but a pain when a person needs someone to come in and help set up something like what I am doing. To much travel time. Green Acres isnt always what its cut up to be. But if you want your fence mended, they got you covered.
Excuse me wile I go out and feed the pigs. Rod:meal:


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## Wayne A. Pflughaupt (Apr 13, 2006)

Expounding on brucek's recommendation a bit...


brucek said:


> You're easiest solution is to use a BFD as your sub equalizer. This provides stereo input, then you could combine the stereo output of the BFD with a passive combiner (since you don't care about crossover at that point).


...if the sub has left and right inputs, you may not need a combiner at all. You could send each channel of the BFD to one of the sub inputs. I once tried to "daisy chain" two subs by running a cable to the left input of one and jumping from the right input to the second sub's input. It didn't work, so I assume they keep the inputs internally separate. 

P.S. moving the thread since it has nothing to do with mics, meters or soundcards. 

Regards,
Wayne


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## roddey99 (May 5, 2009)

Wayne A. Pflughaupt said:


> Expounding on brucek's recommendation a bit......if the sub has left and right inputs, you may not need a combiner at all. You could send each channel of the BFD to one of the sub inputs. I once tried to "daisy chain" two subs by running a cable to the left input of one and jumping from the right input to the second sub's input. It didn't work, so I assume they keep the inputs internally separate.
> 
> P.S. moving the thread since it has nothing to do with mics, meters or soundcards.
> 
> ...


Thanks,its a Seaton Submersive sub. I dont know if it is left and right XLR input. I was assuming it was mono xlr. Does anyone know offhand?


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## roddey99 (May 5, 2009)

roddey99 said:


> Thanks,its a Seaton Submersive sub. I dont know if it is left and right XLR input. I was assuming it was mono xlr. Does anyone know offhand?


Well I got a Valodyne sms-1. I found out that will do me for now. The inexperienced here. Thanks all


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