[subsonic1050]

What is the recommended way to hook up the servo subs? Are people using the High Level in with speaker wire or are they using the Line in with RCA cables?

[ACHiPo]

Line level is the preferred approach, but either works.  Line level requires secondary line outputs from your amp.  I recently ran into an issue where I had a hum issue that I was unable to fix using line inputs, so bought a pair of these to convert from speaker level to line level (my Rythmik subs don't have high-level inputs). 
https://images-na.ssl-images-amazon.com/images/I/71rwPv767-L._AC_SL1500_.jpg

[subsonic1050]

Makes sense ACHiPo - I'm used to the line level being the preferred method but I'm not at all familiar with these servo subs. Thanks for the response!

[subsonic1050]

I'm resurrecting my own thread because I'm still curious about this. I'm in the market for an integrated tube amp - but only a couple have line level outputs. What are the advantages and disadvantages of using the high level vs line in inputs on the Rhythmik amps for servo subs?

[JackD]

The people at Rythmik always recommend line level connection as they don't want inexperienced owners damaging the subs amps by improperly connecting them speaker level to Class D and other amps where the negative amp terminals have floating ground.  If the tube integrated you chose doesn't not have this issue then speaker level connection is the preferred method from a sound perspective.

[EdwardT]

You could build a pad. https://www.epanorama.net/circuits/speaker_to_line.html
I have a tube amp on order and it won't have a line output like my current amp does so I’ll be building this circuit. I could be wrong but it also seems like taking the signal from the speaker output would also give you the best point of integration for the sub(s).

[mikeeastman]

I use this to convert line output to RCA to feed my servo subs, it works great.

https://www.parts-express.com/Jensen-Iso-Max-SP-2SX-speakON-to-XLR-Speaker-Level-to-Line-L-246-0131?gclid=Cj0KCQjw_dWGBhDAARIsAMcYuJyMu1Pr4xLoWBA48wq5tpgh3g1s8xC5DETnP8OjS4eswBap3joWv0kaAhPFEALw_wcB

[DigIndig]

First a disclaimer: I play in both the professional audio and audiophile worlds, so I may be more pragmatic than some when it comes to workable solutions. Rather than fight a holy war about the merits of one cable over another, I would rather invest in quality gear and rely on my own ears to determine if the results are good or not. (True story: I used to harass a friend of mine who was a dealer for highly-regarded $100k/pair speakers that the signal path started with a musician singing into a $100 mic into a $15 cable).

I will be in a similar situation as I will end up with four amplifiers  (two stereo tube amps and a pair of chip monoblocks) in my system to swap between to power the Oticas with no good way to integrate the subs in that mix without serious recabling every time I want to change things up. I am going to try something like this:

https://artproaudio.com/product/splitmix4-four-channel-passive-splitter-mixer-2/

By placing it between my source/preamp and the amps, I can send the signal to all three amp combos plus the subs at the same time, and tweak the input levels going to each amp. Yes, the level controls might inject some problems, but it's cheap enough that I'm willing to give it a try. Then I'll only need to move the speaker cables from the Oticas to the amp I want to use.

If that doesn't work, then I'll dig some more and find a mixer or an overpriced distribution amp to get it done.

[Chewbacca]

I have the PEQ3 amp, and use line in for music (second output on preamp), and LFE in for HT (separate HT preamp) with great results!

I cannot say it's the best... Honestly, I'm not sure why people are saying line in is better. BUT I have no experience with it, and would love to hear the reasoning!

FYI, it looks like Danny uses Line In, maybe he can chime in with his thoughts on this:







Looks like he uses output 1 on his preamp for the subs, and an unlabeled output for his speaker amps.

With fear of looking like an idiot and exposing my ignorance and likely faulty reasoning, here I go... Wouldn't you want the most unadulterated signal possible for the sub? Why would you want to push it through another series of amplification (and cables) before the sub? Wouldn't this (no amp is perfect...) degrade/color the signal with the amplifiers characteristics to some measure? - I assume the Rythmik amp isn't actually using the full power signal (like your speaker) from the amplifier, and is somehow just reading the signal and amplifying it with the Rythmik amp?... Clearly I don't exactly understand high level in

Also as JackD said:

+

But I haven't found anything from Rythmik saying High Level In is the best for sound quality. Maybe a private conversation with Brian (I think that's his name?) from Rythmik?

[Vince in TX]

I use this to convert line output to RCA to feed my servo subs, it works great.

https://www.parts-express.com/Jensen-Iso-Max-SP-2SX-speakON-to-XLR-Speaker-Level-to-Line-L-246-0131?gclid=Cj0KCQjw_dWGBhDAARIsAMcYuJyMu1Pr4xLoWBA48wq5tpgh3g1s8xC5DETnP8OjS4eswBap3joWv0kaAhPFEALw_wcB

This is timely as I was just looking at how I was going to connect to my servo subs.   Are you converting the XLR to RCA?   I don't believe the amps have XLR inputs.

[DigIndig]

Chewbacca - I share your reasoning, although Paul McGowan from PS Audio apparently wants the sonic signature of his amp in his subwoofer as well. I personally aim for a neutral signal, so I prefer the idea of the line levels closer to the original source as well.  From what I've read, high level inputs use resister networks to bring the signal level down into the required spec for the sub amp. Probably perfectly fine, but I prefer to keep my path as pure as possible.

That being said, I also realize there is a lot done in the studio to most commercial music to color and shape the sound, including the purposeful introduction of noise and distortion, so maybe it doesn't really matter in the larger scheme of things.  I record live music, and have spent a lot of money getting the most pristine signal path I can manage so that what you hear on the recording is what I heard in the room. I shared a few of those with Danny when I visited GR Research last year. In particular, he had the commercial release of Vienna Teng's live show in Philly; I have the recording straight from the board that reflects what it really sounded like before a recording engineer decided to "fix" things after the fact.

[subsonic1050]

Now we're getting somewhere. I really appreciate this discussion. It seems that Rhythmik recommends using line in, but is that because it has better sound quality or because they are worried about people damaging their subs as JackD mentions? Both ACHiPo and mikeeastman use a separate device to convert high level to a low level signal. This makes sense, but I worry that something like that could degrade the signal in the process. I guess the essence of my question is this:

Since I do not already own an amplifier that I like which doesn't have line out (in which case it seems you can find a workable solution to hook up your subs), should the decision on which integrated amp I go with be driven by whether or not it has line outs? I'm trying to avoid a separate preamp if possible.

[mlundy57]

Now we're getting somewhere. I really appreciate this discussion. It seems that Rhythmik recommends using line in, but is that because it has better sound quality or because they are worried about people damaging their subs as JackD mentions? Both ACHiPo and mikeeastman use a separate device to convert high level to a low level signal. This makes sense, but I worry that something like that could degrade the signal in the process. I guess the essence of my question is this:

Since I do not already own an amplifier that I like which doesn't have line out (in which case it seems you can find a workable solution to hook up your subs), should the decision on which integrated amp I go with be driven by whether or not it has line outs? I'm trying to avoid a separate preamp if possible.

In the past I've used both speaker level and line level inputs to my Rythmik amps. I can't tell any difference in the sound but I did blow up an NAD C372 amp once using speaker level inputs so I'll stick with line level.

That's assuming you have access to line level. If not, speaker level will work. Just be sure both pairs of speaker cables are connected to the same pair of binding posts of the amp. If you have two pairs of binding posts and one is marked Speaker A and the other Speaker B and there is a switch to choose A, B, or A+B, DO NOT connect one pair of speaker wires to A and the other to B and set the amp to A+B. This is how I blew up the NAD C372. The speaker level inputs on the Rythmik amps do not have enough impedance for this which shorted out the NAD.

The other caveat which has been mentioned is when your amp has balanced outputs to the speakers. In amps built like this, the negative speaker post is not ground. It carries a signal opposite of the one on the positive post. If your amp is built this way, check with Rythmik on how to safely connect the speaker level outputs to the plate amp. However, most tube amps do not have balanced outputs so this shouldn't be an issue for you. Just check to make sure.

[Chewbacca]

That being said, I also realize there is a lot done in the studio to most commercial music to color and shape the sound, including the purposeful introduction of noise and distortion, so maybe it doesn't really matter in the larger scheme of things.  I record live music, and have spent a lot of money getting the most pristine signal path I can manage so that what you hear on the recording is what I heard in the room. I shared a few of those with Danny when I visited GR Research last year. In particular, he had the commercial release of Vienna Teng's live show in Philly; I have the recording straight from the board that reflects what it really sounded like before a recording engineer decided to "fix" things after the fact.

Makes sense about the engineers "fixing" or coloring the sound to their preference, or the artists preference, or their managers preference, or however that chain of command works... BUT, I only want to hear the coloring that THEY add, I don't want my system to add additional coloring to the already colored... color.. Even if it is just the bass frequencies. I'll take all the fidelity I can get! (obviously the signal is still colored by the preamp, and source)

That being said... I still can't say I see the full reasonings behind using High Level. Paul's reasoning of the full frequency range being the same "color" doesn't come close to selling me on it (I MAYBE know .01% of what he knows... so don't take my advice too seriously lol), but IMO it's not worth the extra signal deterioration of extra inputs, outputs, cables, resistors to bring the signal down, to just be reamplified... ehhh.. My ignorant brain isn't seeing it

[corndog71]

My preamp only has one pair of RCA outputs so I made splitters for my sub amps and my tube monoblocks.



  I never liked the idea of speaker levels inputs on the sub amps.  Like others have said, why add more stuff in the signal path if not necessary?  I have tried it when using solid state amps and they worked but now I mostly use tube amps and just don’t want to risk it.

[mikeeastman]

Vince in TX , my jensen has line level input and both RCA and XLR outputs so it will work with either way.

[EdwardT]

That being said... I still can't say I see the full reasonings behind using High Level

In my case it was both coloration from the speaker transformers and the phase relationship. I want the tube output everywhere, to me that gives the best chance at integrating the sub with the primary speakers and having it dead in phase with them.

[Chewbacca]

In my case it was both coloration from the speaker transformers and the phase relationship. I want the tube output everywhere, to me that gives the best chance at integrating the sub with the primary speakers and having it dead in phase with them.

Well, you're not really getting tube output everywhere. You're getting tube coloration/distortion (whatever you want to call it... change to the origin signal) that was once amplified imperfectly then brought back down to be again, imperfectly amplified and colored by the plate amp. I assume you're running your speakers full range if you're worried about such slight phase variances? I would think the 180° fully adjustable phase would be able to get you about perfect regardless, unless you're trying to run the sub at something like 160hz+?

I sincerely may not understand. That's why I'm here.

[JackD]

With the Rythmik subs that have both line and speaker level inputs it makes no difference as to whether or not the integrated you chose has a line out or not.  Speaker connection to the subs is a simple process that requires no extra parts, pieces or gadgets to make it work.  It simply requires a second set of speaker cables of good, not expensive, quality with the opposite connector on the amp end that you use for your main speakers.  In my case I use spades on the amp end for the mains and bananas on the amp end for the subs.  Then left-right to one pair of speaker binding posts of the sub on each one. Companies like REL and Vandersteen have been doing it this way for decades. What tube integrated amps are you looking at?

[subsonic1050]

Thanks everyone for the input. This conversation is very valuable to me. JackD - thanks for the responses and question. I'm considering the following 3 amps - this will be with the NX-treme's and triple servo subs.

Doge 10 (excellent reviews, has line outs, even phono) The other guy I'm building speakers for actually bought this amp. I'm wanting to buy something different so we can do some comparisons and see what we like best.

Willsenton R800i - also good reviews, although not as many. No line outs. Similar price to Doge 10

PrimaLuna Evo 300 - Has line outs, but is twice the price of the Doge 10.

Also looked at amps from Line Magnetic and have looked at the 300b kit from Elekit. I'm slightly worried that the 8 or 9 watts per channel on the Elekit will not be enough for the NX-tremes, also is only an amp - not integrated - would need some kind of preamp.