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audio research ls2 mk II preamp a good preamp for the emotiva airmotiv 6 active speakers

post #1 of 5
Thread Starter 

 I recentlly bought a pair of emotiva airmotiv 6s for the  holiday sale price.I had airmotiv 5s but I found that while they were great for my desk top in my computer catch all spare second bedroom they just were not enough speaker for my living room sound system.

 So I bought a pair of the airmotiv 6s.They are only about a week old and I have played them sporatically so they are not broken in yet.But they have gotten somewhat better sounding and are sounding more open.I have been using a peachtree decco 2 as a preamp to drive them but with the peachtree I have to turn the volume control up to between 12  and 1 oclock before the volume is sufficiently listenable but nowhere near loud even at that level.There is just not enough gain in the decco 2s preamp section to get the emotiva actives to rock.So I have been trying a couple of used more affordable high end preamps to see how they worked with my active monitors.I tried a audible illusions modulus III a and the results were disappointing the sound was just way too midrange orientated with not much extension at the top or bottom.This pairing did not have much impact when watching movies for video sound purposes.So I was browsing the net and found a audio research ls2 mk II available at a local audio emporium in my area.So I went down to look at it and it looked to be pretty appealing.So I took it home hooked it up and away I went.Well after it warmed up a bit for a few hours I gave it a listen.First with my airmotiv 5s beacuse they are pretty much broken in.Things were much better sounding than with the decco 2s preamp.I was getting a lot more volume from the 5s and at a much lower level(around 9 o clock) on the volume knob.There is just much more gain with the ls2.The sound was worlds more extended than the audible illusions preamp.It was also a lot more gutsy and revealing than with the decco 2s preamp section.

  Frankly considering this preamp is at least eighteen years old you would not think so if you heard it.The detail is all there and it has very satisfying dynamics and bass impact.The sound signature seems to be of the more neutral camp of preamps.Paired with the emotiva actives it plays to the strength of them letting them strut their stuff openly and with little restriction at least none that I can detect.

   I next hooked it up to my airmotiv 6s.The difference between the 5 and 6 now seemed more marked.The 6s sound if anything even tighter than the 5s and the impact from the larger low frequency driver and larger cabinet not to mention the added steroids provided by the more powerful onboard amp is now much more apparent.The sixes definitely rock more freely than the fives and looks like it will be satisfying for living room duty as a music and video sound set up.

  I am buying the audio research ls2 mk II.I have never owned any audio research products before but this one rocks.I have heard audio research products before but they have usually been quite expensive at least for my budget.And I had heard through the grape vine that some of their products have not been the most reliable.But the fact that this preamp is at least eighteen years old and that it sounds and works this well at least in my case is assuring of long term satisfaction.

  To expand the description of the ls2 mkII preamp it is a hybrid design combining a solitary tube with a solid state output section.

The power supply is of the solid state variety.This preamp is vey quiet and I hear no tube rush from the speakers like you do with some tube preamps.It has two sets of balanced outputs and a single analog rca output set.The preamp is just a line stage and has no phono preamp.There is a nice feature on this preamp that bypasses the function selector for a hot rod set up.There is a dedicated direct input on the preamp that accomplishes this and it does work the sound is audilble superior when used the sound beeing more revealing and more resolved in general.I will be using this input for my preferred source.There is a toggle switch on the front panel that selects between the direct input and the normal selector path which routes the signal through the function selector and whatever source it is switched to.The preamp has a mute toggle and a tape loop toggle as well that defeats the tape loop function on the preamp.The power supply looks to be of high quality with a toroid and a second conventional transformer.The caps and internal components are of very high quality.The power supply is onboard.I wish it had a headphone input that utilzed the capable preamp section for headphone use it would have been nice. The preamp has a motorized volume pot in it but the dealer said the customer did not include the remote when he traded it in so I do have the option of ordering a replacement if I deem so at at a later date.

   My search for a suitable preamp for my emotiva actives has ended.


Edited by buson160man - 1/24/13 at 10:28am
post #2 of 5
Thread Starter 

 I have made a recent change on the preamp that has made a significant improvement in the ls2s performance.The preamp came supplied with two rubber O ring dampers on the single dual triode tube that was implemented on this preamp.
 I have recently been exploring a couple of tube dampers and their effect on the sound.In particulat the herbies audio labs rx-9 tube damper.I replaced the O ring dampers with the herbiies tube damper(rx-9 damper) and things have improved a fair amount.I had thought originally that the preamp had a somewhat overdamped presentation.Well not anymore things are more immediate and the focus of pretty much everything has improved norticeably.The soundstage has also improved a fair amount as well.Apparently the rubber O ring dampers were damping things a bit too much.

  I am now a lot more satisfied with the ls2s peformance as a preamp and have elevated my opinion of it as a preamp.

I highly recommend the use of herbies audio labs tube dampers on the input tubes of preamps.


Edited by buson160man - 5/5/13 at 11:01am
post #3 of 5
Thread Starter 

Well I have rolled the tube in the ls2 mkII preamp with a Conrad Johnson sourced 6922 tube and the difference in sound quality is nothing short of amazing. The Conrad Johnson 6922 tube is excellent .My ls2 sounds completely different with the cj tube .The dynamics,the soundstage, the tonality, the bass, and pretty much everything is superior to the electro harmonix 69222 gold pin tube I was using . The harmonix tube has now been relegated to the bullpen and probably the minor leagues when I get a back up or two from the cj dealer . My opinion of the ls2 has greatly improved with the new cj tube . The cj 6922 is a killer tube.

post #4 of 5
Thread Starter 

Well I since moved on to the stealth 8 from the airmotiv 6. But I recently made another change in my set up. I have changed the 6922 tube in my audio research ls2. I am now using a gold lion genalax 6922 tube. Wow what a difference the abilities of my emotiva stealth 8s are nothing short of amazing. It is almost like listening to music using a sonic microscope I am hearing elements in my cds that I have never heard before.

  I am happier than ever before with the Audio Research LS2 MK II preamp

   This is a update on my opinion of the LS2 preamp.

post #5 of 5
Thread Starter 

 I have recently did a tube swap that has elevated the performance yet again. I felt it was time to spin my observations with the tube swap.

I was using a Conrad Johnson sourced electro harmonix 6922 tube which was very good sounding. But I decided to give a gold lion tube a spin. The gold lion is a genalax 6922 . I changed the tube and started the break in process. Now that process seems to be complete it is time to comment about the performance of the LS2 MKII preamp with the gold lion tube. While the Conrad Johnson sourced 6922 is an excellent tube in its own right I have to say the Gold Lion Genelax brings more to the show. I feel it is a better all around performer than the Conrad Johnson 6922 there just seems to be more there when playing music. I am hearing more things going on with better clarity. I would like to add that while my hebies tube damper seemed to help when I used it with the Conrad Johnson tube tightening things up and helping with the clarity of the sound. I find the herbies tube damper to deaden the sound on the Gold Lion detracting from the presentation. I removed the damper from the Gold Lion and wow the sound gets much more involving and exciting without anything seeming over the top.

   Well I am now happier than ever with my LS2 MKII .

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