Anybody Felt Lower-End ARC preamps Bass-Shy?

Any folks here who upgraded their lower-range Audio Research preamps to better ones and noticed a considerable improvement in the bass department? I own the LS-16 and thought the bass doesn't go to deep. Will the LS25 or LS26 have much better bass compared to the LS-16?

Thanks in advance.
My father owns the LS16 and he has incredible bass with Vandersteen Wood Quatro speakers, maybe your speakers or room or even placement could be an issue. I am not saying for sure the LS16 is not the problem or that any other equipment and so forth are your issue, simply the LS16 performs great in my experience.
Thanks for the reply Chadnliz. I am quite sure it's not the speakers since I am running them in high-pass configuration and the bass is entirely handled by the subwoofer. The reason I was suspecting the LS-16 was when I stumbled upon another user here who also felt that the LS-16's bass does not go too deep. Maybe I'm over-reacting although I might be getting a more-than-enough bass response.
I've had the LS-15 and LS-16mkII and currently have
LS-25mkII. There was a considerable difference in bass response from LS-16mkII and the 25mkII however the LS-16 had very good bass response.
There are other things that affect bass response such as room size,type of cables used, speaker brand and type etc..
System senergy is also important.
Ryder, define enough bass please. Without hearing your system how can anyone know how well bass is reproduced by it?

I had an LS-15, the older version with the REL capacitors and it did lack bass impact and drive. I upgraded the caps to TRT Dynamicaps and the bass performance was improved big time. I can't call the LS-15 with Dynamicaps bass shy at all. Your LS-16 has Infinicaps, same is in my LS-25.
My point is that the bass on the LS-15 with TRT Dynamicaps was not any better or worst than I now have with LS-25. It's the same as far as I can tell. The added advantage of LS-25 is its adjustable gain and this means you can up the gain to drive your amp harder to give more bass, but it may be at the expense of top end smoothness and midrange may become a bit forward sounding.

My suggestions to you to improve on the bass in your system:
Get the single-ended interconnects out of there.
ARC performs better when run balanced. So is your Krell cdp and Plinius amp. You have to run balanced from player all the way into the amp balanced. This will get you 6db more out of the preamp into the amp and will drive the amp better and I am pretty sure bass will get tighter, plus you will lower the overall noise floor and resolution will be better.

Also, try some NOS tubes in the LS-16. I don't know what you're using there right now, but I am using Mullard made by Amperex in Holland NOS 6922 tubes from Brent Jessee and these tubes do bass on completely different level than the stock Sovtek or Eh tubes do.

Bottom line is, you have to experiment.

Good luck.
I had an LS15 and bass was not one of its strengths. It was replaced by a VAC Renaissance which does do bass with impact but of course there is a substantail price difference too. I would guess the more expensive ARC preamps would offer more bass.
I owned an LS-25 mk1 (6922tubes) Infinicaps for many years. While the bass went fairly low, rhythmic drive/impact was sorely lacking.
Ryder, with so many variables in the system, amp, preamp, cd player, cables, subwoofer, settings, placement, recordings, it is tough to have any idea if you have a lack of bass and if so, where it might be coming from.

One thing I have discovered with some of my customers is the importance of finding out if they experience a lack of bass all the time or just with some recordings.

What music/recordings do you listen to? Is the bass great with some and not with others, or does it feel light weight all of the time? That might help to shed light on what you are experiencing.
10-02-07: Reb1208
I owned an LS-25 mk1 (6922tubes) Infinicaps for many years. While the bass went fairly low, rhythmic drive/impact was sorely lacking.

In relation to what other tube preamp?
I have had the LS-16 in my system and the bass response was rather poor in the upper registers.
Thanks for all responses.

Ryder, define enough bass please. Without hearing your system how can anyone know how well bass is reproduced by it?

That is the reason why I have asked if anyone has got better bass after upgrading to a better preamp. Most questions posed in the forums are often subjective and opinions are accepted based on rationale.

Anyway I appreciate your advice on running the whole system balanced. Unfortunately I can't since I have my subwoofer inserted in between the LS-16 and Plinius amp. My speakers are high-passed. If I run full-balanced, I can't hook up the sub in high-pass configuration and my speakers are limited to 35Hz only. Furthermore, I reckon the bass roll-off much higher with their current placement. Without the sub, the bass is much weaker compared to what I'm getting now. I have balanced cable from my Krell CD to the LS-16 though.

Since you mentioned the bass on the LS-25 may not be too different from the LS-16, I guess I can be rest assured it's putting out decent bass. Looks like I have to keep experimenting.

Music used was mainly Pat Metheny's earlier works "Letter From Home"(which happens to be my most listened record now), and "Still Life Talking".

May be other variables involved. I was hoping the bass can be slightly more visceral. Will keep experimenting.

Thanks for all inputs and advice.
I'm not familiar with the mentioned Metheny discs. But being "earlier" works, as you say, is it possible these records are just lacking the ultimate bass?

You may want to try running some sort of a reference cd, may be even stereophile test cd 1 or 2 with bass frequency test tones.
Or may be get a cd with plenty of bass. I recommend Brian Bromberg "Wood II" cd that I often use for bass test and actually enjoy listening. In case you are not familiar with Bromberg, he plays acoustic double-bass and the recording quality on "Wood II" is very good.
Have you checked if the output impedence of the preamp e.g 100 Ohms is compatible to the input impedence of the power amp e.g 20 KOhms? Anything less than 200 (20000/100) can mean bass will suffer. ARC will normally state the minimum input impedence of power amps necessary for its preamps.
I would suggest for more pure sound to use the single ended outs from your preamp for the sub and use the balanced outs to your amp. Let the mains run full range. This will take the extra electronis from the crossover out of the mains which should give a much richer sound.
It is possible that the earlier Metheny's discs are lacking in ultimate bass but most of my favourite tunes are in these albums. I have a few reference cd's such as "missouri sky" by Metheny/Haden, quite good bass but music wasn't as good as the earlier ones. I've read about Brian Bromberg in another thread and will look into getting his album later.

I've checked the LS-16's specs.
Input impedance is 150k ohms balanced, 75k ohms SE.
Output impedance 600 ohms balanced 300 ohms SE, 40k ohms minimum load.
Input impedance on the Plinius SA-100Mk1 is 47k ohms. Mk3 may be not too far off. I guess it's okay?

Rwwear, I've tried running the mains full-range before but the Plinius was struggling to drive these speakers. I was switching back and forth between full-range and high-pass and found that dynamics was greatly reduced when running the speakers full-range. The rhythm and drive were missing even at low to moderate volumes. I then realized my amp was underpowered in driving these speakers and by high-passing them the load on the amp was considerably reduced resulting in a more dynamic sound.

I think I'll just get another Plinius power amp and run in monoblocs since I need the watts anyway. Then I can run my speakers full-range without losing drive and dynamics and just let the subwoofer fill in the low bass. Another option worth considering.
After reading the responses from the other thread "Mono blocks are better or Stereo power amp?", most likely I'll be getting another Plinius amp and run in monoblocks.

Thanks all.
Ryder, LS-16 to Plinius should be OK. The amp is lacking power for your speakers and that needs to be addressed. I don't use subwoofer in my system and can't complain about the bass now with the 250w/ch, but when I had a 100w/ch amp the bass was lacking. Amplifier is the key in this case. Your LS-16 is fine. If you get an amp that can drive your speakers ful range with ease, you should get better balanced sound overall.
Be careful not to tune your system to fit one, perhaps not so great, recording. If your system is neutral and truthful it will show you how some recordings are wonderful and many are not.

Your system should not be making bass that isn't present on the recording.
Hard to believe the Plinius is having a tough time with 805's, but if you say so. I have dual Mk3's and one of the main reasons is to go fully balanced, which is not possible with RCAs.
Ngjockey, I am not driving the 805's with the Plinius as they are 'easy' speakers. It's the PMC LB1 Sigs which have Dynaudio drivers. It's surprising these monitors can be quite power-hungry -250W/4ohms with a rather low sensitivity. The SA-100Mk3 only delivers 180W/4ohms and the difference is clearly apparent between running the speakers full-range and high-passing them. I also wished the Mk3 was sufficient for the PMC's but this didn't seem to be the case.

Although I felt the system sounded good high-passed with a subwoofer, I was intrigued by the benefits of running the speakers full-range after reading some comments from others here.

Thanks for the link on the informative thread.
Ryder, I run my ARC LS-25 with Pass Labs X250.5 amp driving the B&W N803 with absolutely no problems. Bass is the best it's ever been in my system, courtesy of the Pass amp.

Try getting an amp or double up on Plinius so the speakers can be given adequate amounts of power so they can be run full-range. To me this is probably the way to go...unless you are used to your sub and you'd rather have it in there.

Dynaudio are very good drivers, but almost every speaker I have heard that used Dynaudio drivers, like plenty of power.

Good luck.
Hi Audphile, I suppose you won't have any problems driving the N803's with the X250.5 since it's a powerful 250W amp that can run into 4 ohms load. I will most definitely get a 2nd Plinius amp and run my speakers full-range but the sub still needs to be there since the PMC's are limited to 35Hz only, and there's a lot of low bass missing.

Off-topic. I just recently listened to some Marten Duke speakers driven by Gryphon Tabu amp. The highs on the Marten Duke is better with a cleaner and more refined sound(due to the ceramic tweeter that extends to 40kHz) but midrange down to the bass the PMC's are better to my ears. Not too bad since the Dukes can buy 2 pairs of my speakers. I think I'll be sticking with my speakers for a while.
Ryder, it depends on what kind of music you're listening to. For example, the lowest note on acoustic double-bass is 40hz. Lowest note on the piano is 28hz.
With PMC speakers you may still be able to reproduce 28hz. I don't know how they roll off.
Run some test tones to hear how deep they go. But wher I do see you need a sub is that the PMC may simply lack the cabinet volume to have a lot of bass impact. But as far as playing a certain low frequency, they may do fine.

Check out this interesting chart
Audphile, thanks for the link. I never thought piano notes could go that low. I've just had a quick check on my piano and have to say that most music does not go past the lowest natural D note at 37 Hz. Most low piano notes are in the region of 40Hz and above.

Not too sure about organ though but I don't think I have any music on organ. I don't see any category for 'drums' but if double-bass has covered that then I think I'm fine.

Anyway I'll see how well the PMC will perform in full-range when I feed them with more power. I agree that the lack of cabinet volume will affect bass impact to a certain degree but the current speakers are just right for my room size. Bigger floorstanders will not be too ideal
I know. It's not in every piano piece that the lower notes come into play, but if you have a chance to pick up Grieg's Piano Concerto in A Minor, the opening has a seven octave descent all the way to the lowest note. It's a great piece of music. If you don't own it, I highly recommend it.

Anyway, good luck and please update this thread if you can when you get everything in place. I'm curious how the PMCs will do full range. Dynaudio drivers are usually very competent.
The Bromberg Wood recording is a powerhouse onto its own and will make any system sound like it has incredible bass. It should never be used to determine the bass capabilities of components, except as an ultimate satisfaction test.

Caution: Be very careful with this recording. If a system is not capable of loud dynamics and deep bass, you could blow the woofers! Especially on the Beetle's Come Together.
Zear, I was actually referring to "WoodII" disc.
Aside from being a recording of a double-bass, I do not really find the bass overdone on it.
I am not familiar with the original "Wood" recording. I will try to pick it up. Should be interesting to compare the 2 discs.
Audphile, I didn't know there was a Wood II Bromberg recording. I do want to somewhat retract my statement that the Bromberg Wood "should never be used to determine the bass capabilities of components." I would like to rephrase that. The Bromberg recording has incredibly lifelike, uncompressed, powerful bass, which will reveal a system's capabilities, especially of speakers. However, one should take into account that this recording can lull one into thinking the bass out of your preamp or amplifier but be incredible, when it might be simply mediocre. You need to switch in another preamp/amp that is considered a bass champion performer to hear and judge your component.