Your simply running out of steam and need more amplifier. It takes current to produce large quantities of bass. Once the amplifier is saturated, it will not be able to reproduce the current demanding bass as easily as it can the non-current demanding mids and treble. The end result is exactly what your experiencing, thinning out at higher volumes. On top of this, clipping causes an immeasurable amount of harmonic content to be generated, causing even more mid and high frequency energy to be passed onto the speakers. This is the reason that "clipping" burns out tweeters. They are simply seeing a far higher ratio of energy than they would under normal listening conditions.
If your driving your Aleph 3 this hard, adding another will NOT be enough to do the job correctly unless you ran them as monoblocks. Quite honestly, i don't know if those can be easily converted or not. Even if they could, i don't think that it would give you everything that your looking for. In effect, you would really need to at least quadruple your power in order to maintain a reasonable amount of headroom IN MY OPINION. If you REALLY like this amp and want to keep it, you might want to think about using it for the top end and picking up a similar ( larger ) amp and going into active bi-amplification. That is, if your speakers will support something like that. While this could become pretty costly, especially if you went with another "beefier" Aleph model, it would be about the only way to maintain the same sonic signature while avoiding clipping or "thinning" at high volumes. Sean
Sean,thanks for the reply.I should have been clearer.I would run 2 Aleph-3's as monos.I believe this may work.Anyone doing this?
Assumming you can bi-wire your speakers, you can try vertical, passive bi-amping with 2 Alephs and it should make a very noticable improvement. Part of this is because you have twice the power available (3 DB) but also, each amp will see the load from only one driver and that driver's half of the x-over and not the entire x-over. Also the impedance of the woofer half will tend to rise with increasing frequency and that of the tweeter will tend to rise with decreasing frequency. This will unload the amps somewhat from having to deliver as much current compared to looking into the entire x-over. Sound stage will get wider & deeper. The presentation will be more dynamic as well as more at ease. If you can get another Aleph 3, I highly recommend you try it. If you still run out of gas, try the Aleph 2.
One other consideration is the pre-amp. I say this because the Aleph 3 has a very low gain of only 20 DB. This means that you may actually be asking your preamp to supply some gain as well (in these days of digital & analog stages with high output voltages, most pre-amps are acting as attenuators). There is the possibility that you are stressing the pre-amp as well.
David- I had an Aleph 3 for a while and then went to the 2s, and I can tell you if you are looking for a lot more power the 2s may dissapoint you, as they don't really go that much louder. I think that the 3 may even sound slightly better. The few times that I clipped my 3 it was not something that was hard to notice, it was very apparent. By the way I was able to play fairly loud volumes with an Adcom GFP 750 in passive mode and a set of Dunlavy 4 speakers (91 db sensitivity)
My speakers are 92 dB 8 ohm.It sounds wonderful at moderate volume but when I push it hard it becomes very bright.I have tried different tubes in my 99,different interconnects,speaker cables,different speaker placement,room treatment.I have tamed it a bit but not enough.My 99 output impedence is 100 ohm.I guess I will have to get used to listening to my rock and metal at moderate levels which is still quite loud but I thought I would get more (clean) volume out of this lttle guy.
If your listening to rock and "metal" with 92 db speakers, 200 wpc is not enough to REALLY "jam". You've got the wrong amp for what your trying to do. Sean
I would say 200 wpc with 92 dB speakers is plenty of power for rock and metal and probably over kill! The Pass is 30 wpc and Im almost there now.It plays louder than I need but as I have said it gets bright at very high volume.Its a single ended amp and has a midrange to die for.I wouldnt trade it for an over kill amp anyday.Lots more to music than volume anyway,and this amp plays music! Tubes,single ended and analog is where its at for me.I have a friend who just bought a 225 wpc amp and sure it plays louder but not as much as I imagined it would.It just goes to show in this hobby you cant have everything but I still will keep the Pass.
David: Other than my lengthy off forum reply, there are certain speaker cables that give a boost to the area of sound that you describe (upper midrange). I have found that some of the lower priced Kimber Kables that I have tried have done this in both of my systems (4TC, 8TC & 4VS to a lesser extent). I assume that other cables also have this characteristic as it does add a sense of liveliness to the sound, that I like as long as it is not too extreme. I am not knocking Kimber at all because I use them myself, but I would not advise them for your setup. Some people feel that "covering up" a system defect is not the way to go, but I just look at it as fine tuning and not accenting what I don't care for in the sound, all cables are tone controls to a certain extent. I once memo'd a pair of Transparent cables (lot of talk about them lately). They were Music Waves that retailed for around $300.00 for a 12 ft pair. They did not accent this area at all, but had a less engaging sound in my system at the time (my room is not very lively either). Anyway, I wonder if something like this would get the best out of your system?
Dekay,I had Kimber 8TC, Harmonic Tech.Pro-11 and MIT T-2 biwire for an audition and I went with the MIT.They pushed the upper mids back a bit without losing detail.They also have the best bass of the bunch.The soundstage seems more natural also.Thank you for your off site response.I plan on getting back to you (too many kids around today)
David, all i can tell you is that if you think 200 wpc is overkill with reasonably efficient speakers for doing "metal" volume levels, you better never come to my house for a "jam session". Just "shows to go ya" that everybody has different ideas about what is loud, quiet, smooth, bright, warm, dark, clean, etc... Keep in mind that a power rating means nothing if the speakers are reactive at all. Some amps, even though rated for "brute strength" in terms of rms power, just don't deal well with anything but an easy load. The Bryston 4B that i had was like that along with a few other "respectable" amps. Gutless wonders when it came to low impedance / low sensitivity loads. While none of Nelson's amps fall into that category (in my opinion & experience), they are by no means "earth shaking" by any stretch of the imagination. Sean
I have to disagree re the drive potential of the Aleph 2 vs the 3. The 2 monos EASILY pump 200w into 4 ohms (a typical impedence seen in many speakers in the upper bass), and will play MUCH louder than the Aleph 3 in the lower octaves.
I also recommend investigation of the preamp match. Alephs' low input impedence can be problemmatic. I chased a used Aleph P to ensure full driveability.
I'm grateful for the comment re cables, as I too am using a lean transparent cable (Nordost Red Dawn), yet I find the overall system balance slightly lean at ALL SPLs. There's no change with loudness (outside Fletcher-Munson effects).
C'mon, Sean...200w/ch into 92dB/w yields what...115dB??!!
This is truly dangerous, no? I'll defer to your experience, but phew...can you hear me?
On third thought I wonder if the Aleph 3 is truly saturating, given the 92 db/w sens of your speakers. Does the impedence drop to 2-3 ohms in the bass? Is your pre not fully driving the amp?
I too will chase a warmer, yet detailed interconnect to flatten the upper mid bump a bit. (Note that I attribute this mild tonal anomoly to the use of a 5" midrange in my system. 6.5 or 7" midranges generally are a little flatter
between 400 and 1200 Hz, in my experience, though they may have more problems crossing to the tweeter than a 4-5" mid.)
So I'd look at the preamp first, the IC second, and if you're still running out of steam on peaks, chase some used Aleph 2s like I did. Good Luck. Ernie
the thing that took the high frequency hardness out of my system was changing the preamp. also i'd suggest putting yout tt inside a sound proof booth at 115dB haha. back to smooth sailing, woohoo!
Something has come up in this thread that i want to discuss, but it is of another subject matter. As such, i'm going to follow my own advice and start a new thread so that we can stay "on topic" here. Sean
david, as we've prewiously discussed, both here and *off* a-gon, i tink perhaps rogue's claim of 100 ohms output impedence for their 99 preamp is a bit optomistic. and, yer speeks' efficiency of 92db means that the aleph-3, which should be able to handle lo-impedence loads, will be able to drive *sustained* 107db levels w/o clipping. pretty loud, imho - especially in a real-world-sized room, where it may be even 3-6db louder. as we discussed off-list, assuming the pre's output impedence *isn't* the problem, perhaps yer speeks are hardening/compressing at these loud levels...
Dud,Im starting to swing your way with your concerns of the possiblilty the 99's impedence specs are tainted.It could be my metal dome tweeters also or a combination.Im curious if the headphone output would be a clue.I have to turn it up to at least 3 oclock to get decent volume with my headphones.The 99 drives them alone,the amp has to be off for the jack to work.Would this be an indication of something wrong in regards to the reported 100 ohm output of the 99?
defeating the speaker outs w/the headfone input doesn't necesarily indicate a problem w/output impedence imho - it could yust be a conwenience thing - when yure listening to headfones, it could be assumed that not wanting to disturb others is a possible motivation for the headfone-listening, & therefore ewe woodn't want the speakers active when listening thru the headfone yacks...