Very strange problem when bi amping

[brad1138]

Provided that both amplifiers are working properly, then double blind testing would beg to differ with your statements regarding a difference in audible output. Unless of course you're the human anomaly, and CAN actually hear a difference. Amplifiers don't and shouldn't affect a sound signature, if it does, then it is malfunctioning.

I would say there is no such thing as a perfect amp, and all amps are going to vary to a degree in their pursuit of perfection. That variance is going to manifest in a slightly different "sound". Imaging is fairly tangible, it isn't hard to hear the better imaging in my BIAMP amp, it is subtle but there.

For the sake of argument, I will concede that the difference between the BIAMP and Citation are VERY small, and MAYBE even in my head. But I can say without question that there is a HUGE difference over the Adcom amp I have.

One question I would like answered is why would anyone buy any amp more expensive than Adcom (a decent low cost amp) if they all sound the same?

Brad

 

[yepimonfire]

yep, ive never heard the same exact sound from different amps. im gonna take a guess and say the reason imaging can be better is because of better shielding from within the amp itself so that channels dont bleed through.

 

[adwilk]

One question I would like answered is why would anyone buy any amp more expensive than Adcom (a decent low cost amp) if they all sound the same?

Brad

Because marketing, sales, and margins drive that particular part of the industry. Just like speaker cables and interconnects.

Like you said, no amp is "perfect", i'll give ya that, but the technology is good enough nowadays that the differences in almost every amplifier available is beyond the human threshold of hearing. Exotic high end amplifiers provide nothing more than advanced cosmetics over lower end capable amplifiers. Longevity might be another topic.

It is weird that you have the problem you outlined in your first post, though. I'm curious to see what you figure out. By the way, nice gear. I bet you really enjoy it.

 

[yepimonfire]

there is also the factor of wpc power, like emotiva sells amps that can give an 8ohm spkr 300 wpc all channels driven.

 

[brad1138]

your citation amp is capable of driving around 150w rms into them

It isn't a big deal but I am not sure how you got that figure. It is 4x100 @ 8 ohm or 4x175 @ 4ohm, so probably about 4x150 @ 6ohms. When I use 2 channels for each spk I am getting right about 300 per side. When bridged, it is rated at 300X2 @ 8ohm. So anyway, I have about 300 wpc running the speakers which is just about perfect. The BIAMP is rated 100x2 @ 8 ohm and 150x2 at 4 ohm, so probably 130x2 or so at 6ohm, slightly less, but that isn't an issue running the mids/tweets.

 

[yepimonfire]

i think we have given up on figuring out why its crackling so were coming up with things to ramble about lol

ok maybe not but it sounds funny

 

[brad1138]

Because marketing, sales, and margins drive that particular part of the industry. Just like speaker cables and interconnects.

Like you said, no amp is "perfect", i'll give ya that, but the technology is good enough nowadays that the differences in almost every amplifier available is beyond the human threshold of hearing. Exotic high end amplifiers provide nothing more than advanced cosmetics over lower end capable amplifiers. Longevity might be another topic.

It is weird that you have the problem you outlined in your first post, though. I'm curious to see what you figure out. By the way, nice gear. I bet you really enjoy it.

Thank you, I really do. I guess we will have to agree to disagree, in that I know my Adcom has a very different, much poorer sound. I do appreciate your comments though.

Brad

 

[adwilk]

yep, ive never heard the same exact sound from different amps. im gonna take a guess and say the reason imaging can be better is because of better shielding from within the amp itself so that channels dont bleed through.

There is absolutely no evidence whatsover to support this, except subjective human perception. Like I said, double blind testing overwhelming indicates that when an amplifier operates in its specified range, its differences are not audibly noticeable when compared to another operating in its range.

 

[yepimonfire]

like i said taking a wild guess

 

[yepimonfire]

somewhat, it said 100wpc at 8 ohms and 175 at 4, the spkrs had a nominal impedance of 6 so i went inbetween.

 

[brad1138]

i think we have given up on figuring out why its crackling so were coming up with things to ramble about lol

ok maybe not but it sounds funny

I do have a couple more tests I want to do as soon as I can get my kids off the PS3 Also going skiing the next couple days, so it might be Sunday before I have time.

 

[yepimonfire]

good luck finding it out and getting the results you want

 

[adwilk]

Thank you, I really do. I guess we will have to agree to disagree, in that I know my Adcom has a very different, much poorer sound. I do appreciate your comments though.

Brad

And I appreciate that as well. I would, however, be curious if your thoughts would change if you could set up a level matched blind test with your Adcom (a very capable amplifier) and either one of your other amps. Even just a small change in SPL can make a huge difference in perceived sound quality. Louder almost always is equated with "better" and if you haven't listened to each amplifier level matched, you can't say one sounds better than another, blind or not. But okay, agree to disagree on this one. There are already enough threads on the subject here.

Now, go figure out where the crackling is coming from....

 

[adwilk]

I do have a couple more tests I want to do as soon as I can get my kids off the PS3 Also going skiing the next couple days, so it might be Sunday before I have time.

Just pack up and send all your gear to me and I'll have it figured out in about 6 months or so. I'll do the honorable thing and let you take care of the shipping...

 

[PENG]

I do have a couple more tests I want to do as soon as I can get my kids off the PS3 Also going skiing the next couple days, so it might be Sunday before I have time.

You may have some bad capacitors.

 

[highfigh]

yea, maybe at pure 1khz sine waves, your forgetting harmonics and actual music is involved

you try getting 85db at 100hz using one watt, not going to happen. this was the point i was trying to make earlier, bass uses more power then mid and treble. if this was the case that you can get 85db of sound out of 1w, then there would be no point in making 100wpc amplifiers. you try driving your massive floorstanders with the amplifier in your laptop computer speakers. with my music at a loud level, (loud enough that people would have to shout to get my attention) i draw around 50wpc, all channels driven and the sound is around 85db

A good amp wil have no trouble reproducing 100Hz at any power level. Look at the specs- if it says 20-20KHz+/-.1dB, there's not enough SPL difference across the whole range to heara variation. I don't have massive floorstanders (they aren't necessary in a small to medium sized room) but with my calibrated mic and 1/6 octave Real Time Analyzer, mine measures well down to 30Hz with the sub on. Human hear, however, isn't very acute at low or high frequencies so at low SPL, 100Hz is far less audible than 1KHz. There are plenty of 1W-5W amplifiers out there that do just fine when it comes to flat frequency response. I don't expect my laptop to do well- it's not something I care about. I do want my stereo to sound good at all levels, though. My sub is amplified and my main speakers have 6-1/2" mid-bass drivers that do well down to about 45Hz and by themselves, they sound good but the bottom octave is conspicuous in its absence. My amp is rated at 100W/ch and it's from the time when Sony's equipment exceeded the specs. If I want it loud, it gets loud.

 

[highfigh]

Thank you, I really do. I guess we will have to agree to disagree, in that I know my Adcom has a very different, much poorer sound. I do appreciate your comments though.

Brad

How old is this amp? I think someone mentioned the caps and if it's an older model, I would agree that the filter caps may be a bit "tired", especially if they're operating near their voltage limit. Is it kind of mushy on the low end? That could be the caps not performing at their best.

 

[brad1138]

How old is this amp? I think someone mentioned the caps and if it's an older model, I would agree that the filter caps may be a bit "tired", especially if they're operating near their voltage limit. Is it kind of mushy on the low end? That could be the caps not performing at their best.

The BIAMP amp is ~20 years old and the low end is not mushy. I would agree with that, but, it has no problem running the Mirages when I have them entirely hooked up to it. I can turn them up and there are no problems whatsoever. I can drive them to the 100+ db range and it sounds fine. Only when the BIAMP is just running the mids/tweets and the Citation is running the woofers is there a problem at as low as 85 db.

 

[brad1138]

In case anyone is curious, here is the whole system.

 

[highfigh]

The BIAMP amp is ~20 years old and the low end is not mushy. I would agree with that, but, it has no problem running the Mirages when I have them entirely hooked up to it. I can turn them up and there are no problems whatsoever. I can drive them to the 100+ db range and it sounds fine. Only when the BIAMP is just running the mids/tweets and the Citation is running the woofers is there a problem at as low as 85 db.

If you have a multi-meter, check across the two positive and negative terminals on each speaker. This almost sounds like there's some connection that's causing problems for one of the amps.