[dhiebert]

Am I missing something?

I am evauating a pair of D-100 monoblock amps and I am having trouble noting any improvement over my current Adcom GFA-5500 amp. I am using a Rotel RCD-971 CD player with a VPC-1 passive volume control and Quad ESL-63 speakers.

My primary musical interest is classical. I have carefully listened to a variety of selections and swapped my cables back and forth between these two amps and I can't seem to detect any significant difference. I have listened to vocal, organ, instrumental, and orchestral selections. For the past four days, I have been doing a burn-in using 8W resistors just to see if that makes a difference.

I fully anticipated a notable improvement over my current Adcom 5500, considering the praise these D-100 amps have received, yet careful listening doesn't show this to be the case. I am not unhappy with my current setup--I just wanted to find out if I could improve upon it. I did gain much improvement when I changed to the VPC-1. which drove me to try the D-100.

Should I be surprised? Is my Adcom amp better than I assumed it is? Are there any suggestions of what I should listen for, either types of music or musical details?

[CIAudio]

My best guess is that the combination of source, speakers, and program material, are not up to the task to notice the performance difference.

The Rotel is your weakest link and is most important because that's where the signal originates. A more revealing source would probably make a big difference as the amplifier can only amplify what is fed into it. What you've discovered is that the amplifier is not your weak link.

The Adcom is simliar in that it is capable of high current and is known for good bass response and smooth midrange. The D-100's should be much more detailed through the midrange and top end while still sounding smooth and natural. Soundstage width and depth should also be better.

Aside from improved sound quality, the D-100's will run much cooler and  consume less power.

[CIAudio]

Seems to me your ears are telling you everything you need to know.

tvad4 is right (to a certain degree)

If you're happy with the way it sounds...leave it alone.
If you want to make an improvement, I'd look for a better source component.

[Charles Calkins]

dhiebert:
  Welcome to the crazy audio world! Many and I mean many times have I brought home a piece of audio gear expecting to hear a vast improvement. Many and I mean many times have I scratched my head and was wondering why I didn't hear any difference.

               Welcome (And cheers)
               Charlie

[Nick B]

It sure seems the Rotel would be the weak link. Since you have gone this far, why not look for a used, modded CD player. There should be enough available on Audiogon etc and then you can make a more informed decision.

[suits_me]

I guess when you posted this exact same thing, word for word, on audioasylum you didn't get what you're looking for.

"Am I missing something" would be a passive aggressive evasion of, "I don't care for these monoblocks." In my opinion, of course.

[dhiebert]

I guess when you posted this exact same thing, word for word, on audioasylum you didn't get what you're looking for.

"Am I missing something" would be a passive aggressive evasion of, "I don't care for these monoblocks." In my opinion, of course.

Well, no, this post is not word-for-word the same. I acted upon suggestions made in that forum and my present post reflects that. I don't know what you are implying here, though it is clear you didn't bother to read them both closely.

There is no need for you to publicly air your personal evaluation of my personality or motives. I did not, in all honesty, hear a difference, and I wished to solicit other experience to perhaps learn something. I don't regard my own system, nor my own experience as infallible and I am open to learning something new. I hoped for something more enlightening than your reply.

[dhiebert]

The Rotel is your weakest link and is most important because that's where the signal originates. A more revealing source would probably make a big difference as the amplifier can only amplify what is fed into it. What you've discovered is that the amplifier is not your weak link.

Is it your opinion, Dusty that if I were to try your VDA-1 with the Rotel, using the Rotel as a transport, I would hear the improvements you describe? Or would it be likely that the Rotel is still not up to task as solely a transport either?

I could try my turntable as a source, since I have your VPP-1 also. But I suppose my Shure M97HE cartridge might be the bottleneck then? If so, the implication is that one can never evaluate a piece of equipment without a comprehensive upgrade of the entire system (yikes!).

The Rotel RCD-971 was well regarded in reviews by Sensible Sound ("so good that I'm almost left speechless") and Hi-Fi Choice, winning an EISA award in 1999 (not that I put much emphasis on reviews, which are often noncommittal and hyped-up). It uses the Burr-Brown PCM-63P 20-bit DACs together with the Pacific Microsonics PDM100 HDCD 8x oversampling digital filter.

[flintstone]

To understand why the two amps did not have night and day differences you first have to ask...why should they?

If the Adcom is well built and it's power supply is more than enough for the job at hand then any difference between it an any other well built amp with enough power supply will always be small on the audiophile "blew me away scale".

One thing that could have made a big difference (seems it did not), would have been your passive preamp...ie, one of the amps could have been a poor match for passive volume control.

I'm not trying to say that amps don't sound different...they do (I have 4 of them), just that the differences can be somewhat small untill one of them is asked to do something it was not designed to do.

Dave

[CIAudio]

I could try my turntable as a source, since I have your VPP-1 also. But I suppose my Shure M97HE cartridge might be the bottleneck then?

I would definitely try the phono rig as well, and would be glad to let you try a VDA-1 on the Rotel. We're also coming out with a higher end VDA-2 24/192 dac in a couple months. Feel free to call me so we can discuss what you're try to achieve and how to get there.

[miklorsmith]

I'm not of the camp holding the weakest link dictates ultimate fidelity.  I think the systems approach is more correct, though also more complicated.  I have little doubt the Channel Islands (great name, btw) amps are better, the question is how badly you want to find out.

If trying them was merely a passing fancy, though I doubt it for the price, return them and be happy that your musical reproduction is adequate for your needs.  Or, if you're trying to build a better system, research and ask a lot of quesions.  Superior fidelity IS out there, and the CI amps CAN be a part of it.  The trick is how to do it on the cheap.

[kenk]

I'm not trying to say that amps don't sound different...they do (I have 4 of them), just that the differences can be somewhat small untill one of them is asked to do something it was not designed to do.

I have to agree with flintstone as most amps measured flat 20-20k and if they are operating within their limit, the diff can be really small (amps within the same power class and types).   Based on my exp, changing preamp actully make more diff than power amp (don't really know why).

Ken

[Grover]

dhiebert originally wrote:
Should I be surprised? Is my Adcom amp better than I assumed it is? Are there any suggestions of what I should listen for, either types of music or musical details?

I think I've read that the D 100 amps need about 50 hours of break-in.  Most amps don't develop their full potential until after they've been used awhile.
So give 'em some time, if you haven't already.  

There's nothing "wrong" with Adcom amps.  I've found them to lack a bit of finesse compared to pricier amplifiers - proper reediness of woodwinds, expressing the breath of vocalists, separation of background vocals and instruments.  But it's not like the Adcom sounds like a clock radio.  It's all a matter of degree.

The type of music you use to demo any piece of equipment (IMHO) are selections you are familiar with and that you enjoy.  Don't worry about whether it's audiophile approved or got 5 stars in recording quality in the last Stereophile magazine record review.  Just play what you know and like.

When demoing and comparing different components, I've often played one or two songs, then swapped the component out and played the same one or two songs, and "tried" to hear a difference between the two.  It's very difficult for me to tell a difference doing it this way and I've been listening for more than 20 years.  Was the bass as deep on those drums?, did the cymbals have that same shimmer?, did the saxophone have the same air?  Did that female vocal exhibit the same breath and chestiness?  As another poster said, I think it's harder to do this for amplifiers than it is for preamps or even source components.

My suggestion is to listen to the D 100 for a few days, playing things you know.  Do some "critical listening" and do some listening for enjoyment and relaxation.  After a few days, put the Adcom amp back in and do the same thing.  My hunch is that you will come away from that experiment wanting to put the D 100 back in the loop again.  I heard the D 100 at a show and thought it was a remarkable listening experience.

But you know what, if you find the Adcom meets your needs then you've spent some time having fun (hopefully) and made a useful discovery.  What's right for others in their systems doesn't make it right for you (and vice versa).

[Tim S]

I don't recall my D-100's needing much of a breakin period, but I can attest to the fact that the better DAC can make all the difference. When I tried the Nuforce amps a while back, it interfered with my stand alone DAC forcing me to use the ones in my CD player for the evaluation. With that configuration, I couldn't hear much of a difference between my previous amp and the Nuforce's so they went back. When I got the CI amps, they worked fine with the the good DAC and the difference between amps was noticable and substantial. Just for comparison I have also tried it with the CD player's DAC and again the differences in amps were much smaller.

Point is: source matters. I don't know about the Rotel CD player, but my CD player is a decent Cambridge Audio model that also got very good reviews. It wasn't up to the task so it is entirely possible that the Rotel is in a similar boat.

Tim

[audiojerry]

Hi dhiebert, looks like you are fairly new to the forum, so welcome.
I haven't participated much lately, but I happened to have some free time...

As a former Rotel owner, I rate the build quality and reliability highly, but the sonics rather poorly. The Rotel may be the problem. I experimented by using it as a transport with a very high quality dac, but it did not offer any noticeable improvement. Then I auditioned the same high quality dac with an equally high quality transport, and the difference was night and day. I would recommend replacing the Rotel and auditioning a state of the art digital source. CD players have improved tremendously over the last 3-4 years. If you are happy with the improvement, you may want to revisit your amp comparison - you may then be able to hear differences.

Then again, your Quads may work so well with each amp, that it really won't make a noticeable difference. Have you auditioned other systems, and if so, do you feel they brought you closer to the music? Where do you live, maybe there is an AC member living nearby that you could share listening sessions with. A lot can be learned by listening to what others have assembled.

[dhiebert]

Where do you live, maybe there is an AC member living nearby that you could share listening sessions with.

I live in north Alabama. There is no easy way to listen to much else. The nearest hi-fi dealers are at least 100 miles away. That's why I need advice from others with broader experience.

Reading the "professional" reviews of equipment is pretty useless because of the (Secret) Rules of Reviewing. This leaves me with scouring what  others say to derive which products are worth seriously investigating. This is what led me to the D-100.

I will mention one development, though, in support of what you and others have said. Last night, one local friend allowed me to borrow his Krell KAV-300CD CD player to help me see if a better source allowed me to hear a difference between these amps. I first confirmed that I could hear a difference between the Rotel and the Krell CD players through one amp. Then I stayed with the Krell, swapping between amps. I did find that on at least one recording (Kind of Blue), I heard a definite improvement in the imaging of the instruments--one that noticeably increased my emotional enjoyment of the music. Back-and-forth I went and yes, I did hear a difference--and one that was clearly better, rather than just different. I felt that with the D-100, I could "see" the instruments right there in front of me. The point from which the instruments' sound came from was distinctly smaller.

Previously, I had focused most of my comparisons on trying to see if I could pick up musical details through one amp that I couldn't as easily hear through the other. It's so hard to A/B amplifies because of the time it takes to swap out source and speaker cables back and forth. Now that I have a point of reference, I will spend some more time focusing upon this detail when going back and forth between amps.

Thanks for the helpful input you have all offered.

[Phil]

By now you may have more advice than you need.  But, here is yet one more opinion.  First, I agree completely that CD playback has changed greatly over the last few years (even the last two year).   It seems you have confirmed that.

Secondly, I've found that some systems are not dynamic when using a passive preamp.  I've used both and my preference depends upon the system.  If you have the chance, it would be instructive to try an active amp.  I've found that tube preamps are great with chip amps.  But that is just my preference.

Good luck and have fun along the way.

Phil

[dhiebert]

I agree completely that CD playback has changed greatly over the last few years (even the last two year).   It seems you have confirmed that.

The Krell model was actually introduced the same year as my Rotel, so technology related to date of manufacture is not responsible for any difference.

Since you are the second one to mention how much CD playback has improved over the past few years, does anyone have any suggestions on recent CD players which demonstrate this improvement (I realize this runs the risk of taking the discussion outside of the intent of this forum)? Just a few suggestions of recent players I should look at would suffice.

[nickspicks]

the ol' "crap in, crap out" theory.  it is true!

buying a high end source is strong advice, especialy if everything under it is of good caliber.

might I suggest keeping your rotel and just buying a good DAC?
there are great deals out there on quality products that are certainly sweet.

bel canto
benchmark
the Grace 902.

[chadh]

I've been using a Rotel RCC-955 multi-disc player for the past year and a half - my wife was keen to have multi-disc capabilities.  So I complimented this with a dac and other goodies (I actually use a Monarchy DIP reclocking device, a Bolder modified smART DI/O as dac and a little bybee purifier device on the input to the the DI/O).  The sound has been a significant improvement over the Rotel unit.

Chad