I picked up a 5-channel Rotel RB-985 power amp and the matching RSP-980 preamp today. The RB-985 sports a toroidal transformer and four main filter caps. The DF is a respectable 180. I'm thinking about using my Classe HT preamp with the Rotel. Or, I might wheel and deal and use the net proceeds to get something else. Audio is fun!

nice find Sam, you might be surprised at how much you like how these sound.

The DF of 180 holds some promise for the forward sound I like. I've been thinking about HT for my DVD collection but have never followed through. Maybe this time...

What year of date are these? Any chance if pics?

Has to be around late Nineties or early 2000's. There is a Mk.II version of the amp which differs only by having greater DF.

Attractive looking setup. I've never spent any serious listening to Rotel kit, besides one piece, only passive listening sessions, and it sounded very good to my ears. I was unaware it sported a forward sound.

The only Rotel I've really spent time with is the excellent 1072 CDP. Really like it.

Well, I said goodbye to the Rotels this afternoon. The buyer brought over his speakers for an audition and it took an hour and a half to close the deal. He wanted to try with his Ipod, which I think are amp and speaker killers. Sure enough, one of his woofers failed and he was about to walk out. I got my tools out for a look. Luckily, one of the leads had come undone. This two minute fix saved the deal. I didn't get top dollar but there is nothing like a one day turnaround. Hmmm. Getting closer to another MAC.

On a side note, this deal was close to a retail sale given the amount of selling and service I gave. I HATE retail.

For future reference, the Rotel manuals can be found here:

http://www.bwgroup-support.com/default.htm

Why do you think this? I think I have an idea but would love you to elaborate.

I have some concern myself on this- but more concerned around the tweeters than woofers.

Fill me in- I am interested.

This is my theory and is not to be taken as fact. MP3 players are ouput devices like CDP's and preamps. They have a power supply and filtering. IMO, the larger the power supply, the better the output device is able to resist sagging and flat-lining when confronted with complex music passages. That's why I always pick preamps with the most robust transformers and the largest filters. An MP3 player can be overdriven as the user tries to maintain gain when confronted with a battery drawing down. In this scenario, the MP3 player is MORE likely to flatline the peaks which the amp reproduces. I'm not sure if this is similar to clipping or even if this phenomena causes amps to stress or VC's to heat up. Whether this results in damage to amp or speaker is a theory but I will not take any chances with my gear.

Damage potential aside, the quality of sound can't be as good as a well endowed CDP like my Yamaha CDX-1100U which has dual transformers or my Sony TA-E90ES preamp which has a medium sized toroidal. I am old school and firmly believe the more the metal, the better the sound. With amplifiers, I believe there is a strong positive correlation between size of components and speed which means better reproduction accuracy. All of the better preamps I own or have heard follow this trend.

My other objection centers on IC chips MP3 players use to amplify the signal. I prefer discrete components for better separation and signal integrity. Mobility is not important to me.

Huh, actually I was off base here.

I, on occasion, run the iPod via a plugged-in dock through the HT receiver for dozing-off music. This seems to keep the power supply flux a non-issue.

Nonetheless, even with uncompressed files, or with a Red Wine modded iPod, indeed it's easier to achieve better sound quite easily and not at any significant cost, relatively speaking.


My concern was the abnormalities that some files develop. A poor transfer, or an out-of-print record downloaded off a blogspot occasionally introduce some gawd-awful sounds into a system.

I usually experience this in the upper frequencies only. Painful to hear, pants-crapping to what it makes the speakers sound like.

Is it damaging? I dunno- but it sure doesn't sound nice. Often it is loud- seems to eek by any volume settings or limiting controls. Absolutely unpleasant and totally nervewrecking.



Thanks for sharing your theory. Food for thought.

Actually, I was thinking about the hardware and not the software so perhaps I was "off base." Perhaps you can help me with some file format knowledge. MP3 and even loss-less involves some sort of coding and decoding which must be achieved by some sort of on-board converter. The better CDP's and standalone DAC's have dual DAC chips and sometimes two per channel. I'm thinking the diminutive MP3 players are introducing some form of crosstalk or harmonics because of poor separation? Or perhaps there is something in the algorithms that cannot properly filter harmonics?

Hardware may indeed play a role in Performance hindrance. Let me take that back- I know it does. The "out" on an iPod basically boils down to either using a headphone out or placing it in a dock and using the dock's "line out".

The inner DAC is a Wolfson- the real weak link is the inner amp.

The Red Wine mods do a hardwire of the wolfson, bypassing the internal amp. They also add an upgrade of Black Gate caps.

http://www.engadget.com/2007/05/16/red-win...or-audiophiles/


http://i.tuaw.com/?date=2007/05/17&slug=re...t&commentspage=

The Red Wine mods supposedly get the iPod up to a respectable and possibly even audiophile level.

No compressed files here- garbage in, garbage out. Sorry, but remove 90%, 80%, 70% or so of any audio file and kid yourself all you want, you ain't getting the whole pie.


I don't mess around too much with compression formats- but indeed a file compressed at a low bitrate sounds a lot like a worn, factory recorded cassette to me.


The problem lies somewhere in that file getting corrupted. This corruption of 0's and 1's can present itself as a "chirping" sound, not too unlike a skipping CD, but worse. It seems to get around any hardware or software volume limiting too.

Hmmm, interesting mod. Correct me if I an wrong, the Red Wine mod turns the portable iPod into a non-portable iMod? For home application, why not get a proper music server with an audiophile power supply?

Thed, as always thanks for the knowledge and the discussion. However, I'm still not entirely convinced these little players are NOT gear killers.

The mod is basically an alternative to a larger music server. I have seen other versions that mount in a wall slot and can be remote controlled.

Kinda hard to read, I'd think, from across the room, eh?


Now here's something to think about. I've seen Phono pre-amps that are 9v battery powered. Do you think this could pose an issue towards gear?

And headphone Amps that are battery powered- defaulted because the signal is being sent to headphones and not acting as a source input? Same perhaps for chip amps that are battery powered, like the T-amp sending a signal off to speakers?

How about tube buffers that are battery powered?