Rb-1090

[BWLover]

Hello all. What is a used RB-1090 worth these days? Also what is an RB-1080 worth used? Thanks!

[srb]

They both usually sell for around 50% to 60% of original price. RB-1080s usually sell in the $500 - $600 range and RB-1090s in the $1000 - $1200 range.

Steve

[wkhanna]

Agreed.

But I would not part with my RB-1090 for 2k, if it were offered.
After PewterTA's minor mods, its performance is at least in that range.

As always, JMHO, YMMV

[BWLover]

I'm thinking of selling my 1080 and getting a 1090. This is the ad

http://app.audiogon.com/listings/solid-state-rotel-rb-1090-amp-silver-2012-10-08-amplifiers-68510

[srb]

That one may be a bit high, but the seller is open to offers. The last 1090 listed previous to that one was listed for $1050 including shipping - http://app.audiogon.com/listings/sol...plifiers-11010

It was marked Expired prior to the 30-day automatic expiration, so it may have sold or may have been cancelled by the seller for whatever reason.

Steve

[BWLover]

I offered $1100

[wkhanna]

Best of luck with your search.
I do not think you will regret it.

OT- I see you recently added the Project Turn Table.
Maybe you could post some of your impressions over at our Analog Audio forum?

[BWLover]

Ya for sure. Once I get some more time with it to compare to my cdp.

[PewterTA]

If you get the 1090... and ever decide to make a trip to Pittsburgh... and are driving... throw the 1090 in the truck and let me know, I'll mod it for you and you'll be very pleasantly surprised by the changes to the amp.

Heck, Bill didn't want to give back my 1080 because he liked it better than his 1090 when I moded his 1090 for him. I had to re-assure him the 1090 would sound identical just with better Bass. I don't think he got steered wrong.... at least he hasn't sold it yet. LOL

[BWLover]

What do you do to the 1090 mod wise?

I'm getting my 1090 this week. One question. Would you plug it directly into the wall? Or into the "High current" amp outlet on the RLC-1040?

My 1080 has been on the 1040 while I've had it.


Thanks

[wkhanna]

I used to run my RB-1090 from my APC 15 till it fried a few months ago. It has since been replaced by a surge protector on loan from a friend till a replacement is decided upon. During this period I confirmed the same results as Dan (PewterTA). Running the amp directly from the wall outlet provided a slight, but noticeable improvement in dynamics & transient response.

I used to feel it prudent to ‘protect’ my amp by tapping it through the surge protector/conditioner, but find the added performance overrides any concerns of potential harm from the unfiltered power source. There are many hi-end manufactures who recommend by-passing any conditioner or surge protection for their amps, stating the internal circuitry will provide sufficient protection while providing the best performance.

On the other hand, Dan’s 1090 recently required repair for what our local audio shop estimates was the result of a large voltage spike. Fortunately the repair was made in short order (a few days) at cost of less than what it would of cost simply to ship the unit to Rotel’s repair facility just the other side of our state. His unit is no worse for the wear & performs like new. I don’t know if Dan had his amp running off of his APC unit or not when the damage occurred. Hopefully he can clarify for us.

Whether one feels the ‘risk’ of running your amp direct from the wall or not is a prudent decision ultimately comes down to personal choice. I will continue to keep mine plugged directly into the wall outlet, knowing if I do have an issue down the road, I have a top-notch repair shop locally that is capable of resurrecting the unit with little pain.

What would be of great intrest is for you to try both configurations & tell us what you observed.

[BWLover]

I will definitely be doing that. And comparing the 1080 to the 1090.

[madmac]

I mistakenly answered your question in your power-cable post.
For continuities sake I did a C&P here:

I used to run my RB-1090 from my APC 15 till it fried a few months ago. It has since been replaced by a surge protector on loan from a friend till a replacement is decided upon. During this period I confirmed the same results as Dan (PewterTA). Running the amp directly from the wall outlet provided a slight, but noticeable improvement in dynamics & transient response.

I used to feel it prudent to ‘protect’ my amp by tapping it through the surge protector/conditioner, but find the added performance overrides any concerns of potential harm from the unfiltered power source. There are many hi-end manufactures who recommend by-passing any conditioner or surge protection for their amps, stating the internal circuitry will provide sufficient protection while providing the best performance.

On the other hand, Dan’s 1090 recently required repair for what our local audio shop estimates was the result of a large voltage spike. Fortunately the repair was made in short order (a few days) at cost of less than what it would of cost simply to ship the unit to Rotel’s repair facility just the other side of our state. His unit is no worse for the wear & performs like new. I don’t know if Dan had his amp running off of his APC unit or not when the damage occurred. Hopefully he can clarify for us.

Whether one feels the ‘risk’ of running your amp direct from the wall or not is a prudent decision ultimately comes down to personal choice. I will continue to keep mine plugged directly into the wall outlet, knowing if I do have an issue down the road, I have a top-notch repair shop locally that is capable of resurrecting the unit with little pain.

What would be of great intrest is for you to try both configurations & tell us what you observed.

Hummm....spike/power conditioner affects end sound???.....Hummm.....have you done a blind test on that concept??

[wkhanna]

Hummm....spike/power conditioner affects end sound???

To my ears, yes. The difference was slight, but obvious enough that the improved dynamics & transient response was immediately apparent regardless of source or genre of music.

My guess, & this is only a guess……..the RB-1090 instantaneously draws significant current during periods of loud, transient or significant bass passages. The inrush of current can be restricted somewhat due to the topography of the surge/power conditioner. In other words, the surge/conditioner acts as a resistor/impedance to the power required from the amp. In the case of the 1090, & depending on the efficiency of the speakers, this current demand can be quiet significant.

.....Hummm.....have you done a blind test on that concept??

Yes, Dan picked it up right away, & I did not even tell him anything had been changed since the last time he had heard my system.

Have you ever tried it?

[madmac]

To my ears, yes. The difference was slight, but obvious enough that the improved dynamics & transient response was immediately apparent regardless of source or genre of music.

My guess, & this is only a guess……..the RB-1090 instantaneously draws significant current during periods of loud, transient or significant bass passages. The inrush of current can be restricted somewhat due to the topography of the surge/power conditioner. In other words, the surge/conditioner acts as a resistor/impedance to the power required from the amp. In the case of the 1090, & depending on the efficiency of the speakers, this current demand can be quiet significant.

Yes, Dan picked it up right away, & I did not even tell him anything had been changed since the last time he had heard my system.

Have you ever tried it?

No...but now you have me worried and I might try it. I really don't want to have my Rotel taken down by a spike and have to pay hundreds of dollars to fix it. I will however, plug it straight into the wall and try it. I did not have a spike protector and when I installed one, I did not hear any difference but then again I was not expecting or looking for one. Very interesting

[wkhanna]

What do you do to the 1090 mod wise?
Thanks

Hey Dan....

Can you link to your post on the 1090 mod....?
I tried a half-hearted search & came up empty...of course.

[rdram]

Don't want to get into the whole power cord debate, but I have my 1090 plugged directly into the wall...not to my 1040. Main reason is I didn't think the 1040 would handle the power demands of the 1090, and I didn't want to put any unnecessary restriction on it. From a practical standpoint, there is no reason not to plug it into the wall. What could happen? I live in an area of pretty stable power. If there is a storm coming, then I won't power up the 1090. If power goes out, then oh well...no big deal. I will say that the best thing I did was put a direct 20 amp line from my breaker box to the HT room. Did that last year. Terminated to a PS Audio power port. That's what the 1090 is plugged into. Don't have the fluffy verbage of an equipment reviewer, but my whole system seemed to take a step toward "Quiet" with the dedicated circuit. Best thing I ever did from a "tweek" standpoint. Would definitely recommend.

Rich

[PewterTA]

Okay... lets get things somewhat straight.... a pure surge protector... like what you'd buy at Walmart/Target... is not going to effect the sound of an amplifier and should not. However a power conditioner like the 1040 and Bill's and Mine that conditions (mine also has a battery backup)... that will limit the current and keep it "nice and smooth." So this is exactly what is causing the issues with some of the transients and loud bass passages that would in effect limit them.

So Madmac... if you just have a surge protector then you'll probably not notice anything, if you have a power conditioner, then you will probably notice a difference... similar to the effect of choking off the amp.

It had been a couple of weeks from the time I had heard Bill's system and the next time I was over when he had the amp off the conditioner and I instantly asked him what he had done (well didn't ask, said he plugged the amp right into the wall ha ha)... So it was that noticeable that I was able to pick up the difference even after a few weeks not hearing things.

What I did to all my equipment and to Bill's Amp was solder all the internal wiring to the connections. Not directly soldering the wires to their connection points, but every single wire in the system was crimped with a loop connection or Y connector on it. I used the silver solder to solder the wire to the crimp connector and for serviceability I used deoxit Gold when I screwed them back into place or reconnected them. Ideally I would've soldered those to make the best connection as I possible...but I didn't want to go that far... and honestly I don't know if it would've really done that much more.... It took about 2 hours for me to do all the soldering and put the amp back together and the differences were pretty outstanding. Enough so that I did my other amps (1080, 1095), my RSP-1098, my Cambridge Audio 840c CDP, and my APC S15 power Conditioner the same way.

The biggest things I gained was clarity and speed in the sound. But a long with that my sound stage opened up like it never had before. I definitely think it was the best thing I've done to my system. Now I want to get the OP amps changed out on the 1098...but giving it up for a week or so will be rough. Course my current thought process is to get the Classe CP-800 and something like the Emotiva UMC-1 for surround sound... some type of a pre for the HD movie soundtracks.

[srb]

Your blanket statements on power conditioners might be a bit misleading.

Although many small power conditioners (like my Rotel RLC-1040) might limit current delivery to a power amplifier, sufficiently large isolation transformer-based power conditioners like the Plitron/Torus and others combine energy storage within the magnetic field of the transformer and a much lower output impedance to provide far greater instantaneous peak current reserves to an amplifier than is normally available directly from the wall outlet.

The downside is that they are generally very expensive.

Steve

[wkhanna]

Agreed.
Point well taken & thanks for the detailed info.

[BWLover]

I got my 1090!

[wkhanna]

Great news!
We must assume it arrived undamaged & in good health.
Welcome to the 1090 Club……
We anxiously await you your impressions.

BTW, I hope you got the ‘all Black’ one, right?
I mean, everyone knows the Black one sounds Waaaay better. :W

[PewterTA]

I saw 2 RB-1090s on ebay.... Soooooooo wanted to buy them!

Definitely let us know of your impressions... and of course the offer still stands for the modification of them which will make it a VERY impressive amp.

[bigburner]

BTW, I hope you got the ‘all Black’ one, right?
I mean, everyone knows the Black one sounds Waaaay better.

That's right Bill but you only get the benefit if you use red interconnects because as everyone knows they produce a slightly warmer sound.

Nigel.

[BWLover]

This amp is INSANE!

[wkhanna]

SEG


(Schiit eat'n Grin)

[PewterTA]

Another satisified customer. ... and we can make it even better.

[Stilgar]

That's right Bill but you only get the benefit if you use red interconnects because as everyone knows they produce a slightly warmer sound.
Nigel.

I use red interconnects with black rb 1080! sounds gooood! :B

Unfortunately it's quite complicated to buy rb 1090 in russia and completely impossible to buy black one. :B

How 1090 sound against 1080?

[BWLover]

Does anyone know what the "High current" spec of the 1090 is? Like HK speaks of "High Instantaneous Current Capability (HCC)" in there specs. Rotel talks about there amps having quite a bit of current/amps behind them. But it's not an official spec I see listen on many spec sheets.

[wkhanna]

The ‘Instantaneous Current Capability’ may be an ‘Official’ measurement for HK, but as an industry, when it comes to ‘Specification’ for audio equipment, numbers & claims fly as fast & furious as excuses for poor campaign performance.

One company may list its products performance capabilities using a completely different set of test conditions than another company. I know it may hard to believe, but some of these companies' marketing departments may actually pressure the engineers to intentionally come up with misleading information in order to sway potential customers. Unthinkable, isn’t it?

For example, the current load placed on the RB-1090 by a speaker with 90 dB efficiency at 8 ohms will be drastically different that an 85 dB efficient speaker that offers an average 4 ohm load. These ‘specs’ offered by marketing departments are often not comparing apples to apples.

One spec that I have found to be ‘generally’ reflective of an amplifier’s performance is Damping Factor. From Wikipedia, “Over a range from less than 1 to up to around 50, damping factor describes the ability to which the amplifier helps to control the oscillation of the speaker, expressing the degree to which the amplifier does not exert a resistance against the current generated by the speaker. A damping factor of 50 is high, indicating that the output impedance of the amplifier is negligible compared to the internal resistance of the speaker and the speaker cabling.”

A Link for some more info on the subject.

[wkhanna]

Rotel talks about there amps having quite a bit of current/amps behind them.

That reminds me of the older Rolls Royce sales literature that always specified the horsepower rating of their automobiles simply as 'Adequate'.

[BWLover]

The ‘Instantaneous Current Capability’ may be an ‘Official’ measurement for HK, but as an industry, when it comes to ‘Specification’ for audio equipment, numbers & claims fly as fast & furious as excuses for poor campaign performance.

One company may list its products performance capabilities using a completely different set of test conditions than another company. I know it may hard to believe, but some of these companies' marketing departments may actually pressure the engineers to intentionally come up with misleading information in order to sway potential customers. Unthinkable, isn’t it?

For example, the current load placed on the RB-1090 by a speaker with 90 dB efficiency at 8 ohms will be drastically different that an 85 dB efficient speaker that offers an average 4 ohm load. These ‘specs’ offered by marketing departments are often not comparing apples to apples.

One spec that I have found to be ‘generally’ reflective of an amplifier’s performance is Damping Factor. From Wikipedia, “Over a range from less than 1 to up to around 50, damping factor describes the ability to which the amplifier helps to control the oscillation of the speaker, expressing the degree to which the amplifier does not exert a resistance against the current generated by the speaker. A damping factor of 50 is high, indicating that the output impedance of the amplifier is negligible compared to the internal resistance of the speaker and the speaker cabling.”

A Link for some more info on the subject.

Interesting. I knew that specs were somewhat fudged. I just had hoped that ampridge was something that was somewhat standardized. My dad has a Harmon Kardon receiver and Nuance speakers. He's always concerned with how much ampridge the HK's have because that's what was explained to him at the shop he got it from. They told him Nuance speakers need a lot of ampridge to drive them. Presumably because they are very inefficient. So now that I have a 1090 I was wondering what "ampridge" it has compared to the HK's.

[BWLover]

As for my initial impressions on the 1090. Holy. F***ing. S**t. The bass handling is exponentially better then the 1080. When I cranked up the 1080 and watched the bass drivers, they would be exerting a lot of force. I.E. going in and out very far, reaching the limits of the voice coil (I believe that's the correct term/part). Now on the 1090, when playing very loud, there (still speaking physically) they are tight and very controlled. Not struggling to produce the spl's that the 1080 had trouble with. They hardly move more then maybe 1cm. On the 1080 same vol. they'd be going maybe 2-2.5 cm in and out. If that makes sense.

[srb]

Glad that you were able to realize an improvement and that the additional money and transactions paid off.

Not sure I really understand how the cone excursion is less with the 1090 than the 1080 at the same volume, but perhaps it has something to do with a better real-world damping factor (regardless of what the specs say) to control cone movement.

BTW, I think the term you meant to use for the number of amperes of current flowing in a circuit is "amperage", not "ampridge"!

Steve

[madmac]

Interesting. I knew that specs were somewhat fudged. I just had hoped that ampridge was something that was somewhat standardized. My dad has a Harmon Kardon receiver and Nuance speakers. He's always concerned with how much ampridge the HK's have because that's what was explained to him at the shop he got it from. They told him Nuance speakers need a lot of ampridge to drive them. Presumably because they are very inefficient. So now that I have a 1090 I was wondering what "ampridge" it has compared to the HK's.

Well, in a nutshell.......is has lots more!! :T

[mpauline]

As for my initial impressions on the 1090. Holy. F***ing. S**t. The bass handling is exponentially better then the 1080. When I cranked up the 1080 and watched the bass drivers, they would be exerting a lot of force. I.E. going in and out very far, reaching the limits of the voice coil (I believe that's the correct term/part). Now on the 1090, when playing very loud, there (still speaking physically) they are tight and very controlled. Not struggling to produce the spl's that the 1080 had trouble with. They hardly move more then maybe 1cm. On the 1080 same vol. they'd be going maybe 2-2.5 cm in and out. If that makes sense.

I have a 1080 driving my B&W 803 Diamonds and have my eye on a 1090. Sounds like it was a good improvement for you. Then maybe I will switch my 1080 to just drive my center channel. Seems like a better option than the $6200 ($8000 retail) Byrston 6BSST2 that I had home on the weekend 8O

I really like my 1080 it is just that the 803's need a little more juice.

[BWLover]

I would recommend that as well. A vast improvement on my 683's. So I imagin that the 803's would benefit greatly with the extra power.

[PiDD]

PewterTA,

I finally did the mod. The worst part was cutting off all the plastic shielding on the terminals. Well that and recalling what damn wire went where! I put it all back together and plugged it in and blew the breaker! LUCKILY nothing else. (3 red wires going to the same connector block! (Label the cables if you take this on)

I will be honest.. I didnt expect anything from this. Now... Im mixing up my own batch of koolaid!

The first thing I noticed... my soundstage snapped into place. I had to get up and make sure my center channel wasnt on. Next was the quickness or a more clean sound. The third was the texture of the sounds. I would believe it unless I heard it for myself.

Back to listening! Thanks for the tip!

[wkhanna]

Well done, PiDD!!!

It can seem a risky proposition at first. & such minor mods intuitively should not produce such drastic results.

I was in disbelief after Dan performed the mod on mine.

So V glad to hear of your success & that you have found the same improvements as us.

[PiDD]

Im still shocked! Im now listing to a bunch of DVDA 2ch music again... for the very first time! lol

[PewterTA]

Great to hear it PiDD!! At least that now confirms Bill and I aren't completely nuts! ha ha

First time I heard the amp I couldn't believe the difference as well, it was like listening to a whole new beast of an amp. It was enough that I took on the rest of my components. Another big changed came when I did both my Cambridge Audio 840c CDP and APC S15 Power Conditioner. The pre-amp helped...but didn't make as much of a difference as the other two.

Though I did hear a very nice $5k tubed Pre-amp and I as very surprised at how close my RSP-1098 sounded to it... Not much difference and even better focus on the soundstage, but the 1098 didn't have the sustain of the other... but still impressive I think.

Enjoy the listening, you'll be surprised the whole time on it and happy you took on the risk. Mission Accomplished my friend!

[BWLover]

Can someone explain watts in regards to amps? Likes uncle is an electrician and doesn't believe it has 360 watts. Why doesn't a person get electrocuted when touching the wires lol.

[wkhanna]

Maybe this will help....

Maybe not......

link to audioholics.com article

[PiDD]

At least that now confirms Bill and I aren't completely nuts!

You might be but with great ears! lol

Did you do anything to your 1098?
What did you do to your power conditioner? (I have the RLC-1040)

[PewterTA]

Well at least were not super crazy when it comes to listening and sound... everything else, yes we're nuts! lol

Same exact thing as you did with the 1090... any wires with crimp connectors I soldered and used deoxit Gold on the spade connectors that were held by screws. I also used Deoxit gold on eact circuit board pin connectors for the analog, digital, video, etc. Only places I didn't were the connectors to the front display and knobs/buttons.

For the 1098 it helped improve the sound some, slightly more detailed and cleaner sound, but out of all the components this changed the sound the least.

In the APC unit, I did the exact same thing, all connections taken apart and soldered where I could and Deoxit Gold where I didn't want to solder. Only one place I didn't do was the battery connector to the board. It was so tightly connected to the board and in a bad location that I was too afraid of breaking stuff, so I just left it (how often does it ever run on battery anyways while listening... never I think)... The Wires that ran to the plug connectors I believe I soldered on the metal strapping side, but not on the connection to the circuit board.

The changes I noticed when done with the APC is my sound stage moved. Before the sound was more in your face and felt like it started a foot or two infront of the speakers then after I was done, it dropped to in line or a foot behind the speaker. It also seemed like instruments went further back beyond the rear wall which NEVER happened before. That's the only real difference I can say I noticed... I don't think the sound changed any and I've always had a very quiet/silent/black type of a sound when nothing is playing, so I don't think there was any change that way.