Jmodified Posted January 1, 2012 Share Posted January 1, 2012 Just purchased a set of Original RF-7'S and was wondering if anyone is using a 5802 to power theirs. I currently have a pair of class d audio sds258 monoblocks. I have these bridged mono at 1000 watts each into 8 ohms. I am looking for a good 2 channel amp that can handle the impedance dip of these. Considering a Parasound a21, Krell ksa250, B&k ref. 2220 or an adcom 5802. Anyone with input is appreciated. The class d amps make them rock, but at fairly loud levels they become a bit harsh. Considering the crossover upgrade using some Clarity cap mr's like i had in the klf-20's they replaced. Quote Link to comment Share on other sites More sharing options...
stormin Posted January 1, 2012 Share Posted January 1, 2012 Just from the amps mentioned the Krell is in another league but was originally priced about 4 times that of the other amplifiers. Quote Link to comment Share on other sites More sharing options...
willland Posted January 1, 2012 Share Posted January 1, 2012 I am looking for a good 2 channel amp that can handle the impedance dip of these. Considering a Parasound a21, Krell ksa250, B&k ref. 2220 or an adcom 5802. Anyone with input is appreciated. Between the amps mentioned, I would go with the Parasound A21 or the B&K Reference 2220 factoring in price/performance. The Parasound A21 is one great amp with crazy amounts of power that even used commands a good chunk of $$$. No problems with this amp driving just about any load out there. I have the B&K EX4420 which is a generation or two older than the 2220 and it is one beefy amp. Plenty of high current low impedence handling power with a sweet velvety midrange that is hard to top at it's price point. Good bottom end with a somewhat soft rolled off treble that would mate very well with the often described brightness of RF-7's highs. It drove my RF-63's with no issues at all except for softening the top end a little too much for my liking. The RF-63's/RF-83's by design are softer on top than the RF-7's. What is your budget? The Parasound can be had for $2299.00 new and around $1500.00 used. http://www.audioadvisor.com/prodinfo.asp?number=PAHA21 http://www.audiogon.com/cgi-bin/cls.pl?ampstran&1330005504&/Parasound-A21-Great-amp. The B&K can be found used for $600.00 to $700.00. http://www.audiogon.com/cgi-bin/cls.pl?ampstran&1328117916&/B-K-Ref-2220-Big-bang-for-the- Here is another option if you want a low impedence handling and tank-like build quality amp. http://www.audiogon.com/cgi-bin/cls.pl?ampstran&1329957483&/Aragon-8008BB-200wpc--stereo-p Bill Quote Link to comment Share on other sites More sharing options...
stormin Posted January 1, 2012 Share Posted January 1, 2012 The most powerful amp by far that can handle just about any load under the sun is that Krell no matter which way anybody tries to twist it. Now is it the best match for the RF 7's I doubt it but it will have the most ease driving them if thats what your concerned with. Quote Link to comment Share on other sites More sharing options...
AnalogWave Posted January 1, 2012 Share Posted January 1, 2012 The most powerful amp by far that can handle just about any load under the sun is that Krell no matter which way anybody tries to twist it. Now is it the best match for the RF 7's I doubt it but it will have the most ease driving them if thats what your concerned with. You can heat your entire house with it, too [] Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 2, 2012 Author Share Posted January 2, 2012 I have only listened to the 7's with a b&K 200.2 that is in my brothers system. I would like to stay under 2k used, havent heard the Krell or Parasound. I guess i should hook up my B&k 200.3 and see how they sound. I have been looking for a 200.3 for a while with no avail. The 7;s sound great with the class d's its just when really cranking them you can tell the load on them seems to start making the highs seem very bright if that makes sense. Of course that is at insane listening levels that no one would realistically listen at. Thanks all! Quote Link to comment Share on other sites More sharing options...
willland Posted January 2, 2012 Share Posted January 2, 2012 I have only listened to the 7's with a b&K 200.2 that is in my brothers system. Your brother's B&K Refrence 200.2 is the same amp as the B&K Ref. 2220, just a little newer. The schematics are the same. Same goes for the 200.3 which is the same amp as the 3220 which is basically the same as the 4430. I was driving my front soundstage(RF-63's/RC-64) with a B&K Ref. 4430 for some time and was very pleased. I added my EX4420 to drive the fronts and then let the 4430 drive the center and surrounds. That made an audible difference that was noticeable to me. I think if you will be keeping the 200.3, adding a 2-channel B&K to drive your 7's is the way to go. Bill Quote Link to comment Share on other sites More sharing options...
Hclarkx Posted January 7, 2012 Share Posted January 7, 2012 Whoa, think about this a minute. The RF-7's have a sensitivity of 102 db!! Hence they require six times less power than a typical speaker set with 93 db sensitivity for the same SPL. The RF-7's 250W power rating (1000W peak) is impressive but will never happen in practice with a 102 db speaker. I've driven mine with as little as 50W per and could drive them as loud as I dared with no loss of quality. You don't need a class AB amp of more than about 100W rating for the RF-7's to remain in the class A (highly linear) region virtually all of the time. Even at Xmax they won't be much out of the Class A region of a 100W AB amp. Hence I would worry more about the quality of the amp than the power rating since the RF-7's will reveal any imperfections in the amp or elsewhere in your system (including a less than high quality D/A in your CD player .... or receiver depending on where you convert your CD digital signal). Unless your home theater is in a large barn, 100W will be enough. And 100W may be more than you need there. Some tube fans drive these with 20 and 30 Watt tube amps. You will want high-end amps especially if you go class D since the RF-7's will reveal any digital artifacts that make it to the output. That will come across as harshness, and sound much like a low-end CD D/A computer. Quote Link to comment Share on other sites More sharing options...
Fish Posted January 7, 2012 Share Posted January 7, 2012 I had the 5802 on my 7'w for a while.It sounded OK but I actually got the clipping lights to light up occasionally.I also had a BK amp of about 1/2 the power and it sounded just as good.The Parasound is one of he better amps I had, along with Outlaw(ati), of course Rotel and my current Emotiva amps also work well.I have found much less difference in amps than pre's or sources.The advice to get quality over power is sound advice. Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 8, 2012 Author Share Posted January 8, 2012 I just had the opportunity to purchase a 5802 and was checking to see what experience poeple may have had with them. I have owned a lot of different adcom gear 15 years ago and had a 5800 on some Forte ii's that sounded good. I hooked up my b&k 200.3 to my rf-7's and while it sounds great i prefer the class d audio monos i built. I have listened to the ice asp 1000's and prefer my class d audio sds258, they are quality units and i dont like the rolled off sound of the iceamps. I am not looking for a ton of power per say as i dont listen to it that loud. Just looking for an excellent 2 channel amp to go with my new 7's. The class d will drive these into tomorrow without even breathing hard. I had an active bi-amp setup with these driving 4 channels at 250w then i bridged them to see the difference and preferred them bridged. Really deciding to build another mono class d amp for center and another for the rears. I have a 15wpc ecl82 tube setup in my 2 channl room with klf-20's that drives them very well. Really just figuring out what i want to do for the theater system. Actually i was looking at either the Parasound halo 5 channel a51, or the a53. 125 per chnnel would be plenty for home theater, I just always liked having the headroom 250wpc amps. Make sense? Good replys and thanks for the responses! Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 8, 2012 Author Share Posted January 8, 2012 I understand about the sensitivity, every 3 db requiring doubling amp power and all that. I use a Cambridge 640cv2 that i have re-clocked, re-capped all of the electros with high quality caps, changed the regs to dexa discreet regs. And have actually bypassed the output stage pulling a lead right off of the wolfson dacs to a 1uf clarity cap mr straight out of the unit. As the wolfson dacs are current output, not voltage output dacs they have the current to send to my pre bypassing the opamps. Very clean, detailed and nuetral. I have a Marantz av7005 that i purchased from Dave at the Upgrade Company new that he did his shielding and damping treatment to. Excellent sounding piece. I have listened to several iceamps including BelCantos, Muranos, Hypex, and prefer the class d audio over the iceamps. Never really liked the smps in the ice amps. I built my sds258 monoblocks with oversized torroidal's at 600va each and capped the power supplys with Nichicon KG gold tunes. I really like the bass control, pinpoint imaging, and tubelike midrange of the class d amps. I was a little worried at first using them bridged with the 7's because of the impedance dips that so many talk about. After using them for a week i find they stay very linear, even at loud listening levels. I think i would put my class d amps up next to any on the market, and i think they will hold their own. Many people use the same modules and do some mods or tweaks on the iceamps including input trafos which to me makes them sound too rolled off in the highs. Quote Link to comment Share on other sites More sharing options...
Hclarkx Posted January 8, 2012 Share Posted January 8, 2012 J, I think you've got it handled well. My experience with Class D was very early and not a good one. I moved away from Class D before getting my RF-7's. At first I thought the RF-7's were crap ... way to harsh. Then I figured out they were just revealing issues with my CD player. That suggested the RF-7's wouldn't work well with a Class D, but, from your points, it's clear Class D has come a long way and are up to the RF-7's. I think the 7's reputation of being harsh is just them revealing inferior equipment upstream. I did have an Adcom 5803 for a couple of years and was running it when I got the RF-7's. It didn't take long to figure out the 5803 had far more power than I needed for the RF-7's. Moreover it ran very hot even at idle as most FET amps do. That heat made arranging and protecting my precious equipment difficult. I think it was when I got the Audyssey Sound EQ Pro that I really understood how little drive the RF-7's required since it tells you clearly the relative drive each speaker needs in db. I should qualify my observations though. I only drive my RF-7's down to an 80 Hz crossover to my subs. I assume everybody does that and maybe that's not a safe assumption. Crossing over at 80 Hz reduces the power the RF-7's need. If one is driving them full-range, then power will be more of an issue. Fish, were you driving the 7's full range when you saw clipping lights on the 5802? I never did with the 5803 and would get them fairly loud in a 1400 square foot room (when my wife was out). I also found I needed four 15" subs to keep up with the RF-7's and get flat response down to 20 Hz and below. This is done with an Audyssey Sub EQ and four large sealed subs and using four channels of an Adcom GFA-7500. Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 8, 2012 Author Share Posted January 8, 2012 I have decided to keep the class d amps, i have new mills resistors and musicap film and foils coming for the rf-7's. I have sold my rc-64 and purchased a rc-7 that i will put in mills resistors and musicaps to match the mains. I feel another class d mono build coming up for the center! I run a Marantz av7005 upgraded by the Upgrade Company and love the Audyssey setup for theater. I have all of the speakers crossed at80 and the sub at 120hz. When running 2 channel i only listen to pure direct, analog from Cambridge cd, the bass from the rf-7's is incredible, the highs are airy and detailed. If the caps and resistors make them smoother i should be in for a treat. Eventually i will build a stereo 250w class d for the rears to match the rest. Love the efficiency of the class d amps, and they dont tax my 20a designated circuit. Took a week to get used to listening to the 2 ways vs. my KLF-20'S In the end the rf-7's are very dynamic and accurate compaitively. Salute! Quote Link to comment Share on other sites More sharing options...
Lpusedyou Posted January 9, 2012 Share Posted January 9, 2012 Nice John! Happy to hear you joined the RF-7 gang and love them. I'm sure it took some getting used vs. your awesome KLF-20s like you said. i can vouch for how awesome your Class D amps are because they sounded so clean all the way through. Where did you end up getting an RC-7 by the way? Just curious Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 9, 2012 Author Share Posted January 9, 2012 Thanks! I have been wanting a pair of rf-7s for a while now, but as you know i replaced so many other things i was patiently waiting for a pair to show up local. A pair showed up less than a half mile from my house and i pounced on them.Grill pegs were broken but i have a new set coming tomorrow. Just received my musicaps today for the tweeter circuit and i have no idea how i am going to stuff thwm in the x-over. Wow i thought my clarity cap mr's were huge on the klf's. I am sure i will make it happen. I purchased a rc-7 from flea-bay, overpaid for it but it looks very clean and i have never had a speaker like that shipped so i hope it arrives in good shape! Gotta say i love the rf-7's, honestly i cnat believe the sound of them. I thought my klf's were good! I see you have some monoblockks for sale also huh? What are you using for an amp now? Quote Link to comment Share on other sites More sharing options...
Fish Posted January 9, 2012 Share Posted January 9, 2012 I'm a klf fan and owner too, really like em', but the 7's just have something special going on.Sounds like you got a good handle on things. Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 10, 2012 Author Share Posted January 10, 2012 Youre right about the 7's having something special. Probably the difference between cones handling 750-1900hz where the horns take over on the klf's at 750. I have to give a slight edge to my klf's in the smoothness of vocals. Probably because of the outboard crossovers with the clarity cap mr's. Clarity cap doesnt make the right values for the tweeter circuit in the 7's, and they would cost more than the speakers to use them, once my resistors get here i am ready to tackle the tweeter circuit and they sould sound even better. B Quote Link to comment Share on other sites More sharing options...
Lpusedyou Posted January 10, 2012 Share Posted January 10, 2012 Oh yea I think I saw the ad for those - were they black RF-7s? Originally listed for like $1300 or so? Pffft grill pegs broken big whoop. Mine were too but I love the look of them without the grills anyways. Yea they are already huge beasts and once you're done frankenstein-ing them they will be even larger haha. But they're gonna sound amazing. So you kept you're KLF20s then right? Yes, I am selling 5 Marantz MA-500 monoblocks. If you know anyone looking let me know. I like them but soon after buying them I came across a old man selling a mint condition, less than 2 year old ATI 1800 3 channel amp. It's one of those modular ones where you can install up to 7 cards but just has 3 right now which is all I wanted for my front sound stage - the two RF-7s and RC-7. It sounds great to me and the bass is so much tighter and controlled coming from the RF-7s. Very clean sound. I think I read it's rated at about 210 wpc. So that made the Marantz monoblocks seem quite weak even though they are great little units. Quote Link to comment Share on other sites More sharing options...
Jmodified Posted January 10, 2012 Author Share Posted January 10, 2012 They were the ones for 1300, i offered him 900 and he acce3pted. Just got my grills in today, they are pretty much mint i small scratch on one side i repaired. Other than that they are like new. Rc-7 will be here on Thurs. I might know someone that i sold my ma500 to. He might be looking for some more, i will let you know. You like the rc-7? Quote Link to comment Share on other sites More sharing options...
Lpusedyou Posted January 11, 2012 Share Posted January 11, 2012 Nice dude that's a smoking deal for sure! Especially if they are in great condition like you said. I LOVE my RC-7. It is the perfect match for the RF-7s (obviously I know)! But I've listened to my friend's RC-64 (v1) and it does not compare in my opinion. And he has RF-83s with the 64 too so it's not like he has a bad system or anything. Yea let him know for sure. I'll even make him a decent deal since he's a friend of yours. Quote Link to comment Share on other sites More sharing options...
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