50-99wpc of tube. I know you are looking for monobloc amps, but a Manley Stingray integrated tube amp would be a lovely match given that you speakers appear to be two-ways, 87dB/2.83v/m, 8 ohm rated, (maybe) 6 nominal, (maybe) 4 ohm minimal, and the fact that I'm just guessing based on reported synergy with the 2-way revel m20 and the stingray (and the arcam fmj cd-23).
Take a look at Welborn Labs recommendations for speaker and tube amp matching at: http://www.welbornelabs.com/recomendspeaks.htm There you will see "minimum recommendations for speaker sensitivity are as follows:"
3 watts or less - 94dB minimum sensitivity
8 watts - 90dB minimum sensitivity
15 watts - 88dB minimum sensitivity
25 watts - 86dB minimum sensitivity
"These are general guidelines and can vary by plus or minus 2dB depending upon the impedance of the speaker, the type of music listened to, the size of the listening room and how loud you like to listen to your music." They walk you through some examples.
The speakers that they recommend are "either very high efficiency or medium efficiency with relatively benign impedances." You might want to look into this with regard to your speakers.
Anyway, I think Welborn Labs is a great place to start. Good luck.
That's WELBORNE LABS. If I'm going to quote someone, I should at least spell their name correctly. Cheers.
IMHO, impedance curve is probably most overlooked stat. for speaker use with tube amp. Check what frequency minimum impedance is at. Tube amps not good for impedances which have wild swings.
87dB sensitivity isn't very great. Recommend sticking with a larger push-pull amp.
Don't make mistake of running minimum wattage. Allow yourself headroom. You might be able to get by with minimum if you listen mainly to jazz. However, if you like to rock out occaisionally or listen to classical
Often overlooked is crossover slope. Recommend a 1st or 2nd order xover for use with tube amp.
Check reviews online to see what amps reviewers are using with speakers.
E-mail manufacturer for recommendations.
How much power do you have now, as in 8-Ohm rating AND 4-Ohm rating? Do you feel you have enough power? Or are you clipping at your loudest levels now?
Beavis, I think your comment regarding the impedance curve of a speaker is truly overlooked.
I'd been told that my ProAc Response 2.5s despite their 86dB sensitivity rating would be SET friendly because of its mild impedance curve. To be honest, I have no idea what the impedance curve of my speaker looks like, but this weekend I found that my new 37wpc Bel Canto SET40 has more than enough beans to drive my ProAcs to very high listening levels. I was quite surprised to find that it had nearly the dynamics and bass weight of my BAT VK200.
thx for all the responses and links friends, from what i am reading here if i understand correctly i should be looking at driving 20-25w into these loudspeakers, yes?
Beavis, when you said "87dB sensitivity isn't very great. Recommend sticking with a larger push-pull amp.", are you saying that these loudpseakers are not appropriate for use w/ tube amplifiers at all? i should mention this setup is only for my home office, and will not be driven too loudly nor is it meant to serve more than casual personal use... i will be feeding the system w/ balanced audio output from my computers, into a tube preamplifier.
i should also mention, i do not have these loudspeakers yet, they are being built and are on their way in a couple of weeks... thx once again for all the input friends, and have a wonderful day..!
Daisho, I think what you need to consider is how Beavis' second point relates to his first point. If the speakers has a gentle impedance curve that doesn't have wild swings in it and doesn't dip too low, speakers with an 87dB sensitivity rating might be OK. My speakers are rated at 86dB but my 37wpc SET has no problems driving them with authority.
hi Gumbei, thx once again for your reply. i'm afraid my lack of knowledge and experience is going to start becoming more and more apparent w/ every post, i am reading up on what to me is unfamiliar terminology (impedance curve, sensitivity rating, etc.)... my experience w/ audio equipment is fairly limited, and all from the solid-state world, i have a Linn 51xx setup for my home theatre.
on a recent business trip i had the opportunity to hear a tube-based system for the first time at a clients house, he had a small setup in his office made up of a pair of Linn Katan loudspeakers and monoblock 'Dared' (?) monoblock amplifiers... while i don't know the specifics of his setup aside from the above, he did mention that none of it was anything too pricey, as far as audiophile equipment goes. now the sound produced however, i will admit, i was just stunned.
the sounds had such a rich tone and warm quality, so very different from the digitized hard-edged tones i am used to hearing from audio equipment. i decided i wanted to do the same thing and enjoy such wonderful output in my home office as well... i apologize for my absolute lack of 'snap' when it comes to this subject, i will be doing more reading to try to get a handle on what kind of units i should go w/, and if anyone can offer any other general input on what sort of monoblocks i might be wanting to look at for my soon-to-arrive RBHsound 61-SE's would be great, even if it were just loosely suggested specs as far as wattage, or any factor that should be important when making such a selection.
i should add, i'm looking to keep the amplifier purchases somewhere under the $2000 USD mark, for what its worth... thx again all..!
You should't have any problem with sensitivity. I was under impression you wanted to use as home speskers & sit approximately 6-9 foot away from RBH's. Sitting in nearfield overcomes a myriad of volume level problems. You should be able to easily tell when your amplifier is reaching power (wpc) limits and starts clipping when it starts to distort & bass no longer gets louder as you turn up volume (level) control. When you start hearing audible distress, back off the level control. Most people don't realize how loud 87dB is when your speakers are less than a meter away. See example impedance curves at http://www.stereophile.com archived speaker reviews.
Gunbei says he has no problem driving 86dB ProAc speakers despite 86dB sensitivity due to "mild impedance curve." My previous speakers were Spica TC-60s. Thier sensitivity is only 87dB with relatively flat in impedance curve. I had no problem driving with 8wpc tube amp. However, I rarely exceed 85dB, maximum. Just realize you don't have inexhaustible power & drive RBH's accordingly.
E-mail manufacturer for recommendations. They should know thier products better than anyone. Take advantage of thier expertise. Also, check out online reviews to see what amplifiers reviewers use & why.
About the only thing I would be concerned with since reading subsequent posts is crossover slope. 3rd & 4th order crossovers have tendancy to dissapate the first 4 or 5 watts as heat, not a good thing with low-powered tube amps where wpc are precious. Be sure to read Welborne Labs comments on "Some Insight into Proper Speaker Selection" at http://www.welbornelabs.com/recomendspeaks.htm (you have to scoll about 2/3 down page). It really is a good primer for plain talk about MINIMUM speaker sensitivity recommendations.
An inexpensive speaker tweak is to get an isolation cone or small piece of scrap wood to tilt your speakerss back so tweeter is aimed at ear level. Most speakers designed to be listened to on tweeter axis.
BTW, I can't speak with authority on Dared amplifiers since I've never heard but did notice several in AuduoGon auctions today. Sound like they could be what you're looking for.
Beavis, thx a bunch for your reply and all the great information... more reading for me this evening it seems!
so, i take it from your response regarding my listening location distance (1m tops) that i don't need to worry too much about wattage overhead then? would i be fairly safe in assuming that amplifiers that output 20w will work out ok for this scenario? i also see many units that are rated at 16w output, considering my listening distance would these perhaps be sufficient as well, or should i err on the side of caution of assume it would be better to have too much wattage instead of too little?
i will also do as you suggest and contact RBHsound directly to ask about recommended wattage for these particular models (61-SE) and see what kind of input they can provide...
thx again for all your help friends, its nice to not get slammed on a public web forum for a lack of knowledge, and rare in my experience..!
Yes, you shouldn't have problem regarding overhead with 20 wpc amplifier.
But do check with RBH about impedance curve & crossover slope. Believe me, you'll fell much better to have another opinion. One who's opinion I would trust over mine.
Be sure to say you will be using speakers for computer/desktop set-up & you will keep volume level under control.