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Tube power?

M

mbeigh

Active Member
Hi,

I am considering moving from solid state to tube monoblocks. oo I am currently throwing 200w of ss power at mu Infinity RSIIIa speakers. What kind of tube wattage would I need to adequately power the Infinity's?
Any suggestions as to what I should look for? Would also probably look for a tube preamp. As always, looking for the most for the least $.

Thanks
M Beigh
 
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I went from about 300w of sand, to 40w of glass, and I have no idea of how much is missing... Amazing the difference between tubes and SS as to what you can actually get by with tubes..

I've got Quicksilver monoblocks, and have thought about another pair.. for the price to quality and wattage, they very hard to beat as to going used prices.
 
Assuming they're biampable...

mbeigh said:
Hi,

I am considering moving from solid state to tube monoblocks. oo I am currently throwing 200w of ss power at mu Infinity RSIIIa speakers. What kind of tube wattage would I need to adequately power the Infinity's?
Any suggestions as to what I should look for? Would also probably look for a tube preamp. As always, looking for the most for the least $.

Thanks
M Beigh
Click to expand...

I'd save your sand for the bottom end and add your tubes up top. 30 WPC or more is the number I hear being bandied around. As far as a tube pre goes, how much money do you want to spend?
 
What kind of load does the top half of RSIIIa present?

Does the OP need to be sure that whatever his tube amp choices are, they have 4 ohm taps?
 
I think it would be worth the while to rewire the crossovers to allow biamping...

200wpc SS for the woofers and 30wpc tube on top would be quite the system with your speakers.

Regarding going from SS to tube exclusively.... It can be amazing how powerful a small tube amp can sound. I think its due to the softer clipping characteristics of a tube versus a transistor. That, and the speaker will be running off of more voltage than current as compared to a solid state amp.

YMMV, though.
 
zenith2134 said:
Regarding going from SS to tube exclusively.... It can be amazing how powerful a small tube amp can sound. I think its due to the softer clipping characteristics of a tube versus a transistor. That, and the speaker will be running off of more voltage than current as compared to a solid state amp.

YMMV, though.
Click to expand...

Totally agree with the softer clipping etc. characteristics as the reason tubes seem to be more powerful than their rating. Watts are watts regardless of SS or tube. Of course, the assumption is that both would be measured under the same conditions for that to be true.

I think the part about the speakers running off more voltage or current isn't likely to be a factor though, because this relationship is defined by Ohm's Law and cannot be broken regardless of the type of amplifier.
 
Ohm's law stands, of course, BUT I brought this up because (most) tube amplifiers have more voltage drive and less current. Probably due to the output transformers and the type of power supplies typically used.

Watts are indeed watts, but If you are running power-hungry speakers full-range off of a tube amp, you may lose steam way too early because of the lack of current. Remember, lots of people bump up the bass and loudness on their preamp 3dB or more, that'll eat up a lot of reserve power in a tubed amp.
 
I know that for the RS IIBs, Infinity recommend 75 - 300 WPC for the woofers and 50 - 200 WPC for the EMITs and EMIMs when bi-amping. They stuck with the 75 - 300 WPC number in single amp configurations. They also warned (reminded) users that these units were low impedance, and to choose amps accordingly.
 
I think I see where you're coming from...and certainly agree this is true on the inside of the amp. But, after the output x-former, wouldn't it all be the same again? :dunno:
 
Would it be? If anything, using anything but the 8-ohm tap on a tube amp will affect frequency response. If the OPTs are very high quality, then yes, the differences would be nil.
 
mbeigh said:
think, to biamp, I would have to get inside the speakers and rewire the crossovers.
Click to expand...


Yes, but biamping would probably be your best bet since the RSIIIa's needed somewhere around 150-200 watts to drive them well and loud. Since they only have a sensitivity level of 89dB, they're only average on the efficiency levels. As we tube amp owners know by now, another 10dB to 15dB of speaker sensitivity lets our tube amps run much less hard, and much louder.

The crossover points are 600Hz and 4KHz, but I'm not sure which 'order' crossover network they use. I'd need to see a schematic and/or clear, close-up photos inside the cabinet.

However, with that said, if you weren't planning to drive the system too hard, you may be able to get away with just a pair of 40 watt + monoblocks driving them with the original 3 way setup.

. . Falcon
 
zenith2134 said:
I think it would be worth the while to rewire the crossovers to allow biamping...

200wpc SS for the woofers and 30wpc tube on top would be quite the system with your speakers.

Regarding going from SS to tube exclusively.... It can be amazing how powerful a small tube amp can sound. I think its due to the softer clipping characteristics of a tube versus a transistor. That, and the speaker will be running off of more voltage than current as compared to a solid state amp.

YMMV, though.
Click to expand...

?:scratch2:

I would think long and hard about trying to run those Infinitys with tubes, then if I decided I absolutely had to, I'd start looking at damping factors first.
 
Oh, you got me all wrong, Jay. I was simply making a generalization about tubes versus SS, and totally agree those speakers need lots of power to do their thing.

Damping factor of '10' won't cut it :D
 
mbeigh said:
Hi,

I am considering moving from solid state to tube monoblocks. oo I am currently throwing 200w of ss power at mu Infinity RSIIIa speakers. What kind of tube wattage would I need to adequately power the Infinity's?
Any suggestions as to what I should look for? Would also probably look for a tube preamp. As always, looking for the most for the
Click to expand...

Please post sensitivity of your speakers (in dB/W/m), their resistance (4/8 ohms), and size of your room, I will tell how much W you need. For what I have I am need only about 1W (one, not one hundred) per channel (in 20 sq.m. room) either from tube either from SS amp.
 
In my experience, 30 tube watts is fine . . . as long as I use a powered subwoofer. I've even used 15 watt with 7189 outputs. The natural rolloff in any but the largest speaker boxes is crossover enough.
Most vintage equipment has a center channel tap or second set of speaker leads that can go out to a single or pair of powered subs. Then the output to the subs also varies with the volume control. So, I guess that conforms to what Zenith and drewbolce have said earlier except instead of biamping, I run full range to the speakers and use a solid state powered sub to take care of the low lows.
Let's put it this way, I haven't had a problem yet but I do use speakers with a minimum efficiency of 82 - 84db@1Watt@1 meter. Speakers tried: Spendor BC-1, SP1/2, S20, S1, SP1/5, and also Ohm Walsh 4s, some infinitys (don't remember which) and some JBLs (don't remember which either). The Spendor BBC tradition speakers tend not to be very efficient and run 8-11 ohms and even at that there hasn't been a problem.
I did compare my Fisher 500-C (35/channel with 7591s) to a Levinson 200Watt/channel amp with heat sinks to make any gearhead proud and the Fisher did just as well in a full range application. I would say the Fisher bested the Levinson, and the owner of the Levinson would say the Levinson at least held off the Fisher. You know how it is when you own something.
audiodon657
 
zenith2134 said:
Oh, you got me all wrong, Jay. I was simply making a generalization about tubes versus SS, and totally agree those speakers need lots of power to do their thing.

Damping factor of '10' won't cut it :D
Click to expand...

I hear ya, I'd bet those big SS amps could be upwards of 100, where you'd be lucky to get 10 with tubes. I wouldn't want to steer anyone away from tubes, there's just a lot more to consider than watts here.:yes: This could be one of those situations where the best place for the money is speakers.:scratch2:
 
Maybe I should keep the adcom GFA-555 amp and mate it to a nice tube preamp. Would this warm up the sound? I am currently using a PS Audio 4.6preamp.
 
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