I would say most tube amps aren't practical for Maggie's in most cases. I would definitely suggest looking into a tube preamp , it will allow you to experience and experiment with tubes and still have plenty of power for your speakers.
Question about wpc on tube amps
I have been kind of looking at tube amps based on what people seem to think about them.
Here is my question- whenever I look at the wpc, they are remarkably low vs. a solid state amp for the money.
It leaves me scratching my head. Then, somewhere I read that you can't compare a tube amp with a solid state amp . Something along the lines of "10 watts of tube power equals 100 watts in a SS amp".
What? Is this real? Seems unlikely to me.
Are the wildly low power ratings on the tube amps I am looking at simply due to the fact I am looking at $1,000 amps vs the bajillion dollar amps you guys buy?
Would I be better off spending the money on a tube preamp for the "tube" sound I always hear about.
I am running Magnepan . 7's with a Bryston amp. Since the . 7's are power hogs are tubes even a realistic thing for me in my lowish budget?
Thanks!
34 responses Add your response
Depending on the specifics and the configuration of a given amp, tube amps tend to breakup much more gracefully so don't need as much headroom to avoid hard clipping. I'm driving average efficiency speakers in a large well damped room with about 12 watts in triode, and can play louder than I want to listen. My amps are a pair of Dynaco 70s with the VTA mods run as monoblocks. You can get a single stereo version for ~ $1300 (kits are less), but I have no idea how well they'd push your Maggies. |
Thanks guys, you all confirmed what I was thinking. I just wasn't certain since I haven't any experience with tube gear. I will move forward with a tube preamp! I need a better one anyway. Besides, I never had any beef with my Bryston. It drives the Magnepans quite well. In fact, I bought it on a suggestion from a member on this forum. Thanks again! |
I am a big tube fan and run very low-powered tube amps with some fairlyefficient speakers. I have also heard various maggies run with tube amps, some not so powerful, and the sound can be quite amazingly good. But, there were limitations on how loud the maggies could play with lower powered tube amps. As for high-powered tube amps, I tend not to like the sound of such amps as much as I like lower powered amps; the high-powered amps tend to have a brittle sound. Where higher power is a must, I prefer solid state, particularly where there are budget constraints. I don't think it would be easy to find ANY kind of tube amp at $1,000 that would have enough power and would sound good. A used tube amp would be a possibility, but, used gear is something someone with experience with tube gear can buy and service, whereas someone without experience might not be as suited to owning such gear. |
I’m a big fan of tube amps, but when it comes to sheer power, watts are watts. There’s no magical "tube watts" that’s going to make 50 Watts act like 100 (etc). And as for tubes’ famed "soft clipping" -- a push/pull tube amp with feedback (typical) can clip hard too, if you push it too far. The reason you get a mythology of "tube watts" has many facets. For one, tube amps typically have higher gain than their solid state counterparts. Sometimes much higher. Especially "per watt". So on the same volume setting (on your preamp dial), a lower powered tube amp may sound much louder. But its peak loudness will still be limited by its power rating. The gain tends to be higher thanks to high gain input tubes like 12AX7, 12AT7, 6NS7, and the lower amounts of global feedback used in tube circuits -- more feedback reduces gain and many Solid State amps use LOTS of it because it improves the spec sheet (arguably at the expense of sound quality). Another reason for the mythology -- tube amps typically sound great to the very last watt! Solid State gear can be all over the map. Some sound bad at low volumes, others sound bad when you start to push ’em, Some sound bad at any volume 🤣 Maggies are a classic match with Rogue tube amps. You a get lot of tube power for the money, all built in the USA, and with fantastic customer service. They’re not as sweet sounding as other tube amps, but their dynamics and bass are a thing of beauty. M180s (180 Watts /ch) or Apollos (250 Watts /ch) would be perfect, but even a Stereo 100, Cronus Magnum, or Atlas Magnum would be great too (each 100 Watts /ch). When you get enough tube power -- real tube power -- it’s amazing :) |
A statement such as 10 watts of tube amp power equals 100 watts of SS power is from a marketing textbook and not a physics or engineering text. Power is consumed by a load -- a light bulb, toaster, motor, space heater... or a transducer (loudspeaker). The amplifier is simply an interface between the speaker and the wall outlet that converts the wall outlet to a lower voltage and causes the fixed 60 hz wall voltage to mimic the signal voltage and varying frequency. The only power an amplifier consumes is the wasted heat through the tubes or transistors. As far as the speaker is concerned, it matters not whether it's one or the other. If either type of amplifier can maintain voltage throughout the speaker's load impedance then both will operate identically as far as energy conversion is concerned. |
+1 Tube amps also seem to sound a bit more powerful for their wattage, but the most obvious strength is when pushed. You do not want to plan for pushing your amp. High powered amps cost lots of money, worth it if you can afford them. Just my amp have over $1200 in tubes. Definitely start with the best tube preamp you can get. That is how I started. I would look for a used, the best you can stretch to get. It can be the center of your system for a long time. |
Ah, I neglected to the heed budget of $1,000, sorry 😅 I agree with others, that’s not a budget where I’d typically recommend a tube amp, especially at the power levels needed for Magnepans. However, if it’s not a hard limit, with some patience you can get under $1500 for a used Rogue Stereo 90 (the older version of their Stereo 100). This is a GREAT amp for the money and it can exceed 100 Watts. Avoid the temptation of cheap Chinese tube amps. Absolutely not recommended. |
@gs5556 Wrote:
I agree! @timintexas Wrote:
Yes! Mike
|
While I agree that 10 watts of tube amp does not equal 100 watts of SS power, I'm not sure about the idea that tube amps won't work with Magnepan speakers though the small budget would be a problem unless something used can be found. Here is another Audiogon thread on the topic: https://forum.audiogon.com/discussions/tube-amp-for-magnepan?highlight=magnepan%2Btube%2Bamp I had always heard that it wasn't necessarily the amount of the current, but the quality of the current that makes the Magnepans sing.
|
@ghdprentice Just bought new tubes for my VAC Renaissance 70/70 Signature-$1720 for 8 Gold Lion 300B’s! OP: I’ve used this amp exclusively with speakers with self power bass internally. (Genesis V, Goldenear Triton 1.r and soon to arrive Legacy Audio Focus XD’s) All these speakers are 90+ dBa 1 watt/1 meter so I get explosive dynamics with 65 watts per channel. The Legacys are rated at 95.6 efficiency. |
If anything, a claim/rating of 10 wpc by a tube amp builder is LESS than 10 wpc of a typical solid state smp. Most tube amp “ratings” are at extremely high distortion levels while solid state amps are typically rated well short of clipping. But, I suspect the notion of tube amp watts being “more” than solid state watts has to do with tube amps sounding more full, saturated, and weighty at lower volume than typical solid state amps. The can play at lower volume and still satisfy. |
ditto @mulveling his advise is sold. I am not sure if you can find one but search for the old Lafayette KT-550 tube amp around 50wpc stereo. Probably would be the only tube amp I would attempt in your price range. I tubes 7025A tube (if I remember correctly) can be easily converted to El based tubes with a move of a few wires on the tube socket. Happy Listening.
|
@timintexas as you've already concluded, in your case - I'd second the notion of buying a really good tube preamplifier and pairing it up with your Bryston instead. |
First of all: 1. Observe systems synergy! Speakers that are high current / high excursion, demand specific amplification, and the experience will not be a good one unless the amp is specifically designed for that task. 2. Tube amplifiers operate with output tansformers. The taps of the output transformer define which speakers they are designed to drive. Hence, it is vital to get the right match. (Eg right size shoe for the foot - if not, you can't run, or worse, it will even bleed..) 3. Watts define only what is the RATED peak output of an amplifier.Also, the ratings apply for power into a RESISTOR. Solid state amps can put out LESS than the rated powr into an actual speaker, while tube amps put out MORE into an actual speaker than into a dummy resistor used for rating. A push pull tube amp with lots of feedback only slightly more than rated, but a zero feedback SET can put out even up to x10 the rated power into a real loudspeaker. However, the wattage only implies PEAK SPL capacity. In every amp we are going to observe problems before that peak spl is reached. Solid state amps show signs of strain already below 1% of their peak wattage output. Single ended triode amps show strain around 50% of their rated peak output, provided their power supply is adequately designed (many commercial models are not - not the fault of tube technology, but result of cutting corners to make sales). Also, we cannot generalize tubes / solids... Among solid state amps class A low feedback designs can handle much higher output without distortion, so for example, an 50W class A solid state amp can put out about 0.5 clean watt. (Clean enough for my personal demands.) For a class B solid s amp, the clean power is much lower. (I found it's non-existent, but others will find a few adequate watts there...) For tube amps, the clarity of watts is defined by the power supply, which you will not find out based on the watts number. For example, a tube amp rated for 1W output but with a power supply that is designed to supply a 300W demand will be able to deliver a cleaner output than a 200W class A solid sate amp. Of course, the 200W amp can go much louder, but the perceived quality at the 20-200W range will be much inferior to the milliwatt to few watts range. In short, when going for watts alone, then usually: 1 SET watt = 10-100 solid state watts (provided the SET has ample power supply - if not, it might not even be 1 watt..._) 2 Push-pull tube watt = 5-20 solid state watts Also, provided the tube amps are matched with speakers that they were designed to drive. (Eg have the appropriate taps! ) We often hear complaints that tube amps cant drive a high current speaker, because its impedance drops to 1.7R or something similar low value. The issue is not with the tube technology, but those "conoisseurs" who are so clueless they want to drive 1.7R speakers off 4R and 8R taps.... Talking about trying to squeeze in a watermelon into an orange juicer! Such loads need a tube amp that has a 2R or even better, a 1R tap... that's another story, but something that has to be clear to everyone who is new to tube amps and wants to find the right tube amp match. BEFORE YOU LOOK AT WATTS, MAKE SURE THE AMP HAS THE RIGHT TAPS TO DRIVE YOUR SPEAKERS. And not the brochure specified bogus number. The actual measured real impedance, which is specified by the dip.Sadly, a lot of manufacturers nowadays lie shamelessly, calling even 2-3R speakers as 8R... When a loudspeaker is advertised as: "This is an 8R loudspeaker that dips to 2R at 120Hz" , then that means that it's a 2R loudspeaker, not 8R! You need a 2R tap to drive it, 8R tap will be entirely completely insufficient and utterly useless. Not because it's an inadequate tube amp by itself, but because the delinquent is choosing the wrong shoe for the foot, so to speak. As in life, not all shoe fits all feet. Just because it does not fit, does not mean it's poorly made shoes, and would be terrible on the feet of those whom they were made for.... systems synergy is all. ;
|
Greet overall suggestions here… But since you’d already mentioned you’re going to get a preamp to run with that excellent Bryston, definitely look into a decent used Rogue audio pre at that money. But there are other brands that do really well at lower cost to offer well designed and great sounding tube pre’s. Van Alstine and Quicksilver come to mind. It would just be a matter of matching with your Bryston. |
@timintexas : I only speak from my own experience, so please take this with the appropriate grain of salt… Rated wpc doesn’t tell you much of an amplifier’s story. Someone else wrote that this one specification only describes the amplifier’s maximum output within the parameters of how the manufacturer tested it. This number can be “optimistic”. The power that an individual uses is typically (should be) much less than the maximum rated power of any amp. What you have to determine is how much power you actually “need” to play the music you like at the volume level you listen at. I’ve found that it is absolutely true that some amps with lower rated power sound more powerful than other amps with higher rated power. There are many factors that go into this. But it is not because “tube watts” are more than “solid state watts”. A couple of the big factors have also already been stated: 1) The fact that SS starts sounding strained earlier than a similarly powered tube amp, and 2) If the input sensitivity is lower on one of two amps being compared, the amp with the lower sensitivity will play louder at a lower position on the volume knob, which gives the perception that it is more powerful, when it is simply ramping up its power sooner… Another point; I have found that a tube amp has more of a “tube” influence on the sound of a system than a tube preamp - and I have nothing to say against trying a nice tube preamp.. I’ve owned many, but tube amplifiers are what really made me fall in love with the sound. Also: I have owned many different models of Magnepans over the past ~36 years, and I’ve used dozens of amplifiers of all (almost all) types, with a wide range of rated wpc, and I myself personally have usually preferred the sound of tube amps. They are definitely capable of driving Maggies very well “for Me” in “My systems”! You should be able to find a used tube amp for close to $1000… maybe more like $1300-$1500 as a lower cost starting point (I picked up a Music Reference RM-10 for about $1300 several years ago and it sounds amazing with my 3.7s). All that said, Bryston makes very good amps too, so there’s nothing wrong with trying a tube preamp with it. I think some experimentation is in order. Let us know how you make out. |
@timintexasWPC is just an rough/partial measurement of capability to drive speakers by an amplifier. There are multiple factor in really world how amplifier behave when driving a particular speaker. e.g. Tube Amplifier most likely using output transformers which is an energy storage/converter, which helps boosting transitional burst energy when driving a speaker with linear impedances or speakers with capacitive load characteristics such as electrostatic speakers. Also tube amplifier tends to handle overload nicely. That is why people observed that tube amplifier seems be able to drive same speaker louder vs a solid state amp with same “WPC" ratings. However, tube amplifier would suffer greatly when used to drive low impedance speaker or speakers with non-linear frequency-impedance responses, such as full range ribbon speakers. |
One would not want to play an amp rated at 2 watts at that level for any sustained period. So, let's say one operated it at only 1 watt. With my speakers that would be an output of 99 db under the rating conditions. Those conditions are in free air (i.e., no nearby boundaries) at one meter. But, in my room the room contains the sound and increases the loudness as compared to free air. Also, I run stereo, so there are two speakers playing. I do sit a ways back from the speaker, which reduces volume at my ears, but all in all, I could probably get close to 99 db from 1 watt per channel. That is pretty loud. I run these speakers with an amp that puts out about 5.5 wpc, so I have some headroom. I don't play my system at high volume levels so I get by with such modest available power. |
Thank you for Great comments, this is the most I have learned when it came to tube amps. I'm trying to find a way to biamp using solid state for bass and tubes for the mid/tweeter. My existing solid state mono block amp has plenty of power for my main speakers, but I'm pursuing a fantasy that biamping with a tube amp would generate benefits. I'm looking at the recently designed Ss/tube combo amplifiers from McIntosh as a way to better address versus doing four separate monos to do biamping, which may not be that worthwhile to do. amazing comments, and very very technical, clearly a lot to think about. |
