Matching speakers with tube amps

I bought my first tube amplifier last year. After some months of only headphones listening, I got myself some speakers, the Revolution DC4's from Tannoy. This is a really good sounding duo.

However, in the manual to the speakers, it says recommended amplifier power is 20 - 100 Watts. It even says your amp can get damaged if it's any weaker. And my Luxman SQ-N100 amp can deliver only 12 Watts. My dealer told me this is nothing to worry about, and said something about tube amps being different from solid state amps, they need less power I think it was...

I am kind of curious about Tannoy Revolution Signature DC6 speakers. Specs as below. Will my amplifier be able to drive these speakers? I have a small room and play music at pretty modest levels most of the time.

In general, what is important to look out for when looking for new standmount speakers for a tiny tube amp like mine? Sensitivity, impedance, whatever?

Man, it's not easy to understand all this stuff!

TANNOY REVOLUTION SIGNATURE DC6
Recommended amplifier power 20 - 150 Watts RMS
Continuous power handling 75 Watts RMS
Peak power handling 300 Watts
Sensitivity 88dB (2.83V @ 1m)
Nominal impedance 8 Ohms
Frequency response 46Hz - 35kHz (-6dB)

 

A tube amp will have soft clipping characteristics and therefore aren't subject to destruction as transistor amps would be under harsh conditions. You will definitely hear distorted sound long before you experience amplifier damage. The real concern is to be careful not to damage/destroy the tweeters if you drive the amp into clipping. 88db sensitivity isn't really as high an efficiency as normally sought for matching to a 12 watt amp. Try it, if it plays loud enough for your needs, and sounds good, yer home free.

 

Thanks. Yes, I have tried to find speakers with high effiency, but they are rare it seems. Most I have seen are around 88-89 dB. Luxman actually has a speaker with 90 dB / 6 Ohm eff that was designed especially for this amp, but I can't buy it as I am not too fond of the design and color!

 

I'm a fan of horns and enjoy Klipsch loudspeakers. I certainly can understand that they aren't for everybody. I'm addicted to the efficiency factor, and enjoy rustic aesthetics in most products.

 

Therein lies the rub with most tube gear, even moreso with single-ended triodes. Even if you get highly efficient speakers, you may not like the sound. Personally I'd never go any lower than my current 35 wpc push/pull EL34 design. With 87 dB / 6 ohm monitors (and a self-powered subwoofer) it just gets loud enough, but barely, for when I want to listen to loud stuff.

Your dealer is feeding you bull concerning power. Power is power. While you will get a different distortion characteristic overdriving a tube vs. solid state amp, there is no difference between "tube watts" and "solid state watts".

 

When it comes to speakers, the uglier they are the better they sound

 

Nonhuman, I checked their website, and they do seem to have what I'm looking for. I will definitely consider Klipsch. Thanks for the advice!

 

Yikes, I hope you're wrong!

Like I said I don't play too loud in this room. I do that in the living room where I have a 110 wpc solid state amp.

 

Its true!

Eg:

 

I run SETs using the WE300B and they put out a maximum of 8 watts. My speakers - Coincident Super Eclipse Series 2 - are in no way ugly.

You have quite a few choices for efficient speakers. Salvatore posts a good list of SET friendly manufacturers:

AcuHorn rosso superiore175
Affirm (formerly Maxxhorn) Lumination & Immersion
Aspara Acoustics HL1 Horn Speaker
Audio Note ANE SEC Signature
Avantgarde Duo and Trio
BD-Design Oris and Orphean Models
Bottlehead Straight 8s (Discontinued)
Brentworth Sound Lab
Coincident (Total) Victory II (and most of their other models)
Decware (Various Models)
(DIY Hi-Fi Supply) Crescendo Ribbon Horn Speaker System
Fab Audio Model 1 (Toronto, Canada)
FAL Supreme-C90 EXW or EXII
Horning Hybrids (Various models)
Klipschorn and La Scala
Living Voice OBX-R2 (UK)
Prometheus II
RL Acoustique Lamhorn 1.8 (Montreal, Canada)
Sonist Concerto 2
Supravox Open Baffle
Teresonic (Various Models)
Tonian Acoustics (Various Models)
WLM (Various Models)
Zingali Horns
Zu Definition

http://www.high-endaudio.com/RECENT.html#July

 

Hey, that's quite a list, thanks. I checked Ken Kessler's review in Hifi News & Record Reviews, and he said this amp was "a lot of fun with the equally adorable Tannoy Autograph Mini". As far as I can see, they are 88 db / 8 ohm. But I guess they will sound at their best with some of the speakers in your list, and I will do some research on those speakers.

 

As you might expect, Salvatore is looking at the higher end of the market, so you won't find all the bargain high-effeciency models that may be around.

 

These Klipsch are 99db sensitivity:

http://cgi.ebay.com/Klipsch-Forte-I...50?pt=Speakers_Subwoofers&hash=item3cb04c8d2a

 

Local pickup only - Indiana. Don't think Sweden is considered local.

 

Yep, I checked ebay Sweden first for an example auction however there weren't any current listings. Hopefully there are a few pairs in Sweden somewhere.

 

I disagree. Tube watts put much more music into the room than SS watts. I've heard 30 or 40 watt tube amps that filled a room with more music than a SS amp with considerably greater power. For the OP, the main thing is whether his 12w tube amp is powerful enough to provide a sufficient SPL of musical enjoyment. If not, he may have to step up, as you suggested, to about 35 watts of PP power.

 

It's interesting how many people perpetuate abstract and creative beliefs about something as scientifically exact as a measurement called "Watts".

Watts can be defined as current (amps) times voltage (volts). No mystery at all. The only mystery is how conservatively an amplifier manufacturer may choose to rate their particular device.

Watts is basically a heat rating. Tube power amplifiers consume more watts of power to output a given amount of audio output (watts) than an identically rated solid state amplifier. That's why tube amps are considered inefficient, and that's why they get so much hotter than solid state amps.

In audiophile terms the heat dissipated across the voicecoil of a speaker driven by a tube amplifier per 1 watt output, will be identical to that driven by a solid state amplifier per 1 watt. This is the same condition to be found for any electrical device such as a lightbulb. 1 Watt is 1 Watt. However many people are convinced that a 20 Watt Halogen bulb dissipates more heat than a 20 Watt standard incandescent bulb. Not so. Different type bulbs may give off more light measured in lumens per watt of power consumption (heat) but the light is measured in lumens not watts. A watt is a watt is a watt.

 

My current SET has 24 Watts and they drive the Wilson Sophia Mk 2 easily. Sensitivity is 89 if I recall correctly top of my head.

Next month my CJ LP140Ms will arrive, more power than I will ever need.

With 12 Watt you might want to look for a speaker with sensitivity in the 90s.

 

Is tons of current better?

The Voltage and Power Paradigms

 

I don't know a lot about these speakers but most JM Reynaud speakers have efficiency ratings above 90 and, from what I've read, are well respected.

 

That is the definition of power in a direct current application - Joule's Law. A watt is the SI unit of power - 1 watt is 1 amp times 1 volt. Other measurements of power could be used.

Not strictly correct. The electrical power is being converted into other forms of energy - mechanical energy that makes the voice coil move in the magnetic field, and heat energy, which is wasted.

 

You may find speakers of 88-91dB efficiency that play just fine with 9-12W amps. If you want to listen to heavy metal at high voumes, maybe they wouldn't be the best match!

Myself, I use 9W SETs to drive ~90dB monitors (2002 'vintage' Triangle Tituses) which are well known to 'fly with flea-powered amps' as Stereophile writer Sam Tellig puts it. I listen in the relative nearfield (~7' from speakers, which are on stands out into the room). I use a decent sub to fill in bass <60Hz.

These can get very loud, and certainly louder than I like to listen normally.

I would say after a quick look at the Luxman and Tannoy gear, that this pairing would likely be among the best sounding gear on the planet. If it plays as loud as you desire, as someone said above, simply enjoy!

As far as damage, I think it IS true that tube amps tend to 'just not get any louder' above a certain point. Gross overdriving could, I guess, cause some problems; SS amps (of yore) would (IIUC) generate high-frequency nasties when overdriven. Not a good thing.

I think modern amps of both persuasions are better behaved, but I stil think tubes would be 'gentler' in this regard. If it plays as loud as you like, and there aren't fairly obvious distortions/crunching sounds being made (that are not on the recording!) you should have nothing to worry about.

BTW, reading 6Moons review of the Luxman, it sounds like a great amp, and has a wonderful headphone sound as well. It even has a phono input. Excellent choice!

 

rereading your OP, seems like this should work great. I certainly look at Sensitivity and impedance as a first step in 'evaluations' for low powered amps. The Tituses have about a 4 ohm minimum, and are pretty flat across the spectrum. Double hump in the bass due to the ported loading, and a 'hill' up to about 8 ohms or so around the 4kHz region. Even if the impedance curve is more 'lumpy' or peaky than this, if it sounds good, it is good!

Tube amps (with little or no feedback) typically 'follow' the impedance curve in their output to some extent due to their own 'highish' source impedance. Quick explanation: if am amp has a 2 ohm source impedance (not atypical for low powered tube amps) and the speaker is 4 ohms, the 'damping factor' is only 2. This might mean the bass could sound a little 'flabby' (but as my monitors only go down to ~50Hz, not a problem). Most SS amps have a very low source impedance, maybe around 0.1 ohms. So with a 4 ohm speaker, the damping factor is 40. I have seen factors of 1000 claimed!

So the frequency response would be flatter with a speaker whose impedance is all over the place. But of course, that is NOT the only criteria for good sound! and these measurements are not always available ...

Making it even MORE confusing is the fact that 'output impedance' is often listed, but is actually just the speaker impedance the amp is capable of driving (like 4 or 8 ohms).

I couldn't find an actual curve for the Tannoys, but a reference to "Under our in-room far-field measurement regime, the DC6 comfortably met its 88dB sensitivity rating and did so alongside a relatively straightforward nominal impedance of 8 ohms, with an easy-to-drive minimum at around 200Hz."

Sounds like you have nothing to worry about ...

 

Thanks Rick, those were useful posts. I will audition the Tannoys later this month. The dealer said he had tube amps similiar to mine so we'll hook 'em up to one of those amps. I don't play loud in that room, so volume is not an issue, really.

Yes, the Luxman is a great amplifier, I am very happy with it. I also have the matching CD player. It's a nice duo.

 

Watts are only a measurement of current into a load. High current is what can drive a low impedance load. Watts are not all watts with Solid state either. I have an old antique Harman Kardon 20 Watt per channel receiver with transistors that will embarrass most Pioneer, sony, Kenwood, etc type stuff rated at 40-45-50-60 watts.