Why is a 10 watt SET (single-ended triode) amp not bad?

Why is a 10 watt SET not bad?

Hello,

I am becoming more interested in tube/valve audio technology lately. As I understand it, SET audio technology produces "natural" even order harmonics during the amplification process which apparently makes music sound more "musical", "warm" and "natural".

The question I have is can one really enjoy the sound of an amplifier that only produces 10 watts RMS through a channel? Can speakers run on that? Why is it that a 100 watt RMS solid state system not sound as good as a 10 watt RMS tube amp? Is there more to this game than just watts? Should I be looking at something that has more amps as opposed to more voltage when calculating the wattage? Do any of these questions make sense?

Thank you in advance for your enlightning words.

 

It depends on what you mean by "enjoy."

10 watts is enough to drive many, many speakers to "reasonable" listening levels. If, however, you like to listen to large-scale orchestral works or head-banging rock on inefficient speakers you will not enjoy the performance.

OTOH, 10 watts mated with ultra efficient speakers can easily blow you out of the room, but when played at reasonable levels produces music that is very different--and to many people more seductive and involving--from that produced by high-power amps and inefficient speakers.

I have played around with very low power SETs (on the order of 1-2 watts per channel) and find much of what they do captivating. For my preferred speaker choices, however, they were not a perfect match.

John K.

 

In the words of someone else, "it doesn't matter if you have 1,000 watts if the first watt sounds like crap". It is VERY important to insure that first watt sounds great cause they're not gonna sound any better. SET amps have the advantage in sonics by eliminating phase inversion and maintaining the signal throughout the circuit for a purer sound.

I agree with what John says about SET amps and speaker matching but that's true with any amp-speaker combination. SET amps are more concerned with a friendly impedance since their output impedance is typically much higher than push-pull.

Also, not all SET amps are "flea-powered" 1 and 2 watts. There are some extraordinary sounding SET amps producing 100 watts per channel that can drive a lot of average sensitive speakers to bone crushing levels.

And not all SET amps are created equal. Some have better circuits, some have better transformers (extremely critical to SET amps), some have better coupling capacitors and some have no coupling capacitors. Some are slow, soft, mushy, colored and rolled off and some are more neutral and fast in their presentation.

I would suggest looking for the speaker-amp combination that satisfies YOUR tastes and desires. Just keep in mind that all SET amps sound different and have different power levels just as all push-pull amps sound different and have different power levels. And no amp will fit every speaker and no speaker will fit every amp.

Just my 2 yen......

 

Many Variables

Many might not agree but, I do think you pick the amplification to drive the speaker system and not the other way around. That's just the start of it. You could have the identical speaker system loaded into different spaces playing different music at widely differing levels in that case there could be multiple choices as far as amplification goes.

While a couple of watts can drive an efficient speaker to high SPLs the sound (dynamic headroom) might not be quite what you want. I have driven my Khorns with everything from low output SETs very to high powered SS amps and they all have their respective strengths and weaknesses.

In my particular situation running about 10 meters (33 ft) of speaker cable per side I find that a relatively low powered 60wpc SS class 'A' type amp combined with a tube SE pre-amp fits the bill. I'm sure that a high output tube amp would work also but I'm happy with what I have right now.

The only way you are really going to find out what is suitable is to actually try different combos out in your own system.

 

Gamma, you can learn a lot about "flea-powered" SETS here at Decware.com. I have the basic Zen and like it quite a bit. It constantly surprises me that it only outputs a couple of watts...

http://www.decware.com

Ray

 

Jim & Steve,
Thanks for the great explanations.

 

The Zen is quite amazing - esp for the money. One of these little amps (1.8 watts) drives my pair of Reference 3As in a small room and sounds fab with Jazz and even classical.

It is not necessary to use a pre with it, but I find that the right pre does compliment the Zen.

In short, though it's a good place to start without investing too much money. Retubing and rolling is inexpensive - no need to bias...

Also interesting - and certainly worth a look are the Bottlehead amps - both DIY and assembled available.

Regards,

~Michael~

 

Steve, when you say "double-ended" do you mean "push-pull"? Also, are you saying that "horn" speakers are really an ideal match for tube amplification for the fact that they are more efficient?

Mr. Ricketts, does "impedance" have anything to do with speaker "efficiency"? Do SET amplifiers need a nominal 8ohm load or would a 2ohm load be better? What types of transformers should I look for?

I thank each and every one of you deeply. Your explanations and viewpoints will give me a great basis to go start experimenting. However, if I had the money I think I would just go straight for a pair of the top-of-the-line Wavac HE-833 mono amps. But hey, I don't make that much money yet.

Again thank you all for your knowledge and input. This board is truly a treasure.

 

GammaSpace,

FWIW, you don't necessarily have to spend a lot of money to get quality sound in each and every instance.

I recently went to a well-known local Cary dealer / guru and advised him that I was considering a pair of CAD-300SE Signature amps ($5K). He said not to waste my money and purchase a ASL TULIP 2A3 instead ($1K).

He added that the ASL "smoked" the Cary and after all these years of selling Cary (10 years) he was questioning how the company justifies a $5K pricetag...

Sometimes we (collectively speaking for audiophiles) want the "label" on the amp for the sheer prestige of it - when in reality a set of tricked out Bottlehead amps may well have a superior sonic signature.

Just a thought from someone who used to go "label" shopping....


Regards,

~Michael~

 

Generally speaking, SET amplifiers have a higher output impedance than push-pull so a bit more care must be taken when choosing the matching speakers. Typically, the higher the speaker's impedance the better. As long as you choose speakers with 4ohm or higher, you should be fine. The more powerful WAVAC models can deal with lower impedance speakers better than say 10w 300b amplifiers.

WAVAC use customized versions of Tango transformers that are noted for being one of, if not the best sounding trannies with ultra wide bandwidth. Nobu Shishido mentioned in an interview that to do transformer coupled SET amplifiers correctly, one must use very high quality transformers as it is so critical to the final sound.

As a note in passing, the HE-833 100w/ch monos are extraordinary albeit a bit costly. The new MD-805m monos with 55w/ch give a lot of that same purity at ~ a third of the price. Affordable ultra-high end, relatively speaking of course.

Hope that helps - feel free to contact me directly.