What speakers suitable for 15 w El84 amp ?

crossroadazn · « **on:** 9 Sep 2006, 12:59 am »

Hi all ! I have a 15w EL84 amp but wonder how sensitive (db) speakers should I purchase ? Thanks.

Brad · « **Reply #1 on:** 9 Sep 2006, 01:24 am »

Everyone is going to tell you "it depends"

How big is your room?
What types of music do you listen to?
How loud do you like to listen?

I would say 90db or higher, with a gentle impedance curve (the impedance may be more important in matching correctly than the exact sensitivity) and probably a simpler xover - if you don't go with a single driver model.

I have used my Scott 222c with speakers ranging from 89db to 96db. It gets pretty darn loud with the 96db Omega A8's. It also drove the AE Evo 1's @ 89db pretty well in a smaller (12x15) room.

JLM · « **Reply #2 on:** 9 Sep 2006, 01:35 am »

15 watts = 11 dB of gain

Add 3 dB for two channels

The rest is my rules of thumb, YMMV:

Subtract 3 dB for every 2,000 cu ft of room size

Typical live peaks: jazz 100 dB, classical 105 dB, rock 110 dB

Typical live averages: jazz 80 dB, classical 75 dB, rock 100 dB

Aim to reach the peak levels you listen to in your room. This will provide sufficient power to provide commanding grip of the speaker so it can reach its full potential.

G.Michael · « **Reply #3 on:** 9 Sep 2006, 03:15 am »

Kudos on having an EL84 amp. I have one, a home-built based on an old Dyna design. In my experience, EL84 tubes typically have a sweet, musical sound. (I'm using pairs of Amperex.)

I'm driving a pair of small 2-way speakers, Michael Green Studio 5's, 89 dB I think, with lots of bass response, and the amp pretty much coasts along.

The speaker sensitivity rating probably isn't as important as the simplicity of the speaker's impedance, and just how big the woofers are. (Case in point: a friend of mine has 3-way speakers with a 94 dB sensitivity rating and 10" woofers, yet a small amplifier just can't drive them adequately. It seems as though the woofers just don't get moving. But the speakers sound very good with a bigger amp.)

My guess is that you'll be fine with lots of 2-way speakers, but of course not ones that obviously require big amps.

I'm assuming that you're not trying to "rock the house" with this amp--not really the nature of an EL84 amp.

As with most amps, the power delivery depends a lot depends on how hefty and fast the amp's power supply actually is. This, too, is a factor in what speakers the amp can drive.

ZLS · « **Reply #4 on:** 9 Sep 2006, 04:00 am »

Hello,

The Omega line of single driver speakers are magical with EL84 tubes. In fact, there is a thread on the Omega Circle dealing with just that. I have a Heath 151 intergrated amp running in 7 watts pure triode. I have the Omega floorstanding B200 speakers. The combination reaches down and grabs my heart or my balls depending on the music I am listening to.

Try it, you'll like it

Scotty · « **Reply #5 on:** 9 Sep 2006, 07:43 am »

Depending on your budget,the Reimer Speakers McCullough GS might be a good choice. It has a 93 dB sensitivity rating and a stable 4ohm load. It has a phase correct quasi-second order series Xover network. The frequency response is +/-3db 36 to 26 khz.

You might check out the website for more info, See link http://www.reimerspeakers.com/
Scotty

JLM · « **Reply #6 on:** 9 Sep 2006, 01:26 pm »

Many (perhaps a majority) of tube amps have poor damping factors, meaning that bass gets bloated (exagerated, not tight). Using a powered sub would solve that as damping only affects the tube power amp section. So I'd stay with smaller one or two way speaker designs.

I'm a huge fan of single driver designs. They provide coherence, imaging, and by definition active (one amp per driver) advantages while keeping everything simplier and focusing on the all important mid-range and beyond (typically at least 80 - 10,000 Hz). The sound doesn't change (from one driver, usually driver type too) as you move along the frequency spectrum. And importantly for small amp owners, there's no power robbing crossover. Some two-way designs act a lot like single driver designs in that the main driver covers all but the top octave with only a capacitor in place to protect/roll off the tweeter. The DeCapo is such a speaker (see owner's circle below) and it's efficient.

Single driver designs can be as simple as a pre-finished shelf with a $38 Fostex FE127E mounted in open baffle style (amazing sound for the price) or $2000 AER drivers mounted in huge rear loaded horn cabinets. The Horn Shoppe and Omega (see circles below) offer single driver designs that would work too.

PaulFolbrecht · « **Reply #7 on:** 9 Sep 2006, 01:57 pm »

Quote from: JLM on 9 Sep 2006, 01:26 pm

Many (perhaps a majority) of tube amps have poor damping factors, meaning that bass gets bloated (exagerated, not tight). Using a powered sub would solve that as damping only affects the tube power amp section. So I'd stay with smaller one or two way speaker designs.

Respectfully, really a gross oversimplification there. Often, a damping factor as low as *2* can be entirely adequate to make the bass as tight as it ought to be - that is, to sound the best and most realistic. The type of driver has a huge bearing here - larger than the damping factor itself. Some are largely self-damping. Then there's the fact that too much damping can entirely ruin bass as well. It all depends on the speaker/amp interaction.

Look here:

http://homepage.mac.com/tlinespeakers/vaughn/downloads/Damping-Factor.pdf#search=%22%22damping%20factor%22%20dynaco%22

I have found, in general, tube bass to be preferable with the right speakers. This is over several different brands and types of speakers along with many different tube and solid-state amps.

The AES Six Pacs I used to own, for example, which have a very high output impedance with the negative feedback off (which is the only way to run them), produced wonderful, taut, hard bass with my Joseph Audio RM25s. The damping factor could not be more than 3.

I currently have Hyperion 938s run by 28W 845 SET monoblocks. I experimented with bi-amping the bass modules with a 240W solid-state amp but eventually took it out. Now, in this instance, actually the SS amp did do a bit better on the bass but the slight loss in the seamlessness of the sound wasn't worth it. But the positive differences were quite subtle anyway.

I do have to say I have NOT run any tube amp on speakers with TRUE full-range bass, that is down to 20Hz or below. There is a LOT of extra energy involved in that last 10-15Hz and it may be that that's where SS really shows its stuff. Instead I tend to use a powered sub for that last octave.

But, most full-range floorstands are starting to roll off in the 35-40hz neighborhood and to my ears, IF the speakers are tube-friendly (even if the damping factor still ends up being very low, like 3-4), you can get GREAT bass out of tube amps.

I think this is one of those very common misconceptions based on - whatever. Maybe the 1st guy who tried to run his B&W 802s with a Dynaco amp from the 60s.

Paul

JLM · « **Reply #8 on:** 9 Sep 2006, 11:38 pm »

Paul,

Thanks for the Eddie Vaughn link, I respect him a lot. I know that I was "painting in wide brush strokes" and so couched my comments. Many factors play into whether or not damping is an issue for a particular amp/speaker pairing.

But, I've heard it via my single driver speakers and many folks report the same.

PaulFolbrecht · « **Reply #9 on:** 10 Sep 2006, 02:59 pm »

You did couch your comments. I am just saying there is a lot of misinformation on the subject - generalities that get repeated again and again that aren't quite so true. I've heard muddy bass from tube amps but it was a case of very bad speaker matching... definitely true that if you're using tubes you just have to think about the speakers. Of course.

I wonder if it's a coincidence that speakers that seem to work best with tubes are the ones that tend to sound the best anyway. I think wild impedance & phase swings frankly do harm ANY speaker/amp combo just about regardless of the amp in question. For the people that swear by the 300W+ transistor behemeths - probably nothing else sounds so good on your speakers because your speaker designer designed them with this in mind.

But you're talking about fullrange drivers that are the epitome of tube-friendliness. Hmm. I have Zu Druids in my 2nd system. really like them. I recently auditioned a 30W Red Wine Sig 30 against my little 2A3 SET amp... bass differences were not what really caught my attention - not enough to really influence the decision there. (The RW amp is the best non-tube amp ever I think and almost sounds like a SET in every way.) I wish I'd have taken notes now, but again there were no majar differences in tightness or fullness that lept out at me. Of course a 30W amp represents nearly inifinite power to 101dB speakers with no crossover and the DF there is also hundreds of times greater than the SET amp.

Paul

boead · « **Reply #10 on:** 10 Sep 2006, 05:37 pm »

Thousands of dollars on speakers is ludicrous! Sheesh, and people get all bent out of shape spending a few hundred dollars on wire yet don’t bat an eye on a pair of speakers for $5000 or $10000! It’s absurd since the actually components for any speaker is cheap! The most expensive part of ANY speaker is the cabinet. I can account for a lot of $$ for that but still, anything, regardless of design that cost more then $2500 is shear insanity!
The technology is old, the designs are hardly original and the components are all off the shelf made by one of a few speaker manufacturers on the planet, ok maybe a slight custom variation by some but please, don’t tell me its anything more then that!

Reamer speakers Tetons:
http://www.reimerspeakers.com/tetons_gs.htm
$9000 !!!!
They can go F themselves!

Zu Druid mk4
http://www.zucable.com/druid/index.html
$2800

Zu Definition mk1.5
http://www.zucable.com/definition/index.html
$9000
They can go F themselves too!!

Oh and when you approach $20,000 or more for a speaker they best come with a lifetime (mine that is!) of oral sex.

crossroadazn, I have a 2 wpc (and that being generous!) with EL84's.

I have a pair of Parker Audio 95db sigs with ribbon tweeters (MTM) that cost about $1000 and sound wonderful (http://parkeraudio.net/)

Ed Schillings’ HornShoppe Horns!!
http://www.thehornshoppe.com/model1.html

These Decware MG944’s (MTM) are an awesome bargain!
http://www.decware.com/newsite/MG944.htm
$850

These Decware RL -3’s are awesome too.
http://www.decware.com/newsite/RL3.htm
$2000

http://www.decware.com/newsite/speaker%20line.htm

There are Klipsch speakers in excess of 95db that are properly priced and sound great with low powered amps.

PaulFolbrecht · « **Reply #11 on:** 10 Sep 2006, 05:45 pm »

Whatever. Your definition of "ludicrous" is an arbitrary as anyone else's. My current Hyperion 938s at $4700 retail offer a midrange smoothness I've never heard in a cheaper speaker *with everything else as good too*. My previous Gallo Ref 3s at $3000 are equally stunning in other ways and also cannot be touched by cheaper speakers.

I'd never be able to nor really care to spend, say, $20K on a pair of speakers but there are $20K speakers that offer things that you can't really get for cheaper. Certainly, the more you spend the less you're getting per $. This is one reason I'd never care to spend $20K.

You're off-base about materials costs. There are $20K+ speakers that have no more retail markup than the average $1K pair of speakers because their materials are indeed far more expensive. Including the cabinet - yeah, it's generally the most expensive component - and some of them cost the manufacterer thousands of dollars to build.

There are also plenty of cheap speakers that sound really good and, you know, it's the emotive connection with the music that really counts anyway and that always takes some imagination.

boead · « **Reply #12 on:** 10 Sep 2006, 05:56 pm »

Quote from: PaulFolbrecht on 10 Sep 2006, 05:45 pm

My previous Gallo Ref 3s at $3000 are equally stunning in other ways and also cannot be touched by cheaper speakers.

Says who?
I know a few that have had or heard the Gallo and have also heard speakers from Decware for half the price that blew them away!!

Quote from: PaulFolbrecht on 10 Sep 2006, 05:45 pm

I'd never be able to nor really care to spend, say, $20K on a pair of speakers but there are $20K speakers that offer things that you can't really get for cheaper. Certainly, the more you spend the less you're getting per $. This is one reason I'd never care to spend $20K.

Again, says who? The guy making the speakers?

Please there is ZERO justification for a speaker costing more the $3000 and even that’s a stretch!
Unless you’re making a piece of furniture but that has NOTHING to do with audio!

Quote from: PaulFolbrecht on 10 Sep 2006, 05:45 pm

You're off-base about materials costs. There are $20K+ speakers that have no more retail markup than the average $1K pair of speakers because their materials are indeed far more expensive.

Speakers have a markup by an order of magnitude. Its absurd.

PaulFolbrecht · « **Reply #13 on:** 11 Sep 2006, 12:35 am »

Despite your forceful argument and liberal use of exclamation points, I still disagree. But let's not bogart this thread any farther.

boead · « **Reply #14 on:** 11 Sep 2006, 02:11 am »

Ok, no more bogarting.

I’ll pass it back to the owner.

gitarretyp · « **Reply #15 on:** 11 Sep 2006, 02:14 am »

Quote from: boead on 10 Sep 2006, 05:56 pm

Speakers have a markup by an order of magnitude. Its absurd.

Although some speakers are marked up a bit high, most manufacturers do not charge an unreasonable amount (2-3x parts cost is reasonable for most box type speakers). Let's take a speaker whose parts with which i am familiar, the selah audio peridot. Rick sells the kit (drivers, completed crossovers, wire, binding posts, screws) for 1075/pair (the same parts at madisound cost ~950). He charges ~4500 for the completed speakers, shipped (~4300 less shipping). Wood, veneer, finishing supplies, screws, glue, and other miscellaneous parts probably bring the parts cost to 1750-2000. So, he charges about a markup for 2x. Now, in that markup you have to consider the time spent designing the speaker (50+ hours as a rough guess), the 50+ hours spent building and finishing the speakers, the inclusion of warranty replacements, shop up keep, and customer care. In hours alone, your basically paying him 20/hour to build the speakers. If you think 4500 for those speakers is absurd, you need to adjust your economic views.

Sorry for the rant. May the thread continue peacefully.

So long as you typically listen at <~100db, 15 watts should drive 88+db speakers fine. You need to take a look at impedence curves too, however. If the impedence drops low or has wide, rapid swings, the speaker will be tougher to drive.

SET Man · « **Reply #16 on:** 11 Sep 2006, 02:19 am »

Quote from: boead on 11 Sep 2006, 02:11 am

Ok, no more bogarting.

I’ll pass it back top the owner.

Hey!

Hey! Man.... that is a freakin' cool smiley you've got there man... look like these guys are everywhere and could do anything man.... peac man!

Take care,
Buddy

Scotty · « **Reply #17 on:** 11 Sep 2006, 02:26 am »

boead, I assume you expect to paid for your time spent laboring at your job.
A person engaged in hand building a complex loudspeaker cabinet also requires
adequate compensation for the time spent on the speaker cabinet construction
as well as the time that was spent in R&D on the design. In the case of the Teton's there are over 25 different pieces of mdf used in the enclosure that all must be cut to less 1/64 inch tolerance. Likewise the veneer has to be applied
perfectly as well. The finish is also a time consuming multi-step process that also
must look perfect to the customer. A complex cabinet and an attempt at perfection in the exterior finish of the speaker is a time consuming process.
Compensation for labor is delicate subject and frequently the cause of negotiation. If you feel that the price of the loudspeaker does not fairly represent
proper compensation for the labor and materials involved you are free pay less.
Before you damn a loudspeaker mfg. you should
probably listen to their speakers first. The performance that a pair of speakers can deliver may handily justify their cost and then some.
Scotty

boead · « **Reply #18 on:** 11 Sep 2006, 02:35 am »

Well, I think maybe you aren’t seeing the real cost.

The retail cost of parts is likely marked up quite a bit. My guess is that the actual wholesale cost for the parts are closer to $500.

“…Wood, veneer, finishing supplies, screws, glue, and other miscellaneous parts probably bring the parts cost to 1750-2000…” ?? Again a gross over estimation.
I’d say the cost for raw materials by a manufacturer are likely hardly another $500.

Even a small time manufacturer can likely pull off a low material cost and I won’t argue the cost of labor but Garner, NC, I’m sure the labor cost value is relatively low.

Electronic component manufacturers don’t make that much of a mark-up. I believe the reason is the enormous number of speaker maker competition. Its many times higher then any other part of the industry and they need to get a bigger piece of the pie? That and good old fashion greed by taking advantage of what they can, just as the cable and wire guys do.
Scotty, those are similar arguments I use for the cable manufacturers.

And again, a furniture finish has nothing to do with audio, I can give a rats ass about the finish and if I do that I’ll be the first to admit that these $5000 speakers are rally only $1500 in a $3500 peaty box to match my wife’s curtains.

Sorry, that was my last toke!

Scotty · « **Reply #19 on:** 11 Sep 2006, 02:50 am »

While I will agree that appearance has nothing to do with how a loudspeaker may perform it remains nonetheless a important criteria to many loudspeaker customers yourself not included. Likewise the finish on your car has nothing to do with how well it performs is function as transportation but I venture to say that you would bitch mightily if your brand new $20,000 car had dents in it and runs in the paint regardless of how well it ran. Different strokes for different folks. As well as my final toke.
Scotty