[JLM]

SETs and horns have been used together for decades.  They synergize well for a number of reasons, most obviously the lack of deep bass from "reasonably sized" horn cabinets and the forward presentation of horns versus the midrange warmth of most tube designs.

With the advent of low powered digital amps, the power and price questions seem to be turned upside down.  The SI/Clari-T synergizes well with some rather low efficiency speakers that are thought of being hard to drive (like Dynaudio Contours) but doesn't do so well with some 90 dB/w/m speakers.  

If you're willing to add a powered sub, the number of higher efficiency speakers expands greatly.  Here at AC The Horns and Omega are just two reasonably priced examples.  Alternatively for $800 plus baffles and powered sub you could get into a Clari-T amp and Visaton B-200 drivers (8 inch, 96 dB/w/m, 6 ohm, Qts 0.65, 40 - 18,000 Hz).

I agree with DB that small rooms behave differently than large rooms (the bigger the better).  I also agree with DVV that high efficiency speakers are usually colored and that the ear subsitutes dynamics for spls.  And I agree with Scott that the dynamics available from high efficiency speakers driven by simple circuits can be amazing.

With new products like the SI and B-200 the envelope of high efficiency/high quality/attractively priced equipment has been pushed, but the human condition demands that we'll never be satisfied as the perfect playback system will never be created.

[rmihai0]

I am fighting with the same question: how much power I need.
I am lost. And I need your help. I just bought a nice pair of Ellis 1801b speakers and I don't know what amplifier shoul I look for.

Specs: Sensitivity 84db
Impedance: 8 ohms nominal ;dips to a low of 6.2ohms in the bass region.
Sound Pressure: 90db

My music: classical 2/3; anything else (from rock to jazz, world and folk) 1/3. Only Lp's.

My room: 18 x 20 feet (5.4m x 6.1m)

My requirements:
- to have 300b tubes
- to work best with KR tubes
- to be in my budget: $1000 (max $1075)
- can be used or vintage

I just need an amplifier, I already have a pre-amp that I will replace it later.

If the 300b's won't work with my speakers (due to my limited budget), please advise for what else should I look for.

Thanks a LOT

[Scott F.]

Hi rmihai0,

Hate to tell you this but if you are using 300B's (or want to use 300B's) with the Ellis speakers, you will probably not be happy with the end result. Reason I say this is the low sensativity (84dB). To reach even moderate spl's in your room you'll be driving the 300B's into clipping (if not full time, at least on transients). By moderate listening levels, I'm talking about 90dB (or so). Even at lower levels you will be pushing the amps pretty hard all the time.

What you really need (if you plan to keep the 300B's) is a much higher sensative speaker. Take a look at the Audio Note AZ Two's. Bill at Response just sold a pair to one of the local guys (here in St Louis) and they do a damned fine job. They are sitting somewhere near 92dB efficient. With 300B's, you should be able to get reasonably decent listening levels while maintaining some headroom in the amps for the big transient peaks of the music. They are right around $1000 new. If you contact Bill, he can set you up with a pair if you don't have an Audio Note dealer in your area.

Another choice is a pair of used Klipsch's. eBay has tons of Heresy's that can be picked up for about half your budget. If you get lucky you could pick up a pair of LaScala's or Cornwalls for your budget. Keep in mind that the Klipsch's are horns. If you've not heard a horn, I strongley suggest you find someone in your area that has a pair so you can see if you enjoy the sound. Horns are definately something that you have to wrap your mind around when you first hear them. If you like them, you'll find that they are a great match to a 300B.

There are many more out there though most of them are vintage like the Altec Valencia's.

If you are looking to keep the Ellis speakers, I'm afraid you need to look for more power, in fact lots more power (if they are 84dB efficient). Guessing, 100 watts a side should get you where you need to be.

The usual disclaimers apply,
YMMV, IMHO, etc, etc.

[DVV]

... If you've not heard a horn, I strongley suggest you find someone in your area that has a pair so you can see if you enjoy the sound. Horns are definately something that you have to wrap your mind around when you first hear them. If you like them, you'll find that they are a great match to a 300B. ...

This is VERY good advice and cannot be repeated often enough.

I agree completely with Scotty on the horn issue - they have the odd effect that you either love them or hate them, more or less. I'm in the love camp, but I have seen people react unfavorably to them.

So, ebay price notwithstanding, you should give them a whirl somewhere, just to make sure that's what you need. Especially with the Klipsch speakers, they are a whole new ball game unto themselves.

Cheers,
DVV

[DVV]

I am fighting with the same question: how much power I need.
I am lost. And I need your help. I just bought a nice pair of Ellis 1801b speakers and I don't know what amplifier shoul I look for.

Specs: Sensitivity 84db
Impedance: 8 ohms nominal ;dips to a low of 6.2ohms in the bass region.
Sound Pressure: 90db

My music: classical 2/3; anything else (from rock to jazz, world and folk) 1/3. Only Lp's.

My room: 18 x 20 feet (5.4m x 6.1m)

My requirements:
- to have 300b tubes
- to work best wit ...

As a very rough guide, you can consider power requirements as the power needed to attain realistic normal, long term sound pressure, plus 6 dB of extra power as a reserve for transients. +6 dB means four times the power used.

Work it in opposite. Think of the power you need as one quarter of what the amp will deliver in nominal terms. So for a say 100W amp, your actual usable long term power is 25W.

Applied to your speaker, as you defined it, and assuming 90 dB sound pressure level (SPL), you would need +6 dB over their nominal sensitivity, or four times the power, 4 watts. Your amp would theoretically need to have four times that, or 16W.

This is theory - in practice, low power amps are almost always done with much cost cutting, and few are able to sustain higher power levels for any period of time. Next, your speakers are NOT a linear load, their impedance will vary, as will their phase shifts. If the phase shift goes into the minus stage, that means more current. For example, if your speakers have a minimum of 6.2 ohms, and a phase shift of -45 degrees, what the amp will face is the equivalent to an impedance of 4.4 ohms, meaning it will need to deliver more current. Since tube jobs just plain hate current, your amp would have to have a nominal power rating of 50W into 4 ohms to be capable of this.

So, you either go for more efficient speakers, say 92 dB, and keep the amp, or keep the speakers and go for a more powerful amp, if you want to hear the dynamic range preserved.

Cheers,
DVV

[rmihai0]

Thank you very much Dejan - your answer - as always - HIGHLY aapreciated.

So, if I understood right, a 50W will do the job. Because I am considering a Kora Galaxy, rated at 50W per chanell. SNR 100db. And this is in triode mode. I am not very happy about the used tubes (Sovtek EL84M), but I cannot find something better for my budget.

[JLM]

Like anything else all horns are not created equal.  First they come to varying designs: front loaded, rear loaded, single driver, multiple driver, and even the math behind the exact shape of the horn is a matter of debate.  Some speakers use semi-horn designs (corner loading or "wave guides").

Most horns I've heard are fast, forward, colored, and shouty.  Due to the laws of physics they trade efficiency for deep bass, so to reach 20 Hz  requires a room/garage sized enclosure.  Because of their speed and lack of deep bass, pairing them to a sub is highly problematic.  Note that they require drivers with a low Qts (around 0.2).

All that said, what horns can do is amazing.  Not all horns are created equal.  Typical warm, slow tube amps help alleviate much of forward/shouty horn sound, but now you're adding colorations on top of other colorations.  But if you want to play in the SET pool, horns are the obvious starting place to look for efficient enough speakers.  IMO speaker efficiency and colorations seem to corrollate.

I'd like to reinforce that dynamic range varys from 10 dB to 30 dB.  That equates to 10 to 1000 times the power from "average" levels.  Overall a design goal of 105 dB peaks should serve you well, but depending on your taste, etc. even 95 dB peaks can work with good amp/speaker synergy.

[gonefishin]

I am fighting with the same question: how much power I need.
I am lost. And I need your help. I just bought a nice pair of Ellis 1801b speakers and I don't know what amplifier shoul I look for.

Specs: Sensitivity 84db
Impedance: 8 ohms nominal ;dips to a low of 6.2ohms in the bass region.
Sound Pressure: 90db
...  

    Hi rmhai,

   Have a look at this thread in the Ellis Audio Circle.  Right now, I'm fairly impressed with the AKSA amps on speakers ranging from 88db to my over 100db EdgarHorns.  The sound is just clean without the annoying edge in other SS/horn combinations I've listened to.  I've also tried the AKSA (25Watt) amp on some modified Altecs and was quite impressed with these as well.  

    But, this may be a nice marriage for you.  Right now there's a Bent S&B Tx102 based preamp/AKSA 55n Kit/modified ART DI/O for sale in the Trading Circle.  I have no affiliation what so ever with these items or person.  But it may be one heck of a nice match up.

    I might have to look into the 1801b's too.  I'll be needing a new set of bookshelves for my work area.  My wife would go nuts if I was breaking in amps at moderate levels on my horns  



  How much power do you need?  It really depends on your system, room and listening preferences.  I know that even with higher efficiency EdgarHorns (Titans or something like my DIY) some 45 amps sound nice.  But when playing  more complicated music (such as orchestra or  percussion)  the 45 amp seems to fall apart before I reach my desired listening levels during the more dynamic passages.  

   But I think you also have to keep in mind that all speakers aren't going to play well in the mid to low 90db  with peaks going much higher.  There's some speakers that I may not turn up much passed the mid 80db level.  While others I can occasionally (I know I shouldn't) play in the mid 90's with peaks easily over 100db.  (Plus I'm a sucker for brass and percussion   )

  How many Watts is enough?  

   I would say just a few more than you need


  dan

[rmihai0]

Thank you Dan,

I was considering the AKSA55n+ . But after I took the schematics and I discussed with a serious technician he told me that there is no much difference before it and an NAD 3020. Basically he told me that there is kind of a copy of NAD. Maybe the parts are better in the AKSA55n+. Maybe that is why the price is so high. Bottom line, his opinion was that the AKSA55n+ is far from deserving $600 for the kit. And he argued that the n+ option is WAY too expensive. I tend to believe him, as long as he was one of the Oscar Peterson technicians.

[DVV]

Thank you Dan,

I was considering the AKSA55n+ . But after I took the schematics and I discussed with a serious technician he told me that there is no much difference before it and an NAD 3020. Basically he told me that there is kind of a copy of NAD. Maybe the parts are better in the AKSA55n+. Maybe that is why the price is so high. Bottom line, his opinion was that the AKSA55n+ is far from deserving $600 for the kit. And he argued that the n+ option is WAY too expensive. I tend to believe him, as long as he was one of the Oscar Peterson technicians.

That technician is either VERY green behind the ears, or is a fool.

No-one in their right mind would ever presume to judge the sound of anything according to its schematic.

By that standard, AKSA would be old hat. But most of the beloved here and elsewhere tube audio would be stone age.

Yet we can hear anything from so-so to outright outstaning from the same basic circuit topology.

Let me go on record here and now - I believe the AKSA 55 is well worth the money asked for it.

Yes, it has a simple circuit - but that's the whole point, isn't it, make it as simple as possible, it will be more reliable and repeatable that way than with very elaborate designs.

Yes, that particular circuit is essentially based on the RCA data sheet from 1969, but wasn't the legendary Harman/Kardon Citation 10 (or 12?) also based on it, yet had a wonderful sound? Isn't it a masterpiece of a circuit when NAD and others are still basing their current designs on it?

I am well acquainted with NAD amps, and in my view, while their design is a very good one, it is that for a mass produced item. It is not up to AKSA's standards.

This is like comparing a present day Mini, much improved over the original by Sir Alec Issigonis from 1961, to a present day hand made Morgan. Both do the same job, but while the Mini is fun at best, the Morgan is a ride in style, which still allows you to burn rubber if you wish. It has poise. So does AKSA.

Cheers,
DVV

[AKSA]

Hi Rmihai,

Thank you for your comments;  you sought technical input from a technician, good idea, but you found the wrong guy........

Dejan is right on the money.  Let me apprise you of a few facts:

1.  The price of the AKSA includes service.  This can be considerable, particularly if the builder has little electronics experience.
2.  The price reflects the quality of the parts.  Pay peanuts, get monkeys.  The schematic (incidentally, please destroy your schematic, this is valuable intellectual property and I don't want it distributed, particularly if it's in digital form) only tells a portion of the story and anyone who says they can tell what an amp sounds like from the schematic is either lying or ignorant.  For sixty years the technical folk have been telling us that circuit schematics and distortion measurements tell us all we need to know, but most discerning audiophiles know better.  Why does a gorgeous single ended triode amplifier produce 2% or more of distortion at listening levels?  Why is this not objectionable in a world where 0.05% THD is regarded as unacceptable?
3.  It may be that you are looking in the wrong market.  You could be interested in DIY because it saves you money.  It won't.  It's a life experience, and in a way you are also hiring an expert to teach you the ropes.  A cheap discount box made in China (or used) is by far the cheapest way to enter the audio world - but no-one here would suggest it reliably gives you the best sound.
4.  The kit amps cover a broad spectrum of quality.  Some are dirt cheap and give you the bare functionality and performance;  but a few, such as Erno Borbely's SS kits from Germany, Scott Deckert's SET from Decware and the AKSA Class ABs from Australia, are full-on audiophile quality components designed to compete with high end.  As in everything in life, yer pays ya money.....
5.  There is finally the matter of intellectual property.  There is so much more to audio design than a circuit schematic;  notably component choice, layout, dimensioning, ease of repair and operating points.  These are the aspects which consume a lot of design time, and it is reasonable for the creator to ask a fair price for what may be years of time invested to come up with a thoroughly commercial design which really works.  And when the AUD was 52c US, perceived value was very good;  now that the USD has dropped to almost 80c to the AUD the value perception has changed.

I'm sorry if I sound a bit aloof, but your words surprised me.  If you want value for money vis a vis cheap imports, then the AKSA is not for you.  If you want a stunning experience in high end, both listening and learning, then the AKSA is outstanding value for money compared to the components with which it competes sonically.  These markets are very different.

In conclusion, I could drop the price of the AKSA to compete better with Rat Shaque offerings.  But the market cred of a product depends as much on its asking price as it does on quality, and this is not a sector of the market in which I wish to compete, since I live in a developed country with attendant high costs of production.  Many have suggested to me that the AKSA will be taken more seriously if I double the price;  you might consider this in your equation too!!

Thank you for considering the AKSA.  I appreciate the attention, and hope you eventually place an order.  Incidentally, according to David Ellis, the 55W N+ would suit your 1801s very nicely......

Cheers,

Hugh

[rmihai0]

Hi Hugh,

I far from me the interest in arguing with you. And, on most point you are probably right. I cannot make any comments as long as I never seen or heard an AKSA. My technician maybe oversimplified and I do not want to enter in an argument between the 2 of you as long as I do not posses the technical knowledge.

What you said seems reasonable, except one think - and here I can argue (because I do have a MBA and a CFA - Chartered Fiancial Analyst). I can argue about the price point. And my technician make a comment that I couldnt say a think: How comes that AKSA started being sold for $147 as a kit and now it is $600? About Borbely and Lindsay Hood, Pass Nelson - the technician knows most of these kits and he assambled them. So, he knows his stuff.

If you think that doubling the price you will do better go on - but I doubt. I think that your price for the kit and Nirvana Plus upgrade is already about 10% more than it should be. But this is just my humble opinion. Of course - your business your prices. Who don;t like it don;t buys.

[gonefishin]

Then it sounds like you should simply buy what your technician tells you to buy.  


   getting back to the power issue...
 

    ...I will doubt that a 300B amp will suit your taste, unless your in a small room and listen at low to slightly moderate levels.

  Good luck with the amp search!

  dan

[AKSA]

Hi RMihai,

And I won't argue with you on price!!

However, the original AKSA price did not include power supply components;  it now does.  You must compare apples and apples.  The introductory price of $AUD250 four years ago is quite different to the present price of $AUD430 on basis of components supplied and sound quality offered.  But why don't you buy second hand, if price is the issue?  Al Garay has an AKSA for sale at a most reasonable price, fully built, what's more.........

Nonetheless, I would stress again, if you are buying on price alone, the AKSA is not the product for you.  The AKSA is about the best possible sound quality for an audiophile kit.  Further, as an MBA with an appropriate and well paid job, you could probably afford to buy an AKSA anyway, so your approach properly represents your wish to get the best possible deal.  While I applaud this attitude, it means you will have to work at it pretty hard, and involve a lot of people over time as you seek advice, which you now realize depends very much on whom you talk to.

Cheers,

Hugh

[rmihai0]

Thank you Hugh,

yiu are right in the money.

[PSP]

Hi Rmihai,
With all due respect to your audio technician friend, the NAD 3020 and the AKSA are sonic "cousins"... sonically they are related, but one is fast, agile, wears extremely transparent clothing, and handles the high end and the low end in ways that you will never forget.  The other cousin, while having something in common, is slower, more opaque, and much less interesting in the night with music.

Before I bought my first AKSA 55, I spent two years tweaking my old NAD 7020.  I replaced all the wiring, all electrolytics were replaced with Nichicon muse or Black Gates, the power supply got FRED soft recovery diodes (huge difference), and I pulled the soft-clipping circuit (much better!).  When I got done, I was very, very happy with the sound.  I bought my first AKSA amp because I wanted to biamp, and I planned to use the AKSA for the bass, along with the 7020 for the tweeters.

When I first heard the AKSA, it was familiar, a cousin to the 7020 amp section, but very much more interesting.  Speed, detail, transparency, layering, musicality, emotion, and bass were all way better than the 7020 (please don't accuse me of messing up the 7020 by the way... I tweak very slowly and deliberately.  I reversed many a tweak because it was a step backwards).

So, IMO, your friend is correct... the two amps are "related".  But topology is only one aspect of the design.  Hugh has driven his amp to the edge of stability and (just like a jet fighter) this makes it extremely agile.  You won't get that from NAD (and I like NAD gear... but I love Aspen gear).  

I still have the 7020... my wife likes the simple controls and analog tuner section... so if you are ever in Minneapolis, I invite you for an evening of music comparing these two amps.

Best regards,
Peter

[stvnharr]

rmihia,

I think you are WAY off base here my friend.  It's rather hard for you to just the SOUND of an Aksa without having heard one.  And you are making all the WRONG comparisons.
Once you get the kit completed you will have invested somewhere around 600 USD.  If you don't think that is CHEAP in the audio world, then you are VERY unknowledgable about quality audio products.  Of course if you are talking cheap mass market products then that is different.  You have to decide what it is that you want!!!

As for NAD, they do make quite good products.  The 3020 has been a stalwart in the NAD lineup for a long time.  Again it's hard for you to do a direct comparison since you don't have an Aksa to listen to.  I tend to discount others opinions of A/B comparisons, however I have had the experience to A/B my Aksa (btw, the one that Dave Ellis listens to, the VERY SAME one), with a friend's NAD 3020 while we were doing some speaker comparisons.  There was a very big difference in the quality of the sound.

Also, if you are just interested in pinching pennies, then spend some time over on audiogon.com and see what your 600 USD will get you.  There'll likely be some NAD products there as well.

[stvnharr]

rmihai0,

I posted too quickly, and I apologize for mispelling your moniker.

I think You have already answered all your points fairly well.  Namely, you are a guy in a suit who doesn't really know anything about diy hobby audio, other than the appearance of the possibility of saving money.  Yes, some money can be saved if you have the knowhow and intuition to Do It Yourself.  
If you perceive than your technician friend is correct and the Aksa is just another NAD 3020, obviously you had better get the NAD 3020.  
If you perceive that an Aksa kit is too expensive, then DON'T BUY IT.
And don't waste your time complaining about the price.

[rmihai0]

Thank you very much to all of you. Your points were taken. regarding my suit and MBA - take it easy - I use to play for several years in a progressive rock band - and I know very well how the real sound should be like.

IF someone understood that I am complaining VERY much about the AKSA 55N+ kit price, I am sorry - was not my intention. I jsut say that MAYBE is slightly overpriced about 10%. Can the market pay for those 10%? Yes - of course, because as you explained is a HIGH-END kit, not just another kit.

My problem for puting togheter an AKSA 55N+ is not exactly the price of the kit. Is the price required to invest in in transformers, chassis and to pay someone else to have it assambled.

All the quotes that I got until now, will rise the final price to around $1320. About this aspect I am unhappy - not about the AKSA kit price.

I hope you understand me know - and I want to let know my decision - yes - I will get an AKSA kit, but not the 55N+. I will order the 100N+!

Thank you very much all of you for your time and your info. Was really instructive and helpful.

[pem]

Dear rmihai,

while I was considering the Aksa for my Ellis 1801. Both Dave and Hugh recommended me to take the 55N+ instead of the 100N+. They told me that 55W were sufficient. On the Ellis forum you can read that the 55W may be a bit better than the 100W for the 1801B.
What is sure, is that the 55W will cost you less (power supplies are cheaper).

 kind regards,
 Pierre-Etienne