4 amplifiers to drive 1 pair of speakers?

This doesn’t make sense to me. Not trying to be rude.

When you say the speakers are more like 4 ohms in real life, you’re saying the impedance swing occurs with changing frequencies, which is true. However, A well designed speaker at 8 ohms uses quite a bit less current. Impedance may swing to 4 ohms every now and then, but it will not remain there for long.

I don’t think you would need a power amplifier. That’s probably overkill. An integrated amp that is pushing about 40 watts per channel or more at 8 ohms will do fine. Vintage gear that was made in Japan is probably the best value.

Last thing - on the back of any speaker amp you’ll see something like:

8 ohms - 16 ohms
4 ohms - 16 ohms

Lower impedance = more current required.

@thegreenman.... You are correct to worry about Impedance dips.  It does somewhat matter about where (what frequency) they are, but the real problem is to try to get an impedance/phase sheet on your speakers.  Normally impedance dips are accompanied by phase angle dips.  This is where many many tube amps crap on themselves.  
I read that each speaker had 2 binding post?  So yes, assuming that you are running them as mono's, you could conceivably run your  amps that way. 

Well, you should try it first. :)

But active bi-amping may be a much better way to go.  Use a solid state amp for the low end.  Put a capacitor in series with your top end amps.

THe thing about passive bi-amping is your amp still has to reproduce the full voltage swing (+ or -, corresponding to in/out on the speaker).  You do reduce the current, which stiffens up the amp, but if you can remove the bass from the amp the full power becomes available for the high range.

Very weird idea.

You can monostrap stereo tube amplifiers if you are careful. But generally speaking they don't sound as good- less delicate, more heavy-handed.


So a Y adapter is used at the input and the outputs are wired in parallel. However, the 16 ohm tap becomes the 8 ohm output and the 8 ohm tap becomes the 4 ohm output.

Bi-amp with valves units.. The only issue for me would be heat. It's tough enough to deal with valve amps in the summer months, much less 4 of them.. You might want to rethink that one.

Eric offered SS for BASS duty that is a lot better ides. COOL running class Ds will certainly liven up the joint.. I quit using valve amps for bass duty 20+ years ago.. They work better NOT doing bass. Pretty simple.

Regards

You need more power.

What are your speakers? That amping scenario is unwanted complexity

Does your experience come from working in live concert, pro audio sound staging? If not then I’m not clear what your home audio objectives are. From a quick power ratio calculation, what you’re doing will quickly lead to equipment failure—meaning dollars wasted. 

why would anyone want to use 4 amplifiers to power a pair of speakers?? awhile back i did have 2 amps powering 1 pair of speakers. 1 amp powered the low end and the other amp powered the high end!

Hi Erik and Oldhvymec,

Thanks for your suggestion for the bi-amping with solid state for bass. However I note from some reviews eg Steve Guttenberg it isnt that easy to get a good matching of the amplifiers (eg he tried with zen triode at the top and schiit aegir at the bottom end) and it wasnt a good match.

Hence I was apprehensive about bi-amping. I know some solutions eg Mcintosh MC901 sounds really good, but those are out of my budget and also it is a pre-matched solution.

Thanks!

Hi 

I am using kef reference 5 with recommended 50-400W needed to power it. Most of the impedence on the chart is around 4ohm instead of 8 ohms. Lowest dips to 3.2 ohms. Although it is 90db at 8 ohms, there are 4 woofers, 1 tweeter and 1 midrange on each speaker - hence may require more power/current. 

From what I understand tube amps (or at least SET amps - not 100% applicable here as they are PP) should not be pushed past their 25% limit to have a good sound.Hence for a 18W 300b PP monoblock amplfier to drive my speakers will likely be insufficient. Hence exploration of 4 amplifiers and whether anyone has tried it before/if it is feasible. 

@scchengmus what do you mean by power ratio calculation? Why will there be equipment failure? :) sorry am not well versed in that

Thanks

Hi @atmasphere 

Thanks for sharing the idea on monostrapping! Was reading up on it. How about what if I do not monostrap? Monostrap kind of puts the amplifiers in series if Im not wrong? So if I place the amplifiers at parrallel will they actually sound more musical/less harsh and heavy handed?

Thanks

I can see maybe 2 at most ,it creates too many issues the input sensitivity of each amp is different if not the same ,
a amp for the bass for sure a quality SS amp, tom tube or SS 
and a Tube preamp , SS amp is widely used or tube .
your speakers will determine this too by their efficiency
thrn if you have to add a external crossover  that more added in the circuit which dips never better less sonic purity ,less is always better in 5he signal path . No mention of the speakers being used 
and space size needed , if monitors ,then judt get a good powered sub with nice modern app like a Svs ultra 16, or Svs- SB 3000 sub. Then you only need an amp on top .

thegreenman, excellent job of thinking creatively in terms of system setup! Most people do not have the vision to see such potential. It is through exploration of options that would not necessarily be considered that some very cool things can happen. Note well: multiplicity of amps does not equate with superior results. Many factors go into the result, and simple higher quantity of amp channels is no guarantee of superior sound. 

You have been given superlative advice from seasoned veterans that it may not be an ideal setup. In general, over many years of building hundreds of systems, it has not been the quantity of amp channels, but the quality, i.e. not only the build quality and preference for SS or Tube, but Watts and current delivery, that has been THE most important aspect. 

I have many times tried unusual configurations such as splitting the pre output in order to do additional channels, and nearly always a simply superior amp yields a much preferable result to use of several amps. There is a HUGE difference in systems set up with even one stereo amp and bi-wiring versus multiplication of lesser amps, or additional amp channels. That may sound counter-intuitive to you, but you need to trust me and others who are guiding you.  :) 

Listen to the old warriors; they know whereof they speak.  :) Personally, I would not dream of using so little power on any nearly any speaker, regardless of its efficiency. I have speakers above 90dB sensitivity, and I drive them with hundreds of Watts. I would not wish to drop down in power, because even they would sound relatively anemic in comparison. You may disagree now, but that is lack of experience. You are absolutely wasting those speakers with 18Wpc.  :(  You are getting nothing close to what they could do, and with zero loss of beauty of tubes.  

You will get a fresh take on amps in my upcoming article at Dagogo.com in regard to the Legacy Audio i.V4 Ultra Amplifier. The world is changing, and in this case, much for the better!  

Now, there will come along someone who will suggest i have it all wrong, 
that even the 18Wpc is "plenty" to drive the speakers. True. Is it superior, the best you can do? No, not even close, imo. Of course, opinions will vary, and you must choose your authority - and get your results.  :) 

Was reading up on it. How about what if I do not monostrap? Monostrap kind of puts the amplifiers in series if Im not wrong? So if I place the amplifiers at parrallel will they actually sound more musical/less harsh and heavy handed?

I think you'll find that by monostrapping you'll be able to drive the speakers far more easily! The only tricky bit it you need two identical stereo amps to pull it off.


BTW instructions on how to do this are in the Dynaco ST70 manual. I used to run monostrapped ST70s when I was in college.


BTW you **can't** use this technique with solid state amps- you'll blow them up!! It is possible to monostrap them too, but the technique is entirely different.

Hello,
Nope, this will not work. There are so many high efficiency speakers and KEF Reference 5s are not one of them. You need a much better damping factor. Those woofers need a decent amount of power. There are so many good tube amps. Rouge, Macs, BAT, prima Luna. One thing these amps have in common is they usually have high power. I think you should buy a pair of Tekton or ZU speakers but I will have to warn you the wait time is really bad. Similar sound and frequency response but high sensitivity. You have no need for a second 300b amp. So either buy a new amp from the list above or sell you KEFs and buy the Tekton/ Zu speakers. I am going to suggest getting a new amp. The Rouge Chronus Magnum. 55 watts per channel integrated amp. You will lose too much on the KEFs. If you are in the Chicagoland area the Hifi store where I shop has the full line of Rouge. https://holmaudio.com/If you have a preamp you like I would suggest the Rouge ST100 or DragaN if you want to try the new 300 watt per channel hybrid. They are a KEF dealer so you can listen to these amps on the KEF Reference speakers in the store. If you are out of the area call the store about trading in you 300b amps for something new. I did this with some of my gear last year. You will lose less money on the amps than you would on the KEFs and are much easier to sell due to being able to ship them. 

Hello the greenman! You're thinking creatively and that's good. My own system uses eight channels of amplifier for a pair of four way speakers. Each speaker has it's own amp - but - I use an electronic crossover, so each speaker (tweeter, upper mid, lower mid, and bass) has it's own amp. Your suggestion proposes four amps for two speakers if I am understanding you correctly. Doubling the power to a speaker only results in a 3 db increase in volume in the room. You won't get much "bang for the buck" that way. I have several low wattage amps - all sub 10 watts. I find I can play any speaker system in the house with a single set of input posts to satisfying volume with any of them. If you want to play your music loudly, that's where you need POWER. What I would call "normal listening levels" seldom exceed five watts. If you want to play at the actual sound level of real combo or orchestra in your listening room - so you can't hear the phone ring, or your partner calling you to dinner, or the baby crying - you may want more power, but not just a little more. To hear your music 10 db louder, you need an amp with 10 times the power of whatever the starting point is. If you have watched power meters dancing on the faces of expensive amps, you know a 10db difference only sounds three or so times louder. So . . . now you know why lots of folks like the sound of 100 watt + amps.

You are unlikely to do any damage by using you 300B amp to drive your speakers directly. If you run out of power, the sound will just become unpleasant, that's all. If heat problems worry you, use one of the really fine class D amps out there. I use  three Starke Sound AD4.320 amps on my main system which uses 11 channels of sound. It is big, heavy, and non-descript but it sings like a choir of angels and costs less than $1500.
Four 200 watt channels for way under two grand. The best bargain in amps! As good as the fancy NADs which are getting great press.

Just be sure you are using decent speaker wires (14 gauge zip cord for starters) to get your 300B's output to the speakers. Yours are efficient enough to a good job with 8+ watts. I have filled a huge room with background music for a fancy dinner with a nine watt class A amp driving Magnepan 1.7i speakers (notoriously power hungry). Don't let anyone talk you out of being happy with what you've already got! Enjoy the music. If it doesn't play loud enough, get an amp with at least 10 times the existing amp's power. If you want to roar - 100 times the power. If you go that way, be sure you can afford speakers that won't catch fire when their voice coils melt!  Enjoy your music. If it sounds fine, buy music, not electronic gear! Remember, in the early days of quality audio, 20 watts was considered a lot of power.  Keep Smiling!

Get a high powered SS amp and be done with all this stuff!

 Or save and get the carver 350 amps. 
  4 amps on 1 speaker?.
  HUWWHHAAAT!!

I would not want to do this to drive a pair of speakers if you need more power from the 300b amplifier there were some amp makers that made push pull 300b amps that were quite good.

@atmasphere thanks for your advice! :)) ok sure will go and look for the dynaco manual! :))

Always thankful for pros like you giving advice! :)) 🙏🙏

@hshifi thanks! Im actually using primaluma...just tt i prefer the sound of big tubes eg 300b, 211 , 845. Im thinking of different solutions I can use to circumvent the power problem

@boomerbillone wow thanks for sharing! Haha 8 channels must sound really powerful! Hahaha if I have a chance would be great to listen to your system! Haha I have seen videos on Thomas & Stereo where he shows off someones system using 3 mcintosh amplifiers 1 high 1 mid 1 low. Looks really magnificent hahaha
Will your set up work without a electronic crossover?

@douglas_schroeder  thanks for your input! :) haha wow you sound very experienced! Oic! Always was wondering why I dont see multiple amplifiers rather than 1 stereo / pair of monoblocks used! I guess that must be the reason! 

Ok sure, looking forward to your article! Haha so what amplifiers are you using currently? Your speakers are the legacy audio speakers?

thegreenman, you only see what I want you to see...  ;) 
(Quite mysterious, eh?) 

There are certain ways using multiple channels may (for the community's sake, notice the word "may") sound better than a stereo amp or monos. 
Do not be overly impressed by rigs with many amps; it is not a sure indication of superior sound quality. In several respects, a more streamlined rig is preferred. It is far easier to screw up the result when multiplying functions, and it is far harder to dial in a rig to perceived perfection as well. 

If you would like to see the list of amps I have reviewed, check my reviewer profile at Dagogo.com under the "Staff" tap at the top. 

I just sent back some mono amps, so at the moment I have the Kinki Studio EX-M1+ Integrated Amp, the Redgum Audio Articulata Integrated Amp,  and the Legacy i.V4 Ultra Amplifiers here. I have another top secret on coming soon. Sorry, I do not typically reveal the identity of review items far in advance of the article. I can tell you this; it will be a stereo amp and about 100Wpc. I suspect it would sound very good with the Legacy Whisper DSW Clarity Edition speakers you mention. 

To give you some idea of how vastly amplification can range in terms of performance, the Redgum integrated amp has bested several other SS stereo and mono amps. It has terrific ability to push less efficient speakers such as electrostatic speakers. Amazing rigs can be built with monos, stereo, integrated, and multi-channels. 

There is often something lost in the effort to push toward the lower power, higher efficiency end of the spectrum. When you have heard both ends many times, you understand that. A person has to make a choice between the set of attributes most desired, and you usually cannot have both. 

@douglas_schroeder  haha ok sure will check out your reviews! Haha interesting surprise gear you are going to review

Haha I probably lean way more towards the tube camp :p when I have enough funds will want to upgrade to horns with low powered tubes actually :pp what do you feel is lost? 

Thanks

thegreenman, The genres of speakers that can be driven with low powered tube amps is unacceptably narrow to me. I do not wish to limit my experiences based on the inability of an amp to drive different genres of speakers well/properly. Some accept that limitation, but I choose not to.