Sonic qualities of SET output tubes?

I have no idea how many watts my HO generates, although as a recent one it’s maybe 17 watts (it’s not a "Hot Rod", although those claim about the same wattage as mine), but at least 12…I currently prefer it with KT88s and  a Shuguang 274b rectifier (I mean really…a cool looking tube), and these amps come with zero published specs other than what can be gleaned from forum conversations and Had’s comments (and a published log book page  of Hads with various parameters noted in pencil…great stuff…), a somewhat unique thing with no warranty or anything other than good faith from Dennis. Also it wasn’t expensive…relatively...

I had his Firebottle amp with the KT150 tubes. Tried to drive 92db sentitive speakers in a large space and the combo did not work. I like the build quality and Dennis very much. I was actually selling the amp for a friend and put it into my rig.  Wish I could of heard it on speakers better suited for it. 

Ralph, besides Classic Audio, what would you recommend to use with your amps? Also, do you believe that short length Mogami RCA cables are just as good as XLR? I mean 2497 wire.

If you keep the cables short you can do pretty well with single-ended connections. I can't comment about the single-ended Mogami- not tried it.

Regarding speakers, Audiokinesis, older Quads (newer ones need the ZEROs), Sound Lab (with our bigger amps), Coincident, Devore, Lowther, PHY (will need a speaker protection fuse as they only handle 20 watts), most horn systems and single-driver systems, AvantGarde, Merlin, Magnaplanars (use ZEROs, Eminent Technology (may need to use ZEROs) Vandersteen, Certain Avalons such as the Eidelon, JM Labs, Rogers LS35a, certain Sonus Fabors, Pipedreams, and many more.

The trick is similar to what you look for with an SET or any tube amp using no loop feedback, which is to say that the woofers should be the same impedance generally speaking as the midrange. Dual woofer systems that are 4 ohms in the bass and 8 ohms otherwise don't work so well. The difference between our amps and SETs is that we can work with speakers of much less efficiency, but personally I do prefer efficient speakers as I like to crank the hell out of the system once in a while and don't see the point of struggling to do that.

Stfoth…Mine came with the Gold Lion KT88s, an Amperex USA 6SN7GTB from some NOS vintage, and a JJ 5Y3S rectifier. I've since bought another Amperex that sounds identical to the supplied one (different getters, but labeled a USA tube), a new issue Gold Lion GZ34/U77 rectifier which works great with the 88s, and the 274B which sounds like the GZ34 but looks cooler. I also have a set of JJ KT77s but they lack the resolution and sparkle of the 88s in this amp. Note that none of these tubes are particularly expensive (the Shuguang 274B was 18 bucks shipped from China), and you need less of 'em for this amp anyway.

Hi Bill,
I’d truly be honored to be a beta tester for this "unique " 300b-digital (all in one audio product). This sounds unusually interesting . Bill I thought you had tried the Zero transformers in the past and had mixed results. If I’m mistaken then my apology.
Charles

Ralph, thank you, appreciate your response.
So.. 8 ohm average 89db two way speakers with one 8" woofer and 1" tweeter schould work well enough in a medium size room, generally speaking.

Charles, I did, but that was with completely, totally, absolutely, different speakers! Soundlab M1s with all manner of dramatic impedance swings. 

Bill, 
 Okay I see. Yes I  know the Sound Labs speakers.  Your Crescendos are a  very different scenario. 
Charles 

Grannyring > The trying not exceed 20% of an amp's power was specifically mentioned by Ralph for SET tube amps …. His statement does not include SS, Class D, OTL and other type amps.


Blindjim > thanks a lot. Now that makes more sense. I knew I was missing something. Just like the part on “lower power, better sound”.



saki70 > Have you given any thought to PSET's ? in your area, Where would you go to hear different tube amp demonstrations? Good Luck .


blindjim > thanks. The learning experience continues and that is always enjoyable. Getting there is another story.
Yes. In fact higher output tube amps or PP amps were and are my only exp with tube amps I have owned. They are the first amps I thought about before trying to learn more on the SET platforms, so I might minimize or eliminate a very big mistake.
As well, the PP glass amps just made more sense given the speakers I was admiring or dreaming about. All had or have mostly decent Eff, but low IMP.
The only SET ish amps I’ve heard to date were the Thor TPA30s at. a dealership in Clearwater largo area. Years ago. In a room near my size, they were driving a pr of VR4 JR pretty well. I’ll never forget that sound.
Apart from that joint, there are not any venues I know of nearby at all. Friends in a local club have some tube gear but its not the more prevalent setup. Most there like Panel speakers and Pass amps. There are likely others I’ve not met that may have glass power running. One was using AR lots o watts amp tube monos to drive their panels with, another was using Avant Gard Unos.

My ‘radar’ is on for any and all Triode and Ultralinear amps, INT, MONO or 2ch.



Atmosphere > This is all about distortion, which all amps make so the ’percentage of usable output power’ has to do with the **kinds** of distortion that are particularly objectionable to the human ear. These are the higher ordered harmonics (5th and above, particularly the 7th), IM distortion, and in the case of class D, inharmonic distortion (caused by intermodulations with the scanning frequency; similar to aliasing in digital audio).
Its my opinion and also my experience that four ohms has no place in high end audio (IOW if high quality audio production is in fact the goal). The cables are more critical and all amps sound harsher and less detailed on four ohms as opposed to eight or sixteen all other things being equal.


Blindjim > Whew!! Super. Got it now. Thanks.
Nearly every spkr I’m growing more fond of have 4ohm IMP!! So its appropriate to echo Charleton heston, kind of, “Damn you speaker makers! Damn you all to Hell!” lol


Atmosphere perhaps you could PM me or enter a link to which speakers your exp has shown are amenable to lower powered glass amps. Certainly, yours and perhaps others too.


My usual approach before this thread was to force a #12 foot into a #10 shoe, amp & spkr, respectively. Merely Add more watts to either overcome the low IMP of the spkr and try to avoid .clipping and or distortion, or with easier spkr loads yield better driver control. Control is an often overlooked facet. Its undeniable when listening however, if its absent.


I’d sure like to see a chart that reveals the equivalency between glass watts and SS watts. SET; OTL; PP; etc.

If tube amps could only manage higher damping factors it might make this affair an easier task.


I’m looking at or trying to figure out just which road, and then which block to land on by making one upscale purchase, and be done. Not at all a ‘cost no object’ affair, but then a ‘destination’ for me, may not be a or the destination for you, though we will both wind up with our own destination arrangements. Unless we just can’t leave well enough alone.


It do get complicated once all the factors are taken into account trudging down the road of better sound. Rooms, $$$$, esthetics. Amp & spkr matching. Topologies. Personal preffs. Logistics. Auditions. Sheesh.



charles1dad > The irony is that the vast majority of high End speakers are in the 4 ohm range. I do believe Ralph's assertion that higher speaker impedance is beneficial to all amplifier topologies. It seems many speaker builders would disagree with him given the predominance of 4 ohm speakers in the marketplace.


Blindjim > sure seems like it to me too as nearly every one on my short list is 4 ohms. Over 90DB but still….
And NONE of them are under $14K, several are above that point. Well above it.



wolf_garcia > Silverline Preludes (allegedly 91 db) with 2 REL subs You can simply turn the amp up to test the limits (at a certain point it just loses it's mind… absolute clarity at the levels I choose to listen, and I'm very picky about noise and distortion


blindjim > My previous Silverline Sonata IIIs were relatively an easy spkr to push too. Current iterations in that line up have just lost their ever loving minds with price increases. OMG.
Congrats with the Pre’s & Rels. You bring up a great point saying two subs are in use.



Swampwalker >   It was this whole issue of sounding "loud" when a system should not sound loud when turned up. Rather, the performance should simply swell and grow with greater impact etc....


Blindjim > Illuminating! About exactly what I needed to see/hear. It troubles me that you and I are on about the same wavelength pretty often. In fact, it should concern you even more. Lol


My impression here is semantics. What if we interpose subtlely ‘irritating’ for too loud, or just ‘loud’, or refer to it as ‘‘subliminally grating’ ?

My first forays into putting t together a stereo commonly ran into OK at low levels, above that, not OK.

Loads of factors abound that were influencing those sonic annomolies. Lots. Not merely ‘synergy’.it was a pretty harsh and lengthy learning curve. Thereafter, from this venue, I found all the answers I needed. Latter rigs never showed themselves as anything but ones I could listen to for any length of time.

Presently, it sure looks likely riding down the middle of the tube road is where I’ll land once more…. Moderate power, moderately high eff speakers with an easy IMP… if I feel its doable.

To that end, the main item to avoid IMO is a glass power train that emulates SS sonics. It would be absurd!

Regardless, the info from this thread has so far been in a word, ‘revealing’.



charles1dad > In addition to the VAC REN amplifier, believe that the Atma-Sphere S-30 , M-60 and the Linear Tube Audio ZOTL 40 would serve Blindjim well


blindjim > I’m eternally grateful for any and all mentioned amp options or possibilities as much as thoughtfulness and home work are required to pursue ANY system errection, logistics too play a big part. The greater the budget the more concern there will be for making or introducing errors or an outright failure in synergy.

Of course, one might just stumble into a room and find it all right there but that seems a long shot IMHO. Would be nice, a turn key outfit along with a pretty fair bargain. Done.

Otherwise, its just a best guess scenario. Regularly. You can have all the specs in hand and still it doesn’t butter your bread at the end of the day. Might be very close too! Just no cigar.


Even finding a few possibly desired items in close proximity to each other seems daunting at the moment.



Swampwalker > Of course, you COULD opt for the WAVAC HE-133 150 wpc SETs @ $77K. That would maximize your choices for speakers, if in fact you had any $ left over to buy speakers ;-)


Blindjim > the goal is to get in and out for way less than what those amps run. Way less. The longer I fuss around with it, the lower I want to go $$$ wise. Lol

Given my ‘front ends first’ approach, I’m all about a solid amp selection and a great source choice. Then… very nice spkrs. What ends up happening is a true mystery at the moment. What where and even when are still in the fog.


Naturally, the amp & spkr combo will be reciprocally introduced.

Regardless, my ‘approach’ works. Has worked well. More than once. It will work again.

More will be revealed.

anyone have exp with Pure Audio Project loudspeakers?

has anyone established a reasonably current list of High Eff spkrs anywhere?
All I can think of are: Zu; Coincident; deVor; Avant Gard and some horns, which I sure don't mean to dengrate at all. it is merely their esthetic that is a tad hard to take.

Blindjim,
Here’s are a few more,
Horning
Vaughn Speaker
TonIan Labs
Sonist
Ocellia
Trenner-Friedl (certain models in their line)
Audio Note
Tekton
Coherent Speakers

Charles 

Dumping the output transformer is the key to getting the very best out of tubes.  I have a David Berning pp 300B integrated that puts out 20-25 w pure Class A drives my Rockport Aviors (89.5 db) with ease. The sound is absolutely stunning with Genalex 300Bs.

@charles1dad

Here is a picture of the one box solution I referred to especially conceived for you. In fact it was inspired by your system and posts. I see you as the DHT evangelist. Yes, this is a compliment of the highest order Charles. Introducing the 1DaDDHT music making tour de force! 

Ok, I am not talented enough to make this hybrid digital, Class D, DHT, DSD dac, room correction one box unit that I dream of for you and others.

Here is what it could look like if Lyngdorf made it.

http://s1097.photobucket.com/user/grannyring1/media/1DadDHT%20mod/DHT%20Mod_zpspmsxhs4w.jpg.html?sor...

Great list from Charles1dad, to which I would add
Classic Audio
Audiokinesis

Also Ref 3A are not true high eff but are definitely tube friendly due to part to minimalist crossover. 

Also note that not all horn-loaded speakers look like the Avant Garde horns. 

A couple of other thoughts:
Another way to skin this cat in terms of using moderate power tube amps is the way I am going at the moment...Atma S-30 driving quasi-full range Feastrex field coils above 60 hz.  NHT X-1 Active crossover  250 wpc Class D ss amp driving 2, 10" woofers per channel.  These are DIY open baffle speakers bought from an A'goner in CA.  You reduce the power demands on the tube amp by not requiring it to reproduce deep bass. If you've ever had an amp w power meters, you can watch them swing in time w the bass line. A somewhat simpler way would be to use monitors or single drivers and a pair of powered sub-woofers with built-in crossovers. 

As far as finding desired products in close proximity and/or being able to buy a "turn-key" system at a good price, I'll repeat what I mentioned above...go to one of the good high-end shows.  Despite all of the known problems of auditioning there, you will NEVER be able to hear as wide a range of speaker/amplifier combos at one time as you can at, for example, RMAF or T.H.E Show.  Never been to Capitol or Newport, but they seem to be similar.  If you hear a combo that floats your boat, you can probably cut a good deal on the show demos. 

I tried dumping the output transformers and the amp exploded and nearly destroyed my double wide. Lesson learned.

wolf,

You should have stayed with the dual toaster outputs,probably wouldn't have issues.LOL.


Kenny.

If " dumping the output transformer " were the best way - everyone would be doing it. Ralph and Davis are not the only capable tube amp designers in the world. This is a complete nonsense.

Inna,
I wholeheartedly agree there are power amplifiers with sublime sound quality that utilize the output transformer.  I do sincerely appreciate the high quality of the Atma-Sphere,  Berning designs.  There are however other extremely talented amplifier builders who do superb work with other topologies. 

Bill, I was unable to download the picture of your unique amplifier 😊
Charles 

Charles, that is a shame.Seems to work for me and others? Ok, I have a listing for a grab bad of DIY stuff here on the gone. Only a couple of listings there and mine will be easy to find.  Look under the DIY stuff as I will add it there for a day or two.....it is the last of 6 pics.

Ralph, would you like to tell us about disadvantages of OTL amp design? 0.5% distortion at full power is quite an achievement.
One thing is certain - more powerful SET amps done right are very expensive.

Upon further review….
Until I gain more personal exp this project will be done on a much more limited basis. So it’s a secondary system effort for me going forward.

I simply don’t feel confident enough to move ahead all in with the limited exp I presently have. This means too, speaker choices should have grown a bit.

To date, both EL34 amps I’ve heard I’ve really really loved their sound. The Thor 30’s in triode, and the Dodd monos in ultralinear. And, in that order.

Going forward, speaker choices will attempt to will lend themselves towards easy IMP curves, and higher sensitivities so a future triode amp might could swing with them occasionally.

Blindjim > Charles > your list is quite welcomed. Thanks.

Blindjim > Swampwalker, THX for the nod to Columbia, you’re right. The very next step will be to travel. Do a show or two. Hopefully things will settle up before CES.
BTW… I sort of figured all along relieving the what ever amp of duty below 100 - 120Hz was just about a given, and subs would take over from there down.

Maybe there are some nifty dealerships around the Birmingham area I can check out as that is my next stop for a follow up on some medical issues in a couple months or so.

Inna > One thing is certain - more powerful SET amps done right are very expensive.
Blihndjim > Inna would you mind shooting in a few SET amps done really right options here?

I see nothing with regard to how should I say it, more main stream high eff speaker makers like Coincident … Daedalus… grand Venna… etc. being submitted? Do these ‘main stream’ units pale by comparison to the ones just now listed?
Not efficient enough?

I’m putting Ayon triton III INT, Coincident’s 211 monos, the top Prima Luna monos, Atmas monos, Bernings amp, on the so far short list of tube amps. Manley, VAC and VTL come and go from it periodically. I’ll count out no one at the moment. Nor dismiss buying pre-owned. It ain’t gotta be monos. My pride will accept a 2ch one chassis amp. I just won’t tell anyone about it. Lol

All of the Input here has been and is simply fantastic. And greatly appreciated.

blindjim,

Thank You for starting this thread,
It's been a wealth of knowledge for me and others.
There is a bunch of high quality tube amps on the market nowadays and sometimes it just makes picking one that much tougher.

I look at myself traveling down this audiophile road and I know It's a journey and my ears are in the drivers seat while the rest of my body just kicks back and enjoys the music,because all of this gear we buy and or talk about is really just the "Means to the enjoyment of music playback in our homes"and for me It's all about the music.

I wish you the best of luck in your journey of finding the sound that gets you a closer connection to the music you Love.

Kenny.

blindjim > Kenny. no problemo.

life is a learning process and with any past time learning is key. it will diminish the hurt of buying the wrong thing or things, or paying too much... or not enough.

so long as I keep learning, I reamin young. to stop learning, allows the aging to progress.

Yup, not paying enough is the biggest mistake audiophiles make. Paying too much is the second biggest mistake.
SETs done right? I already mentioned LAMM and Wavac. Never heard the latter but some here did.

Interesting info re: tube amps.
Lotta talk about speaker compatibility.
Anybody got a short list of favorite tube amp compatible speakers?
I struggled to find speakers for a 300B Woo WA5 but finally gave up and now just use the headphone output.
Also have a PrimaLuna HP Integrated. More power but still swapping speakers in and out. Not completely satisfied so far.
Any suggestions would be appreciated.
Thank you!

@blindjim 

Did you buy that set of Thor TPA30s on Audio Mart? If so, killer deal and good for you. I owned this amp twice. I have done numerous upgrades to them and they represent some of the best PP tube sound one could ever purchase. Wonderful el34 design getting the best out of this tube. I wanted so badly to buy them again and upgrade the film caps, but not enough power for me. 

Replace those Hovland caps with good copper foil PIO caps from the likes of Jupiter, Duelund, and Audio Note. Very nice improvement for sure.  

Hi Leotis,
I posted a list of potential speakers on this thread yesterday. I don’t know what your specific budget is but the Tekton Double Impacts and the Coherent speaker a floor standing 2 way (Canadian)are in the 3000-3500.00 dollar range. Different design approaches but both are said to mate  well with a 300b SET amplifier. Worth looking into I believe. 
Charles

Thanks Charles dad,
Didn't realize this had gone to 2 pages when I posted. Will check it out.
(BTW, thanks for the balanced power tip on a different thread.
I now have 4 EquiTechs. Balanced power seems to be one of the best kept secrets in audio.)

Leotis, 
You are welcome.  Balanced AC electrical power is a major asset for audio systems in my opinion.
Charles  

So I take it that higher impedance speakers make tubes sound better somehow.
So I used the 4 ohm taps on my PrimaLuna HP Int to my "8 ohm" speakers instead of the 8 ohm taps, giving the speakers relatively higher impedance vis-a-vis the amp.
And it does sounds better. More presence, more nuance, fuller sound, more real sounding.
But what is actually happening? Is it lower voltage and more current? Or vice versa?
Maybe it doesn't really matter, but is there a simple explanation for the difference between the 4 ohm and the 8 ohm outputs?
Thanks.

Inna > I mentioned LAMM and Wavac.

Blindjim > huge thanks Inna can’t say how much I appreciate all your feedback. yes, you sure did. I’ve been reading furiously on every suggestion, and all the technical data. I am getting confused with all the input I’m gathering, though I do have notes on nearly everything so far.

Saw at least one LAMM amp needs manual biasing. For me that’s a deal breaker. Its ticket is another I suspect, for now at least.


Grannyring > Did you buy that set of Thor TPA30s on Audio Mart?

Blindjim > sorry man, no. Not able yet to do anything worthwhile yet. Still waiting.
Yep. Bone stock, they were the best sounding little goobers I’ve heard to date, and on run of the mill Eff spkrs. That sound is why I bought the TPA 1000 Mk II line stage, and those VR4 JR spkrs. Although not in that order.

If or when possible, I’d buy them or the 60wpc versions in a heartbeat depending on a few buying selling issues.

saki70 > take a look at those with built in amps for the bass units

blindjim > Thanks man. Got it. I’ve seen a few but have decided to go only partly in on low power high eff as a secondary system now.
It could change, though the odds say it won’t, but all of the jury isn’t back yet. So we’ll see. Mostly it looks like a PP amp.


Leotis > So I used the 4 ohm taps on my PrimaLuna HP Int to my "8 ohm" speakers
is there a simple explanation for the difference between the 4 ohm and the 8 ohm outputs?

Blindjim > Leotis, been there and done that myself.
When an amp has optional output taps, the amp is designed to output the total voltage and or current it produces into that load. Ie., 60wpc amp via 4 ohm tap = 60wpc. Same thing for the other taps provided the load or IMP of the speaker is similarly matched, unlike SS amps that automatically see or ‘feel’ the changes and react differently.
.
Essentially, using a lower output tap or lower IMP on a higher IMP load or speaker will cut the power output by 50% or so. In any event it will be less power to the speakers if set up that way.

Speakers should be transparent enough to reveal upstream and room concerns, changes, and problems. For them to do their job as such, they need the right amount of power and the correct electrical operating environment, or as best is possible.

You can look at speakers like rocks. Look at an amp like a bulldozer or truck.

As strong as is a truck or bulldozer, it can only push a particular size of rock. Sure, it can easily push little rocks, or medium sized rocks, and even a larger 4 or 2 imnpedance sized rock but it has to match up to the rock as well with its gearing too, not merely its engine.

Using lower IMP taps sends less power to the speakers, IF the speaker IMP is much higher.

Highs will roll off, bass will be more bloomy, and usually the sound will be smoother and warmer because the speakers are being starved and can not fully demonstrate what they are capable of providing. Resolution will suffer, leading edges will get rounded off.

The sound will tend to be darker and more euphonic than normal as the speaker lacks the power to yield speed and fully demonstrate the entire bandwidth properly.

I did that mismatch with a couple different amps trying to get them matched up the best way possible. You don’t truly know what the imp curve is on many speakers, but amps do. They will tell you IF you pay attention and try the amps various taps..

Usually, the spkr maker gives you a really good indicator of what a nominal IMP for their spkrs run but that’s at one particular freq at one designated voltage. Like 1KHz at one watt, or 2.8 volts or so.

But what about power needs at other freqs? ImP will change then and music is made of many frequencies and volumes.

Its at times a best guess scenario so we use the amp to tell us what it likes, and we listen for the best match.

I liked the mismatched setting on a pair of speakrs I had as they were brand new and not fully run in. they sounded bright and thin on the right 8 ohm tap so I slid them onto the 4 ohm tap. Sounded much better then albeit a whole lot darker though.

after about three or four months I switched them onto the higher IMP tap and whoa! Night and day different! By then they were run in quite well. I begin getting loads of resolution, impact, better dynamics, more transparency, greater extension, every aspect of the reproduction improved. Thankfully they were 93db and an easy load of 6 – 8 ohms and I did not push them hard so the obvious lack of power did no harm to the tweeters. From clipping.

following the uptick to 8 ohm taps, and the greater resultant transparency ai was able to determine what did or did not work well in the system. Wha twas making things bright, rolled off, was buzzing, if there was a ground loop causing the trouble, more exactly how wires were contributing to the affair, etc., bedcause then I could hear things better.

Until then, I was like the system mostly in the dark. But for a while, it sounded OK to me. lol

Thank you for the very interesting answer!
Will have to study it a bit.
I did the swap using only 1 cut for a quick comparison.
What you say seems to correspond with what I heard.
Speakers are Revel F206. Even though nominally 8 ohm, the impedance curve looks mostly around 5 ohm or less.
http://www.soundstagenetwork.com/index.php?option=com_content&view=article&id=1238:nrc-measu...
Will need to experiment a bit more.
I really appreciate your response.
Leo

@inna 

Ralph, would you like to tell us about disadvantages of OTL amp design? 0.5% distortion at full power is quite an achievement.
One thing is certain - more powerful SET amps done right are very expensive.

We get that figure without using feedback. With feedback the THD can be as low as 0.05% but we don't like feedback for the same reason that SET designers don't: it adds brightness.

OTLs have several disadvantages- speaker choice is an issue, as the smaller OTLs can't do 4 ohms very well. Generally speaking, if the speaker works with a low power SET it will work with a low power OTL too- the difference being that the 'low power' OTL will likely have several times the power of the low power SET.

The next issue is the number of power tubes, for example we use the 6AS7G which is good for about 10 watts. So you need a few of them if you want to make any power. Some OTLs use the EL509 or EL519, which are pentodes but the most common alternate is the 6C33. Four 6C33s will make about 60 watt in an OTL.

Finally, the smaller you make an OTL, the less efficient it becomes. So while our M-60 is perfectly comfortable on 8 ohm speakers, our S-30 is a lot more finicky about that- it can do well on some 8 ohm speakers but if there is a wild phase angle or the amp has to work hard it may not like it. Conversely, the bigger the OTL the more efficient it becomes so even though the class of operation has not changed, the bigger amps tend to have lower temperatures on each tube because more of the power is dissipated in the speaker rather than in the output section. 

leotis > Thank you for the very interesting answer!

Blindjim > No problem. I’d keep them on the higher taps for a while, listen, closely. That is of course once the amp has settled in on that portion of the circuit. A few days more or less should suffice. .

Another analogy for incorrect IMP matching of amps to spkrs could be like driving a 5 speed vehicle only in 2nd gear. It will take off and it will run but overall performance will suffer.

Another will likely be able to definitely say this more accurately, but I tend to think the taps on tformer output amps were designed to run in a range, not just one specific imp load. So I’m figuring the 8 ohm tap means about 8 ohms, and from above 4 to 8.
This is unless ther is a 6 ohm tap on the amp too. Then the range for the 8 tap diminishes to between 6 & 8 or above.
The 4 ohm tap is for that section of IMPs at or below 4 ohm loads.
Follow?

The only real worry is as said, clipping. Its when a driver is starved for power predominately. Usually it’s a tweeter. Ordinarily clipping occurs when running the spkrs at higher levels and the power a driver asks for can’t be provided appropriately or comes intermittedly. That’s when actual . damage to the loudspeaker can take place. It happened in a pr I had bought preowned. His INT did not have the power to satisfy those speaker’s demands and one of the four blew out. Quit working. The factory fixed it eventually. Once I paid for shipping and so forth.

Ralph, thank you, now I got it.  Yeah, relatively limited speakers choice. Number of tubes would not be a problem for me unless each cost $1k and lasted only for a year. It's a bit more difficult to do amp first approach than speakers first approach. But with Atma-Sphere and LAMM I would still do exactly that.

Directly heated triodes are quite linear devices, and they tend to take on the characteristics of the driver circuit.

The larger transmitting triodes (211, 845, GM70) are particularly difficult to drive, which is why you see some of the esoteric Japanese designs employing power tubes for the job.

The 300B is an interesting animal. It has a stereotype of being lush to the point of sounding bloated and slow. Again, this is a driver tube issue (let’s not forget about adequate power supplies, of course). You’d be surprised how "quick" a 300B amplifier can sound when driven correctly and I’ve heard very few 300B SETs that get this right.

Everyone has their opinion about various architectures (DHTs vs. pentodes, OTL vs. transformers, etc.).  My stance has always been that there's a convergence in architectures as the designs get better and better.  While I'm a big DHT/transformer coupled fan, I recognize that this is personal preference (no accounting for taste), and not an expression of superiority of one architecture over another.

Cheers,
Thom @ Galibier Design

Number of tubes would not be a problem for me unless each cost $1k and lasted only for a year. It's a bit more difficult to do amp first approach than speakers first approach. But with Atma-Sphere and LAMM I would still do exactly that.

We warrant the tubes in our gear for a year and they are relatively inexpensive.

The only real worry is as said, clipping. Its when a driver is starved for power predominately. Usually it’s a tweeter. Ordinarily clipping occurs when running the spkrs at higher levels and the power a driver asks for can’t be provided appropriately or comes intermittedly. That’s when actual . damage to the loudspeaker can take place. It happened in a pr I had bought preowned. His INT did not have the power to satisfy those speaker’s demands and one of the four blew out. Quit working. The factory fixed it eventually. Once I paid for shipping and so forth.

The mechanism for this is when the amplifier clips, the distortion generated is high enough in frequency that the crossover allows it through to the tweeter(s), which usually only handle maybe 2 watts or so. With solid state amps in particular, overloading the amp is a good way to toast the tweeters.

This is considerably more rare with tube amps because they generate less higher ordered harmonics when overloaded (which is usually caused by bass notes) but still can happen.

If you see tweeters blown and nothing else, its a sure sign that the speaker was exposed to an amplifier that was clipping. Most manufacturers would not consider that as a warranty claim as it is clearly abuse of the speaker.

thom_mackris > huge thanks tom.

Blindjim > the design topology I irrefutably decree best, is the one that sounds the best, can drive the speakers I like, and is within reason, affordable.


Blindjim > atmosphere thought you might clear that clipping item up better. Thanks.
I am ever grateful to VSA for bailing me out on damaged spkrs sold as working properly. That was quite the learning experience all in all.

in fact VSA changed out both left and right associated tweets, not merely the bad one. I ran them in properly and sold them so I could get higher Eff spkrs. And use tube power for a change.

It was the worst decision I’ve made to date. Its like going into the ‘big room’ at a dealership first, instead of just dealing with what you can actually buy instead. Trying to remain intent on the lesser goods then sure is harder. I often lose interest and become quite depressed.

You get used to the increased performance that is available! Going back to ’lesser goods’ can be a bit depressing. But I find that if you are careful, good sound can be had on almost any budget.

We are chasing great sound not good. Good is easy.

Atmosphere > good sound can be had on almost any budget.
Blindjim > thanks. My depression lifts.

Inna > We are chasing great sound not good. Good is easy.
Blindjim > … and its back. lol

I’ve been delving deeply and steadfastly in between the lines of articles where possible on Coincident and Devore loudspeakers. And feel there yet may be a light at the end of the tunnel, that ain’t a train.

As a secondary outfit, an all Coincident system could wind up landing fairly inexpensively and be like my last Honda ’73 750cc bike…. A SET starter kit. Actually, the Harley owners called the Honda a harley starter kit.

After the military, my Kawasaki full blown streetable drag bike was very different. It ate Harley’s for breakfast.

I suppose, one must begin somewhere at some level and thereafter merely follow directions from those who have been there before, to achieve a similar destination.

Life is so simple. Only money complicates it.

Life is so simple. Only money complicates it.

**That** certainly seems to be true.

The Coincident loudspeaker concept (tending to higher impedance) that Israel has had for the last 10-15 years or so was developed using an OTL, not an SET. Unless you get a fairly powerful SET, I think you will find that in most rooms the Coincidents really are not efficient enough to bring out the best of such amps, although they are otherwise easy to drive- I find most of them need about 60 watts as a good minimum in most rooms (we've showed with Coincident a bit in the past at CES and had them in our shop so this is based on direct experience). We had one customer (also a reviewer) that ran one of the smaller Coincidents with our S-30, and while it sounded fine, she found that she was wanting more power. 

We had a set of Coincident Total Victory loudspeakers here at our shop for several years; they sounded just fine but if I had to rate the efficiency I would say they were around 93 db.

We had a set of Audiokinesis loudspeakers here too; Duke of Audiokinesis rated them at 92 or 93 db 1 watt/1meter but they seemed more efficient than the Coincidents (Duke tends to be very conservative with his ratings; we've yet to see any of his speakers that didn't play well with our S-30).

We also had ZU Druids which were obviously more efficient (rated 101db which I think was a bit optimistic as well; 97db seems more accurate- otherwise also about 10 ohms) and also Classic Audio Loudspeakers which are 98db 1 watt/1meter (and 16 ohms).

So I have good reason to think the 93 db number I suggested above is pretty close.

In a nutshell, while Israel's amps sound just fine, on any of his speakers (unless you only play at lower volumes) I would think his amps won't make enough power although they do sound good together.

" she found that she was wanting more power "
Right. Women are always wanting more power. So are men.
I agree with Ralph philosophically. Just because it overall sounds good doesn't mean that that's enough. Double the power while maintaining the rest. At least double.

I owned the Coincident Total Victory II and found they also needed more watts to sound their best. However, I know Charles1dad has had, and continues to have, stellar results with his 8-10 watts on his set of Coincident Speakers. I am sure he will chime in.

grannyring,

What amps did you like with the Coincident total victory 2's when you had them and how big was your room.


Kenny.