[crbc]

Quote:

So to sum up, we have:

1. Enough power to run the toughest headphones, though the only offered power spec is 6.25mW.
2. An amp that runs slightly warm to the touch while supposedly generating huge amounts of power.
3. An OTL with high output impedance masterfully driving low impedance headphones.
4. A new method of driving a tube that generates huge power while extending the lifespan from 1,000 hours to 100,000 hours.
5. All of this powered from a battery.

It doesn't add up.

If there is an explanation, it is time to tell everyone.

Having owned and enjoyed my Continental now for a couple weeks, I've read this thread of mind-numbing, techno babble with great interest. 
 
Obviously, there are better headphone amps out there, such as the Cavalli Liquid Fire at the high end and the Schiit Lyr (which I own) at the moderate level.
 
But the iPod/Solo/Continental comb delivers very, very pleasing sound to my Audese LCD-2's  relative to its tiny form factor weighing only 1.5 lbs., enabling me to have some great music with me as I travel and even when I'm playing catch with my golden retriever in the back yard.   It is a trade-off.  
 
I don't know how the iPod/Solo/Continental combo does it, nor do I care.   Maybe there is a mouse running a treadmill inside the Continental's case.   But it sure sounds good to me.  Amazingly good in fact.  As an Absolute Sound subscriber since Issue #1 (1974), I subscribe to Harry Pearson's core philosophy - "Trust your ears".
 

 

[Naim.F.C]

Quote:

I'd never buy a product from ALO... if any problem arises they will not help you, as was the case with a $500 time I got from them. They are only in it for the bottom line. many people had this problem with them.
 
71B all the way man, I even preferred the 71B to my WA6SE

I can't comment on the 71B, but many Head.Fi'ers have stated that the 71A is better than the 71B single ended. I can tell you that the ALO Continental to me anyway, is a much more accomplished portable amp than the 71A at least with the T1's, talking purely single ended here. It has a more dimensional sound stage, a warmer tone, smoother highs and better bass emphasis. It has a lovely smoothness about it that adds a much desired warmth, texture and naturalness to certain more articulate, sharp or bright cans/IEM's. It does all that with a lot more power and rechargeable batteries (so far 5 hours and counting since my last charge, which I'm taking time stamps on) to boot. Some might prefer the 71A (which is a bit more clinical or neutral in tone, perhaps slightly more high emphasised with less on the lows or bass), but with the T1's, The Continental is by far my most addictive combo.
 
In other words, it's a fantastic portable amp. The best I've used yet in-fact. I can't comment on 71B vs Continental (neither can you since you've never used it and are just injecting loaded judgements) but do bear in mind the Continental is a good degree cheaper. For the power you get in the Continental, I honestly do think it's great value for money. You'd be hard pressed to find as much power from a portable for the same price.
 
I will say that whilst Ken's responses do take some time (he's likely a very busy man), he has always been extremely helpful and informative on everything I have asked of or from him. So I have to reject your notion that ALO are just in it for the bottom line. They make sublime products of the highest quality that thousands have been immensely impressed with, and do it whilst retaining a good standard of customer service. 
 
I forwarded this thread on to Ken and he did respond, his engineers and he will look to gather some clarifications.
 
Quote:

Originally Posted by crbc /img/forum/go_quote.gif

I subscribe to Harry Pearson's core philosophy - "Trust your ears".
 

 
This cannot be emphasised enough. Asking questions is fine. It's healthy, advisable and welcome right as consumers. But armchair engineers injecting random conjecture and judgement based on assumptions and misinformation is less flattering.
 

 

[skeptic]

     Quote:

I don't know how the iPod/Solo/Continental combo does it, nor do I care.  
 

I'm glad you are enjoying the sound of your rig crbc, but if it is ultimately determined that you bought a product that substantially deviates from how it was advertised (i.e. a limited edition portable "tube amp" which is using a "6111sub-miniature low gain, ultra-low micro-phonics, dual triode with a characteristic open sound stage and smooth delivery" to amplify the signal), you really should care.  
 
Given that you've evidently spent the last 37 years of your life reading about audio gear, it seems a bit surprising that you would try to write off all of the legitimate questions raised in this thread as "mind-numbing, techno babble."
 
Edit: at the end of the day, I earnestly hope that we are talking about a simple error in the napkin math and/or the published specs, and that ALO can set this thread back on course.  However, I'm not sure what the supposed "misinformation" is that Naim is referencing.

 

[Naim.F.C]

Quote:

 
Edit: at the end of the day, I earnestly hope that we are talking about a simple error in the napkin math and/or the published specs, and that ALO can set this thread back on course.  However, I'm not sure what the supposed "misinformation" is that Naim is referencing.

I was talking about the misinformation surrounding the specs or capabilities of the components. Running temperature, tube life span, tube use, circuitry (notion that the tube is not being used at all) and so on. There is a lot of conjecture without a lot of fact. This tube supposedly should run well over boiling degree temp, but what is that based off of? How do we know how these old tests were conducted, under what circumstances etc and how do we know how it compares to the specific use of the tube in the Continental? Simply put we don't (even though some are implying we do). We don't even know the life span of the tube as they were (from what I read earlier) never tested beyond the 1000 hour mark, yet it is has been proposed by some that the life span is exactly 1000 hours. Truth is, no one beyond the manufacturers, or people who have specific expert experience with the tube, can really confirm that.
 
I found this data sheet of the tube. It does mention the very maximum stats, but also typical use. This at least shows us there is a good degree of variance in how they can run.
 
http://tubezone.net/pdf/6111.pdf
 
 
One thing I mentioned earlier however about how they may have used specific testing procedures to speed up or exaggerate stress points and times, similar to how car manufacturers do, evidently turned out to be accurate. Based on this excerpt. 
 
The conditions for some of the indicated tests have deliberately been selected to aggravate tube failures for test and evaluation purposes. In no sense should these conditions be interpreted as suitable operating conditions.

 

[Tonyflo]

Quote:

This thread is about the Alo continental. Please don't detract from the discussion with unsubstantiated claims of Alo service. I have had nothing but good experiences with them.

+1, they handled my CLAS + Rx/Mk2 order flawlessly, talking with me on the phone and rushing shipment because I was traveling soon and needed the gear to arrive very quickly. 
 
While I haven't had any "problems" I would feel 100% confident ordering from them again, and when I get the LCD2's in fact, I will be ordering the recabled version from them .... possibly with the RWA/Audeze amp. 
 
Still, I'm just extremely surprised that nothing has been said or clarified about this product on any of the threads. That's s stark difference to how it was with the CLAS. I know the CLAS is a much more important product for them, but still am eager to hear Ken's thoughts on the specs and what the reality is. In the meantime, I'm giving them the benefit of the doubt. 
 

 

[Squirelrepublic]

 
Quote:

+1  ...wonder why not the same fuss about the GoVibe Portatube, which is lacking in specs also, which seems a better competitor than the Miu (price wise, the GoVibe is far more expensive).
 
Is anyone with the Continental on the GoVibe loaner list?

I got this loan side by side with my continental (which i sold within 10 days). unfortunately my continental didn't pair well with any of my headphones and they are not fully burned, can't use them with any HD218/228/238 (they screech !!!! literary screech i dunno what happen ... sorry i'm a newbie) then went to meet and tried it with a pair of k701 but meh still doesn't work well, didn't tried continental with k1000 don't think it powers them, but somehow it works with my k430,
here's comparison between them in akg k430 :
my source is pico dac, ipod 5th gen, sansa fuze
1. soundstage of continental is substantially bigger than portatube,
2. I prefer the highs on porta tube, somehow i feel continental is too bright, porta tube's high is just sweet with a bit roll off especially on my esw10jpn which makes them sounds ..... more beautiful (i dunno the right word, sorry !)
3. porta-tube sounds more detailed than the continental
4. Separation in both are fine with continental in lead
5. midrange in continental sounds a bit more forward
6. Bass in porta tube is a bit lacking, but continental bass isn't that great either, i feel that continental's bass mostly is just mid-bass hump with least amount of deep bass and they sounds a bit boomy.
That's my impression so far, keep in mind that this is just my opinion and this is tested with a cheap headphones and is not fully burned in so if you try it with better phones the result may be different.
Anyway, they sucks with my Audio Technica, esw10 and w10ltd, it just sounds worst on them.
Well, it's true that they aren't made for them anyway...
 
Oh, porta tube dissipate heat better than Continental, and they are not prone to fingerprint unlike continental. and i feel them a bit lighter than continental. Battery life is about the same, connectivity porta tube has 6.3mm jacks so they are more convenient,
pictures :

 
Just my 2 cents.

 

[Armaegis]

Quote:

Another very interesting thing is that this is an OTL amp. I don't see any output transformers in there. OTLs are notorious for having a high output impedance. If you have an output impedance above the headphone impedance, there's no damping factor and you lose control of the bass. Yet the claim is that this drives low impedance headphones. Again, that would be amazing if it were somehow pulled off.

One of the first things I tried looking for in those pics was some transformers. I was thinking maybe they just cranked the tubes for big sloppy voltage gain without heat or current draw somehow, then used some transformers to step it down... or something like that. I dunno, still doesn't add up. *shrug*
 

 

[Uncle Erik]

Naim, not simply far-fetched. These claims border on the miraculous. No other tube amp operates this way, assuming the claims are true.

As for possibly having some new method, well, possibly.

Though I doubt it for three reasons:

1. If you make a remarkable breakthrough, as this purports to be according to sales copy, you generally lock it down with patents and other IP. If it's true, it would significantly change electronics manufacturing. It'd be worth big money. A quick check of uspto.gov shows no filings. And a major advance would not cost ALO a dime to lock down. They could license it to a big player like General Electric whose army of lawyers would nail it down overnight.

2. The design was released to the public. If you have a major advance, you don't put it out without the IP. Quite a few countries allow first-to-file patents, so there would be loss of control almost immediately. The design is not complex. Anyone with moderate skill could draft its schematics in 15-20 minutes, then have it everywhere on the Internet shortly after.

3. If you have something remarkably new, you put it in the sales copy. The Prius isn't advertised simply as a car, is it?

As for the heat, the datasheets do advertise that they were tested at 200° C, yes. However, it looks like the tube is mostly linear roughly 75% of the way out. It's not like tubes stay at room temperature until they receive maximum power. The heat increases along with power applied, in a very predictable and normal manner. I work on a lot of old radios and other tube gear. One piece of gear I use is a Variac. It's like a big heavy-duty light dimmer. I can adjust voltage from 0-120V with it. Very useful. I can assure you that tube heat reacts in a very linear way as you increase/decrease power. So a tube that has a maximum heat rejection of 400° F will likely put out around 300° F run at 75% of power. That might vary a few degrees, but it certainly won't be room temperature. So if this tube is running where it was designed to, it'd be rejecting around 300° F. The amp isn't that hot, is it?

As for variable lab conditions, etc., that just isn't feasible. All these companies were huge manufacturers. They had excellent equipment. I know because I have old test gear from some of these labs. There was a lot of electronics manufacturing in LA and much of the surplus gear ended up at the W6TRW swapmeet. I've been going to the W6TRW swapmeet since 1986 or so. I've bought a bit of surplus test gear there. It's top-notch stuff. (One favorite is a HP frequency counter with a Nixie tube display - incredibly cool.) I just don't see how the old measurements could be that inaccurate.

Further, tubes are a major business these days. Lots and lots of people use and test them daily. If the old datasheets were inaccurate, you'd find tube hobbyist websites full of corrections and updates to datasheets. But those don't exist. The datasheets have proved accurate for decades.

crbc: how do your ears feel about missing frequencies from 20Hz-40Hz?

 

[Naim.F.C]

Quote:

<Snip>

crbc: how do your ears feel about missing frequencies from 20Hz-40Hz?

I just downloaded each individual low frequency file from this site.
 
http://www.burninwave.com/#lowsweep
 
Starting from 20hz all the way up. Testing each individual sound file, (20hz, 25hz, 30hz, 40hz, 50hz, etc) there is not a single one of the lower frequencies I cannot clearly hear (even at very low listening volumes) using the Continental with the T1.
 
There goes that loaded conjecture! Feel free to add more!
 
As I said earlier, textured, warm, high quantity bass is one of this amps strong suits, not negatives. 
 
----
 
Mini ALO Continental vs RSA SR-71A comparison in-coming.
 
It packs more low end than the SR-71A does. In-fact I just did another short comparison (A/B'ing) of the two, not only with the above frequencies, but also playing Radiohead 15 Step/Weird Fishes over and over. Same as my opinions before. More warmth and low end quantity with the Continental, though just ever so slightly less defined (expected due to extra quantity), though the bass still has more texture. There's also smoother highs and slightly less forward, but thicker mids. Soundstage is also much wider than the SR-71A's, however the SR-71A does still sound slightly sharper and more clinical. For my tastes and synergy/use with the T1, the ALO Continental is a better choice. Transforms the can in to something much more musical, realistic and sombre. The SR-71A is a bit more detailed, compressed and energetic.
 
Sounds strange, but I closed my eyes listening to Weird Fishes with both and just wrote down whatever I could to describe how I envisaged the song being played.
 
Here's what i got lol.
 
Continental - Large'ish moody dimly lit club, atmospheric and addictive. Layered. Euphoric. Beautiful.
 
SR-71A - Small'ish room, packed in, studio like clarity. Close, he's huddled near to the mic. Busy but concise.
 
 
I could go in to more detail about specific instruments etc (which I can make out easier spatially with the Continental), such as drum beats having a more realistic oomph and resonance with the ALO, little miniature taps having a bit more energy or crispness with the 71A etc, but I'd be here forever. Save for the review. But I'll just leave it at that.
 
----
 
 
In any case, the more I listen with the Continental, the more I love it.

 

[Naim.F.C]

On a side note, the battery finally ran out on this last charge. Lasted 6 hours 40mins, give or take 10 or so minutes either way.
 
 
Just a simple iPhone pic for now (DSLR shots later).
 

 

[Wedge]

I 'm looking at the picture of the layout and the tube looks to me is at the input and their are 4 TO(somethings) at the output, probably some sort of discrete op amp output stage.  Looks to me this isn't an OTL amp at all something more like a hybrid.  The amp probably puts out more than 6.25 mW of power, but it certainly not a tube OTL output.  From the picture I'm pretty **** sure that tube is the input gain stage, or possibly even an input buffer just to give it a "tubey" sound.

 

[Naim.F.C]

Quote:

I 'm looking at the picture of the layout and the tube looks to me is at the input and their are 4 TO(somethings) at the output, probably some sort of discrete op amp output stage.  Looks to me this isn't an OTL amp at all something more like a hybrid.  The amp probably puts out more than 6.25 mW of power, but it certainly not a tube OTL output.  From the picture I'm pretty **** sure that tube is the input gain stage, or possibly even an input buffer just to give it a "tubey" sound.

This is what I was initially thinking when all the stir started. I'm not sure the tube is being used to full or normal potential but as you mentioned, perhaps just to inject some of the tube like sound, which thus far seems like it could be the case based on my use of the amp so far. Unless of course there are opamps that offer a similar sort of audio feel and sound that could have been used instead of the tube. Certainly looks seriously cool when it's lit up through the ventilation holes though.
 
Looking forward to clarifications if Ken does provide any, if only so the rampant guess work and hysteria can stop and we can all get back to impressions of the amp itself. Though whatever happens, it won't make any difference to my enjoyment of the amp itself. It's everything I wanted it to be, though I certainly wouldn't say no to more battery life!

 

[grokit]

 
Quote:

I 'm looking at the picture of the layout and the tube looks to me is at the input and their are 4 TO(somethings) at the output, probably some sort of discrete op amp output stage.  Looks to me this isn't an OTL amp at all something more like a hybrid.  The amp probably puts out more than 6.25 mW of power, but it certainly not a tube OTL output.  From the picture I'm pretty **** sure that tube is the input gain stage, or possibly even an input buffer just to give it a "tubey" sound.

 
Quote:

This is what I was initially thinking when all the stir started. I'm not sure the tube is being used to full or normal potential but as you mentioned, perhaps just to inject some of the tube like sound, which thus far seems like it could be the case based on my use of the amp so far. Unless of course there are opamps that offer a similar sort of audio feel and sound that could have been used instead of the tube. Certainly looks seriously cool when it's lit up through the ventilation holes though.
 
Looking forward to clarifications if Ken does provide any, if only so the rampant guess work and hysteria can stop and we can all get back to impressions of the amp itself. Though whatever happens, it won't make any difference to my enjoyment of the amp itself. It's everything I wanted it to be, though I certainly wouldn't say no to more battery life!

 

Sounds like what I was saying 50-something posts ago, much ado about nothing:
 
Quote:

It sounds like it's a hybrid, I don't see the big deal except they should have called it that. And published more accurate specs.
 
It obviously doesn't put much of a load on the tube, that's why it runs cooler and lasts longer. Hopefully ALO will be forthcoming with more information at some point.
 
The bottom line to me is that those who have used it are pleased with its performance.

 

[moodyrn]

In reading the description on their site, they don't come right out and say whether it's an otl, tc, or hybrid tube amp. But their description does give the impression that it is a tube powered amp. If in fact it is a hybrid amp, that's a bit misleading. The power section of a hybrid amp is solid state, and if this is a hybrid amp why not come right out an say it. Like Uncle said earlier, most respected tube amp manufacturers not only tell you exactly what you are buying, but will pridefully boast about their specs. Also, the claim of 100,000 life hours certainly leaves me scratching my head. Now there is a chance there may be some technological breakthroughs we don't know about, but there are many things to scratch your head about. The end result is about how good it sounds, but if they are being misleading, and/or dishonest, that wouldn't even matter to me. I believe the fiio e11 sounds good, and they are not making any bold claims about anything special it does that it actually does not do. So I really hope they chime in and give us an explanation. Do they legally have to? No they don't, but it would show a lot of good will towards the consumers who are on the fence about this. Even if it is a hybrid amp, preamp tubes get hot too. Not as hot as power tubes, but they do get hot enough to be too hot for pocket use.

 

[Frank I]

 
Quote:

Naim, not simply far-fetched. These claims border on the miraculous. No other tube amp operates this way, assuming the claims are true.

As for possibly having some new method, well, possibly.

Though I doubt it for three reasons:

1. If you make a remarkable breakthrough, as this purports to be according to sales copy, you generally lock it down with patents and other IP. If it's true, it would significantly change electronics manufacturing. It'd be worth big money. A quick check of uspto.gov shows no filings. And a major advance would not cost ALO a dime to lock down. They could license it to a big player like General Electric whose army of lawyers would nail it down overnight.

2. The design was released to the public. If you have a major advance, you don't put it out without the IP. Quite a few countries allow first-to-file patents, so there would be loss of control almost immediately. The design is not complex. Anyone with moderate skill could draft its schematics in 15-20 minutes, then have it everywhere on the Internet shortly after.

3. If you have something remarkably new, you put it in the sales copy. The Prius isn't advertised simply as a car, is it?

As for the heat, the datasheets do advertise that they were tested at 200° C, yes. However, it looks like the tube is mostly linear roughly 75% of the way out. It's not like tubes stay at room temperature until they receive maximum power. The heat increases along with power applied, in a very predictable and normal manner. I work on a lot of old radios and other tube gear. One piece of gear I use is a Variac. It's like a big heavy-duty light dimmer. I can adjust voltage from 0-120V with it. Very useful. I can assure you that tube heat reacts in a very linear way as you increase/decrease power. So a tube that has a maximum heat rejection of 400° F will likely put out around 300° F run at 75% of power. That might vary a few degrees, but it certainly won't be room temperature. So if this tube is running where it was designed to, it'd be rejecting around 300° F. The amp isn't that hot, is it?

As for variable lab conditions, etc., that just isn't feasible. All these companies were huge manufacturers. They had excellent equipment. I know because I have old test gear from some of these labs. There was a lot of electronics manufacturing in LA and much of the surplus gear ended up at the W6TRW swapmeet. I've been going to the W6TRW swapmeet since 1986 or so. I've bought a bit of surplus test gear there. It's top-notch stuff. (One favorite is a HP frequency counter with a Nixie tube display - incredibly cool.) I just don't see how the old measurements could be that inaccurate.

Further, tubes are a major business these days. Lots and lots of people use and test them daily. If the old datasheets were inaccurate, you'd find tube hobbyist websites full of corrections and updates to datasheets. But those don't exist. The datasheets have proved accurate for decades.

crbc: how do your ears feel about missing frequencies from 20Hz-40Hz?

EriK I agree with all your conclusions and you have done some research for the community which is much appreciated. I am kind of shocked that  Ken has not addressed the concerns nor commented especially since he is a sponsor here. I have never in 20 years of listening to tube amplifiers of ever hearing of any tube to last 100,000 hours. I think its only proper for Ken to step up to the plate here and advise how this amp works and to address the concerns here of the community. I for one thank you and appreciate you coming to the plate and bringing this to the attention to all potential buyers. Thank you for the effort you put into this.