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ALO The Continental - Page 6

post #76 of 456

I have had other portable amps that used the 6111 tube, in those applications the tube was driving a pair of BUF634. It was the BUF634 that was actually providing the power output to the headphone out. Wonder if that is the case with this Continental?

post #77 of 456

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.


Edited by grokit - 8/21/11 at 6:07am
post #78 of 456

I'm a little confused - I have not looked into this very carefully, but the 6111 is a 6.3V medium mu twin triode with an amplification factor of 20.  By way of comparison, the much more famous 6SN7 is also a 6.3v medium mu twin triode with an amplification factor of 20.  It is certainly possible to create a headphone amplifier from a 6SN7 that would provide more power than described above.  I assume the issue is that the battery power supply cannot provide the 300 ma heater current that the 6111 needs?  I didn't see a spec for the battery, but for a typical 9V battery to deliver the required 300 ma heater current that the 6111 needs to operate "normally", only about 1 hour play time could be expected.  So Erik I assume you think that the tube is being run far under the specified 300 ma heater current, thus impacting it's ability to provide it's rated amplification?

 

BTW: for the record, while I love tube amps, I think battery-powered portable tube amps are a bad idea.

 

EDIT: I just read above that it's also being theorized that the tubes are acting as nothing more than a unity gain buffer?


Edited by Skylab - 8/21/11 at 7:20am
post #79 of 456

Maybe the miu audio guys would be willing to provide us with some explanation as to how these 6111 portables work.  At least they haven't attempted to cover up/obscure the other components on the PCB per the  pictures of the internals that they posted (http://www.head-fi.org/t/547251/miuaudio-ih-tube-headphone-amplifier#post_7587506 ).  Seems obvious that transistors are doing the real work here.  I'll also give miu audio the nod on their case work as compared to the alo version...

post #80 of 456

I am not so sure that ALO tried to obscure the components, that is if your comment is related to the "goo" on some of the areas in the amp. As I recall some builders use similar to help dampen the vibration and thus produce a better sound. Just speculation on my part, just like when I posted the use of a couple of BUF634.

post #81 of 456

Can I just clear up one serious misconception that Uncle Erik has about the amplifier, the fact that it only puts out 6.25mW of power period. While this is true at 100,000 ohms, this is not true at a normal headphone load (anywhere from 16ohms to 600ohms). If it outputs 25VDC into say, 300ohms, then it outputs 2.08 W according to Ohm's Law (I have no idea if it can actually output 25V into 300ohms). 

 

I don't have anything to say about the rest of ALO's inconsistencies, and I'm in no way trying to defend the amp, but the accusation that it only can output 6.25mW is rather absurd. Blindly following statements is clearly a two way street on head-fi.

post #82 of 456
OK, that makes more sense. I was having trouble figuring out why a medium mu triode with an amplification factor of 20 would be limited to 6 mW...but I can see that might be true into 100,000 ohms!

Still, to get 6 hours play time, I think you would need at LEAST an 1800 mAh battery to deliver the rated 300 mA of heater current required by the 6111 tube. Is it possible that the battery they are using can deliver that? And of course the rat of the circuitry also consumes battery, so in reality much more than 1800 mAh is needed for 6 hours if the tube is run at spec.
post #83 of 456
True, logwed. You could also have a circuit that puts 1 Kilowatt into 300 Ohms.

Of course, you need a circuit and components capable of generating 1 Kilowatt in the first place.

All that is offered here is a rating that works out to 6.25mW. Clarification and explanation were asked for weeks ago. The only response was a third-hand testimonial that it "works."

As for a lay explanation, I chose to go after this in terms of heat for a reason.

Eyes glaze over when you talk electricity and use numbers. There is also a widespread perception that "numbers don't matter" and science isn't worthwhile.

Fine. But everyone understands heat. Everyone knows what boiling water is like. Everyone knows the blast of hot air from getting something out of the oven. You do not need an engineering course to remember what it is like to touch a hot oven.

Electricity and heat are deeply intertwined. Generate electricity and you get heat. Heat can generate electricity. The engine in your car generates heat when it creates power. Your body generates heat the harder you work. And I'm sure everyone understands why there's a fan on a CPU. I like to think people understand the relationship between heat and energy on a fundamental, intuitive level.

This is physics. There is a deep amount of research going back a good 140 years on the relationship between heat and electricity.

The 6111 tube generates heat when it generates power. A lot of heat. Fully driven, it will create heat on a level between boiling water and cooking a potato. If it were generating that kind of heat:

1. It would destroy the internal components;
2. It would give the user serious burns;
3. The battery would run out of power in minutes; and
4. The tube (per manufacturer's specs) would burn out in about 1,000 hours, not 100,000 hours.

The only possible conclusion is that the tube isn't really being run at all. It is mostly being lit up for show.

The only way there could be a slight amount of amplification is if other solid state devices (I only see one tube) are creating it.

Now, if someone contends that an an ordinary tube can be driven for 100,000 hours, create loads of power and be cool enough to hold in your hands, I am absolutely astounded. That violates the known laws of physics. It would change not only amps, but the way electric motors are designed, computers, the lightbulbs in your house, and, well, pretty much anything that runs on electricity.

So you can understand why I find this especially interesting.

On the other hand, it could just be an aluminum box with a paltry amount of power generated by some little chips and a lit tube as decoration.

By the way, if anyone wants a decorative tube, I have a box of tubes that sadly had their identifying marks rubbed off. I'll send you a decorative tube for the cost of postage - about $4 in the US. I'll tell you how to make it light up, too, free of charge. For another $25 or so, you could build a CMoy around it. Heck, a CMoy will give you about 35mW of power. You could have an amp with five times the power and a decorative tube for about $30.
Edited by Uncle Erik - 8/21/11 at 4:05pm
post #84 of 456

when i mentioned they are running their tube some special way earlier, i think i mixed this amp up with another..

post #85 of 456
If a tube is creating a lot of power it must create a lot of heat.

There are no two ways about it.

Solid state is just the same. Look at those big, finned heatsinks on amps. You also put heatsinks on smaller solid state devices. Look at pictures of solid state desktop amps. You will see transistors connected to black, finned heatsinks. The heatsinks are often the biggest parts on the PCBs.

If you create power, you create heat.
Edited by Uncle Erik - 8/21/11 at 4:25pm
post #86 of 456

welp.. the first one has hit the f/s forums.. now's your chance to find out ;-)

post #87 of 456
Maybe I'll contact the seller tomorrow. Today is busy.

I need to get my ears candled, spend some time exercising my pet unicorn and attend a séance after dinner.
post #88 of 456

boy, you really have it out for this amp...

post #89 of 456

Has anyone here tried messaging ALO and made them aware of this thread yet? I became sceptical of this product when I saw 100 000 hours of tube life in the specs. I'm no engineer and I've only started to dabble into this hobby but to my knowledge I've yet to ever hear of a tube that can last 100 000 hours. I've heard of 1000, 1500 2000 even as high as 4000 but never 100 000 hours. I say someone with authority on this forum should message ALO present the facts as seen on this thread and give them a chance to explain themselves on the thread. Either the specs are a typo or this product is a sham either way ALO should be given a chance to explain themselves and customers of this product should act accordingly to the final outcome.

 

@ Uncle Erik

Thanks for saying something, being a noob I didn't want to say anything in case it was just my ignorance of specs.

post #90 of 456

they have posted in this thread havent they?

 - nope must be in the official product thread....


Edited by Br777 - 8/21/11 at 4:40pm
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