[cooperpwc]

Interesting amp. I wish that this would work with ultra-low impedance IEMs like the ES5 (20 ohm). It looks like the lower limit is 32 ohms.
 
Maybe someone can try...
 
Also they seem to be skirting the output impedance issue:
 
Quote:

Input Impedance 30K ohms Output

 
What does this mean?

 

[Anaxilus]

Quote:

What does this mean?

It means we still don't have answers.
 

 

[Uncle Erik]

 
SPECIFICATIONS  

Tube type; one Raytheon 6111 NOS tube
Battery Type 1-Cell Lithium-Polymer 
Battery Play Time: Approximately 6 - 7 hours per charge 
Recharge Time: Approximately 3-4 hours 
Frequency Response: 40Hz-20KHz +/- 1dB 
Signal-to-Noise Ratio: >100dB 
Total Harmonic Distortion: 1% 
Stereo Crosstalk: >85dB @ 1KHz 
Input Impedance 30K ohms Output 
Dimensions: 120mm (L) x 72mm (W) x 27mm (H)
One Year Limited Warranty

 

A brief note on the Raytheon 6111 sub-miniature vacuum tube:

The Raytheon 6111 vacuum tube is a sub-miniature low gain, ultra-low micro-phonics, dual triode with a characteristic open sound stage and smooth delivery.  It can deliver a 25VAC audio frequency signal into a 100K ohm load.

The 6111 vacuum tube, with its ultra-low micro-phonics, low power consumption and rugged build is ideal for portable amplification which is why it is at the heart of the Continental. The 6111 is built for rugged use, an ultra long life and low power consumption requirements. The estimated life of a 6111 tube is approximately 100,000 hours. 

So power is 25V into a 100k Ohm load.

Forgive my rusty high school electronics, but if I recall figuring out Wattage, you square the voltage and divide by the resistance.

25V squared is 625. Divide by 100,000 and you get 6.25mW.

Did I get my math correct? Please feel free to correct me; it's been almost 25 years since I took that course.

 

[qusp]

yeah its a bit of an odd spec, 100k is 1000 x the likely load impedance this amp will see. do we have any useful specs?
 
yes Erik, 6.25mW into 100k, of course the current would be higher into a realistic load you would think, but as is there isnt a lot of useful info

 

[Uncle Erik]

It would be nice if more information was provided.

6.25mW seems more like a tube buffer than an amplifier. An iPod gives you 25mW-30mW or so.

If this is mostly a transconductance amplifier, I would love to know more. IIRC, the only commercial one was the First Watt F1. If this is another, it would be a good idea to tell people. That would get the attention of a lot of serious tubeheads.

 

[Naim.F.C]

Just pulled the trigger on one of these. Cannot wait to test them. Will be providing a full review after some comprehensive testing. Gear used will be T1's, D5000's, T50RP's (modded/un-modded), SE535's and Westone 4's. maybe even the 1964-Q a bit later on if I can get the impressions over in time!

 

[evolutionx]

Just got my Continental for few days.  Wondering whether need burning-in to sound its best?  
 

 

[familiarsounds]

Wonder if someone would be fortunate enough to have this side by side with "the continental".
 
http://www.head-fi.org/forum/thread/562045/govibe-porta-tube

 

[CEE TEE]

Another Head-Fier called and spoke with ALO.  They said this amp wasn't for iems.
 
Quote:

Interesting amp. I wish that this would work with ultra-low impedance IEMs like the ES5 (20 ohm). It looks like the lower limit is 32 ohms.
 
Maybe someone can try...
 
Also they seem to be skirting the output impedance issue:
 
Quote:
 
What does this mean?

 

 

[cooperpwc]

Thanks, CEE TEE.

 

[Anaxilus]

I wish there was a better answer though.  There are IEMs that hit 100-125ohms.  Making a blanket statement like that might be selling themselves short.

 

[CEE TEE]

From Ken of ALO:
 
 
Dear Woodcans,

 

Yes the amps a little much for sensitive IEMs. Thats not saying you can not use them with IEMs but when I use them with the amp the volume gets loud very fast with little turning on the volume knob. The amp is best suited for harder to drive full size headphones.

 

Thanks

 

Ken

 

See posts #5 and #12:

 

http://www.head-fi.org/forum/thread/563632/alo-continental-portabletube-amp

 

 

 

[Uncle Erik]

How do you drive a full-sized headphone with 6.25 mW of power?

That is about a quarter of the power from a stock iPod.

In other words, an iPod offers four times the power.

 

[Sharklordy]

Can someone compare the continental and sr-71b in balanced please?

 

[wsilvio]

Quote:

How do you drive a full-sized headphone with 6.25 mW of power?

That is about a quarter of the power from a stock iPod.

In other words, an iPod offers four times the power.

Yeah, there is something wrong with the specs.  The continental has tons of power and has absolutely no problem driving my hd800's.
 
As for IEM's, it sounds great with er-4s'.  And I've also used it with my sensaphonics 2x-s'.  Although with the 2x-s, the volume comes up pretty quickly.