[dBel84]

You are right of course . I have the Porta Tube + which has a usb dac. I have not opened the amp up to see what's inside ( recognised as a TI device ) so just assumed everything is sampled at the std rate but it does a good job never the less..dB

 

[Brooko]

Interesting - any idea which DAC they're using?  If it's a decent DAC it would be a quite nice small footprint desktop set-up.

 

[Stephen L]

I was looking for a portable solution for my iPod, and looked at both the Cypher Labs Algorhythm Solo and the Fostex HP-P1. Granted the Fostex comes as an all-in-one solution with the DAC and an amp, I still did not like the sound at all. Both filter settings sounded very artificial. I was therefore left with only the CLAS. I wanted to pair it with the Solo, but one was not available. The GoVibe Porta Tube was available and I paired it. I really liked the sound. It was not extremely detailed or highly transparent like in a studio setting, but had a musicality to it without being overly lush or sweet. I bought the pair and will do more listening to it over the next few weeks.

 

[dBel84]

This musicality is what you get from running a tube at lower B+ voltages, I had intended ( and still do ) to open up the amp and measure all the voltages so that I knew what was going on inside. I do not have the specific size driver that they used and I started to strip the screws so left it alone until I get the correct driver. I think the amp does exceptionally well considering battery powered tube portable. I took a few pictures 
 
BOX

 
TOP

 
FRONT

 
BACK

 
and a teaser
 

 
 
 
No idea what chipset it uses, the usb is texas instruments so I anticipate one of the common ones such as the PCM270X. 
 
I will try and formalize my thoughts/opinions and post a more thorough comment when I have had a peak inside..dB

 

[rhythmdevils]

Did you buy this Don, or are you just borrowing it with the LCD-3?

 

[dBel84]

Sorry somehow my subscription to the thread fell away. I heard the porta tube at RMAF and spent some time chatting to Wilson ( of Jaben ) , when it came time for me to pack up and head back to reality, he offered me a deal I could not refuse as I have always wanted a portable tube amp. 
Quote:

Did you buy this Don, or are you just borrowing it with the LCD-3?

Too many good things available at this time, hard to choose which ones to get and which ones to keep aiming for. 
 
On the porta tube+ front: 
 
I had really wanted to have a look inside this amp to see what tube was being used for voltage gain and get a sense for the circuitry but my curiosity will have to wait longer as the torx driver bits I picked up still don't fit ! I guess in some ways this is good as I might have been prejudiced by my discoveries. What I can say is that the amp does not sound as if the tube is overly colouring the sound. In many ways it reminds me of the x-can amp that started  my journey into headphones. The bass is strong but can feel a little rounded when compared to my liquid fire. This is not a criticism as the music is still well reproduced and compared to my mini3, it has much better control. This may even be an advantage when being used in transit as noisy environments tend to kill bass. The mids are very good, especially with the planar headphones I tend to use. I did not notice a consticted listening field when using the amp for extended times but when doing A-B comparisons , it does not have the breadth of soundscape that the liquid fire has and does not have the same level of microdetail retrieval. I am not sure this is a reasonable comparison however as the porta tube + is a portable tube amp and as a portable amp it really does a fantastic job. It is significantly superior to my mini3 which I am very familiar with and it has enough power to drive orthodynamic headphones which not all portable amps can claim. I am so out of touch with the market that I had no idea the there were more portable tube amps on the market other then the TTVJ Millet amp which I had the good fortune to have on loan from a fellow headfier for a while. The built in dac is pretty cool too, I am plugged into the LCD3 as I type and have found myself taking it to work so that I can shut the world out and get some work done. colour me impressed, i still want to see under the hood ..dB

 

[rhythmdevils]

I can't believe you're comparing a portable amp to your liquid fire! 

  Any thoughts from memory of how it compares to the TTVJ portable tube amp?  I recently got a good deal on one of those, but find it a bit too colored.  My PPAS seems to beat it in every way in terms of SQ. 

 

[dBel84]

I didn't want to say it but your impressions mimic mine..dB
 
 
edit  - as for comparing, i have little else to compare too , sad isn't it  
 
another edit  -  the ppas is a very special creation, pity it ended so soon after it's design. One of my favourite portables was loosely designed on the ppas , I ran it with 4 x 9V batteries to give it dual 18v rails. Buffer was quite heavily A biased so it chewed through them in about 4 hours, but it was a good 4 hours . I passed it along when i stopped commuting for a while. 

 

[rhythmdevils]

I'm not sure sad is the right word. 

 

[rhythmdevils]

Wow this amp is nearly 700 dollars. 

  I was thinking it would be 350.  What is in that little thing that could possibly cost so much?  My huge EHHAreva only costs 450 to build, granted that's parts cost only but still...

 

[Brooko]

Quote:

Wow this amp is nearly 700 dollars. 

  I was thinking it would be 350.  What is in that little thing that could possibly cost so much?  My huge EHHAreva only costs 450 to build, granted that's parts cost only but still...

I think that's the RRP - if you're talking about the P-T (not the P-T +).  Imagine the street price will be less.  Anyone interested should ring Jaben and see if they will deal.  I won't disclose what I paid - but I thought it was reasonable

.
 

 

[shigzeo]

I've had the opportunity to test this amp out at Musica Acoustics and e-earphones in Tokyo, and find that it is one of my favourite portable amps of all time. Very low noise floor even with sensitive earphones like Sleek CT7, very rich, slightly wild sound with shiny mid-high frequencies. It doesn't have a lot of power to drive phones that have low sensitivities such as the Fischer Audio FA-011, but apart from that sort, it is great for IEM and headphones alike.
 
Every time I try it out, I get the urge to hide a purchase from my wife, but it is hard to hide something that used to be about a month wage. It is worth every penny, but it is a BIG investment. If I had to review it on sound alone, it would be 5/5, but there are a few build quality issues that have me wondering. Still, one of, if not the, best portable amp out there. 

 

[Grev]

^ It's that good eh?  I've got The Continental and The National and always wanted to know how the porta tube sounded.
 
And what DAC chip do they use?  Like all the GoVibe stuff, not much details are presented...  All I can find is this japanese webpage with some photos of the inside. http://handbillofdaiki.blog.so-net.ne.jp/2011-07-13

 

[shigzeo]

I took one apart (as do all sane people) and from memory, it seems the DAC has been sanded down. Or, it could be on the auxiliary board and the battery necessitated to be removed in order to see what DAC it uses. When next I can steal one, I'll try to find out. It is a fine amp.

 

[shigzeo]

I've finally finished my review of the Porta Tube+. Suffice it to say that the Porta Tube(+) is a very fine sounding amplifier, worth its price. Its sound isn't typical of valve amps in the price range that have a little too much bloom and lose resolution except when driving something like a HD600. There is no adverse affect when driving earphones like the Earsonics SM2 or the DT880. Same. Power to both is excellent, and distortion figures are exactly the same. I've not encountered an amp that mates so well to such a wide variety of headphones before, and sustains them perfectly at too-high levels of volume.