[003]

Well first of all, because of microphonics. Some tubes have it more or less than others, but you can bet that any tubes would become microphonic if they were subjected to use in a pocket.

Also, they become VERY fragile when they are hot (not the glass, but the filaments inside the tube).

 

[phergus_25]

It should be noted that the tubes being talked about are not "normal" tubes and not all things that apply to normal tubes are sure to apply to them.

-greg

 

[oicdn]

I'de think transportable is the keyword here, i.e. inside a headroom type bag when just walking around. unless of course, you dig running with an audio bag on your side, commando style, lol.

I don't have much listening experiance with tube amps, but I wouldn't mind buying a battery powered one if it ever came out.

 

[ATAT]

The filaments take 300mA? dear lord.. a AAA would drain in 3 hours, a AA in 8 hours.

Mm still looks interesting so I'll see if I can make a schem for these at some point tomorrow.

edit - as usual I'm an insane human being, so I think I'll go for something like a mosfet output stage.. if you're wasting 300 mA on a filament, why not go all the way eh?

 

[928GTS]

Quote:

Originally Posted by ATAT /img/forum/go_quote.gif The filaments take 300mA? dear lord.. a AAA would drain in 3 hours, a AA in 8 hours. Mm still looks interesting so I'll see if I can make a schem for these at some point tomorrow. edit - as usual I'm an insane human being, so I think I'll go for something like a mosfet output stage.. if you're wasting 300 mA on a filament, why not go all the way eh?

Why not just 4 or 5 AA's in parallel for the filament? Why MOSFET output? Why not just go pure tube?

 

[ATAT]

Tubes for gain, mosfet for output stage.. I'm not insane enough to do multiple tubes for the output stage.. that would result in a ridiculous current draw.

okay.. 4 - 5 AA in parallel is fine, but you need more than 6.3 volts, so thats about 5 AA each (if you use nimhs, its more) in other words you'll be carrying 20-25 AAs.... yeah. no.

Attempting to get a reasonable runtime out of tube portables is not really viable unless you use Lipos.. even then its kinda sketch.

 

[Zanth]

Enough talk more action! I want a small tube amp! I'm a chem eng so I can't do the EE thing but I'm willing to lend me ears! Let them be the guinea pigs!

 

[928GTS]

Quote:

Originally Posted by ATAT /img/forum/go_quote.gif Tubes for gain, mosfet for output stage.. I'm not insane enough to do multiple tubes for the output stage.. that would result in a ridiculous current draw. okay.. 4 - 5 AA in parallel is fine, but you need more than 6.3 volts, so thats about 5 AA each (if you use nimhs, its more) in other words you'll be carrying 20-25 AAs.... yeah. no. Attempting to get a reasonable runtime out of tube portables is not really viable unless you use Lipos.. even then its kinda sketch.

What about one of those small rectangular 7.2V NiCD packs used in entry level R/C cars? Those are atleast 1200Mah or more...

By the way whoever makes one I'd love to be a beta tester for it!

 

[kramer5150]

Doesn't someone make a hybrid amp with those millitary pencil-tubes... ? Soldered directly to the PCB?

I have an image in my head, but can't recall a make/model? Its more trans-portable though than portable.

 

[tomb]

There is always Fa-Schmidt's YAHA amp on Headwize:

Link here: YAHA Amp
and also on several other threads on Headwize.

Sijosae has made several mini-tube amps in a mint tin:

Also:
Altoids Tin Hybrid Amp (6922 + IRF610)
12V Hybrid (6922 + BUF634)
9V Hybrid (6922 + TDA1308)
12V Hybrid (6922 + NJM4556)
iHybrid Nano (6111 + NJM4556)
iHybrid Nano II (6111 + Diamond Buffer)

 

[immtbiker]

Being in a car can be defined as portable (on the go), no

?

 

[Szabi]

Quote:

Originally Posted by immtbiker /img/forum/go_quote.gif Being in a car can be defined as portable (on the go), no ?

OMG!!!

 

[photobob]

I'm actually checking out tube amps, designed for car use... now.


Butler Audio makes an interesting unit.

http://www.butleraudio.com/about.php


There's also a MIllburt brand..very expensive..but Mr. Clapton supposedly has one in his ride.

http://milbert.com/?pg=BaM235ab#Price


Bob

 

[photobob]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif Yes indeed.

Someday................................

 

[Zanth]

Quote:

Originally Posted by immtbiker /img/forum/go_quote.gif Being in a car can be defined as portable (on the go), no ?

How would one know if it would fit in their car? I drive a Hyundai Sonata 2002 model. Could it work?