On Line Tube Learning for newbies.... - Page 13 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th April 2010, 05:11 PM   #121
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
Quote:
Originally Posted by rotaspec View Post
It is a good idea, but it would have to be low voltage for safety, or the seller would be risking legal liability in the event of an accident. Most of the kits available now are not aimed at nor attractive to beginners, so they have little to fear, but it's a different story when a 7 year old tries to put together a 250v PSU.
There are some tubes however that can run at very very low voltages, using some of those into a directly driven sensitive high-impedance speaker should be OK surely?

Some regular tubes even work at very low voltages - I can hear mine still after switch off for a while - as the HV takes a tumble and gets very low indeed!
  Reply With Quote
Old 1st May 2010, 10:07 AM   #122
UnixMan is offline UnixMan  Europe
diyAudio Member
 
UnixMan's Avatar
 
Join Date: Apr 2005
Location: Perugia + L'Aquila, Italy
Send a message via ICQ to UnixMan
tubes which can be operated at safe (very low) voltages - in some extreme cases even as low as 12V - do indeed exists.

But (even setting aside performance considerations) with those you can not do anything more than a preamp or perhaps an headphone amplifier.

In order to deliver enough power to drive a loudspeaker (even an high-sensitivity one) you need much higher voltages. Even if designed to use the least possible voltage, a power amp will require at least some > 90V. Which are really a little in tube terms, but nevertheless more than enough to be dangerous and not suitable for being handled by a child without risks.

Moreover, electrical shock risks apart, there are several other reasons why tubes must be kept out of the reach of children.

Tubes gets hot. Many perhaps not so much, bet usually enough to hurt (...the soldering iron which is almost unavoidably required is even more hot and dangerous with this respect).

Tubes are made out of a fragile glass envelope with high-vacuum inside. If the envelope gets broken, it'll implode!

The resulting glass debris can be very dangerous (especially if they ends up in the eyes...). Moreover, some tubes may contains poisonous substances inside their envelope.

I'd not let any child mess with any tube. At least not without strict & competent adult supervision.
__________________
Quote:
"We should no more let numbers define audio quality than we would let chemical analysis be the arbiter of fine wines." N.P.

Last edited by UnixMan; 1st May 2010 at 10:27 AM.
  Reply With Quote
Old 7th May 2010, 06:25 AM   #123
diyAudio Member
 
Join Date: Feb 2002
Location: Western Sydney
Rod Elliott has useful info:
Valves Index
__________________
Impedance varies with frequency, use impedance plots of your drivers and make crossover calculations using the actual impedance of the driver at the crossover frequency
  Reply With Quote
Old 8th May 2010, 12:20 AM   #124
diyAudio Member
 
Join Date: Feb 2010
Hi,
Can anyone give me information about this tube? Can it be used for tube amp?
Click the image to open in full size.
The only info that I found is this datasheet but it's in Russian which I don't know.
http://www.155la3.ru/datafiles/v2_006_25_tu.pdf
P/S: If I post this in the wrong place please forgive me.
  Reply With Quote
Old 3rd July 2010, 12:01 AM   #125
diyAudio Member
 
Join Date: Jul 2010
Default Great link

Thanks Pedroskova, the Naval Electrical Engineering Training Series(NEETS) link is great.

1000 watt amp
  Reply With Quote
Old 6th July 2010, 05:18 PM   #126
banat is offline banat  Serbia
diyAudio Member
 
Join Date: Dec 2009
Location: near Belgrade
Quote:
Originally Posted by phuong View Post
Hi,
Can anyone give me information about this tube? Can it be used for tube amp?
Click the image to open in full size.
The only info that I found is this datasheet but it's in Russian which I don't know.
http://www.155la3.ru/datafiles/v2_006_25_tu.pdf
P/S: If I post this in the wrong place please forgive me.
This Russian B2-00,6/25 is High Voltage Rectifier tube (Kenotron)(Diode) and is intented for Radar impuls PSU and similar apllication,with Indirect heated filament 5V/3,9A+-0,4A.Think is very hard to use for Audio apllication.Good Luck
  Reply With Quote
Old 31st July 2010, 06:22 PM   #127
diyAudio Member
 
Join Date: Feb 2010
Is it allowed to place a tube horizontal ? Like the ECC83 and EL84 ?
  Reply With Quote
Old 31st July 2010, 10:04 PM   #128
banat is offline banat  Serbia
diyAudio Member
 
Join Date: Dec 2009
Location: near Belgrade
Quote:
Originally Posted by TubeManiac View Post
Is it allowed to place a tube horizontal ? Like the ECC83 and EL84 ?
Yes it is,but with pins 4&5(heater pins) on the TOP
  Reply With Quote
Old 7th August 2010, 12:05 AM   #129
diyAudio Member
 
Join Date: Jul 2010
I purchased a copy of Valve Amplifiers, by Morgan Jones, Elsevier, 2003 (latest edition), following recommendations here at diyAudio. It has pretty much most of the things I wanted to read about, but I am very surprised at the fact that Chapter 5, on Power Supplies, uses transistor circuits almost exclusively in the schematics for the chapter. I have no idea why he did this, as most audiophiles are of the opinion that a good tube amplifier should have a tube power supply since it is felt that the power supply does contribute to the sound quality. And, in any case, the book is called Valve Amplifiers, not Amplifiers in general. Does anyone have any idea why he wrote the chapter that way? To me, this makes the book very much incomplete and borderline ludicrous.
  Reply With Quote
Old 7th August 2010, 05:39 PM   #130
diyAudio Member
 
Miniwatt's Avatar
 
Join Date: Nov 2004
Location: Den Haag
Jones elaborates on tube rectifiers, I don't see the problem.
And on a personal note: PS contribute vastly to the sound quality. That's why I switched to ss rectification..
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 09:07 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2