Advice sought on thermionic headphone amp - Page 3 - 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 7th May 2012, 05:43 PM   #21
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
I think the OP realises that vibrator power supplies may bring problems, but don't swamp him with objections. He knows the sound could get a bit muddy, but he needs to do the best he can with his particular requirement for portability. When immersed in the music he still wants to hear air around the individual instruments.
  Reply With Quote
Old 7th May 2012, 05:46 PM   #22
Simon B is offline Simon B  United Kingdom
diyAudio Member
 
Join Date: Dec 2011
Location: North-East England
Quote:
Originally Posted by jcx View Post
..the OP schematic is a 4/8 Ohm loudspeaker amp with a R divider on the output for a headphone - lots going to waste there - especially for a battery powered project...

Yes, that is wasteful, I'd presumed the resistor divider shown on the original schematic was just for those wanting dual-use phones and speakers. I did intend to use an appropriate OPT and will probably wind my own, as tar-potting doesn't seem to be available as an option now.

Quote:
Originally Posted by jcx View Post
...mechanical vibrator supplies are considered antiquated for good reasons - today the EMI from the mechanical contact opening is unacceptable; size, noise and efficiency can all be improved hugely with modern DC-DC SS designs with integrated chip controllers

I think a good many things that we still enjoy using are considered antiquated by some - including valves in audio equipment. I was told so in no uncertain terms by a university professor - though I don't share his point of view.

I hope to be able to deal with EMI issues to my own satisfaction. Contact breakers were used for many decades in car ignition and suppression was usually quite adequate, with the exception of boy-racers with copper leads and no resistor plug caps.

I'm still keen to hear from members regarding any practical advice they might have on construction issues relating to this particular circuit.
__________________
Engineer: One who can do for 10 shillings what any fool can do for 10 pounds.

Last edited by Simon B; 7th May 2012 at 05:50 PM.
  Reply With Quote
Old 7th May 2012, 06:04 PM   #23
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Just so we get the correct idea..
Is this circuit submersible or amphibious?
Regards
M. Gregg
__________________
What is the sound of one hand clapping?
  Reply With Quote
Old 7th May 2012, 06:17 PM   #24
jcx is offline jcx  United States
diyAudio Member
 
Join Date: Feb 2003
Location: ..
if you're winding your own ouput xmfr then I assume impedance scaling is in order

which then opens up tube choice - small signal tubes save doubly by using less heater power which quickly becomes a limitation with only ~ 1/2 Wrms audio power output requirement


car radio noise floor requirements are abysmal, "audiophile" headphone listening would require < ~ 20 dB SPL out of the headphone

vibrator supply operating frequency in the audible range makes the passive filtering requirement costly

Last edited by jcx; 7th May 2012 at 06:22 PM.
  Reply With Quote
Old 7th May 2012, 06:28 PM   #25
Simon B is offline Simon B  United Kingdom
diyAudio Member
 
Join Date: Dec 2011
Location: North-East England
Quote:
Originally Posted by M Gregg View Post
Just so we get the correct idea..
Is this circuit submersible or amphibious?
Regards
M. Gregg

Well the title says "amphibious", so I was going with that...
__________________
Engineer: One who can do for 10 shillings what any fool can do for 10 pounds.
  Reply With Quote
Old 7th May 2012, 06:36 PM   #26
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Quote:
Originally Posted by Simon B View Post
Well the title says "amphibious", so I was going with that...
Is the battery carried back pack or in a vehicle?

Regards
M. Gregg
__________________
What is the sound of one hand clapping?
  Reply With Quote
Old 7th May 2012, 06:49 PM   #27
Simon B is offline Simon B  United Kingdom
diyAudio Member
 
Join Date: Dec 2011
Location: North-East England
Quote:
Originally Posted by M Gregg View Post
Is the battery carried back pack or in a vehicle?

Regards
M. Gregg

Something like this was what I had in mind:

Vehicle

Though I have to say that in the light of the comments I've received on here - thank you all by the way - I'm beginning to think that the design of this circuit is quite devoid of any consideration of the basic requirements of its stated purpose.

On a positive note, I understand that such vehicles are usually equipped with alternators, which might be helpful wrt the power supply requirements.
__________________
Engineer: One who can do for 10 shillings what any fool can do for 10 pounds.
  Reply With Quote
Old 7th May 2012, 07:01 PM   #28
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Quote:
Originally Posted by Simon B View Post
Something like this was what I had in mind:

Vehicle

Though I have to say that in the light of the comments I've received on here - thank you all by the way - I'm beginning to think that the design of this circuit is quite devoid of any consideration of the basic requirements of its stated purpose.

On a positive note, I understand that such vehicles are usually equipped with alternators, which might be helpful wrt the power supply requirements.
I think its important to understand that if you are looking at creating something to get you the old WW2 feel..the weight was incredible..and that was just the set not battery as well...I have tried one for fun..
If you are thinking New ways to do it thats a different thing..

The circuit as it stands in the 1st post just seems to me like a normal tube amp..car radios had different tubes and were not the normal standard 9 pin we all know..

Some old equipment was very intricate..and very complex..

So I think it depends what you are doing.

Regards
M. Gregg
__________________
What is the sound of one hand clapping?
  Reply With Quote
Old 7th May 2012, 08:34 PM   #29
Simon B is offline Simon B  United Kingdom
diyAudio Member
 
Join Date: Dec 2011
Location: North-East England
Quote:
Originally Posted by M Gregg View Post
....The circuit as it stands in the 1st post just seems to me like a normal tube amp..car radios had different tubes and were not the normal standard 9 pin we all know....So I think it depends what you are doing...

Well I thought that a "vacuum tube one-port class A amplifier - headphone amplifier amphibious circuit", as per the schematic page's title sounded as like something unusual, and possibly fun, one way or another....

It certainly does seem that it might not be the best circuit for the job, in the many ways mentioned so far on this thread, and also that the voltages involved are positively dangerous (the design indicates the negative rail to be grounded). But I believe it to be possible to catch fish en masse by passing electrical current through water, so perhaps the design might be of use to audiophile fishermen wanting bigger catches?



__________________
Engineer: One who can do for 10 shillings what any fool can do for 10 pounds.
  Reply With Quote
Old 7th May 2012, 08:46 PM   #30
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
I suspect you need a decent Chinglish translator to discover what the person who uploaded that circuit thought he was saying.
  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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Advice sought on Class.T Amp for HTPC DanielPool Class D 0 31st July 2010 04:20 PM
Advice sought on medium power triode for tube headphone amplifier rjm Tubes / Valves 13 16th May 2010 04:05 AM
New Cabinet Opinions & Advice Sought Thomo Full Range 8 30th December 2008 11:03 PM
Woofer advice sought cs Multi-Way 7 29th January 2007 09:08 PM
HiFi Advice sought Gina Everything Else 80 11th December 2002 02:19 PM


New To Site? Need Help?

All times are GMT. The time now is 02:38 AM.


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