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 25th February 2003, 02:33 PM   #101
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Followup ...can't seem to be able to edit my original post...

Why it works? Like I said...dunno but just try it yourself! I did not say to you that your el cheapo chokes could not possibly work because of their limited bandwith.

So just take my word for it. Or try it yourself.

Why would Marantz, Luxman et al use a seperate filament supply do you think? Because it did not matter? To make tha amp heavier? To make it more expensive?

Don't think so!
  Reply With Quote
Old 25th February 2003, 02:35 PM   #102
diyAudio Member
 
Join Date: Nov 2002
Location: North Herts, UK
Whilst I have not tried this and so offer no comment. Lynn Olsen has found the same. See his notes on his web site

Aloha Audio

ciao

James
  Reply With Quote
Old 25th February 2003, 02:44 PM   #103
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Both my filament and power transformer have a screen between primary and secondary!
  Reply With Quote
Old 25th February 2003, 02:53 PM   #104
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Joel,

the problem is the interwinding capacitance between the HT winding and any adjacent heater winding. It's typically 1nF, so the spikes as the diodes switch on and off are capacitively coupled to the heater circuit. I've observed these spikes on a 6.3V AC heater. Heater/cathode capacitance can then couple these spikes into the audio department.

Sadly, it really is worth using a separate transformer for the HT...
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 25th February 2003, 03:02 PM   #105
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by 7N7
Sound pressure is sound pressure is sound pressure regardless of black arts practised in its production/reproduction
Yes. But you forget that Eric is superhuman and immune to those weaknesses that afflict us ordinary humans.

se
  Reply With Quote
Old 25th February 2003, 03:10 PM   #106
Joel is offline Joel  United States
diyAudio Member
 
Joel's Avatar
 
Join Date: Oct 2002
Location: Brooklyn, NY
Quote:
Originally posted by EC8010
I've observed these spikes on a 6.3V AC heater. ...Sadly, it really is worth using a separate transformer for the HT...
This is called "listening to your scope". I can pick up radio waves from Jupiter as well - does that mean all broadcasts I listen to are somehow tainted? How are you gaurding your amp against sun spot emisson?

Answer this one question EC8010: are you saying you can hear diode switching when listening to your system?
  Reply With Quote
Old 25th February 2003, 03:20 PM   #107
EC8010 is offline EC8010  United Kingdom
diyAudio Moderator Emeritus
 
EC8010's Avatar
 
Join Date: Jan 2003
Location: Near London. UK
Yes. That was the reason that the scope came out. There was hum, and it had a nasty buzz on it. First, I thought it was HT line hum, but then I found a nasty waveform leaving the driver stage which didn't relate to the waveform on the HT supply, so I looked at the heaters. After replacing a valve and adding some capacitors, the hum was significantly reduced, and the buzz had gone.

Bear in mind that these spikes occurred at 100Hz rate and were visible when the scope was set to display a 6.3V RMS sinewave. We're not talking about cosmic noise here, this was audio frequency hash with RF harmonics, and with significant amplitude.
__________________
The loudspeaker: The only commercial Hi-Fi item where a disproportionate part of the budget isn't spent on the box. And the one where it would make a difference...
  Reply With Quote
Old 25th February 2003, 03:24 PM   #108
7N7 is offline 7N7  United Kingdom
diyAudio Member
 
7N7's Avatar
 
Join Date: Jan 2003
Location: England
Quote:
Originally posted by Steve Eddy


Yes. But you forget that Eric is superhuman and immune to those weaknesses that afflict us ordinary humans.

se



There! I've done it again, made a fool of myself on the Forum. I promise to be good in future; thank you so much for pointing out the error of my ways.

7N7
__________________
Plug them in and light them up
  Reply With Quote
Old 25th February 2003, 03:32 PM   #109
diyAudio Member
 
Steve Eddy's Avatar
 
Join Date: Sep 2002
Location: Sacramento, CA
Quote:
Originally posted by 7N7


There! I've done it again, made a fool of myself on the Forum. I promise to be good in future; thank you so much for pointing out the error of my ways.
Hey, don't be so hard on yourself. You're just being an ordinary human being. You should celebrate it! Imagine the weight of all that extra responsibility that the superhumans must bear saving us ordinary human beings from ourselves.

se
  Reply With Quote
Old 26th February 2003, 02:10 AM   #110
diyAudio Member
 
mrfeedback's Avatar
 
Join Date: Feb 2002
Location: Perth, Australia.
Default He Who Laughs Last, Laughs Best.

Let's get things into perspective.
The rating of 136dBA peak, is for a single frequency (in this case undefined), and that is a whole different thing to broadband music signal.
Yes, the system was going into soft self-limiting, but despite this, realistically the achieved SPL will not be 136dBA continuous on music - simple.
So, you can rest assured that my hearing is not damaged.

Spectral content is mission critical to ear survival when running at the levels attained - ear physiology is the reason here.
The resultant sound that we did get was the smoothest sound that any of us have ever heard, and this factor is important as regards hearing damage - harsh sound will break your ears, and in my experience smooth (the smoothness that we had Sat night) sound is relatively inoccuous.

You guys can scoff all you like, but this treatment really does work (and with video and RF signals too), and very clearly so, and moreover, all who have heard this (pro-audio or consumer) treatment want it for their own systems - simple as that.

Eric.
__________________
I believe not to believe in any fixed belief system.
  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
CCS for tubes/valves: PCBs SY Tubes / Valves 345 8th September 2013 11:01 AM
GE JAN 6072A Valves (Tubes) mozfet Swap Meet 1 2nd August 2008 02:34 PM
Another CCS for tubes/valves: PCBs Doc B. Tubes / Valves 77 23rd January 2008 08:10 AM


New To Site? Need Help?

All times are GMT. The time now is 06:11 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