6V6 line preamp - Page 183 - 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 14th April 2013, 11:57 PM   #1821
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by stajo View Post
Well, I started to interest in measuring now that you bossed me around on it a bit. Common mode chokes are good, with or without crappy measuring tools

But I think I have ruled out GND artifacts now, its the same results with yeallow/green GND in or out.

The thing that enoys me now is that my UNI-T (that say it shall measuere True RMS) follows the scope measurements anoyingly well but on some different scale. When I get 75 mV PP on Pico I get around the same RMS on the UNI-T
The DMM has 10MegOhm impedance, maybe that scope probe is another story. And mV in kHz are not a DMM's AC best sens.
If you want to know your DMM reports TRMS well put it on your Wavetek gen's output. Set the output at 1V range using sinewave. Then press square and triangle. It should show you x1.414 & 0.82 the previous RMS. Use 500HZ.
  Reply With Quote
Old 15th April 2013, 12:03 AM   #1822
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by buzzforb View Post
Yup. Need to invest in good probes, but otherwise works great. $100 on fleabay. Need to get a good sig gen, the PC can't put out clean HF square waves. Perhaps I am doing something wrong. Wrks great for distortion and that is what I got it for.
You do nothing wrong, the PC has a ringing problem with squarewaves. Get GW Instek 1013. 3MHZ DDS +/- 20ppm range stability per year level. Cheap.
  Reply With Quote
Old 15th April 2013, 12:07 AM   #1823
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Buzz you also got 6V6 pre on SSHV2. Was it P2P or based on the black PCB? Did you see any weird 0.32mS periods when scoping the rail on the Tek 465B?
  Reply With Quote
Old 15th April 2013, 12:10 AM   #1824
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
FRom memory, it was pretty clean. First go round, I did my own boards. Only issue was drift of 170, i believe. Maybe due to heat, but I think you now suggest 117. I haev it sitting in closet waiting for two new Lundahl PSU chokes and more filtration. Trying to decide between single transformer and dual prereg feeding dual SSHV or dual allthe way. Got nice EI, but it is 230. NOt big deal to add outlet, as it seems like i nice one.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 15th April 2013, 12:26 AM   #1825
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Fine then.
  Reply With Quote
Old 15th April 2013, 12:31 AM   #1826
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC

Only because i have been distracted. It remains my ONLY fully finished piece of audio gear, other than brothers Folded RIAA. I forgot to say that I had planned to use official boards this time, to make sure it was done right.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 15th April 2013, 01:14 AM   #1827
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
When clean and steady its always right. K117GR was always. K170 was what you got at that point. I suggest dual mono.
  Reply With Quote
Old 15th April 2013, 01:54 AM   #1828
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Mine was defitinitely not a problem. Any change was heat related and was slow and gradual.
__________________
...Shape the sound , Man!
  Reply With Quote
Old 15th April 2013, 01:57 AM   #1829
Salas is online now Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Its just the other type has different Gos and TC. Bit better for the task but not heaven and hell.
  Reply With Quote
Old 15th April 2013, 02:08 AM   #1830
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
My box got little hotter than it should. Had poor layout. One of the reasons for the redo.
__________________
...Shape the sound , Man!
  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
Help me design my DAC/Line Preamp. kuroguy Tubes / Valves 7 2nd April 2009 08:31 PM
preamp line ctt richwalters Tubes / Valves 1 7th March 2008 04:34 PM
Preamp for Line In and Mic blur Instruments and Amps 1 4th January 2007 04:02 PM
Line stage preamp, based on SY's "Heretical Unity gain line stage" Danko Tubes / Valves 23 18th July 2005 04:07 AM
Line preamp for 2A3 amp Petman Tubes / Valves 0 24th May 2002 03:11 PM


New To Site? Need Help?

All times are GMT. The time now is 02:17 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