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 13th January 2013, 09:22 PM   #31
diyAudio Member
 
Join Date: Mar 2003
Location: Haarlem, the Netherlands
I thought it was rather detailed already...

Anyway, attached is the schematic of my test common-cathode stage. The output goes to a 100 times amplifier with an NE5534A. The output of the NE5534A goes to a line input of an Asus Z9200U laptop computer and to an A-weighting filter, the output of which goes to the other channel of the laptop line input. The processing done with GoldWave and Excel is already explained in this thread. See also Linear Audio September 2012.
Attached Files
File Type: pdf Figure2.pdf (21.5 KB, 63 views)
  Reply With Quote
Old 14th January 2013, 08:51 PM   #32
diyAudio Member
 
Join Date: Apr 2007
MarcelvdG,

thanks for your answer. I'm thinking about to make (one more time) a noise measuring set-up, but this time, in a more "permanent" basis.
I have done a well power supply for one of my phono stages, and a pair of Linear Technology LT1115 op amps, that have a very good noise figure.
For measuring purposes, my National VP-7720A could be very suitable.

Cheers !
  Reply With Quote
Old 15th January 2013, 04:24 PM   #33
diyAudio Member
 
Join Date: Apr 2007
In the meanwhile, I have attached a picture of a module that I have built some years ago, and I will use it again, for my "noise-measurements-set-up".
This module have 3 selectors for the gain: the central one have 5 position: 40, 45, 50, 55 60 dB and acts simultaneously for the two channels. The other two selectors, acts one for the left channel and the other for the right one. In this case, they have 4 positions with increments of 1 dB. (0, 1, 2 and 3 dB). This technique is very useful for to use it as "balance" control, for to compensate differences between channels in some cartridges.
Anyway, I will use this module as "noise amplifier". (using only the op amp stage)

cheers!
Attached Images
File Type: jpg pre-web-1.JPG (85.7 KB, 204 views)
  Reply With Quote
Old 15th January 2013, 06:49 PM   #34
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by Wavebourn View Post
For low microphonic I have some other missile-rocket-science tubes. I won't name them, because I am going to buy supply for myself, then reveal all details.
Here you go:

planar triode 6S17K-V with 8 micron grid.

gm = 14 mA/V, mu = ~150, designed for 10 g vibration, or up to 500 g acceleration.
__________________
If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.
  Reply With Quote
Old 15th January 2013, 07:15 PM   #35
mogliaa is offline mogliaa  United Kingdom
diyAudio Member
 
mogliaa's Avatar
 
Join Date: Dec 2009
Location: London
Yep, tested it. A great tube indeed:
http://www.diyaudio.com/forums/3029622-post.html
__________________
"A mistake is always forgivable, rarely excusable and always unacceptable. " (Robert Fripp)
http://www.bartola.co.uk/valves/
  Reply With Quote
Old 15th January 2013, 10:10 PM   #36
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Quote:
Originally Posted by mogliaa View Post
Yess, a killer front-ed tube for microphone and phono preamps!
The trick is, the grid is so close to cathode so it better works with input transformer, and biased by grid leak resistor and own input current, while cathode firmly sits on the ground.
__________________
If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.
  Reply With Quote
Old 17th January 2013, 07:20 AM   #37
diyAudio Member
 
Join Date: Apr 2007
Now, I just have finished to put the power supply into a decent box. Now, I will build some sort of shielded container for the circuits and the "Device Under Test" (DUT). I have not idea how to do it until now, but I will found some cheap solution.
By the way, I'm thinking to use LabView for to make all the signal (noise, actually) analysis and presentation, but I'm new in LabView. Some idea ?
I would like to purchase some good russian valves, but I have seen that all of them (at reasonable prices) are from the outside of the EU. Somebody knows an EU provider ?

Cheers !
Attached Images
File Type: jpg ps-web-2.JPG (40.4 KB, 161 views)
File Type: jpg ps-web-3.JPG (54.8 KB, 159 views)
File Type: jpg ps-web-1.JPG (142.7 KB, 159 views)
  Reply With Quote
Old 28th January 2013, 08:34 PM   #38
mogliaa is offline mogliaa  United Kingdom
diyAudio Member
 
mogliaa's Avatar
 
Join Date: Dec 2009
Location: London
Quote:
Originally Posted by Wavebourn View Post
Yess, a killer front-ed tube for microphone and phono preamps!
The trick is, the grid is so close to cathode so it better works with input transformer, and biased by grid leak resistor and own input current, while cathode firmly sits on the ground.
Hi Anatoliy,
Do you have grid current information from the datasheet to estimate the value of the grid leak resistor?
Thanks
Ale
__________________
"A mistake is always forgivable, rarely excusable and always unacceptable. " (Robert Fripp)
http://www.bartola.co.uk/valves/
  Reply With Quote
Old 28th January 2013, 08:42 PM   #39
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
No, it is not specified, and varies from tube to tube. They did not need high resistances in grids, for intended application in rockets at UHF.
__________________
If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.
  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
Low space / Low cost B20 Trooper46 Full Range 5 13th September 2008 05:01 PM
Extremely low power and low loss transformers percy Tubes / Valves 12 23rd February 2005 10:30 AM
Best low-noise low-distortion buffer? borges Solid State 7 9th December 2003 12:40 PM


New To Site? Need Help?

All times are GMT. The time now is 12:45 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