change to grid choke? - 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 3rd December 2002, 06:32 PM   #1
Joel is offline Joel  United States
diyAudio Member
 
Joel's Avatar
 
Join Date: Oct 2002
Location: Brooklyn, NY
Default change to grid choke?

Anyone have any experience changing the power tube's grid resistor to a choke?
Is there measurable improvement in performance?
Hammond has a 150H, 8mA model. It's only $19, so not much of a risk I suppose.
(tube is the 71A from my SE amp posted before)
  Reply With Quote
Old 5th December 2002, 03:07 PM   #2
Joel is offline Joel  United States
diyAudio Member
 
Joel's Avatar
 
Join Date: Oct 2002
Location: Brooklyn, NY
I'll reply to my own post!

With a plate resistance in the previous stage of 10k ohms, using 2PiFL, the reactance of the choke at 20Hz will be 18,849.6 ohms... so, since 10,000 would be the half power/3dB down point, I will be under that amount at 20Hz. This is pretty good.
And of course at 20kHz, the reactance will be 18,849,600 ohms... no loss at the high end.
How's my math?

So, I think it should work out good.
  Reply With Quote
Old 5th December 2002, 03:20 PM   #3
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Sorry Joel, no practical experience on that. They've banned the most prolific poster who could have given an answer - with his own personal charisma of course...
Theoretically.... there could be some xtra power in the bag, just as the grid is driven slightly positive. Also you might get away with a smaller coupling cap; but beware of resonance
  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
Issues with grid choke phrarod Tubes / Valves 15 23rd August 2009 02:19 PM
Step down grid choke vs. interstage transformer jetbat Tubes / Valves 3 11th June 2009 02:35 AM
Grid choke as I/V? dsavitsk Tubes / Valves 1 8th April 2008 06:44 PM
Coupling caps size with grid choke? DHT112A Tubes / Valves 4 7th December 2006 05:22 PM
Could a filament transformer be used as a grid choke? Saurav Tubes / Valves 15 13th September 2003 12:18 PM


New To Site? Need Help?

All times are GMT. The time now is 06:46 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