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 18th February 2007, 04:44 PM   #1
Gluca is offline Gluca  Italy
diyAudio Member
 
Gluca's Avatar
 
Join Date: Nov 2004
Location: Back to Italy
Default Fixing this 100TH

Ciao,

I am running a 100TH at 20mA/915V/-9V loaded by a 180H choke and 0.1uF coupled to a 2:1 interstage tranny (parafeed). Weird thing is that I get -12db@20Hz and -15db@20kHz. Heck?! I used those irons before with no problems. First time here with a 100TH.

Any hint?

Gianluca
  Reply With Quote
Old 21st February 2007, 01:05 AM   #2
diyAudio Member
 
Join Date: Mar 2003
Location: NYC
hey gianluca,

i figured this would be worth a bump.

Do you have any rough guesses at what the Rp of the 100TH is at your operating point? I'm guessing it is upwards of 40K which could start to explain your problems.

From the simple model of a choke loaded stage, increasing source impedance (Rp) shrinks bandwidth on both ends due to the finite inductance and fixed parasitic capacitances. Something that gives you 2hz-200khz bandwidth with a 1K source will only net you 20hz to 20Khz with a 10K source.

dave
  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
Looking for circuit of SE amp. for Eimac 100TH udonbkk Tubes / Valves 18 23rd November 2012 07:49 AM
Fixing the R30 bjackson Multi-Way 3 16th May 2010 06:10 AM
Need some help fixing this amp mazeroth Solid State 1 13th May 2008 03:04 AM
Need Help Fixing an old NAD 304 li_gangyi Solid State 14 8th December 2004 07:59 PM
Help! Fixing Amp. shajan Solid State 20 29th May 2004 08:06 AM


New To Site? Need Help?

All times are GMT. The time now is 05:27 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