Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

UL - triode switch
UL - triode switch
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
Thread Tools Search this Thread
Old 7th July 2008, 06:46 AM   #1
torrence is offline torrence  United States
diyAudio Member
torrence's Avatar
Join Date: Feb 2008
Location: Oregon
Default UL - triode switch

A lot of SE pentode amps have a switch to change from triode to ultralinear taps on the output transformer. In principle, most switches can't handle the voltage from plate to ground which can often be around 450 V quiescent, plus the AC swing which could easily give 700 V. Do people worry about this, or have bad experiences with terminal to ground shorts? I couldn't find real specs for the max. breakdown voltages for common AC line switches, but even 220 VAC switches wouldn't need to handle more than about 300V max. Are there common switches designed for this that won't cost a load of money? I don't really want to get a lethal shock off my UL-anode toggle switch.

  Reply With Quote
Old 7th July 2008, 07:18 AM   #2
vitalstates is offline vitalstates  United Kingdom
diyAudio Member
vitalstates's Avatar
Join Date: Jan 2006
Location: uk
many use a relay driven by heater voltage.
  Reply With Quote
Old 7th July 2008, 09:58 AM   #3
Tweeker is offline Tweeker  United States
diyAudio Member
Join Date: Dec 2004
Location: Cincinnati, Ohio
An inductive DC load is about the worst case scenario for a switch (does not cross through 0 like AC, arcs stay lit easier). Most switches are rated for AC, not DC, or are rated lower for DC. The rating has more to do with the contacts and their breaking and making than the insulation. I would be wary of switching hot, do not do it if its break before make. Doing so may be hard not just on the switch, but the OPT.

Example of a relatively cheap 480VAC switch. Break before make.
Be sure your foil hat has a good low impedance ground.
  Reply With Quote


UL - triode switchHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Pentode to Triode Switch Sherman Tubes / Valves 40 6th February 2013 12:06 AM
Modding a tonebone to switch to pentode triode operation?Can this be done?? Nicko_Lps Instruments and Amps 7 9th November 2008 11:30 PM
Another 3f4 spice triode model: 5718 submini triode wa2ise Tubes / Valves 0 5th September 2008 04:31 AM
Pentode/triode switch question Stormo Tubes / Valves 6 12th October 2007 08:05 PM
Using a spdt switch to select between triode mode and pentode mode on a guitar amp. G Instruments and Amps 19 15th March 2006 09:15 AM

New To Site? Need Help?

All times are GMT. The time now is 03:36 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio