Needed - Advice on tubelab Simple SE build - 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 29th December 2009, 10:18 PM   #1
Salsero is offline Salsero  United States
diyAudio Member
 
Join Date: May 2003
Location: Texas USA
Default Needed - Advice on tubelab Simple SE build

I am building a simple SE using KT88 tubes with a choke supply - a few questions follow:
1. What value should I use for the R17 and R27 resistors?
2. I am going to use a socket with a filter and fuse - what AC line power rating should I specify?
3. There are several switches used for the amp - the ultralinear and cathode feedback switch. Any recommendations on which switches to select?

Thanks all
Salsero
  Reply With Quote
Old 30th December 2009, 06:00 AM   #2
diyAudio Member
 
boywonder's Avatar
 
Join Date: Jan 2008
Location: So.Cal.
Quote:
Originally Posted by Salsero View Post
I am building a simple SE using KT88 tubes with a choke supply - a few questions follow:
1. What value should I use for the R17 and R27 resistors?
2. I am going to use a socket with a filter and fuse - what AC line power rating should I specify?
3. There are several switches used for the amp - the ultralinear and cathode feedback switch. Any recommendations on which switches to select?

Thanks all
Salsero
See this page from Tubelab's site:

Tubes & Transformers

Study the simulation tables near the bottom of the page.

The output tube cathode resistors (Rk) depend on what output tubes (in your case KT88's) and output transformer primary impedance (load Z) you intend to use, as well as your B+ voltage. The table lists data for 3K and 5K transformers and various B+ voltages. Note that as you lower Rk or increase B+, more current flows through the output tubes, increasing max plate dissipation (listed in watts as power) and power output. The values in red indicate that they exceed the max power dissipation ratings of the typical KT88, although some folks run their amps at these levels comfortably. You may want to try various cathode R values (Rk) once you have built the amp. Some builders here have incorporated switchable Rk values for on-the-fly changes or running different output tubes. If you are using a choke input power supply, you can easily vary your B+ voltage by changing the value of C1 within a small range.

I am unclear as to what you are asking in your "power line rating" question...
If you are specifying the fuse value, use a 1 amp slo-blo.
  Reply With Quote
Old 30th December 2009, 07:51 PM   #3
JdJ is offline JdJ
diyAudio Member
 
Join Date: Nov 2009
The UL and Feedback switches need to be DPDT. The rectifier switch (if you are using it) only has to be a SPDT. I ended up using the ubiquitous Mountain toggle switches available through Mouser and (I think) Digikey. If I'm not mistaken they are rated for 3 amps at 125v. For power I used:

103-0132-EVX from Mouser

Best of luck,

Josh
  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
Tubelab Simple SE v.2 nic6paul Tubes / Valves 3 1st November 2009 01:59 PM
*my* Tubelab SE build... oldmanStrat Tubelab 139 13th July 2009 08:03 PM
Nubie first build Tubelab simple SE Mungo Park Tubelab 65 27th May 2009 06:41 PM
Long time lurker - first build a tubelab Simple SE cjkpkg Tubelab 59 21st December 2008 06:54 PM
Tubelab simple SE help needed...working but only on one channel waam68 Tubes / Valves 11 2nd April 2008 07:32 PM


New To Site? Need Help?

All times are GMT. The time now is 08:45 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