AIKIDO LV WON'T START - Page 2 - 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 17th October 2010, 03:11 PM   #11
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Bill,
looks to me like he might have lost the heater return.

Any thoughts?
  Reply With Quote
Old 17th October 2010, 06:44 PM   #12
diyAudio Member
 
wushuliu's Avatar
 
Join Date: May 2008
Location: Los Angeles
Quote:
Originally Posted by Bill Fuss View Post
If you are measuring 48v from the PS to all the heater pins that means NO current is flowing. I would imagine that R17 is open.

I don't see a jumper at C1, it won't work without a jumper or switch there.
Thank guys! I swapped in a 2.2Ohm 10W Eagle resistor for R17 and now they're working. I'm reading 11.8v between heaters and 25,2v at the V3 junction... Is the 2.2 an okay value?
  Reply With Quote
Old 17th October 2010, 06:46 PM   #13
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
Sounds good to me!

Have fun

Regards
M. Gregg
  Reply With Quote
Old 17th October 2010, 06:50 PM   #14
M Gregg is offline M Gregg  United Kingdom
diyAudio Member
 
M Gregg's Avatar
 
Join Date: Jun 2010
Location: UK
What value is quoted for R17 in the circuit?

As long as you have 12.6V across each heater + or - 5% it should be OK.

Last edited by M Gregg; 17th October 2010 at 06:52 PM.
  Reply With Quote
Old 17th October 2010, 09:46 PM   #15
RIP
 
Join Date: Oct 2005
Location: Central Florida
I'm sure the turn on surge took it out, 1/4 watt was pretty iffy. A 3 watter would be plenty. The voltages across each tube wont match very well but anything close should work fine. Someone a few years ago did conductance tests on a few different tubes at different filament voltages and concluded that most will operate properly well below their rating. There is always a chance that one will not though, but you should be within 5% as M Gregg said.
  Reply With Quote
Old 18th October 2010, 05:06 AM   #16
diyAudio Member
 
wushuliu's Avatar
 
Join Date: May 2008
Location: Los Angeles
Quote:
Originally Posted by Bill Fuss View Post
I'm sure the turn on surge took it out, 1/4 watt was pretty iffy. A 3 watter would be plenty. The voltages across each tube wont match very well but anything close should work fine. Someone a few years ago did conductance tests on a few different tubes at different filament voltages and concluded that most will operate properly well below their rating. There is always a chance that one will not though, but you should be within 5% as M Gregg said.
Yes I think you're right. I'll continue to monitor the voltage.
  Reply With Quote
Old 27th October 2010, 11:23 PM   #17
diyAudio Member
 
wushuliu's Avatar
 
Join Date: May 2008
Location: Los Angeles
I'm pretty good at building things, but math is not my strong suit. I'd like to figure out the output impedance of this 12BH7A LV Aikido but I'm stumped by 1) figuring out Rp. How do I get the value? And 2) Parallel lines - Er, what do they and 'in paralell with' mean?:

the formula in the pdf is this:

Zo = [rp/(mu +1) + R8] || R13 || [rp + (mu + 1)Rk]
  Reply With Quote
Old 12th February 2013, 02:47 AM   #18
halitun is offline halitun  United States
diyAudio Member
 
Join Date: May 2007
Location: New Jersey
Default Aikido LV problem

Hey Guys, I know this thread was a year or so ago, but it helped me debug a problem with the LV. It was working on my bench system and then I brought it to a friend's house and hooked it up to his Adcom amp. It worked the first time and then the R17 resistor must have blown. Sure enough, it's open. I'll pick up a 3 watt 1 ohm resistor tomorrow. I've built several of Broskie's pre-amps and love them all. Next project is his SET amp with the Aikido pre in one box. Thanks!
  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
Luxman Lv-105 Valerio Solid State 81 29th July 2013 02:54 PM
Luxman LV-105u vs LV-107u Radioman62 Solid State 6 9th November 2010 03:58 PM
start-up sequence of Aikido preamp / SS power amp cbutterworth Tubes / Valves 5 7th May 2007 01:29 PM
Luxman LV-117 ? TroelsM Solid State 0 3rd November 2006 03:10 PM
Luxman LV-105 bra Solid State 1 7th July 2003 08:26 AM


New To Site? Need Help?

All times are GMT. The time now is 09:24 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