Tube Noob with a few questions - 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 13th March 2012, 02:12 AM   #1
jjski78 is offline jjski78  United States
diyAudio Member
 
Join Date: Mar 2012
Location: Austin, AR
Default Tube Noob with a few questions

Hello from Arkansas. For some reason beyond my comprehension, the tube bug bit me. I don't know why, all I know is I'm infected. So being the rational person I am, having never touched anything with a vacuum tube, I bought this:

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

I figured "it can't be that hard, it's not a lot of money, and if I can't get it to work I guess it's heavy enough to use as a boat anchor". I know it's a mono 10 watt amp but other than that I have no idea about it. I can't even find a schematic for it. I find the LJ2, 3, and 5, but no LJ4. I'm hoping, if I can get this one up and running, to buy another one and get a pair of Fostex full range speakers and have a nice little hifi rig to play my turntable through in the garage. So that said..hi, I'm Joe, I've never touched a tube amp in my life, and can't find a schematic for the one I just bought. Anyone have anywhere I should look?
  Reply With Quote
Old 13th March 2012, 02:36 AM   #2
diyAudio Member
 
Join Date: Sep 2004
Location: New Zealand
Hi jjski78
And you didn't see my lovely LDR preamps on eBay ! , The tubes are 5Y3GT, 6V6GT x2 and 12AX7 x2
revealed thankfully from the images, So there is your starting point to hunt down those tubes. A full restoration looks to be needed.

Cheers / Chris
  Reply With Quote
Old 13th March 2012, 02:40 AM   #3
diyAudio Member
 
Chris Hornbeck's Avatar
 
Join Date: May 2011
Location: Little Rock
Hello from Little Rock (which is just like Arkansas, but with bad traffic). This little guy isn't complicated enough to need a schematic, but can't hurt if you can find one. I'd recommend getting an RCA tube manual (reprints are common) and getting familiar with the type 5Y3 and 6V6 (probably the octal based tubes missing) and the 9 pin dual triodes like type 12AX7 (probably the other missing tubes).

Before firing it up, you'll want to learn about SAFETY, reforming the electrolytic capacitors, and especially SAFETY.

All good fortune, and write with more questions,
Chris
  Reply With Quote
Old 13th March 2012, 02:41 AM   #4
jjski78 is offline jjski78  United States
diyAudio Member
 
Join Date: Mar 2012
Location: Austin, AR
I already had the tube number written down, but will I have to bias the amplifier when I install the power tubes, or should I be ok as long as I get a matched set? I'm going to replace all the caps in it because I've been reading horror stories about them exploding when they get old. Don't feel like making my wife a widow just yet.
  Reply With Quote
Old 13th March 2012, 02:45 AM   #5
diyAudio Member
 
Chris Hornbeck's Avatar
 
Join Date: May 2011
Location: Little Rock
Quote:
Originally Posted by Chris Daly View Post
revealed thankfully from the images
Wow. You've got a golden future in spy satellite analysis. I can't see that to save my life. Very impressed!

Thanks,
Chris
  Reply With Quote
Old 13th March 2012, 02:45 AM   #6
diyAudio Member
 
Join Date: Nov 2011
Hi jjski78
Just to add to Chris' post, if you can recognise the components and with the tube data on hand, it shouldn't be too hard to trace out the schematic. It would also be a good learning experience for you.
Best of luck on your journey.
  Reply With Quote
Old 13th March 2012, 02:46 AM   #7
diyAudio Member
 
astouffer's Avatar
 
Join Date: Jun 2004
Location: Pittsburgh, crumbling wasteland
Congrats on your first tube purchase Don't even bother reforming caps. They're gonna go eventually so spend the extra $5 and install new ones. Its not a question of "if" they go bad its "when".
  Reply With Quote
Old 13th March 2012, 02:57 AM   #8
jjski78 is offline jjski78  United States
diyAudio Member
 
Join Date: Mar 2012
Location: Austin, AR
Quote:
Originally Posted by Chris Hornbeck View Post
Hello from Little Rock (which is just like Arkansas, but with bad traffic). This little guy isn't complicated enough to need a schematic, but can't hurt if you can find one. I'd recommend getting an RCA tube manual (reprints are common) and getting familiar with the type 5Y3 and 6V6 (probably the octal based tubes missing) and the 9 pin dual triodes like type 12AX7 (probably the other missing tubes).

Before firing it up, you'll want to learn about SAFETY, reforming the electrolytic capacitors, and especially SAFETY.

All good fortune, and write with more questions,
Chris
LOL, I'm just north of you, I know all about the traffic. I was skimming through the RCA manual in the sticky, but it looks to be a bit too old for the tubes in this amp. Still some good info though. I do have experience with some pretty ancient technology, I'm a crew chief on the C-130 and my first bird was a '62 model. I plan on just replacing all the caps in it, just to be on the safe side. Pretty sure I can get those at Radio Shack, right?
  Reply With Quote
Old 13th March 2012, 03:20 AM   #9
diyAudio Member
 
Chris Hornbeck's Avatar
 
Join Date: May 2011
Location: Little Rock
Quote:
Originally Posted by jjski78 View Post
LOL, I'm just north of you, I know all about the traffic. I was skimming through the RCA manual in the sticky, but it looks to be a bit too old for the tubes in this amp. Still some good info though. I do have experience with some pretty ancient technology, I'm a crew chief on the C-130 and my first bird was a '62 model. I plan on just replacing all the caps in it, just to be on the safe side. Pretty sure I can get those at Radio Shack, right?
You're a Zoomy! Thank you for your service.

First plane I ever rode in was a C130, and it was old in 1968. We AFROTC kids were riding up to Griffiss AFB for the day, hanging in the straps on the sides. Pilot walks back, says he can't get the blankety-blank landing gear down, we're low on fuel, yada yada. He opens a door in the floor, climbs down, there's a sound of banging, he climbs up, we land. Most fun I had in the 60's.

Thanks,
Chris
  Reply With Quote
Old 13th March 2012, 04:07 AM   #10
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Tracing out the schematic is definitely a good idea. You rate to find the O/P tubes are self (cathode) biased and no adjustment is needed.
__________________
Eli D.
  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
noob with questions bdiddy876 Car Audio 2 27th March 2007 07:14 AM
Noob questions deriver23 Car Audio 1 26th August 2006 12:06 AM
Noob Questions... MrGeebs Solid State 7 24th March 2006 04:17 AM


New To Site? Need Help?

All times are GMT. The time now is 10:22 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