JE Labs 300b round 4. Wiring, HELP!!! - 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 23rd December 2002, 03:18 AM   #1
diyAudio Member
 
Join Date: Dec 2006
Default JE Labs 300b round 4. Wiring, HELP!!!

Hi Everyone,

Here is were I need major help, understanding the schematic to wire this baby up. I'll post a pic of schematic and pic of what it looks like underneath. Where would one start? Also, where should I put a star ground? Thanks for the help and there will be a ton of posts in this thread, so please check back often. Thank you!!!
Attached Images
File Type: jpg under1a.jpg (48.9 KB, 1259 views)
  Reply With Quote
Old 23rd December 2002, 03:21 AM   #2
diyAudio Member
 
Join Date: Dec 2006
schematic
Attached Images
File Type: jpg stse300bdx-sca.jpg (54.7 KB, 1234 views)
  Reply With Quote
Old 23rd December 2002, 08:02 AM   #3
stigla is online now stigla  Norway
diyAudio Member
 
Join Date: Nov 2001
Location: Trondheim
http://www.aikenamps.com/StarGround.html

Nice article about Stargrounding.

Good luck!

Stigla
  Reply With Quote
Old 23rd December 2002, 08:46 AM   #4
diyAudio Member
 
Join Date: Oct 2002
Location: Amsterdam
Default wiring

Hallo Paul,

Start with the heater wires. Twist each pair tightly, keep the pairs away from each other and close to the chassis. Keep signal wires away from AC wires. If you have to cross, do so at 90 degree angles.

happy wiring

Martin
  Reply With Quote
Old 23rd December 2002, 10:37 AM   #5
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default WIRING

Hi,

Make sure you have the socket layout for the tubes at hand.

Take a copy of your diagram and add the pin numbers of these sockets on it.

Also take note of the colourcoding of the transformer and add this to this copy as well.

Then you can start with heater wiring as Tomatito suggests,than the B+ from the 5U4 to the caps and choke.

From there you can add the anode and cathode resistors for the 6SN7.
Connect B+ (390V on the diagram) to the second half of the 6SN7,
the 36K 1W resistor from that point to the anode resistor of the first half of the 6SN7.
Add the bypass cap to the anode resistor.

Connect the B+ (405V) to the OPT and wire the other end to the anode of the 300B.

Solder the B+ resistor (1k8/3W) in series after the first filtercap and the 100K in paralel (this one needs to be grounded,see below) after the choke.

Connect the trimpot,cathode resistors and bypass cap (watch polarity) for the 300B heater.

Solder the 470R gridstopper as close to the grid of the 300B,the bias resisitor (220K) can share the same solder eyelet.

On the second half of the 6SN7 add the cathode bypass cap (100microF/?),again watch polarity.

You can now hook up the input,volpot and its' output to the grid of the first tube making sure to connect to G1.
Jumper the anode of the first half to the grid of the second tube.

From the anode of the second half you can now solder in the coupling cap to the gridresistor of the 300B.

On the diagram you will see a grounding point at the first cathode resistor and one at the 300B cathode resistor.
You can wire the ground from the RCA connector to the cathode resistor end,add the endwires from the second half of the 6SN7 cathode resistor and bypass cap towards this point.

Make a separate groundpoint at the 300B cathode resistor and solder there to ground.

A third groundpoint is required for the bypass cap at the first anode resistor.

Another one is to be made at the PSU end where you see the 100K/2W bleeder resistor.

As far as I'm concerned groundpoint 3 and 4 can share the same connection provided it is done at the PSU side.

Make sure any unused transformer leads are individually insulated and not touching the chassis.

Visually check for anything forgotten (me or you ) and you can now put in the tubes and fire up the amp.

Actually soldering on the tube sockets is often easier with the tubes in place but I think your sockets are special ones that don't move when you solder on the pins hence...

From what I see you're building these amps as monoblocks,so don't be surprised to measure a too high B+.
This will require adjustment later on especially since the 6SN7 is direct coupled.
Unless you use a different xformer of course.

BTW,I see a UX5 socket as well,is this for measuring purposes?

May I ask fellow members to correct me if I made mistakes or have overlooked something.

Cheers,
__________________
Frank
  Reply With Quote
Old 23rd December 2002, 11:57 AM   #6
diyAudio Member
 
Join Date: Oct 2002
Location: Amsterdam
Default UX5

Only one half of the 6SN7 is used, driven by a 76
  Reply With Quote
Old 23rd December 2002, 12:22 PM   #7
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Default 76

Ho,

Thanks Maarten.

I also forgot to state the obvious:the power on switch as to be wired up as well of course and the amp meter and LS posts.

Also in this case it would be a good idea to wire the 6SN7 on one of the monoblocks so it uses the second half of the tube.

That will allow for more useful life of these since you can than swap them after a couple of years use.

Cheers,
__________________
Frank
  Reply With Quote
Old 23rd December 2002, 12:47 PM   #8
diyAudio Member
 
Join Date: Oct 2002
Location: Amsterdam
Default Maarten

It's Martin. I have killed for less
  Reply With Quote
Old 24th December 2002, 11:45 AM   #9
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Hallo Martin,

Any succes with the common mode filter on your amp?

Cheers,
Bas
  Reply With Quote
Old 24th December 2002, 01:17 PM   #10
diyAudio Member
 
Join Date: Oct 2002
Location: Amsterdam
Hi Bas,

I'm in Ibiza right now, recuperating from a hernia I got after lifting my amp. (dangerous hobby) so the filter has to wait a while.
I'll let you know.

Martin
  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
JE Labs 300b round 2! layout TubeHound Tubes / Valves 12 13th May 2003 08:46 AM
JE Labs 300b round 2 1/2 Copper Plates TubeHound Tubes / Valves 18 9th April 2003 12:30 AM
JE Labs 300b round 5. MUSIC!! MUSIC!! TubeHound Tubes / Valves 14 11th January 2003 12:02 AM
JE Labs 300b round 3. Chassis are Done TubeHound Tubes / Valves 17 21st December 2002 11:50 PM
Je labs 300b round 1 : Ding! Ding! TubeHound Tubes / Valves 9 13th October 2002 08:28 PM


New To Site? Need Help?

All times are GMT. The time now is 01:02 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