Stereo BusBar OK? - 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 12th November 2007, 10:43 PM   #1
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Default Stereo BusBar OK?

I am about to run a bus bar in a stereo valve amp. In the schematic is my plan and some notes. Please review it for obvious bad (buzzzz) ideas. Also tell me if I have to attach the shields of the input coaxes both ends or not, and if not, where.
Attached Images
File Type: jpg busbar.jpg (45.6 KB, 744 views)
  Reply With Quote
Old 12th November 2007, 11:19 PM   #2
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
Hi, personally I don't like the path it took.

If I were to do it, I would, in order of preference-

1) Use star ground. My preamplifier projects benefits from this, none of them are noisy done that way. It does not look pretty (but better than Sakuma's ) and it does the job well.

2) Use "T" style bus. If you'll look underneath the posted picture of my 300B amp, you'll notice (aside from the blue capacitors in the wrong direction ) how I employed the bus. My 300B runs on AC filaments, and you will not hear any hum with your ears within a foot from the speaker cone.

re: shield, I normally use salvaged two-conductor shield wire from old heaphone units. I find them easy to work with and good for the application. So, I have never used a coax. I think the method you mentioned is a practice for interconnects.

Cheers!

ps.

What amp is this?
  Reply With Quote
Old 12th November 2007, 11:30 PM   #3
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Its my design. 12AY7parallel - 12AT7 cascode tail CCS LTP - KT88 PP triode. Unfortunately I use a chassis from an older amp, that has a nice to look at tube placement, but output tubes and inputs are located extreme left and right. I am afraid it has potential to buzzzz. I will sketch a T in a minute so you can tell me a new opinion.
  Reply With Quote
Old 12th November 2007, 11:32 PM   #4
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Assuming V1 and V2 are input tubes and V3 and V4 are drivers, I'd do it like this:
Attached Images
File Type: jpg busbar.jpg (46.3 KB, 656 views)
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 12th November 2007, 11:38 PM   #5
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Default T bar.

Here it is. Better? As for the coaxes, my concern is, that if input interconnects are going to be grounded at the input RCAs connected with the front portion of the busbar, they must not get to the first stage gnd also, it looks like a loop. So I think its better I attach the internal coax shields at the rca rings only.

PS. Thanks SY!
Attached Images
File Type: jpg busbart.jpg (44.7 KB, 587 views)
  Reply With Quote
Old 12th November 2007, 11:50 PM   #6
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by SY
Assuming V1 and V2 are input tubes and V3 and V4 are drivers, I'd do it like this:
SY, in your proposition, the solid copper portion can be safely restricted to the picture's bottom and right 90deg angle part, and the other contacts come with cables, short of sub stars?



In the attached pic is Arnoldc's T method proposition for reference.
Attached Images
File Type: jpg img0474if2.jpg (95.1 KB, 617 views)
  Reply With Quote
Old 13th November 2007, 12:41 AM   #7
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Quote:
Better?
Yes, but still not optimum. I've highlighted the thick copper bus from my earlier drawing.
Attached Images
File Type: jpg busbar.jpg (46.5 KB, 597 views)
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 13th November 2007, 12:45 AM   #8
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
I should add, you want some form of groundbreaker between the amplifier ground and the safety (earth) ground. I show a resistor (27 ohms is a safe value), but it's been pointed out that this could compromise safety. These days, I use a 27-33R resistor paralleled by 1nF and two diodes (in parallel, each "facing" the opposite direction).

Others have used groundbreaking switches or plug assemblies, but those will then rely on the ground integrity of other components in the chain and make me nervous.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 13th November 2007, 12:51 AM   #9
arnoldc is offline arnoldc  Philippines
diyAudio Member
 
Join Date: Apr 2003
Location: Makati
Send a message via Yahoo to arnoldc
Hi Salas, I'd favor the short bus by Sy. Won't look as neat, but might be better.

ps.

Sy, I always have my circuit ground floating. Am I violating any safety rules? Sorry for being lazy...
  Reply With Quote
Old 13th November 2007, 12:54 AM   #10
Magura is offline Magura  Denmark
diyAudio Member
 
Magura's Avatar
 
Join Date: Oct 2003
Location: Denmark, Viborg
Quote:
Originally posted by SY
I should add, you want some form of groundbreaker between the amplifier ground and the safety (earth) ground. I show a resistor (27 ohms is a safe value), but it's been pointed out that this could compromise safety. These days, I use a 27-33R resistor paralleled by 1nF and two diodes (in parallel, each "facing" the opposite direction).

Others have used groundbreaking switches or plug assemblies, but those will then rely on the ground integrity of other components in the chain and make me nervous.

A CL60 thermistor is known to do the job, and do it well.


Magura
__________________
Everything is possible....to do the impossible just takes a little while longer.
www.class-a-labs.com
  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
Stereo in/multiple Stereo outs Circuit MartinByrne Everything Else 3 7th May 2009 01:11 AM
Reprocessed for stereo, Rechanneled for stereo and Duophonic oldheathkitphil Analog Line Level 3 29th February 2008 01:20 PM
Where to buy busbar? weinstro Parts 4 18th March 2005 02:55 PM
Stereo speakers with no stereo klutuk Everything Else 5 6th June 2004 09:45 PM
How do I wire stereo headphones on a stereo tv? hike1 Everything Else 2 10th September 2001 02:22 AM


New To Site? Need Help?

All times are GMT. The time now is 06:41 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