Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 11th April 2010, 10:32 AM   #1
diyAudio Member
 
xecluded's Avatar
 
Join Date: Jul 2008
Location: 10,000 lakes
Default B1 question

My single ended tube amp has it's own volume control and i am just wondering which is the "recommended" way to use my tube amp with the B1:

1. Turn the volume pot on the amp all the way up and adjust volume on the B1 to suit my listening comfort level

2. Turn volume pot on the B1 all the way up and adjust volume on the tube amp to suit my listening level

Thanks.
  Reply With Quote
Old 11th April 2010, 10:59 AM   #2
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
The B1 is a buffer.
You can add a volume control in front of it if you need that attenuation facility.

If you already have a volume control then an extra one is not required.
You just buffer the output of the existing volume control.
__________________
regards Andrew T.
  Reply With Quote
Old 11th April 2010, 11:03 AM   #3
diyAudio Member
 
xecluded's Avatar
 
Join Date: Jul 2008
Location: 10,000 lakes
Quote:
Originally Posted by AndrewT View Post
The B1 is a buffer.

You just buffer the output of the existing volume control.
Great. Now the question is how do i do that
Please let me know in layman term as i am not much of a tech and need instructions step by step. Thanks.
  Reply With Quote
Old 11th April 2010, 11:14 AM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Default building B1 as a buffer

delete r101,201, delete IN2r, IN2l, delete P100,P200.

Connect INr to R102 and INl to R202
Connect INr&L to the tube outputs.

You have now added a buffer to the output of the tube pre-amp.

If there is room inside and somewhere cool enough, you can connect R102, R202 direct to the tube pre-outs and then connect OUTr & OUTl to the back of the output sockets.

This may improve the connection to your power amp if the Tube pre cannot deliver sufficient current to drive the capacitance of the interconnect cables and the RF filter in the power amp.
__________________
regards Andrew T.
  Reply With Quote
Old 11th April 2010, 02:54 PM   #5
diyAudio Member
 
Join Date: Jun 2007
I think you should outline your reasons for wanting to use the B1 in addition to your pre-amp?.
It may not be fixing whatever problem you think that you have.
  Reply With Quote
Old 11th April 2010, 05:44 PM   #6
diyAudio Member
 
xecluded's Avatar
 
Join Date: Jul 2008
Location: 10,000 lakes
Quote:
Originally Posted by AndrewT View Post
delete r101,201, delete IN2r, IN2l, delete P100,P200.

Connect INr to R102 and INl to R202
Connect INr&L to the tube outputs.

You have now added a buffer to the output of the tube pre-amp.

If there is room inside and somewhere cool enough, you can connect R102, R202 direct to the tube pre-outs and then connect OUTr & OUTl to the back of the output sockets.

This may improve the connection to your power amp if the Tube pre cannot deliver sufficient current to drive the capacitance of the interconnect cables and the RF filter in the power amp.
Before I do this, i want clarify that I do not have a tube preamp. My tube amp will connect directly to this Buffer B1. I am not sure where the tube pre-amp came from. Thanks
  Reply With Quote
Old 11th April 2010, 05:45 PM   #7
diyAudio Member
 
xecluded's Avatar
 
Join Date: Jul 2008
Location: 10,000 lakes
Quote:
Originally Posted by WithTarragon View Post
I think you should outline your reasons for wanting to use the B1 in addition to your pre-amp?.
It may not be fixing whatever problem you think that you have.
I don't have a tube preamp. I will use my single ended 45 tube amp with volume control and connect directly to the B1 hence want to eliminate to volume control on the B1.
  Reply With Quote
Old 12th April 2010, 02:55 AM   #8
just another
diyAudio Moderator
 
wintermute's Avatar
 
Join Date: Aug 2003
Location: Sydney
Blog Entries: 22
Hi xecluded, the B1 is a line level buffer. If your amp is driving speakers then you would need to put the B1 Before the amp. If you keep the volume control on the amp, then I don't see any benefit in putting a B1 before it, except to give your source a fixed impedance to drive. I think that Andrew and WithTarragon made the (reasonable) assumption that the amp was a preamp and that you wanted to buffer it's output.

If you want to add a buffer before the amp, then I would instead remove the volume control from the amp, and use the volume control in the B1. But as WithTarragon said what is the reason for wanting to add the B1?

Tony.
__________________
Any intelligence I may appear to have is purely artificial!
Some of my photos

Last edited by wintermute; 12th April 2010 at 02:59 AM.
  Reply With Quote
Old 12th April 2010, 09:28 AM   #9
diyAudio Member
 
xecluded's Avatar
 
Join Date: Jul 2008
Location: 10,000 lakes
The tube amp was built that way with volume control. Using it without a preamp, i felt that it is missing some dynamics to the sound and that's why I am using the B1.
  Reply With Quote
Old 12th April 2010, 07:30 PM   #10
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
what is the input impedance of the tube power amp?
What is the RC time constant of the RF filter fitted to the input of the power amp?
What is the output impedance of the source feeding your power amp?
__________________
regards Andrew T.
  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
question on very high input impedance for B1 wintermute Pass Labs 8 3rd April 2010 01:20 PM
B1 PSSR Question and idea Rick NL Pass Labs 0 11th February 2010 08:52 AM
B1 Preamp Grounding Question jonsmith Pass Labs 8 18th November 2009 11:49 AM
B1 layout question peranders Pass Labs 3 15th October 2009 09:10 AM
B1 pre earth safety question (newbie) scorpio1 Pass Labs 2 16th June 2009 04:30 PM


New To Site? Need Help?

All times are GMT. The time now is 09:00 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