B1 Buffer Preamp - Page 171 - diyAudio
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 26th May 2009, 10:58 PM   #1701
diyAudio Member
 
Join Date: Mar 2009
Default Re: Re: Status of first build

Quote:
Originally posted by Nelson Pass


Those are perfectly fine.

I was all set to order new posts, but single pots are unavailable at this time (backorder). An alternative plan is to use a dual pot and rotary switch instead of DPTP switch and single pots. Considering one of the two dual pots below, and the switch. I do not listen to system at high volume, so I want some useable range from pots at lower volumes. I am begrudgingly living with reverse log taper at the moment and find it not suited to my preferences, yielding too much increase in volume at the lower end of the throw. Any opinions or affirmations will again be most appreciated.

Linear taper dual pot (concerned with 10K OHM rating)
http://search.digikey.com/scripts/Dk...=KKU1031S28-ND
Log taper dual pot
http://search.digikey.com/scripts/Dk...=KKA5031S28-ND
Rotary Switch (very much conjecturing what will work here)
http://search.digikey.com/scripts/Dk...name=GH7102-ND
  Reply With Quote
Old 26th May 2009, 11:37 PM   #1702
diyAudio Member
 
Join Date: Jan 2004
Location: Irondale, AL
Default reverse taper

a quick fix is to revers the outer 2 wires on each pot and use them in reverse ie CW is lower volume, CCW increases volume. Works as long as you remember!
__________________
Been there, Heard that, Forgot what I was listening to!
  Reply With Quote
Old 27th May 2009, 03:44 AM   #1703
diyAudio Member
 
Join Date: Mar 2009
Default Re: reverse taper

Quote:
Originally posted by Lee35210
a quick fix is to revers the outer 2 wires on each pot and use them in reverse ie CW is lower volume, CCW increases volume. Works as long as you remember!

Did that, by accident, but only for one channel. So quickly turned volumes clockwise in reaction, elongating the hair-raising experience. Given my preteens often use the system, I'll invest in the correct taper. It was hard enough to teach them to wait for the tube amp before setting the volume.
  Reply With Quote
Old 27th May 2009, 03:53 AM   #1704
diyAudio Member
 
Join Date: Jan 2004
Location: Irondale, AL
Default Re rewire

Understand completely. was just a quick and dirty fix until can procure correct pots
__________________
Been there, Heard that, Forgot what I was listening to!
  Reply With Quote
Old 28th May 2009, 03:56 AM   #1705
diyAudio Member
 
Join Date: Jan 2004
Location: dark side of the moon
So much information. So am I missing anything if I just build the B1 as designed.
  Reply With Quote
Old 28th May 2009, 11:24 PM   #1706
VT67 is offline VT67  Belgium
diyAudio Member
 
VT67's Avatar
 
Join Date: Jun 2004
Location: Belgium
Maybe off-topic or silly, but would this B1 Buffer Preamp together with a Zv9 make a good integrated amp?

Regards
  Reply With Quote
Old 28th May 2009, 11:59 PM   #1707
Formerly "jh6you". R.I.P.
 
Babowana's Avatar
 
Join Date: Jul 2006
Quote:
Originally posted by budwiser


So much information. So am I missing anything if I just build the B1 as designed.



No, I don't think so . . .


  Reply With Quote
Old 29th May 2009, 02:00 AM   #1708
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally posted by VT67
Maybe off-topic or silly, but would this B1 Buffer Preamp together with a Zv9 make a good integrated amp?
The total gain might be an issue, as the ZV9 has about 13 dB or so.
I tend to use efficient drivers with that amp, so it has not been a
problem for me.

  Reply With Quote
Old 29th May 2009, 03:23 AM   #1709
diyAudio Member
 
Join Date: Jun 2004
Location: Michigan
I have already purchased two of the Pass DIY B1 boards with the matched JFET's.

I bought two because I wasn't sure if one of them would comfortably drive my 100K input impedance amp as well as a typical subwoofer plate amp which are quite often 10 to 20K as far as their input Z. My original idea was to set one up with fixed resistors in the stead of a volume pot for the low impedance load and one with the volume control.

Is this wacky thinking? Is one plenty and not to worry about the 5 to 10 times difference in impedance? If this were in fact a good idea what would be the best way to implement it, i.e. wire this mess together. Perhaps wire the fixed unit for the plate amp from a second output or in parallel from the unit with the volume control?

My second question is about the use of stepped attenuators. I have always hated dual volume controls. I also have no need for a balance control in my room, just lucky that way I guess. Part of my plan in the future may be to use a motorized remote control from Bent Audio on a 20K DACT or 20K or 25K Goldpoint.

I am a bit confused about the whole issue of taper and if the stepped units are suitable. I have some experience with comparing a 100 DACT with a 100k "blue velvet" Alps and there was no comparison in my mind as to which sounded cleaner , clearer or more realistic. It was the DACT all the way. I hope not to offend anyone but It made the Alps sound like a toy.

I am not new to audio just new to DIY and have a lot to learn.
  Reply With Quote
Old 29th May 2009, 06:21 AM   #1710
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Quote:
Originally posted by budwiser
So much information. So am I missing anything if I just build the B1 as designed.
That depends on what you want. If you want to go capless then the standard design will not fit the bill.
__________________
It's only audio. Official member of the Norske Brillegeit Gang.
  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
buffer/preamp? TheDriver41 Chip Amps 2 3rd October 2004 09:40 AM


New To Site? Need Help?

All times are GMT. The time now is 10:37 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