Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Group Buys Members group buys

Versatile and comfortable passive pre-amp
Versatile and comfortable passive pre-amp
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 September 2013, 10:42 AM   #511
jean-paul is offline jean-paul  Netherlands
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Rotterdam ....that explains why you're a good guy Rudi !

Please have some kroketjes with Mama this weekend. Tip: don't talk about Ajax or Amsterdam in general.
__________________
It's only audio. Member of the non modular PCB design committee
  Reply With Quote
Old 13th September 2013, 06:56 PM   #512
nertia is offline nertia  Scotland
diyAudio Member
 
Join Date: Jan 2010
I have finally got to a point where I could play music through the preamp.
I have it connected to a Hifimediy T2 amplifier and it sounds absolutely amazing. I was not expecting such an improvement in sound quality over the Alps pot I was using before.

I have a slight issue that when the volume is turned all the way down, I can still hear music playing very quietly through both speakers. The maximum resistance I measured was 5.7k at minimum volume.

When I was measuring the LDRs I attempted to correct the channel balance by soldering a 33k resistor in parallel with the adjustable LDR's output, and this allowed me approximately match the resistances over the first third of the volume pot's travel. Could this be the reason for the problem? It seems funny that it affects both speakers and not just the right channel.

Having said that, I will quite happily live with this if it cannot be fixed, the music sounds so much better.

Thanks again to Rudi and Uriah.

Mat
  Reply With Quote
Old 14th September 2013, 03:03 AM   #513
wineds is offline wineds  Australia
diyAudio Member
 
Join Date: Apr 2006
Location: Melbourne
nertia that is normal, LDR shunt cannot go to zero resistance like a real pot can
  Reply With Quote
Old 16th September 2013, 06:35 PM   #514
voxxonline is offline voxxonline  United Kingdom
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Versatile and comfortable passive pre-amp
Default issue

Ok gents. I put vcpre into thick cardboard box until I get real enclosure sorted.
Hooked it to cd and old arcam power amp to test. Music plays well for about 30 sec and after that.., click record to listen.
Cannot plug to myref amp yet cause doing some works on it so impossible to say if it is an amp issue.
Any ideas ?
Link to wav:
https://www.dropbox.com/s/nmsg4eqnb9w6xqr/amp%20rec.wav
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 17th September 2013, 10:54 AM   #515
voxxonline is offline voxxonline  United Kingdom
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Versatile and comfortable passive pre-amp
Now I can confirm same issue with another amplifier. Same weird gated sound appearing after approx 30 sec of power on.
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 17th September 2013, 11:11 AM   #516
atupi is offline atupi  Romania
diyAudio Member
 
Join Date: Oct 2010
Location: Bucharest
Check the voltage provided by micrel reg to the silonex optocouplers.
They are in the signal path. Maybe the micrel reg becomes hot or unstable and swings the voltage on output.
  Reply With Quote
Old 17th September 2013, 11:50 AM   #517
ajst2duk is online now ajst2duk  Australia
diyAudio Member
 
Join Date: Apr 2010
Quote:
Originally Posted by billyk View Post
Thanks Uriah!
It should never be a chore!! I for one am very grateful for your dedication to the hobby and to all of us around here. I really think that without you there would not be the many, many of us that now enjoy these !!!
You are running yours into a fetzilla if I'm right? How do you find it?
  Reply With Quote
Old 17th September 2013, 12:03 PM   #518
voxxonline is offline voxxonline  United Kingdom
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Versatile and comfortable passive pre-amp
I have lme49710 can I swap it with mcp6021 to check things ?
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 17th September 2013, 12:26 PM   #519
voxxonline is offline voxxonline  United Kingdom
diyAudio Member
 
voxxonline's Avatar
 
Join Date: Aug 2012
Location: Bexleyheath, Kent
Versatile and comfortable passive pre-amp
If not please advise which legs to test
__________________
How to find time to finish my projects ?
  Reply With Quote
Old 17th September 2013, 12:44 PM   #520
billyk is offline billyk  United States
diyAudio Member
 
billyk's Avatar
 
Join Date: Oct 2005
Location: North Central Mass, USA
Quote:
Originally Posted by ajst2duk View Post
You are running yours into a fetzilla if I'm right? How do you find it?
I wish I could tell you! It is still in the boxes awaiting construction. Oh! The frustration I feel! All those beautiful parts calling me. Anyway, life is very busy for me right now with work and family. I just have about enough time to visit with you folks here.
I hope to take some time off and have some just for me time, then I will get to building!!
  Reply With Quote

Reply


Versatile and comfortable passive pre-ampHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Designing a versatile pre with balanced and unbalanced in/out Nikon1975 Analog Line Level 56 28th December 2012 10:56 PM
Passive pre-amp Davy Solid State 20 25th August 2008 09:11 PM
Is this possible from a passive pre-amp? mr.duck Everything Else 7 3rd December 2006 11:57 AM
passive pre amp mschwilson Solid State 10 27th July 2005 01:43 PM
Passive pre amp vs powered pre amp fatmarley Solid State 21 21st November 2003 02:01 PM


New To Site? Need Help?

All times are GMT. The time now is 08:37 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki