Arjen Helder Buffer V2 - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 15th May 2010, 01:52 PM   #11
rhing is online now rhing  United States
diyAudio Member
 
rhing's Avatar
 
Join Date: Jun 2007
Location: Bay Area, California
Default Loud pop on start-up

Quote:
Originally Posted by Zero One View Post
I have now had some time to listen to the buffer and amp combined and must say it is a sweet combination.

One thing worth doing is to bypass the output caps on the buffer if it is only going to feed the standard amp module. Having done this I found the bass was improved and the whole set-up gained a little more detail.
I followed this advice, and I get a very loud pop on start-up. In the eBay ad for the tube buffer, it states:

"Due to too much POP noise when starting the PREAMP, we have replaced the input capacitors to 2.2uf."


First of all, I thought the 2.2uF caps on the V2 buffer board were the output caps, not the input caps. Should I put the 2.2uF caps back in place?
__________________
Rich
  Reply With Quote
Old 15th May 2010, 09:46 PM   #12
diyAudio Member
 
Join Date: Apr 2006
Location: Goulburn NSW
Hi Rich
The output caps are the large red ones, they can be removed if the buffer is feeding into a module that has input caps on it. You must have a cap somewhere either on the amp module or on the buffer.



Basically with both output and input caps in series you roll off the bass more.


I have no problems with big pops but there will always be a small pop, it was the input caps for the buffer they replaced with a smaller one, there is no need to replace that.
  Reply With Quote
Old 16th May 2010, 03:38 PM   #13
onis_uk is offline onis_uk  United Kingdom
diyAudio Member
 
Join Date: Jul 2004
Location: uk
i have mine all set up now, on power up the speakers are kind of sucked in and slowly return to the middle and i get a very loud pop when i turn it off .... hummm
  Reply With Quote
Old 16th May 2010, 05:39 PM   #14
rhing is online now rhing  United States
diyAudio Member
 
rhing's Avatar
 
Join Date: Jun 2007
Location: Bay Area, California
I measured the DC voltage on my speaker outputs of my TA2020MkIII amp with the MkII tube buffer. On power up, I read -2.4V on both channels. It starts to decay to about +8mV in about 10-15 seconds. The first time I powered up, it sent the T-amp into fault mode. On second power up, I got the same surge, but the T-amp remained on. I can't make any adjustments on the DC bias pots to bring the DC as close as possible to 0mV. After the initial surge on the second power up, I plugged in some cheapie test speakers and I have decent sound out of both speakers. I am very concerned that I cannot use this product with my T-amp, which is a shame, because I really wanted to further improve the excellent sound quality I get from my T-amp.
__________________
Rich
  Reply With Quote
Old 16th May 2010, 08:52 PM   #15
rhing is online now rhing  United States
diyAudio Member
 
rhing's Avatar
 
Join Date: Jun 2007
Location: Bay Area, California
Quote:
Originally Posted by onis_uk View Post
i have mine all set up now, on power up the speakers are kind of sucked in and slowly return to the middle and i get a very loud pop when i turn it off .... hummm
I turned the amp off and I get the really loud pop too. Does anyone have any ideas on eleiminating/reducing this pop on turn on and turn off?
__________________
Rich
  Reply With Quote
Old 16th May 2010, 09:16 PM   #16
onis_uk is offline onis_uk  United Kingdom
diyAudio Member
 
Join Date: Jul 2004
Location: uk
i hope so, ive emailed arjen and he doesnt even know (
  Reply With Quote
Old 17th May 2010, 06:27 PM   #17
Frenger is offline Frenger  Netherlands
diyAudio Member
 
Join Date: Nov 2008
I've got the same problem of the loud pop. I hope someone knows how to solve it.
  Reply With Quote
Old 17th May 2010, 07:41 PM   #18
rhing is online now rhing  United States
diyAudio Member
 
rhing's Avatar
 
Join Date: Jun 2007
Location: Bay Area, California
Arjen has emailed me to inform me that he's working on a solution. I'm not sure how the solution will be implemented (another PCB to buy). For now, I can't risk damaging my speakers with -2.4V DC on turn on. I haven't measured the turn off DC voltage, but the pop is louder.
__________________
Rich
  Reply With Quote
Old 18th May 2010, 05:53 PM   #19
diyAudio Member
 
Join Date: Apr 2008
Quote:
Originally Posted by rhing View Post
I turned the amp off and I get the really loud pop too. Does anyone have any ideas on eleiminating/reducing this pop on turn on and turn off?
with this konfiguration I think itīs best to connect speakers after turned on and disconnect speakers before you are going to turn off the amp.

So let the amp always ON. Itīs also better for receiving immediately best performance without any warm-up
-----------------------
But another newbee question from me regarding the way from the cinch sockets of my CD Player to the V2 buffer amp:
how to handle with the black mass cable on the board which is shared from the right and left input together ? Cinch outputs have for each channel the separate mass contact and if I am not wrong itīs the outer ring which is mass, or ?

Last edited by TheDealer; 18th May 2010 at 06:07 PM.
  Reply With Quote
Old 18th May 2010, 06:16 PM   #20
onis_uk is offline onis_uk  United Kingdom
diyAudio Member
 
Join Date: Jul 2004
Location: uk
yes it will be another pcb that cuts the speakers off with a relay and to be honest i haven't got the room in my case for another pcb plus i dont really want another pcb in the signal path ....not too happy (
  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
Helder MKII TA2020 Amp PSU Wiring Obe1 Class D 10 22nd January 2014 01:33 PM
Good Experience with Arjen Helder mfong Class D 6 10th May 2011 07:07 PM
Arjen's helder TA2020 MKiii went fault :( chchyong89 Class D 13 17th September 2010 10:24 PM
Arjen MKIII Enclosure Recommendation mrdon Class D 2 13th April 2010 11:26 AM
Opamp + buffer, how to bypass buffer at HF for unity gain? Christer Solid State 10 29th October 2003 06:50 AM


New To Site? Need Help?

All times are GMT. The time now is 12:53 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright Đ1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2