Pop/click free HW-based relay attenuator - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

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 17th April 2014, 11:38 AM   #1
diyAudio Member
 
Join Date: Oct 2004
Location: Denmark
Default Pop/click free HW-based relay attenuator

Fully HW-based pop and click free relay attenuator.

All done with some clever use of digital logic and accurate timing.

128 x 0.65dB steps for an attenuation range of 0 to -82dB.

High quality Omron G6K relays, high quality low noise, low distortion 0.1% Susumu RG Thin Film resistors.

Perfect channel balance, from max to min attenuation.

The attenuator needs a 10K termination resistor to maintain a 10K total attenuator impedance.

125mm x 40mm 4 Layer PCB.

EDIT : For those who want a PCB, the price is $20(PCB) + $3(Shipping) to all of Europe and the US.

Send me an E-mail with your DiyA username, real name and adress and I will send you a PayPal request.

I wont be able to send anything before Tuesday, April 22 due to easter holidays.

Furthermore, there will be an updated component placement file showing the exact placement and orientation of the components. Component number, placement and orientation is not shown on the silkscreen since I wanted a clean look so this is as intended.

The BOM is 100% accurate and everything should be in stock at Mouser. Although I would strongly urge people to order 1 extra 1uF, 0805 capacitor on top of the 9 needed for C5-C13. I will explain it later and the attenuator will work without it, although it could be a little "touchy" due to the potential for noise pickup from the potentiometer and long wires, the extra 1uF cap fixes it. EDIT : Explained in Post #17

The BOM is for the PCB mounted components ONLY, everything else needed, like 12 Volt DC power supply, Potentiometer, 3 pin molex housings and crimps, wires etc. is up the builder himself to decide upon and provide.

Have any questions, do not hesitate to ask.
Attached Images
File Type: png RAB V1 - Top.png (32.1 KB, 552 views)
File Type: png RAB V1 - Bottom.png (33.3 KB, 540 views)
Attached Files
File Type: pdf RAB V1 - Schematic.pdf (36.3 KB, 272 views)
File Type: pdf RAB V1 - Component Placement.pdf (10.4 KB, 93 views)
File Type: zip RAB V1 - BOM - Mouser.zip (3.4 KB, 123 views)

Last edited by Neutrality; 18th April 2014 at 09:44 PM.
  Reply With Quote
Old 17th April 2014, 01:45 PM   #2
diyAudio Member
 
Join Date: Oct 2004
Location: Denmark
Sorry for the crappy pictures, I am not much of a photographer.

The board has been assembled and tested.

It works just as expected, no pops or clicks in the audio when switching volume.*

*Apart from the very low noises when a relay is switched in at the top of a waveform, this is to be expected on ALL relay beased attenuators. This is due to the fact that there is way to do zero crossing detection when using relays. It is only detectable at very high volume levels.
Attached Images
File Type: jpg Bottom.jpg (604.1 KB, 583 views)
File Type: jpg Top.jpg (606.0 KB, 557 views)

Last edited by Neutrality; 17th April 2014 at 01:47 PM.
  Reply With Quote
Old 17th April 2014, 05:32 PM   #3
diyAudio Member
 
Join Date: Oct 2004
Location: Denmark
Quote:
Originally Posted by Neutrality View Post
It works just as expected, no pops or clicks in the audio when switching volume.*

*Apart from the very low noises when a relay is switched in at the top of a waveform, this is to be expected on ALL relay beased attenuators. This is due to the fact that there is way to do zero crossing detection when using relays. It is only detectable at very high volume levels.
Sitting here and listening to some great music and playing around with the volume using this new attenuator, I can safely say that it is a non issue.

I might be deluding myself but it does seem to be improved over just an Alps RK27, one thing that is certain though, is that the channel balance is absolutely spot on all the way down to max attenuation.

Why do it in SW when a good old school HW design can do the same thing.

Could not be happier.

Last edited by Neutrality; 17th April 2014 at 05:34 PM.
  Reply With Quote
Old 17th April 2014, 05:36 PM   #4
BigE is offline BigE  Canada
diyAudio Member
 
Join Date: Aug 2008
Location: Toronto
Are the boards available?
  Reply With Quote
Old 17th April 2014, 05:46 PM   #5
syklab is offline syklab  Hong Kong
diyAudio Member
 
Join Date: Jul 2009
Location: Hong Kong
Quote:
Originally Posted by BigE View Post
Are the boards available?
Interested too.
  Reply With Quote
Old 17th April 2014, 09:54 PM   #6
diyAudio Member
 
Join Date: Oct 2004
Location: Denmark
I have som PCBs left.

$20+shipping for a PCB.
  Reply With Quote
Old 18th April 2014, 03:16 AM   #7
ammel68 is offline ammel68  United States
diyAudio Member
 
Join Date: Sep 2009
Location: Southeast, U.S.
Too bad it uses surface-mount devices.
  Reply With Quote
Old 18th April 2014, 03:23 AM   #8
syklab is offline syklab  Hong Kong
diyAudio Member
 
Join Date: Jul 2009
Location: Hong Kong
Quote:
Originally Posted by Neutrality View Post
I have som PCBs left.

$20+shipping for a PCB.
Hi,
How many pub I need for 2 channel?
  Reply With Quote
Old 18th April 2014, 03:24 AM   #9
syklab is offline syklab  Hong Kong
diyAudio Member
 
Join Date: Jul 2009
Location: Hong Kong
Those SMd part doesn't look that bad.
  Reply With Quote
Old 18th April 2014, 08:27 AM   #10
diyAudio Member
 
Join Date: Oct 2004
Location: Denmark
Quote:
Originally Posted by ammel68 View Post
Too bad it uses surface-mount devices.
Surface mounted devices are the way of the future.

I could have made it with through hole components but it would end up a lot bigger. I needed something compact.
  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
FS: Relay based stepped attenuator Earfanatic Swap Meet 7 22nd April 2013 02:08 PM
Switching "click" of VPI HW-19 TT bigpandahk Analogue Source 6 24th February 2012 12:45 PM
Click and Pop TDA2050 32W Amp MjWasHere Class D 0 22nd August 2011 03:20 PM
irs2092 click and pop suppressor not working. nigelwright7557 Class D 3 4th December 2010 12:35 PM
relay based attenuator squadra Solid State 21 1st December 2004 10:10 PM


New To Site? Need Help?

All times are GMT. The time now is 01:10 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