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

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Phono switching with relays.
Phono switching with relays.
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 31st January 2018, 10:10 PM   #1
billshurv is offline billshurv  United Kingdom
diyAudio Member
 
billshurv's Avatar
 
Join Date: Mar 2014
Phono switching with relays.
Default Phono switching with relays.

Another one of those questions where I have been blissfully ignorant for years as never needed to know . I'm building a new preamp, which includes consolidating various functions that have been in seperate boxes into one. I have two turntables and, although most of the time one will be MM and one MC, I want to be able to support all combinations without replugging. And to be difficult I have seperate MM and MC phono stages. Both of these are firsts for me. Looking at the switching requirements to be able to be totally flexible relays seemed to be a good option. Then I started looking at specifications and realised that it's hard to find relays rated for Initial signals under 10mV, fine for a beefy MM but a tad high for a weedy MC, so I run the (worry of the) gauntlet of the contacts not whetting somewhere down the line. And herein is the ignorance. In a domestic environment with maybe 500 cycles a year max is there anything to worry about?

If anyone has recommendations for relays that work in this application and are not billet unobtanium?
  Reply With Quote
Old 31st January 2018, 10:18 PM   #2
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Phono switching with relays.
Pickering reed relays from old blighty..

Pickering Reed Relay - General Instrumentation Reed Relays

Form B and Form C relays are much less reliable than Form A (NO)

Make sure you select relays suitable for low current/low voltage applications and make sure you put no significant current through them. Where an input capacitor is involved include a small amount of series resistance to limit charge/discharge current during contact closure.
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 31st January 2018, 11:14 PM   #3
billshurv is offline billshurv  United Kingdom
diyAudio Member
 
billshurv's Avatar
 
Join Date: Mar 2014
Phono switching with relays.
Any advantage in the wet contact? I see Pickering make it hard to buy, hopefully they will deal with the great unwashed directly.

No capacitors in the signal path, balanced and servo'd all the way. Horrible 8-legs abound . I think I have mission creep down to a point where I can build it in non-glacial time!
  Reply With Quote
Old 1st February 2018, 03:23 AM   #4
BrianL is offline BrianL  United States
diyAudio Member
 
Join Date: Mar 2002
Location: USA
Phono switching with relays.
One of the better small-signal relays I know of is the Panasonic TX-S series. The p/n's with the -1 suffix (see datasheet) are designed for low-level signal switching. I'm not a fan of switching cartridge-level signals; I'd much rather have the phono stage located in the turntable 'plinth'/base. I realize that's not your intent, but I'd consider it

http://www.panasonic-electric-works....022_en_txs.pdf

I doubt you'll be able to get Mercury whetted relays in your country.
__________________
bel
  Reply With Quote
Old 1st February 2018, 09:12 AM   #5
billshurv is offline billshurv  United Kingdom
diyAudio Member
 
billshurv's Avatar
 
Join Date: Mar 2014
Phono switching with relays.
I was historically of that opinion, it's only been in the last year where I have decided to start playing with MMs again. I even have a turntable with a cutout for a pre-amp!

But the wish to be flexible combined with the Memsahib requesting a reduction in number of boxes makes it an avenue worth pursuing.
  Reply With Quote
Old 1st February 2018, 10:49 AM   #6
cliffforrest is offline cliffforrest  United Kingdom
diyAudio Member
 
Join Date: Sep 2004
Location: South Coast, UK
Phono switching with relays.
Reed relays, where the contacts are sealed in an inert gas, fit the bill. Used very widely for low level instrumentation.

I have loads in my loft. PM me if you would like a stick or two to play with.
  Reply With Quote
Old 1st February 2018, 11:43 AM   #7
billshurv is offline billshurv  United Kingdom
diyAudio Member
 
billshurv's Avatar
 
Join Date: Mar 2014
Phono switching with relays.
Thanks, will be in touch.
  Reply With Quote
Old 1st February 2018, 11:46 AM   #8
Kay Pirinha is offline Kay Pirinha  Germany
diyAudio Member
 
Kay Pirinha's Avatar
 
Join Date: Oct 2011
Location: Somewhere in Germany
Why relays? About 35 years ago I've built a control amplifier according to Elektor's Prelude articles. It featured three phono inputs, one MC and two MM's. The MC RCA jacks had fixed connections to the pre-pre amplifier's inputs, whose outputs were wired to a very common Lorlin dual pole triple throw rotary switch, as were the MM inputs. The switche's shaft was prolonged by a rod protruding through the face plate. Still works well without any issues.
Best regards!
__________________
"Bless you, Sister. May all your sons be bishops." (Brendan Behan)
  Reply With Quote
Old 1st February 2018, 11:50 AM   #9
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
Re, whetting, I found references to current of 10mA for gold contacts, no mention of minimum voltage?
Edit, I mean gold for current below 10mA
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote
Old 1st February 2018, 11:51 AM   #10
billshurv is offline billshurv  United Kingdom
diyAudio Member
 
billshurv's Avatar
 
Join Date: Mar 2014
Phono switching with relays.
Because I have two turntables and could have the following combinations in use at any one time
TT1 TT2
MC MM
MC MC
MM MC
MM MM

So I need to switch inputs. If TT1 was MC only and TT2 was MM only then I wouldn't have an issue, but that would be boring.
  Reply With Quote

Reply


Phono switching with relays.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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Muse M20 EX2 TA2020 amp, relays switching on/off Marc G Class D 1 26th November 2017 08:10 PM
Fast/high freq switching audio relays rb46uk Parts 1 8th February 2015 01:33 PM
High Current relays for speaker switching? Zero Cool Everything Else 13 15th December 2006 11:52 PM
Relays for switching i2s or other 3-wire audio bus? mbcouple Digital Source 19 23rd July 2005 08:58 AM
BOSOZ source switching with SE relays Gabrielshorn Pass Labs 2 5th February 2004 08:07 AM


New To Site? Need Help?

All times are GMT. The time now is 05:55 PM.


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