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.

Resistor Choice Stereo/Mono Switch?
Resistor Choice Stereo/Mono Switch?
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
Thread Tools Search this Thread
Old 16th April 2019, 10:46 PM   #11
WntrMute2 is offline WntrMute2  United States
diyAudio Member
WntrMute2's Avatar
Join Date: Jan 2010
Thanks to both of you for your help. I have a bunch of what I believe are carbon comp resistors - they have squared off ends on the cylinders. They look similar in form to ones I know are CC. Is that a defining feature of CC resistors? Also I have some carbon film ones in the same value.

The input load for the Cary SLP-98 line stage is 50,000 ohms.

I'll also fire off another email to GlassWare. Thanks for all the help!
  Reply With Quote
Old 16th April 2019, 11:48 PM   #12
JMFahey is offline JMFahey  Argentina
diyAudio Member
JMFahey's Avatar
Join Date: Mar 2009
Location: Buenos Aires - Argentina
Still donīt know the circuit schematic but guessing the MONO position links both Op Amp outputs together and amplifier has 50k input impedance, an excellent compromise is using 2 x 4k7 resistors.

Carbon or metal film wonīt make a huge (or audible) difference here so use what you have or flip a coin.

Edit: forget carbon comp for any Audio use, itīs dated Technology in a bad way.

A carbon or metal film deposited on a ceramic substrate is WAY more stable and precise than ground graphite mixed with bakelite and clay and cooked in an oven.
Design/make/service musical stuff in Buenos Aires, Argentina, since 1969.

Last edited by JMFahey; 16th April 2019 at 11:51 PM.
  Reply With Quote
Old 17th April 2019, 09:49 AM   #13
DF96 is online now DF96  England
diyAudio Member
Join Date: May 2007
Yes, don't use carbon comp. When I said that type does not matter too much I meant you could choose any decent resistor type - not CC! A few hundred ohms will be about right; it is only there to avoid damaging a poorly-designed preamp.
  Reply With Quote
Old 17th April 2019, 11:04 AM   #14
avtech23 is offline avtech23  Australia
Certifiably addicted to DIY.
diyAudio Member
avtech23's Avatar
Join Date: Dec 2017
Location: South 'straya
Resistor Choice Stereo/Mono Switch?
The ones installed on the image appear to be Brown-Black-Black-Red-Brown so 10k 1%?

Click the image to open in full size.
Click the image to open in full size.

A rotary switch for phono playback that presents three positions: mono, mute, and stereo.
In Mute, the switch is open circuit Lin//Lout & Rin//Rout
In Stereo, the switch is closed Lin=Lout & Rin=Rout
In Mono, the resistors are connected Lin=R1=Lout=Rout=R1=Rin
The ever growing project list.. :NAP140 Clone, NAD 3020i & 3225PE, JLH1969, TDA2050, Fender 5F2A Princeton, NE5532 Pre, SHPA, B1 Korg. : VSQC Phunk Style, Retro 50W, Filmosound 601. : Apex AX-14, TGM-10, TDA7265, LM4780 (Last in line)...maybe
  Reply With Quote
Old 18th April 2019, 03:01 AM   #15
PRR is offline PRR  United States
diyAudio Member
PRR's Avatar
Join Date: Jun 2003
Location: Maine USA
> so 10k 1%?

I can't read those things.

But assuming 10k, and 50k amps, in Mono the signal level drops 1.6dB. Enough to notice. I would tend to a smaller value.

I've used hundreds of Carbon Composition over the decades (from when there was no choice at the local shop) and with 99% satisfaction. Yes, had a couple go drifty, once very educational. However since Carbon Film arrived I have had NO trouble of any sort.

In this case I don't think Composition would be "wrong". The small increase of hiss is swamped by other impedances, and would only happen in Mono. 20% drift would be small mix-shift, and might not happen for decades (I have seen 90% drift in 20 years but that was a very hot chassis).
  Reply With Quote
Old 19th April 2019, 12:18 AM   #16
Mark Tillotson is offline Mark Tillotson
diyAudio Member
Join Date: May 2018
Location: Cambridge UK
Most opamps can drive 2k without struggling and rising distortion, so two 2k2 resistors sounds about right, and is low enough to keep noise under reasonable control.
  Reply With Quote


Resistor Choice Stereo/Mono Switch?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
Stereo to mono with switch: Do my circuits work? Monrin Analog Line Level 11 24th March 2017 11:17 AM
Mono / Stereo Switch javy Everything Else 11 21st October 2014 07:06 PM
Do It Yourself - Mono/Stereo Switch RickJazz Analogue Source 0 20th May 2012 08:19 PM
3.5mm Stereo to Mono w/ Channel Switch? thehallofshields Parts 2 11th October 2010 01:16 AM
mono/stereo switch? col Analog Line Level 8 15th April 2010 01:47 AM

New To Site? Need Help?

All times are GMT. The time now is 11:19 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio