Simplistic NJFET RIAA - Page 575 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, 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 18th January 2011, 02:21 PM   #5741
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
The VDR or Varistor only pass high voltage peaks that come along the mains cables with the 50/60Hz 115/220Vac.

These spikes are usually very short duration.

The purpose of the interference suppressor is to short the HV spike to neutral.

It will do nothing for the amplifier switch on or switch off.
__________________
regards Andrew T.
  Reply With Quote
Old 18th January 2011, 02:51 PM   #5742
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Thank you so much Andrew.

So I can use it to protect the equipment for spikes. Does it leave any signature ? any noise ?

To avoid switch on thump maybe I could use a 0.1u in parallel with the switch... just to avoid arcing... right ?
  Reply With Quote
Old 18th January 2011, 02:56 PM   #5743
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by RCruz View Post
To avoid switch on thump maybe I could use a 0.1u in parallel with the switch... just to avoid arcing... right ?
I doubt it.

A switch on thump seems more like the output conditions of the amplifier are taking time to settle to the audio signal level. At OFF the output has zero volts.
As the amp starts up the output can go +ve or -ve or both at various times in the few ten's of ms that all the circuits take to stabilise to quiescent conditions.

A spark at the switch only occurs at switch OFF and this can give a sharp RF transient to be amplified and transfered to the speaker.
__________________
regards Andrew T.
  Reply With Quote
Old 18th January 2011, 03:14 PM   #5744
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
When I wrote about switch on thump, I meant at switch off... I am sorry for the mistake.

To avoid this spark on the switch can I use a 0.1uF or should I use other value ?
  Reply With Quote
Old 18th January 2011, 03:17 PM   #5745
diyAudio Member
 
merlin el mago's Avatar
 
Join Date: Sep 2009
Location: Catalonia - Europe
Quote:
Originally Posted by RCruz View Post
When I wrote about switch on thump, I meant at switch off... I am sorry for the mistake.

To avoid this spark on the switch can I use a 0.1uF or should I use other value ?
Soft Start in amp
  Reply With Quote
Old 18th January 2011, 05:52 PM   #5746
studeb is offline studeb  United States
diyAudio Member
 
studeb's Avatar
 
Join Date: Feb 2008
Location: San Diego
Quote:
Originally Posted by mhouston View Post
I built this because I though the JAN6418 and OPAMP based phono preamps I was using were not giving me the best. This is a huge improvement over the other two.
Mark,

What opamp phono preamp were you using?
  Reply With Quote
Old 19th January 2011, 10:26 AM   #5747
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
fit a switch interference suppressor across the switch.
fit RF filter at the input of every receiver.
__________________
regards Andrew T.
  Reply With Quote
Old 19th January 2011, 01:59 PM   #5748
diyAudio Member
 
mhouston's Avatar
 
Join Date: Feb 2006
Location: Victoria, Australia
Quote:
Originally Posted by studeb View Post
Mark,

What opamp phono preamp were you using?
The OPAMP version was a kit we once sold where I work. The kit came with inexpensive OPAMPs and I upgraded them to OPA2134s. I upgraded a lot in the kit and converted it to a battery powered unit.

The phono preamp is very good and a few friends use the same one and liked it. I used mine for years before the boozhoundlabs unit.

I sold one of the OPAMP ones tonight (still have another) at my audio club swap meet. Hope the guy likes it as much as I did.
  Reply With Quote
Old 20th January 2011, 11:10 AM   #5749
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Quote:
Originally Posted by AndrewT View Post
fit a switch interference suppressor across the switch.
fit RF filter at the input of every receiver.
Thank you AndrewT

Would you please suggest a cap value for the interference suppressor ?

My search led me to the Vishay MKP 336 X2 but there are too many values to choose from.

Regards

Ricardo
  Reply With Quote
Old 20th January 2011, 02:11 PM   #5750
le´flu is offline le´flu  Germany
diyAudio Member
 
Join Date: Mar 2004
Location: Hoexter
Hello Salas and all,

so o finally took the time and measured my Version (posting 4141) of the
Salas njfet for LyraDorian.
Salas, could you please be so kind and tell me if everything is within the
range?
Q7 d = 17,2 Volts
Q7 g/s = 5,96 V
Q6 c = 11,95 V
Q6 e = 5,3 V
Q3 d = 15,1 V
Q4 d = 14,7 V
Ahhh and forgot: i changed R11 as you mentioned to 2,7K

Greetings Ulf
  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



New To Site? Need Help?

All times are GMT. The time now is 09:57 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