The A.N.T. Audio Kora 3T Phono Stage circuit published. - Page 3 - 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 22nd October 2012, 01:36 AM   #21
fap is offline fap  Australia
diyAudio Member
 
Join Date: Sep 2010
Location: North Queensland.
G'day all, yes I agree with Alex. I tend to only trust a properly soldered connection.

Twenty five odd years of being a Ham Radio operator and a former telecommunications maintenance technician has taught me that! Regards, Felix (vk4fuq).
  Reply With Quote
Old 22nd October 2012, 01:41 AM   #22
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by x-pro View Post
Here is a noise floor comparison between the Kora 3T MM SE and MM LE units I've done some while ago.
That 10dB improvement reflects the upper part of the SRPP contribution we should suppose? Because the lower part owes to be dominated by the K170 en?
  Reply With Quote
Old 22nd October 2012, 01:44 AM   #23
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
P.S. No, you wrote its the MM. So its due to the Mosfet parts change only.
  Reply With Quote
Old 22nd October 2012, 02:00 AM   #24
x-pro is offline x-pro  United Kingdom
diyAudio Member
 
x-pro's Avatar
 
Join Date: Apr 2003
Location: London
Quote:
Originally Posted by Salas View Post
That 10dB improvement reflects the upper part of the SRPP contribution we should suppose? Because the lower part owes to be dominated by the K170 en?
The noise graph is for 2 MM units, so there is no 2SK170 involved there. The noise difference is only due to the two different types of FETs in M1 and M2 positions. As I've said earlier, the BSS139 has a noise voltage density about 15-20nV/sqrtHz at 1kHz, the "LE" type FET has less than half of that, about 6-7nV/sqrtHz at 1kHz. In the MC version the noise contribution of the input 2SK170 is dominating, however there is still some difference in the noise between the SE MC and the LE MC units, about 1.5-2dBA.

Quote:
Originally Posted by Salas View Post
P.S. No, you wrote its the MM. So its due to the Mosfet parts change only.
Yes, I was late with my answer, sorry!

Cheers

Alex
  Reply With Quote
Old 22nd October 2012, 09:22 AM   #25
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
I was looking for a phono stage to build and this could be it.

Would you consider allowing pcb's to be made for a group buy on the forum?

Also, is it just the quality of component choice that is changed for the better versions?

Thanks for sharing, Ian
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  Reply With Quote
Old 22nd October 2012, 10:15 AM   #26
andyr is offline andyr  Australia
diyAudio Member
 
Join Date: Nov 2003
Location: Melbourne (Oz, not Florida!)
Quote:
Originally Posted by fap View Post
G'day all, yes I agree with Alex. I tend to only trust a properly soldered connection.

Regards, Felix (vk4fuq).
Sure Felix, I agree that's optimal. But it means you can't readily change cartridges. Which (facility) is a good thing to have. Just like not having coupling caps is "optimal" ... but not that many components go this way.

I have no doubt it will be better than your ESP phono stage ... but, once you've got your Kora up and running (with the soldered resistor of your choice installed ), I could send up my JFET phono stage for you to compare. (You have my email address.)

Enjoy.

Regards,

Andy
  Reply With Quote
Old 22nd October 2012, 11:11 AM   #27
x-pro is offline x-pro  United Kingdom
diyAudio Member
 
x-pro's Avatar
 
Join Date: Apr 2003
Location: London
Quote:
Originally Posted by UV101 View Post
I was looking for a phono stage to build and this could be it.

Would you consider allowing pcb's to be made for a group buy on the forum?

Also, is it just the quality of component choice that is changed for the better versions?

Thanks for sharing, Ian
Hi Ian,

I am not sure that I should authorise a group buy of an untested pcb. On one hand the Kora 3T circuit is so simple that it can be built on a strip-board in one evening, on another hand I may offer the original pcb (or even a kit) for DIY. The pcb would fit one of the Hammond aluminium enclosures perfectly and would at least guarantee that the performance of the circuit won't suffer from a bad layout. It won't be very cheap thought .

On the second question - I've described the differences in the post #18.

Cheers

Alex
  Reply With Quote
Old 22nd October 2012, 01:14 PM   #28
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
Hi Alex, thanks ;-)

If you we're considering offering some sort of kit or even just the pcb, I would definitely be interested ;-)
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  Reply With Quote
Old 22nd October 2012, 01:25 PM   #29
x-pro is offline x-pro  United Kingdom
diyAudio Member
 
x-pro's Avatar
 
Join Date: Apr 2003
Location: London
Quote:
Originally Posted by UV101 View Post
Hi Alex, thanks ;-)

If you we're considering offering some sort of kit or even just the pcb, I would definitely be interested ;-)
PM me.

Cheers

Alex
  Reply With Quote
Old 22nd October 2012, 02:53 PM   #30
UV101 is offline UV101  England
diyAudio Member
 
UV101's Avatar
 
Join Date: Dec 2008
Location: Oxford
Pm sent, Thanks, Ian
__________________
When Bitstream came out, I thought, “my God, what are we going to do...?” Ken Ishiwata http://www.hifisounds.co.uk
JA-88D Class A, Audio Aero Capitole MKII, Focal and Kimber "Leave Nothing as Standard"
  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
Steve Bench's LR Phono Stage - Cathode Bias Circuit Question Hearinspace Tubes / Valves 6 18th July 2013 03:59 AM
help with phono stage circuit design lightmaster Solid State 3 3rd October 2012 06:54 PM
restore the circuit phono stage vog Analogue Source 0 8th November 2010 05:47 PM
Borbely Audio phono stage biovizier Swap Meet 12 9th February 2007 07:09 AM
Should I replace Scott 222C phono stage with Claret phono stage? Bing Yang Analogue Source 0 22nd August 2005 06:41 AM


New To Site? Need Help?

All times are GMT. The time now is 03:41 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