Simplistic NJFET RIAA - Page 91 - 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 2nd February 2009, 04:19 PM   #901
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Default Re: pcb layout revisited...

Quote:
Originally posted by kstlfido
Here is my revised RIAA board layout... Look any good?

Listening update- still making little tweaks. Playing with load resistors and made some cables out of mil-spec silver plate coax (which did help hum a fair bit).

I accidentally put in some RLoads of 82k (thought they were 8.2k). Better- fleshed out the mid-bass and smoother highs. Less 'shouty' ?!?

-Kent
Hi Kent,

It looks nice to me but I know next to nothing about PCBs. I like it aesthetically
I only guess that the signal ground and PSU ground will have to meet at an external star point with thick wires, so to reference to each other?

You did well to use coax. When it will go in to a box, and the cables will be short etc, your grounds neat etc, you can get 60Hz TT hum down to very low. At least my p2p or Michael's, or the 3rd one for his mate Chris measure -90dB (0dB=1V) hum on the FFT (50Hz in Europe) and -110dB 100Hz, level with the noise floor, i.e. no ripple with the shunt. Did you notice any 100Hz buzz yourself? Because Ikoflexer has strong ripple on shunt's out for some reason and we must find the bug.
  Reply With Quote
Old 2nd February 2009, 04:43 PM   #902
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Default Re: pcb layout revisited...

Quote:
Originally posted by kstlfido
I accidentally put in some RLoads of 82k (thought they were 8.2k). Better- fleshed out the mid-bass and smoother highs. Less 'shouty' ?!?

-Kent
Looks like your cart enjoys the lightest of loads and its generator pumps out easier in the lows? Off course such a high Rload equals more hiss, so I hope that with your final parts choices you will have the ability to voice it with a much lower Rload.
  Reply With Quote
Old 2nd February 2009, 04:57 PM   #903
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by RCruz
How do I measure VGS of Q1 ?

Ricardo
By touching the Voltage meter's probes on its left and right pins (red probe on right pin) when there is power on.
  Reply With Quote
Old 2nd February 2009, 06:34 PM   #904
iko is offline iko  Canada
diyAudio Moderator
 
iko's Avatar
 
Join Date: May 2008
Location: Toronto
Kent, this is a very nice looking layout. There has been some discussion about the 2sk170 based CCS, and it seems that G and S are tied together, while D is separate and connected to the more positive voltage. That would change a bit the ping lettering on J1 on your board.

Those with MM carts, an empty spot for the loading input cap could be added easy enough.

If you're willing to share, is it possible to post the top and bottom layers separately? I don't know how one can print them separately from your image, for etching.

Thanks for all the work, if I was doing another board I'd certainly use your layout.
  Reply With Quote
Old 2nd February 2009, 07:21 PM   #905
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Hi Salas
Maybe it survived because R1 took it like a man (Touching the sinks, the shortest way between GND and +Vin looks like R1)

By the way, R1 is 14r so I believe I = 164mA. (Might reach 204mA without output load)

I am glad because these where the values I calculated before implementation

Now I need a bigger heatsink. Can place a picture so I can get it right this time ?

Ricardo
__________________
RC
  Reply With Quote
Old 2nd February 2009, 07:25 PM   #906
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
OK
  Reply With Quote
Old 2nd February 2009, 07:42 PM   #907
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
1c/w here. You must isolate the mosfets with pads, if on same sink.
Attached Images
File Type: jpg 2080949.jpg (6.5 KB, 518 views)
  Reply With Quote
Old 2nd February 2009, 08:06 PM   #908
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Thank you so much Salas
  Reply With Quote
Old 2nd February 2009, 09:59 PM   #909
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally posted by RCruz
Hi Salas
Maybe it survived because R1 took it like a man (Touching the sinks, the shortest way between GND and +Vin looks like R1)

By the way, R1 is 14r so I believe I = 164mA. (Might reach 204mA without output load)

Ricardo
It shorted from 28V to ground. Not from Vin to ground. Because each drain is electrically connected with each sink as you made it for now, without mica pads. I attach how it sparked.

The current will not change, its constant. The shunt's Q4 heat is lighter with the load on, because they share. Q1's heat never changes if talking shame R1, shame Vin-Vout.
Attached Images
File Type: gif short.gif (4.9 KB, 544 views)
  Reply With Quote
Old 2nd February 2009, 10:24 PM   #910
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
I admit I was completely wrong. These power mosfets can really take it !!!

Nothing like some minor mistakes to make you really learn about the schematics.
__________________
RC
  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 04:07 AM.


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