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 November 2012, 06:46 PM   #8581
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
Success (Alas, Temporary)

OK, hooked things up, and it actually played music. Only listened for a minute or so, then put it back on the bench. I was waving my soldering iron around and heard ZIP and something fried. Dumb!!! I will look at it tomorrow.

Anyway made some measurements across resistors, as shown below. Some differences between channels in a couple places, even though most of the JFETS were pretty well matched, except the LED part and the output buffer.

Do they seem reasonable?
Attached Images
File Type: jpg RIAA-Board.jpg (318.0 KB, 106 views)
File Type: jpg Annotated RIAA Circuit.jpg (91.8 KB, 101 views)
File Type: jpg Shunt-Photo.jpg (20.3 KB, 96 views)
  Reply With Quote
Old 22nd November 2012, 07:13 PM   #8582
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Very reasonable except what you note for current through R10 must be what goes through R6 also more or less. R6 currents are as expected. What happened, some crock slipped?
  Reply With Quote
Old 22nd November 2012, 07:33 PM   #8583
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
I think my iron touched the Vin alligator clip supplying power to the RIAA board and shorted something. Hard lesson.
When I get it working again I will re-check the currents. I know R10 should equal R6 - I will have to check it again.
  Reply With Quote
Old 22nd November 2012, 07:38 PM   #8584
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
Salas, I am trying some WIMA FKP4 caps. Do you have any experience with them?
It may have been a poor choice, but I will give them a chance. I have read they need 100 hours to break in.
  Reply With Quote
Old 22nd November 2012, 08:04 PM   #8585
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
HOORAY!

I went back and reconnected things, and everything lights up and looks OK.
Darn lucky!

Re-checked some voltage drops:

R2 (below Q1) - 2.3 mA
R9 (above Q5) - 6.7 mA
R7 (below Q5) - 7.3 mA
R10 (above Q2) - 4.2 mA
R6 (below Q2) - 4.0 mA
R12 (above Q6) - 7.2 mA

Look OK Salas?
Thanks!
Doug
  Reply With Quote
Old 22nd November 2012, 08:36 PM   #8586
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
The iron tip is normally grounded...

FKP4...good industrial quality. Nothing extra special.

Your last values table makes sense.
  Reply With Quote
Old 22nd November 2012, 08:54 PM   #8587
RCruz is offline RCruz  Switzerland
diyAudio Member
 
RCruz's Avatar
 
Join Date: Sep 2006
Location: Wallis
Blog Entries: 1
Hi Doug

What are those yellow caps you are using in the riaa filter ? I must say they really look good !
__________________
RC
  Reply With Quote
Old 22nd November 2012, 09:57 PM   #8588
Doug R is offline Doug R  United States
diyAudio Member
 
Join Date: Oct 2007
Location: Indy
Thanks Salas,
RC, they are some "vintage" RelCaps.
I think I will get some more. I just wanted to get something working before ordering a bunch of "audiophile" parts. Right now I have a Multicap and a WIMA for coupling. I will see which I like better. I have some russian k40's, but they are .47 uF. The output caps are Angela tin foil.
Also, fortunately I had some Rikens left over for resistors.

Thanks for your encouragement and help.
I will keep you posted on things as they burn in.

Doug
  Reply With Quote
Old 23rd November 2012, 12:03 AM   #8589
diyAudio Member
 
The Space Egg Corp's Avatar
 
Join Date: Sep 2010
Location: London & Miami
Blog Entries: 13
Hi Salas

Still on the parts hunt !

Don't want to use any 'Unauthorised Parts'...
...but...
I found some 'nice' high-stability 1.6megs today.

Should be OK in the 1meg positions ?
Yes ?

Cheers

Si.

P.S. cap-pickers...
...what USSR silver-mica's do people like around here ?
I read the larger ones in the 'metal-cans' are good for bigger values, like 47nF & 15.5nF...
...anyone tried them ?
  Reply With Quote
Old 23rd November 2012, 01:14 AM   #8590
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
No, use 1Meg.
  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 11:38 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