Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Bob Cordell's VinylTrak
Bob Cordell's VinylTrak
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 8th January 2020, 01:59 PM   #121
Bob Cordell is offline Bob Cordell  United States
diyAudio Member
 
Join Date: Sep 2006
Quote:
Originally Posted by Adams_Leo View Post
is there any way to remove the Figure 7 OP IC?and update to use fully passive EQ
Not really. In my view, the notion that fully passive EQ is better is obsolete.

Cheers,
Bob
  Reply With Quote
Old 8th January 2020, 02:08 PM   #122
rsavas is offline rsavas  Canada
diyAudio Member
 
Join Date: Aug 2012
Location: Georgina, Ontario
Figure 7 shows the active 3180/318us LF portion of the RIAA EQ, the gain selection, and DC servo, a re-design basically.
Look at TI app note for passive filter example
AN-1651 Keeping Up with the Expanding Demands of High-Performance Audio
  Reply With Quote
Old 9th January 2020, 08:57 AM   #123
Adams_Leo is offline Adams_Leo  China
diyAudio Member
 
Join Date: Apr 2003
Location: Chengdu
Quote:
Originally Posted by Bob Cordell View Post
Not really. In my view, the notion that fully passive EQ is better is obsolete.

Cheers,
Bob
thanks Bob,the key item is not the passive EQ,my concern is that remove the OP IC,replace with JFET and Bipolar Transistors. this should be crazy.
  Reply With Quote
Old 11th January 2020, 09:48 PM   #124
Hans Polak is offline Hans Polak  Netherlands
diyAudio Member
 
Join Date: Mar 2005
Location: Blaricum
Quote:
Originally Posted by Black Jack View Post
My board finally soldered and tested...
Compare with #82
Hi Black Jack,
May I ask you where to find these very nice RCA sockets and possibly the name of the manufacturer.
The only comparable ones I can find are hideously expensive from WBT and Furutech.

Hans
  Reply With Quote
Old 12th January 2020, 02:20 PM   #125
rsavas is offline rsavas  Canada
diyAudio Member
 
Join Date: Aug 2012
Location: Georgina, Ontario
Hi Hans,

I was looking around for higher quality RCA jacks too, found the same as you did, the jacks would cost more that everything else in the design :-) same cost as the transformer/PS
I went looking at this supplier, which are local to me
RCA Connectors
ridiculous imo
If I do up this vinyltrak design, I'll use these ones,
Switchcraft pjras2x1s__x_series OR
CUI RCJ-21XX OR
Mouser has these ones, which I got one for a sample, they are not too bad imo for what they cost
161-4220-E Kobiconn | Mouser Canada
They say they are gold plated, but that is only the shell, not the center pin, still a good solid connection.

Cheers Rick
  Reply With Quote
Old 12th January 2020, 02:52 PM   #126
Hans Polak is offline Hans Polak  Netherlands
diyAudio Member
 
Join Date: Mar 2005
Location: Blaricum
Quote:
Originally Posted by rsavas View Post
Hi Hans,

I was looking around for higher quality RCA jacks too, found the same as you did, the jacks would cost more that everything else in the design :-) same cost as the transformer/PS
I went looking at this supplier, which are local to me
RCA Connectors
ridiculous imo
If I do up this vinyltrak design, I'll use these ones,
Switchcraft pjras2x1s__x_series OR
CUI RCJ-21XX OR
Mouser has these ones, which I got one for a sample, they are not too bad imo for what they cost
161-4220-E Kobiconn | Mouser Canada
They say they are gold plated, but that is only the shell, not the center pin, still a good solid connection.

Cheers Rick
Hi Rick,
Thanks for your feedback,

Hans
  Reply With Quote
Old 2nd April 2020, 04:15 PM   #127
conan2k is offline conan2k  Italy
diyAudio Member
 
Join Date: Mar 2020
Hello everybody,

I'm repairing my Technics SU-A900 MK2 amplifier. I am searching for information about Toshiba 2SK389-GK dual JFET. On Internet I only find datasheets which contain codes -GR , -BL , -V , but nothing about -GK. They have different IDSS values and different ID-VDS curves.

Most of all I am searching for one piece of 2SK389-GK or something which fits.

Thanks in advance!
  Reply With Quote
Old 2nd April 2020, 11:20 PM   #128
rsavas is offline rsavas  Canada
diyAudio Member
 
Join Date: Aug 2012
Location: Georgina, Ontario
You have already asked this question in this thread
Toshiba 2SK289-GK dual JFET
  Reply With Quote
Old 3rd April 2020, 10:04 AM   #129
conan2k is offline conan2k  Italy
diyAudio Member
 
Join Date: Mar 2020
Quote:
Originally Posted by rsavas View Post
You have already asked this question in this thread
Toshiba 2SK289-GK dual JFET

Yes, I have. The guys who answered were kind and I do thank them, but the topic is not easy and weren't helpful. Later I noticed this thread and wrote here as well. Couldn't I?
  Reply With Quote
Old 6th April 2020, 11:22 AM   #130
PSchut is offline PSchut  Netherlands
diyAudio Member
 
PSchut's Avatar
 
Join Date: Mar 2004
Location: Tilburg
Hi Bob,
With great interest have I been reading the VinylTrak article in Linear Audio and what you added on your home page.
I know it is already a reasonable old article (8 years) but in the time of vinyl playback it is still fresh.
If it is alright I would like to ask you a few questions?
1 Why not use a single LSK389 for the MM stage instead of the LS844? (I don't see the advantage of the 844 in this circuit)
2 would paralleling multiple LSK389 not work for MM, the cascode input stage should minimize input capacity.
3 Why use a current mirror as a constant current source for the input stage instead of a reference based current source? (is that to control startup behavior?

Thanks for a great article.
Peter
  Reply With Quote

Reply


Bob Cordell's VinylTrakHide 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
Bob Cordell's Power amplifier book ihan Solid State 10117 10th July 2020 01:28 AM
Another realization of Bob Cordell's THD Analyzer giulianodes Equipment & Tools 213 23rd January 2020 01:30 AM
bob don't like digital tomtt Digital Source 1 30th August 2006 01:40 PM


New To Site? Need Help?

All times are GMT. The time now is 03:38 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki