Jfet BOZ - Page 14 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 12th June 2007, 01:40 AM   #131
Formerly "jh6you". R.I.P.
 
Babowana's Avatar
 
Join Date: Jul 2006
Default Re: Re: Re: Re: Re: Re: Pass 2SK170 BOZ

Quote:
Originally posted by steenoe


Oh, the J-fet frontend for Zen V4, for a moment I thought......

Steen


A three-day refreshment walking here and there was much helpful in retreatment of my tired body and head. Yeah . . . I was thinking about Zen V4.

Many nice diy audio pictures . . . Err . . . I post my picture even if this is not an audio. Yesterday I took this in Gulangyu Island, Xiamen, where after the Opium War in 1814, 13 countries including GB, France, Japan established consulates, churches and hospitals. My look in the picture is much better than the real shape ^^.


Attached Images
File Type: jpg gulangyu island.jpg (91.6 KB, 2560 views)
  Reply With Quote
Old 12th June 2007, 05:34 AM   #132
steenoe is offline steenoe  Denmark
diyAudio Member
 
steenoe's Avatar
 
Join Date: Mar 2004
Quote:
Originally posted by Manu
Firts some pics of the baby. Tests results follow soon.

Manu
Good job, Manu. Nice little board
Multiturn trimmers will assist in an easier adjustment. You can pretty easily go past the sweet spot with a singleturn pot.


Quote:
My look in the picture is much better than the real shape ^^.
Nice shot JH You look pretty good and healthy on that pic

Steen
  Reply With Quote
Old 12th June 2007, 07:33 AM   #133
Manu is offline Manu  Europe
diyAudio Member
 
Manu's Avatar
 
Join Date: Nov 2002
Location: Vienna, Ostrich
Quote:
Originally posted by Zen Mod
slightly increase source resistors
decrease PSU voltage

after some tweaking,you'll bang on topology limits ;
if you can find your source characteristics and output amp sensitivity in with topology layed boundaries .......fine ;
if not...... nice xperiment ,useful as stage somewhere.
Quote:
Originally posted by Steenoe
Good job, Manu. Nice little board
Multiturn trimmers will assist in an easier adjustment. You can pretty easily go past the sweet spot with a singleturn pot. [/B]

Thank You for the hints. I will try them all and report.
But for now I have to go to work...
Manu

PS : Maybe it was not clear from my post yesterday, so I wanted to point out again that in spite of all this little opportunities (problems) I found the sound having a special magic: the Germans would say "quicklebendig" and the French would say "limpide".

Many Thanks for all Mr. Pass
  Reply With Quote
Old 12th June 2007, 08:43 AM   #134
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
Hi,
this thread gave me an idea to make a simple preamp for OPA549 (sounds very good in inverting topology with a gain of 6 dB - 2x). One JFET alone couldn't do it so I used a BJT to help. Output from my DAC (AK4393) is 2.4 AC V peak and this preamp gives on output 12.5 AC V peak which is enough to drive the OPA549.
First, I simulated the circuit in Circuit Maker 2000 with parts that I had in drawer, and fortunately, the real circuit measured roughly the same.
BF245C is a bit different from 2SK170, but that's what I have at hand.
I tried BC560C and BC639 for Q5, but ZTX550 is the best in this place (needs a heatsink). In the next couple of days I'll try to find a BD139 or something similar to try it.
Sound is great, still neutral but gives more space and instruments' localisation compared to AD823 and AD797 which I used before.
I used IRF610 as power supply voltage regulator as I have them in drawer, otherwise LM317 or something similar can be used.

Here is the schematic and picture of v.1 perfboard prototype:
Attached Images
File Type: jpg jfetkiss.jpg (37.3 KB, 3063 views)
  Reply With Quote
Old 12th June 2007, 10:39 AM   #135
Vix is offline Vix  Yugoslavia
diyAudio Member
 
Vix's Avatar
 
Join Date: Nov 2003
Location: Somewhere on Planet Earth
Default Re: Re: Re: Re: Re: Re: Re: Pass 2SK170 BOZ

Hi,

Manu, what amplifier did you connect Jfet BOZ to? Maybe the reason for distortion is the high sensitivity of the amplifeir,and it simply gets too much...
I am planning to modify (again) my 'F2 lite' into OTA ( a follower with zero voltage gain). Even though F2 lite is a nice amp, I have converted Zen v9 into transconductance amp, so I don need two transconductance amps.... (yes I know, there's always a possibility to send one to Choky for proper disposal, but it's too heavy )


Quote:
Originally posted by Babowana
My look in the picture is much better than the real shape ^^.
Heheheh....Some people look better on photos than real life, and vice versa....

I guess that a nice background has an effect, too. Really nice (the background)




Regards,

Vix
  Reply With Quote
Old 12th June 2007, 11:40 AM   #136
diyAudio Member
 
Join Date: Jul 2004
Location: Toronto, Canada


Very nice work Manu, looking forward to hearing further impressions. My system is taken apart at the moment due to construction in the house, but I have my missing resistors and a few other items arriving today.

Stephen
  Reply With Quote
Old 12th June 2007, 12:12 PM   #137
diyAudio Member
 
mpmarino's Avatar
 
Join Date: Jun 2004
Location: Crunchville, where I don't fit in.
Quote:
Originally posted by mpmarino


I have an idea - you can just build it for me. Just make it light so shipping doesn't cost YOU too much.





ya know that I patented sentence about "safe disposal"..........
copycat?






Manu, thanks for 'paving the way' - looks great!

Babowana, very nice to meet you.

Choky, just looking for a 'little' rise out of you - cause you make me chuckle. No copycat
__________________
Crazy Yankee.
  Reply With Quote
Old 12th June 2007, 01:11 PM   #138
Manu is offline Manu  Europe
diyAudio Member
 
Manu's Avatar
 
Join Date: Nov 2002
Location: Vienna, Ostrich
Default Re: Re: Re: Re: Re: Re: Re: Re: Pass 2SK170 BOZ

Quote:
Originally posted by Vix
Hi,

Manu, what amplifier did you connect Jfet BOZ to? Maybe the reason for distortion is the high sensitivity of the amplifeir,and it simply gets too much...Vix

Hi Vix,
Its an Aleph5. I used a 10K volume pot at output of the pre.
manu
  Reply With Quote
Old 12th June 2007, 02:43 PM   #139
Manu is offline Manu  Europe
diyAudio Member
 
Manu's Avatar
 
Join Date: Nov 2002
Location: Vienna, Ostrich
Quote:
Originally posted by Zen Mod

if you can find your source characteristics and output amp sensitivity in with topology layed boundaries .......fine ;
if not...... nice xperiment ,useful as stage somewhere.
The tech specs of my SA7001 SACD says the output level is 2,3V RMS, and for the Amp, its an Aleph 5 (40V 2,1 bias - pretty hot this days, so if you have some saussages (or cevapi) left.... c )
Thx for your hints. Should I let the drain res at 2K2 if I reduce the Source res to may be 6R?
Manu

mpmarino :
thx

twitchie:
Glad to hear you found at least your missimg 1M resistors. : There is always something one doesn't have in Stock - I have to order some good 25K pots, mine are definitively sh.... no idea why and when I did buy them.
  Reply With Quote
Old 12th June 2007, 03:02 PM   #140
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally posted by Manu

.........................Should I let the drain res at 2K2 if I reduce the Source res to may be 6R?
Manu

.................
Quote:
Originally posted by Zen Mod
slightly increase source resistors
decrease PSU voltage

.....................

hehe

seems that hot weather is cause of confusion..........

anyway.......better than me- I'm confused all the time......

again........increase them,to increase local degeneration - feedback- so stage clipp later
__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa... by Mighty ZM
  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
JFet BOZ Tyimo Pass Labs 14 30th April 2006 03:18 PM
Can I replace BF245C JFET with J201 JFET? bigmike216 Parts 2 7th December 2005 06:50 AM
How to use Jfet? lumanauw Pass Labs 5 7th April 2005 03:12 AM


New To Site? Need Help?

All times are GMT. The time now is 04:22 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