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

Pass Labs This forum is dedicated to Pass Labs discussion.

Gyrator loaded Son of ZV9/F3
Gyrator loaded Son of ZV9/F3
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 18th November 2017, 11:28 AM   #141
volavola is offline volavola  Italy
diyAudio Member
 
Join Date: Feb 2005
Location: Florence
Sorry Juma
The schematics in post #24 but I solder 10Ω on V+ like in post #37 on each channel just to verify the current. So on one channel across the 10Ω resistor I measure 10 mA (0,108V) and on the other 20mA (0,199V)
I'll start to check voltage nodes.
Bye
  Reply With Quote
Old 18th November 2017, 12:17 PM   #142
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
The current depends on Idss of bf862 so your Q3 in one channel is very different from the JFET in other channel.
You should either use parts with same/similar Idss or increase the value of R3 to lower the current to 10mA.
Using similar JFETs is a better solution.
__________________
Please don't use private messages for question related to audio projects. It defeats the purpose of the forum.
  Reply With Quote
Old 18th November 2017, 12:21 PM   #143
volavola is offline volavola  Italy
diyAudio Member
 
Join Date: Feb 2005
Location: Florence
thank you Juma. But you know that select the bf 862 it's not so easy. but I'll try.
Thanks again
  Reply With Quote
Old 18th November 2017, 01:29 PM   #144
ernesternest is offline ernesternest  Europe
diyAudio Member
 
ernesternest's Avatar
 
Join Date: Oct 2007
Location: Cologne
Quote:
Originally Posted by volavola View Post
thank you Juma. But you know that select the bf 862 it's not so easy. but I'll try.
Thanks again
Yepp, pain i. t. a. Gyrator loaded Son of ZV9/F3
  Reply With Quote
Old 18th November 2017, 02:07 PM   #145
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
Who said it's going to be easy ?

If you want easy go with 2SK170V (good luck finding original Toshiba parts)...
__________________
Please don't use private messages for question related to audio projects. It defeats the purpose of the forum.

Last edited by juma; 18th November 2017 at 02:09 PM.
  Reply With Quote
Old 18th November 2017, 02:30 PM   #146
volavola is offline volavola  Italy
diyAudio Member
 
Join Date: Feb 2005
Location: Florence
solder and desolder I found a 12 mA jfet. Now I'll change R3.
Thank you Juma
Bye
  Reply With Quote
Old 3rd January 2018, 04:23 PM   #147
Vix is offline Vix  Yugoslavia
diyAudio Member
 
Vix's Avatar
 
Join Date: Nov 2003
Location: Somewhere on Planet Earth
Quote:
Originally Posted by juma View Post
The only active part you need is this:
Mikro Princ | BS170 | FET | Tranzistori | Poluprovodnici | on-line prodavnica
Kelco - Proizvodi - Rezultat pretraživanja
and it costs 10 cents a piece. The rest is trivial...
Hi Juma,
I bought the BS170 mosfet and I will build a proposed preamp. I think I will try several versions
But, starting with the simplest, if you were to use just a resistor instead of CCS, and you had 60 v supply, but you can afford to drop 40 v across the resistor...should it work? I saw that you draw several variations, but none of them was with just a resistor..I guess that its value should be around 4.7 k, then I could place a 22 k between the Drain and Gate, and a 10k pot between gate and Source, and maybe 4.7 k at the front of the gate. I want to try the "micro-zen" preamp approach. If unhappy, it's easy to make it more complicated
  Reply With Quote
Old 3rd January 2018, 04:28 PM   #148
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
Vix, what schematic - post nr. ?
__________________
Please don't use private messages for question related to audio projects. It defeats the purpose of the forum.
  Reply With Quote
Old 3rd January 2018, 06:25 PM   #149
juma is offline juma  Germany
diyAudio Member
 
juma's Avatar
 
Join Date: Nov 2005
Location: Berlin
I see now, it's from post #132. You got that one explained in detail.
As for 60 -> 20 V RC filter I wouldn't do it that way, but you can try and see what you get...
__________________
Please don't use private messages for question related to audio projects. It defeats the purpose of the forum.
  Reply With Quote
Old 4th January 2018, 08:17 AM   #150
Vix is offline Vix  Yugoslavia
diyAudio Member
 
Vix's Avatar
 
Join Date: Nov 2003
Location: Somewhere on Planet Earth
Hi Juma,
I re-read the whole thread. Right now I am trying various preamps and trying to figure out what it is in the preamps sound that I like and vice versa. Also trying not to get lost among myriads of preamp variations
So, the story goes: I have two amplifiers: Zen V9 and a Mosfet follower, something like MoFo, but with a lightbulb instead of an inductor and with around 45 v suppply. So I was playing with various preamps trying to find which one I like the most. I had a BoZ which I then modified (added Schade feedback) and made it look something like Aleph L. Then I quickly bulit a Jfet Boz, according to your sugestion (with J310 jfet, 220 source degeneration resistor and a 680 ohm drain resistor, 24 v supply). I was pleasantly surprised to find out that I like its sound more than the original BoZ and also the modified Boz. The difference would be described as more natural sound, more open and relaxed, more transparent and easy flowing . (The amp was ZV9)
Wondering why, was it becasue of the Jfet vs. Mosfet (irf610-with a largish input capacitance), lack of feedback, or sometjing else - I don't know. But Jfet boZ with J310 sound more like tube, (I like it) and a Mosfet one with irf610 sounds more like Solid state (I don't like it).

So, as I am trying to make an improvement over Jfet Boz with J310, i am thinking that maybe it is better that I don't mess with BS170 mosfet as a gain device (although I may just quicky try it-I am curious), but instead focus on building this amp, as it is logical step up from a Jfet Boz, with a Jfet at its heart. Even though that means I will have to get the BF862.
To get to the point, I was thinking about the Gyrator circuit. Nothing against it, but have you tried to use a real inductor here instead?

I was thinking, If you happen to have a neon lamp (220 v 18w) inductor, is it possible to use that one instead of a gyrator?

Also, regarding the gain, If I use it with Zen V9, maybe 6 db of gain will suffice, but If I use a follower, I would like to have the option to increase the gain up to 15-18 db...so mabe I should use schematic from post nr.1 as a basis...
  Reply With Quote

Reply


Gyrator loaded Son of ZV9/F3Hide 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
L Loaded ZV9 Help??? flg Pass Labs 76 23rd December 2016 10:28 AM
cascoded gyrator loaded 6H9C to low idle. kees52 Tubes / Valves 11 29th December 2011 04:24 PM
F3 vs. ZV9 - the differences... HVfanatic Pass Labs 8 3rd June 2011 08:03 PM
Gyrator Loaded 12b4A: The Latest Version. SGregory Tubes / Valves 40 3rd January 2011 02:26 AM
First Watt F3 & ZV9 breguetphile Pass Labs 3 10th July 2006 10:53 PM


New To Site? Need Help?

All times are GMT. The time now is 02:05 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki