Go Back   Home > Forums > >

Pass Labs This forum is dedicated to Pass Labs discussion.

F6 Illustrated Build Guide
F6 Illustrated Build Guide
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
Old 20th July 2021, 09:53 PM   #3711
zman01 is offline zman01  Bangladesh
diyAudio Member
 
Join Date: Feb 2011
Location: Dhaka
F6 Illustrated Build Guide
Quote:
Originally Posted by surfinashe View Post
I am in the process of stuffing the two channels for the F6 Amp and my other brother is ahead of me and biasing his F6 but we have been talking and we found a thread where the Zenars in the kit had been switched to three LED's in series which led to some definite improvements in Stability etc.

Problem is I lost the thread that told us the specs on the LED or part numbers to order them and there wasn't much info on which LEDs to get.
I realize that we want Green LED's instead of the Blues but even going through both of our notes we cant find the thread where it mentioned the specs.
Ashley,.

The LEDs recommended were LTL-4231N. Thread link:

Dumb Biasing Mod, applicable to F6 and other Papa Amps. Possibly My Dumbest Idea Yet

It is also recommended the you change the values of R7 and R8 to a lower value like 3.3K:

F6 Illustrated Build Guide

F6 Illustrated Build Guide

Last edited by zman01; 20th July 2021 at 10:00 PM.
  Reply With Quote
Old 21st July 2021, 04:40 PM   #3712
meanie is offline meanie  Singapore
diyAudio Member
 
Join Date: Jul 2018
Location: Singapore
Tweak my F6 again...

Quote:
Originally Posted by 2 picoDumbs View Post
Green LED References
R7 Anything between 2k and 3.3k
R8 Same as R7

Q1 VISHAY IRFP250
Q2 IXYS IXTH64N10L2
R1 0.22 Ohms
R2 0.22 Ohms

R3 100 Ohms
R4 Anything between 20 and 23 Ohms Correction
R11 47R
R12 47R

Bias around 1.5A to 1.75A
I biased mine at 1.65A, but the temp went too high, reaching 60degC on a Conrad MF35.
So I throttle back to 1.5A (0.33v/0.22R), now around 50degC.

Before these, I was using 3 LEDs mod with TA's FQH44N10 recommendation.
It ran very well so far, then I got greedy and try out 2picoDumb's magic mods.
I would like to try TA's Diamond front driver sometime in the future with 1.8A after i upsize my heatsinks.

Initial impression after 2 days of listening...using same SMPS ps with cap bank.

TA's mod: Vocals very pronounced, more bass than stock, silky smooth and relaxed.
Pico Magic mod: More details in mid-high, slightly tighter bass, no longer a "layback" F6

Both are dead quiet with vol to max during NO music. Hope to do some scope work and REW this weekend. Will share my results here.
  Reply With Quote
Old 22nd July 2021, 02:51 AM   #3713
surfinashe is offline surfinashe  Hong Kong
diyAudio Member
 
Join Date: Aug 2020
Location: Park City Utah & Texas
Default Zman01 thank you

Zman01 I wanted to thank you for your response on my questions and the link to the references on the build.

It helped greatly.

I was wondering though since the L.E.D. is Back ordered till mid august if I try to use a different L.E.D. what is the most important spec?

The forward voltage or ???

The reason why I ask Mouser has an LTL-4231NLC Diffused but the forward voltage is 1.9 as opposed to 2.1.

I did put some LTL-4231N on order though its just questionable when they will come in.

Thank you for all your help once again.
  Reply With Quote
Old 22nd July 2021, 03:55 AM   #3714
zman01 is offline zman01  Bangladesh
diyAudio Member
 
Join Date: Feb 2011
Location: Dhaka
F6 Illustrated Build Guide
surfinashe,

Glad to be of help.

2 picoDumbs had recommended this model as he had tested it, and it is a low noise unit; other LEDs with similar specs will work too.

Having said that, Digikey has more than 30,000 of LTL-4231N in stock and ready for shipment. Link below:

Digikey - LTL-4231N

Please let us know if you any questions, and good luck with your build!

Last edited by zman01; 22nd July 2021 at 04:14 AM.
  Reply With Quote
Old 22nd July 2021, 08:14 AM   #3715
strongbow60 is online now strongbow60  Sweden
diyAudio Member
 
Join Date: Jul 2017
I would say that any green (or red) led will work. They have the same basic construction.
See post #30 in the referenced thread where Pico admitted he used whatever was in the drawer.
  Reply With Quote
Old 22nd July 2021, 08:01 PM   #3716
TungstenAudio is offline TungstenAudio  United States
diyAudio Member
 
Join Date: Jan 2014
Location: Kenmore, WA
The mini green LEDs can be constructed such that they fit into the footprint for the Zener diode. Modern bright variety appears to regulate very well.
  Reply With Quote
Old 22nd July 2021, 08:38 PM   #3717
wcwc is online now wcwc  United States
diyAudio Member
 
Join Date: Oct 2011
So are the LEDs set up with the same + and - as the diode?
  Reply With Quote
Old 22nd July 2021, 10:06 PM   #3718
TungstenAudio is offline TungstenAudio  United States
diyAudio Member
 
Join Date: Jan 2014
Location: Kenmore, WA
The LEDs conduct in the forward direction, so their + and – will be the opposite of that shown on the board for the Zener diode.
  Reply With Quote
Old Yesterday, 04:49 PM   #3719
thompsontechs is offline thompsontechs  United States
We the People
diyAudio Member
 
thompsontechs's Avatar
 
Join Date: Sep 2019
Location: Illinois
F6 Illustrated Build Guide
Quote:
Originally Posted by tbrooke View Post
I finished my F6 sounds great, no hum !!!! It is the standard DIYAUDIO chassis.

Special big thanks to @poseidonsvoice for bailing me out teaching me a lot.
Wow, that is the most improvement I've seen I was scared for you when I first saw the inside of that thing. Now it looks great!

Good job with help from new friends.
__________________
Who's your Daddy? Papa of course.
  Reply to this post

Reply


F6 Illustrated Build GuideHide this!Advertise here!
Thread Tools

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
F5Turbo Illustrated Build Guide 6L6 Pass Labs 1283 Yesterday 03:04 PM
diyAudio Power Supply Circuit Board v3 illustrated build guide 6L6 Power Supplies 1716 Yesterday 02:43 PM
Aleph J illustrated build guide 6L6 Pass Labs 6957 Yesterday 12:47 PM
BA-3 Amplifier illustrated build guide 6L6 Pass Labs 784 24th May 2021 01:35 PM
ACA illustrated build guide 6L6 Pass Labs 169 16th June 2020 03:12 PM


New To Site? Need Help?

All times are GMT. The time now is 03:09 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki