Go Back   Home > Forums > >

Pass Labs This forum is dedicated to Pass Labs discussion.

Alternate First Watt Power Supply Schematic
Alternate First Watt Power Supply Schematic
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 30th December 2020, 10:08 PM   #181
darrr is offline darrr  Poland
diyAudio Member
 
Join Date: Jan 2018
Location: Poland
@JeffYoung
You probably have an ltspice model. I have a request to You. Could you check what the 100hz ripple will be in this configuration: 33000uF capacitors and 0.47R resistors? Now the ripple is 170mVpp. Rail voltages under load +/- 21.7VDC from 18VAC on secondaries. Maybe it will be better?
  Reply With Quote
Old 3rd January 2021, 07:21 PM   #182
JeffYoung is offline JeffYoung  Ireland
diyAudio Member
 
JeffYoung's Avatar
 
Join Date: Jul 2017
Location: Ireland
Alternate First Watt Power Supply Schematic
SPICE predicts 75mVpp.
  Reply With Quote
Old 3rd January 2021, 08:28 PM   #183
darrr is offline darrr  Poland
diyAudio Member
 
Join Date: Jan 2018
Location: Poland
Thank you Jeff
Do I correctly suspect there will be a bigger voltage drop?
Regards and Happy New Year
  Reply With Quote
Old 3rd January 2021, 09:08 PM   #184
JeffYoung is offline JeffYoung  Ireland
diyAudio Member
 
JeffYoung's Avatar
 
Join Date: Jul 2017
Location: Ireland
Alternate First Watt Power Supply Schematic
Yes, but not material (~0.05V).

If you're willing to lose some voltage, 1 ohm resistors will nearly halve the ripple again at the loss of about 0.25V.
  Reply With Quote
Old 4th January 2021, 09:28 PM   #185
darrr is offline darrr  Poland
diyAudio Member
 
Join Date: Jan 2018
Location: Poland
I have one more board so I can make a better version without desoldering. I wonder whether to install 4pcs 33000uF capacitors before the resistors and 47000uF on each rail after them . Will it be quieter than all 33mF versions?
  Reply With Quote
Old 4th January 2021, 09:48 PM   #186
JeffYoung is offline JeffYoung  Ireland
diyAudio Member
 
JeffYoung's Avatar
 
Join Date: Jul 2017
Location: Ireland
Alternate First Watt Power Supply Schematic
SPICE says 60mV w/0R47s; 35mV w/1R0s.
  Reply With Quote
Old 4th January 2021, 10:09 PM   #187
darrr is offline darrr  Poland
diyAudio Member
 
Join Date: Jan 2018
Location: Poland
Is there any danger of increasing the capacity and resistance in the filter?
  Reply With Quote
Old 4th January 2021, 10:30 PM   #188
JeffYoung is offline JeffYoung  Ireland
diyAudio Member
 
JeffYoung's Avatar
 
Join Date: Jul 2017
Location: Ireland
Alternate First Watt Power Supply Schematic
More resistance leads to lower-voltage rails and more heat in the resistors.

More capacitance before the resistors puts more of a tax on the transformer (and fuses if you don't have a thermistor or other form of soft-start).

More capacitance after the resistors does too, but to a lesser effect.
  Reply With Quote
Old 4th January 2021, 10:39 PM   #189
darrr is offline darrr  Poland
diyAudio Member
 
Join Date: Jan 2018
Location: Poland
Thank you Jeff.
I was thinking about a slb power supply but the costs will be much higher with a new transformer so I will work on your project

Last edited by darrr; 4th January 2021 at 10:42 PM.
  Reply to this post

Reply


Alternate First Watt Power Supply SchematicHide 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
Separate Power Supply for First Watt Amps Russellc Pass Labs 39 29th March 2020 12:29 PM
FIRST WATT B4 + Linear power supply juanitox Swap Meet 6 26th December 2018 11:45 AM
looking for power supply diagram SE 813 45 Watt flyingman Tubes / Valves 1 16th February 2005 05:30 AM
55 watt Aksa boards and power supply. Tony D. Swap Meet 4 11th August 2004 07:10 AM


New To Site? Need Help?

All times are GMT. The time now is 02:26 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki