The Phonoclone and VSPS PCB Help Desk - Page 103 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

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 31st December 2008, 08:50 AM   #1021
Kevlogg is offline Kevlogg  United States
diyAudio Member
 
Join Date: Dec 2008
Quote:
Originally posted by chrismercurio
I haven't read the whole thread. Has anyone powered this with a battery?
Yes, I have seen several people do it with a battery. However, from what I have read, best results come from higher voltages and also form the toroidal transformer.. Less magnetic interference if I remember from physics.

Quote:
Originally posted by juluska
Kevlogg, this toroidal is enough. 5VA is enough, but the bigger you can use will be better. I've used a 50VA. If you are going to do more projects you can use a bigger toroidal to probe another amplifier pcbs.
A very low noise is always present from the toroidal, if you can chose an en capsulated toroidal.
Think in doing it point to point in a protoboard, is more flexible and funny.
Probe with double bridge fast rectifiers and also with schottky discrete double rectifiers. I've probe this and the sound diferent.
cool, thanks for the reply. I will check out those rectifiers. I will also look into a buffer power supply. What I meant to ask is this.... is there a formula I need to know to to equate (match) the rectifier to the transformer. or will any combination work> I am not familiar with (Va- this must be some kind of power measurement?) and rectifier properties.

( I do have a basic understanding of how it manipulates the power supply from AC to a "rippled DC")

I contacted my professor, and he is willing to work out this first project with me, he remembered his first job working as an audio repair technician
at this point, I can't wait to start!
  Reply With Quote
Old 7th January 2009, 08:54 AM   #1022
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 103
Quote:
Originally posted by Kevlogg
This should work, correct?

http://cgi.ebay.com/ws/eBayISAPI.dll...tab%3DWatching
Its not too surprising to see come around for the third or fourth time. At over 1000 replies, I don't get mad at people anymore for not reading the whole thread...

Don't use a battery. Use the biggest, best transformer you can afford.

Realistically, though, a 25VA or 35VA toroid with 2x12VAC will do the trick nicely. That one on ebay, or something similar from Digikey or wherever. It should be about $20, less if surplus.

Diodes: use a bridge rectifer, or two, bigger current is better, but anything above 1A and 100V is fine.

And don't forget the fuse.
  Reply With Quote
Old 7th January 2009, 03:33 PM   #1023
diyAudio Member
 
chrismercurio's Avatar
 
Join Date: Aug 2006
Location: Silicon Valley
Dumb non-EE ?,

What is the formula for voltage after bridge rectification? (please use the VSPS as the example)

Thank you,

Chris
  Reply With Quote
Old 7th January 2009, 03:54 PM   #1024
troystg is offline troystg  United States
diyAudio Member
 
troystg's Avatar
 
Join Date: Apr 2004
Location: In a dream... Please don't wake me.
Quote:
Originally posted by chrismercurio
Dumb non-EE ?,

What is the formula for voltage after bridge rectification? (please use the VSPS as the example)

Thank you,

Chris

secondary AC voltage x (times) 1.4 will get you the DC voltage assuming you have filter caps.

12VAC x 1.4 = 16.8VDC
__________________
Troy
Thinking positive doesn't make things better, it makes you a better person.
  Reply With Quote
Old 7th January 2009, 03:54 PM   #1025
juluska is offline juluska  Ukraine
diyAudio Member
 
Join Date: May 2008
12 V X 1.41 - (2X0,70) =15,52 V
  Reply With Quote
Old 7th January 2009, 03:59 PM   #1026
juluska is offline juluska  Ukraine
diyAudio Member
 
Join Date: May 2008
2 X 0,7 is the voltage drop if you have a full wave rectifier bridge, if you have only one diode it will be only 0,70, and if you have schottky diodes it will be about 2 x 0,30 or 0,30
  Reply With Quote
Old 7th January 2009, 04:14 PM   #1027
troystg is offline troystg  United States
diyAudio Member
 
troystg's Avatar
 
Join Date: Apr 2004
Location: In a dream... Please don't wake me.
You are absolutely correct, but if a person doesn't know how to calculate AC to DC voltage I wasn't going to throw diode voltage drops, wire/trace resistance and cap ESR at him.

But you are 100% correct...
__________________
Troy
Thinking positive doesn't make things better, it makes you a better person.
  Reply With Quote
Old 7th January 2009, 09:49 PM   #1028
diyAudio Member
 
Join Date: Aug 2005
hello how much gain in db is the Phono clone when i use this cart ?:
coil imp 22 ohm
load imp 100 ohm
load cap 150 pf
output voltage 0,5 mv

i hope you can help me with this
  Reply With Quote
Old 7th January 2009, 09:58 PM   #1029
diyAudio Member
 
chrismercurio's Avatar
 
Join Date: Aug 2006
Location: Silicon Valley
That first circuit analysis class was quite a few years ago...and never put into practice.

thanks guys.

Chris
  Reply With Quote
Old 7th January 2009, 11:27 PM   #1030
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 103
12 VAC secondaries gets you about 17 V DC, 16 V if you use a bridge rectifier on both windings.

The simplest (VAC x 1.41) formula works quite well here, because the diode drop and ripple is compensated by the load regulation of the transformer. i.e. you lose about a volt to the diodes, but gain about a volt because the transformer is only lightly loaded.

/R
  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



New To Site? Need Help?

All times are GMT. The time now is 07:48 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