Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 17th June 2006, 09:55 AM   #1
diyAudio Member
 
Join Date: Jan 2005
Location: Bari
Default three legs caps and other questions..

I should replace the big electrolytics in my guitar amplifier but I discover it use huge caps with three pins (with a triangular configuration) all pins are soldered, could I use standard two pins instead wich is the correct way of solder it???
Also in series with the speaker there's a parallel of two resistor of 4.7Kohm rated for 5W each (the amp is 50watt) putted here by some tecnichian or so... they are the big white square type of ones used in Xover, what do You think about?
  Reply With Quote
Old 17th June 2006, 12:31 PM   #2
diyAudio Member
 
Groundloops's Avatar
 
Join Date: May 2004
Location: fubar Germany.
There are electrolytics with three pins where the third pin is only for mounting on pcb, means it has no electrical connection.
And there are others where are two pins for + and one for -, so those are two caps in one package. Mostly to be found in older gear of the 70s.

In the first case you can use any cap of equal or higher voltage and equal capacitance, a higher capacitance can be used if the caps are part of the psu.

In the second case you would need two caps with the above characteristics and tie the - pins together.

A circuit drawing or a photo would make things clearer ...
  Reply With Quote
Old 17th June 2006, 02:03 PM   #3
diyAudio Member
 
Join Date: Jan 2005
Location: Bari
This is a little italian vintage amplifier, if I remind well the center pin of each electolytic is connected at the same part so I think it's for a sort of caps shielding (since the caps have a alluminium shield) and the two caps are connected in series for the standard PSU configuration: V+ - 0 - V-

Late I will post a photo of the PCB, hope this helps...
No idea above the 2.35Kohm resistor in series with the load it's a common configuration?
  Reply With Quote
Old 17th June 2006, 02:47 PM   #4
diyAudio Member
 
Groundloops's Avatar
 
Join Date: May 2004
Location: fubar Germany.
The resistors are absolutely uncommon. Maybe someone added them as kinda short-circuit protection. Such a big resistor in series (and with nothing parallel to it) to the speaker does nothing than increasing damping factor and output. What is the minimum impedance rating of the amp?
  Reply With Quote
Old 18th June 2006, 06:20 AM   #5
diyAudio Member
 
Join Date: Jan 2005
Location: Bari
4 Ohm
  Reply With Quote
Old 18th June 2006, 12:18 PM   #6
diyAudio Member
 
Groundloops's Avatar
 
Join Date: May 2004
Location: fubar Germany.
Weird thing. I have no idea what purpose the Rs could have. Id throw them out.
  Reply With Quote
Old 19th June 2006, 01:19 PM   #7
kubeek is offline kubeek  Czech Republic
diyAudio Member
 
Join Date: Dec 2005
Location: Prague, Czech Rep
Send a message via ICQ to kubeek
notice they are in prallel, not in series. I guess it is some kind of dummy load.
  Reply With Quote
Old 19th June 2006, 01:35 PM   #8
diyAudio Member
 
Groundloops's Avatar
 
Join Date: May 2004
Location: fubar Germany.
Quote:
Originally posted by kubeek
notice they are in prallel, not in series. I guess it is some kind of dummy load.
Oops ! Right you are, he wrote of parallel, not series ...
So I follow your opinion.
  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
which ferrite beads for mos legs? richwalters Power Supplies 4 28th June 2011 08:48 PM
Beads on FET legs argonrepublic Parts 2 17th January 2006 10:52 PM
Few Questions on Caps for CD Mod kptseng Digital Source 1 15th December 2005 10:28 PM
fake Alps with 4 legs - how to connect it Stabist Parts 6 13th January 2005 10:41 PM
Volume Pot with 4 legs ?!!! gchrist Parts 28 16th May 2004 11:28 AM


New To Site? Need Help?

All times are GMT. The time now is 02:03 PM.


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