Yamaha A-550 - diyAudio
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 18th October 2003, 05:39 AM   #1
angel is offline angel  Norway
diyAudio Member
 
Join Date: Oct 2003
Location: Norway
Question Yamaha A-550

Has anyone had any experience with the Yamaha A-550? I recently got my hands on one, and it works like a charm. It has a rather laid-back/warm sound, and for once, my better half even approves.

However, it is worn, and before starting to change parts, I would like to know more about the design, so I don't screw anything up. Searching around the net for information, especially schematics, yielded no real information. One site refers to it as a class A integrated amplifier, but the heatsink would suggest class B. The transistors used appear to be older types, with a four digit designation, not even listed on my equivalents list.

If anyone has the schematics, or any hints about it in general, I'd be most grateful.
  Reply With Quote
Old 17th January 2006, 03:46 AM   #2
diyAudio Member
 
Join Date: Apr 2005
Location: Toronto, Ontario
I found this msg on search for info on A-550.

A neighbour put one of these out for the trash pick up tonight.

It is in excellent shape and works fine.

Anybody got specs on this unit???
  Reply With Quote
Old 17th January 2006, 04:03 AM   #3
KBK is offline KBK  Canada
diyAudio Member
 
Join Date: Dec 2003
Location: The Wilds Of Canada
Look to the voltage of the main PS capacitors. If it is 63 Volts, then it is likely to be 'about' 75 watts per channel. I believe the A-550 was that wattage..and all the 5 series were 70-75W/Ch. (500, 550, etc)

They were overall...well built. Back when the world was still seen as an endless supply of natural reserves..and an endless garbage dump..and we could afford to put quality into gear for reasonable costs.
  Reply With Quote
Old 17th January 2006, 05:02 PM   #4
anatech is offline anatech  Canada
diyAudio Moderator
 
anatech's Avatar
 
Join Date: Jun 2004
Location: Georgetown, On
Hi angel,
I used to service Yamaha under warranty. With most manufacturers, class A only meant "turned the bias up way too high and now it will not last as long". In class A, it's still a class AB amplifier. There was no difference in sound quality, it was all marketing.

Yamaha service manuals were not expensive in Canada, try your distributor.

-Chris
  Reply With Quote
Old 18th January 2006, 02:22 AM   #5
diyAudio Member
 
Join Date: Apr 2005
Location: Toronto, Ontario
Quote:
Originally posted by KBK
Look to the voltage of the main PS capacitors. If it is 63 Volts, then it is likely to be 'about' 75 watts per channel. I believe the A-550 was that wattage..and all the 5 series were 70-75W/Ch. (500, 550, etc)

They were overall...well built. Back when the world was still seen as an endless supply of natural reserves..and an endless garbage dump..and we could afford to put quality into gear for reasonable costs.
Thanks for idea on checking out power supply.

Power supply is +/- 41VDC

Power output transistors are 1 x NEC B616A (PNP) and 1 x NEC D586A (NPN) per channel.

Max collector current spec appears to be 5A and power diss. spec is 80watts for these devices.

There is not tolerance for over voltage with capacitors in power supply. They are only 6,800uf @ 50Vdc
  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
Yamaha AX-930 jleaman Analogue Source 6 21st November 2010 12:43 PM
Yamaha cdx 900 stex Digital Source 4 23rd January 2010 12:44 PM
Yamaha RX-777 quasi Solid State 4 15th November 2007 01:58 PM
yamaha ns m-50 RogerG Solid State 13 24th March 2007 01:10 AM
Yamaha CDX-490 newbie123 Digital Source 1 3rd December 2005 04:31 PM


New To Site? Need Help?

All times are GMT. The time now is 01:31 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