Opinions or inputs on Altec 1570B amplifiers - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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 4th February 2007, 02:20 PM   #1
diyAudio Member
 
Join Date: Nov 2002
Default Opinions or inputs on Altec 1570B amplifiers

http://www.audioasylum.com/forums/vi...ages/4477.html


This is an excellent article on the 1570's and modifications that have been reviewed by Joe Rosen in Oct of 2001

I am trying to get some ideas for re doing the bias circuit. I have some feelers out as I am trying to locate two of these amps with the 16492 output transformers in them. I had several of them about 15yrs ago and like a fool let them go.

Anyone have any ideas?
  Reply With Quote
Old 4th February 2007, 04:06 PM   #2
diyAudio Member
 
Join Date: Nov 2002
http://www.triodeel.com/al1570b.gif

copy of schematic
  Reply With Quote
Old 4th February 2007, 06:39 PM   #3
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Silly article (sorry Joe) describes some good ideas found in the article he criticizes.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 4th February 2007, 07:31 PM   #4
diyAudio Member
 
Join Date: Sep 2001
Location: Salt Lake City
I used to repair alot of these amps as they were used in many Movie Drive Ins. Almost all of them eventually experienced either power transformer failure or output tranny failure. Since the power supply is quite high voltage on them BE SURE YOU GROUND THE CHASSIS VERY WELL AND EXCERCISE EXTREME CAUTION and be sure you have the proper size fuse in place!!Almost all of these amps that were used in the Drive Ins ended up in the garbage dump. This Altec was a cheaper way to powering all the ramps at a Drive in... there was always a main amp and a backup amp and for good reasons. Better drsigned Drive Ins used multiple small tube amps and there was a single backup amp that could be switched into any ramp in case one went down. All in all they are a fire hazard in my opinion.

MArk
__________________
KSA-100 WIKI
  Reply With Quote
Old 5th February 2007, 11:51 AM   #5
diyAudio Member
 
Join Date: Nov 2002
Quote:
Silly article (sorry Joe) describes some good ideas found in the article he criticizes.
Silly as it may seem it is still some type of information and it seems it is all I can find on the 1570's. I would be more interested in your positive input and comments as a result of your vast experience. Anything you would care to share would be most appreciated.

Quote:
I used to repair alot of these amps as they were used in many Movie Drive Ins. Almost all of them eventually experienced either power transformer failure or output tranny failure. Since the power supply is quite high voltage on them BE SURE YOU GROUND THE CHASSIS VERY WELL AND EXCERCISE EXTREME CAUTION and be sure you have the proper size fuse in place!!Almost all of these amps that were used in the Drive Ins ended up in the garbage dump. This Altec was a cheaper way to powering all the ramps at a Drive in... there was always a main amp and a backup amp and for good reasons. Better designed Drive Ins used multiple small tube amps and there was a single backup amp that could be switched into any ramp in case one went down. All in all they are a fire hazard in my opinion.
Well I guess different people in different areas of the country do things quite differently. We never used 1570 for drive in theatre amps around here.

Its amazing to note that there are still a number of 1570's in service in large facilities like football stadiums and convention centers. Within the last several years the company I work for did a large new system and replaced 20 some 1570's that had given excellent service and were still functional and had lived their life without incident. I guess there is a lot to be said about the quality of any installation and maybe that was the problem with the drive in theatres in your area.

Heck, if you have some ideas on the 1570 please do share them as I'm sure others would be as interested as I am to hear them.
  Reply With Quote
Old 6th February 2007, 11:29 PM   #6
diyAudio Member
 
Join Date: Nov 2002
Seems to be a lack of interest in this animal. Do I give up the idea?
  Reply With Quote
Old 7th February 2007, 12:06 AM   #7
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Hi burnedfingers,
I wouldn't give up on the idea. I haven't seen too many of these used in drive ins either. It's been a number of years since I last saw or worked on one.

I always understood them to be quite reliable, and the ones I rebuilt needed very little work to get them going again. Not really sure where Wavebourn is going with this one..

I have worked on at least a dozen of them over the last 15yrs or so, and I have not seen one with a bad power transformer or output transformer.

Unfortunately in this neck of woods they now command pretty princely sums of money. I have seen functional pairs of 1570B selling for well over $2K in the last year or so.

They sound pretty nice when not overtaxed on the low end..
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 7th February 2007, 12:23 AM   #8
diyAudio Member
 
Join Date: Nov 2002
Kevin,

Thanks for the reply. Do you have any ideas for the bias section?
  Reply With Quote
Old 7th February 2007, 12:50 AM   #9
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
My service information is buried beyond quick rediscovery, any chance you could post a schematic or link to one?

IIRC The main issue with these amps was the input transformer and how to get around it..
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 7th February 2007, 01:16 AM   #10
diyAudio Member
 
tomtt's Avatar
 
Join Date: Aug 2002
Location: kansas city mo, and on occasion, around the world ...
Blog Entries: 15
strangely, 12th down, under power amplifier


http://www.altecpro.com/products/vintage/index.htm



1570B Power Amplifier Manual ZIP


scema-


http://images.google.com/images?svnu...f&q=altec+1570


154
Attached Images
File Type: jpg altec1570.jpg (85.9 KB, 336 views)
  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
Altec Amplifiers peter hawthorne Tubes / Valves 6 28th August 2007 01:52 AM
Altec Tube Amplifiers peter hawthorne Tubes / Valves 0 16th August 2007 11:31 AM
Altec 1570B choppers Tubes / Valves 1 4th August 2005 03:19 AM
Opinions about T.A.C. amplifiers? Netlist Tubes / Valves 1 24th September 2003 03:43 PM
Altec 1570B amps puppyslugg Tubes / Valves 3 22nd November 2002 06:49 AM


New To Site? Need Help?

All times are GMT. The time now is 01:57 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