Sony stereophonic amp (60's tube) - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 3rd March 2013, 08:26 PM   #1
cancon is offline cancon  Canada
diyAudio Member
 
Join Date: Mar 2011
Default Sony stereophonic amp (60's tube)

Here's a new one for my bench - a small stereo amp made by Sony (model SRA-3). Service manual (with schematic).

The most pressing issues are that the monitor outputs have some hum happening, regardless of what's connected to any input. The record head outputs are quieter, but they must have some ultra low (or high) frequency content going on. I can't hear it, but my compressor goes crazy when fed from those outputs.

Going in through the mic inputs on the front, I couldn't get a signal until I used a cheap low Z XLR to high Z TS adapter, then the signal became too hot to use for anything other than the quietest sources. Using the aux input the signal was pretty clean even with the input gain cranked (this is contradictory of this amp's reputation, as I hear lots of praise for its distortion characteristics).

So my first guess that I need to replace the 20uf (x3) filter section and possibly coupling capacitors. The VUs don't work, I haven't poked my head inside yet, but the schematic offers little insight. I want to add a 1/4" or XLR output - but how do I choose which output to tap? I assume some are better than others based on their designed impedance, but I'm not too familiar with tape deck hookups.

Any help or advice is appreciated. Thanks!
  Reply With Quote
Old 3rd March 2013, 11:42 PM   #2
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
What you actually have is the record electronics for a tape recorder as stated at the top of page 3. It's normal for high end boost in record amplifiers. The mag phono input equalization is not very impressive and certainly doesn't follow RIAA too closely. The meter can be adjusted all the way to 0 and can be overridden to 0 depending on the setting of S2.

This will not be a satisfactory preamp for general use until the bias and EQ networks are disabled and then has no power output to drive speakers.

G
  Reply With Quote
Old 4th March 2013, 12:48 AM   #3
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
What you have is totally unsuitable for your intended purpose, and further there are people actually looking for these units. (They're fairly rare) I had one and was able to find it a new home with remarkably little difficulty, many tape aficionados like these units. (With a minty ReVox G36 MKIII I really had no need for one of these units)
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 4th March 2013, 03:07 PM   #4
cancon is offline cancon  Canada
diyAudio Member
 
Join Date: Mar 2011
Sounds good, I have passed that info along. Thank you!
  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
Ampeg J-12T 60's amp issues? Help! Goldstache Instruments and Amps 23 14th September 2012 07:00 PM
Bell Stereophonic 3030 Integrated Amp W/Telefunken and RCA tubes 250 or trade AtomiKM Swap Meet 5 2nd November 2010 08:35 PM
60's era op-amp modules? theAnonymous1 Everything Else 6 21st May 2010 04:39 AM
60's Peerless 12" Drivers P Zolt Multi-Way 9 3rd February 2008 12:31 PM
Bell Stereophonic 3030 help AtomiKM Tubes / Valves 2 23rd September 2006 11:37 PM


New To Site? Need Help?

All times are GMT. The time now is 12:09 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