Distortion in Fisher 800C - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 2nd November 2005, 05:13 PM   #1
diyAudio Member
Join Date: Feb 2004
Location: Victoria
Default Distortion in Fisher 800C


I have a 1964 Fisher 800C stereo and I have noticed that it sounds
good at low volumes with the Loudness on but if I turn it up past about 4
(loud off, bass and treble flat) I get pretty severe distortion.
This amp is connected to fairly decent Energy loudspeakers through the 8Ω
The amp puts out 30 Watts RMS per side and the speakers are rated for at least 100 Watts.
CD player through Aux input.
All of the tubes in the audio path have been replaced with Audio Harmonix
(Junk, I know) and DC bias levels etc. are OK.
Is this distortion normal at these levels?
I thought I should be able to crank it up pretty much all the way without
getting distortion.
Am I living in a dream world?????
  Reply With Quote
Old 2nd November 2005, 06:57 PM   #2
SY is offline SY  United States
On Hiatus
SY's Avatar
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 2
Two things:

Separate the concept of "gain" from "power."

Separate the concept of "power handling capacity" from "sensitivity."

Let's do a car analogy. Car A and car B both have the same engine, gearing, and weight. Car A's accelerator is set up so that the throttle is wide open when you push the pedal all the way to the floor. Car B's accelerator is set up so that the throttle is wide open when the pedal is only halfway to the floor. Which is more "powerful"? Clearly, neither. Which will put out more power when the pedal is pressed, say, 1 cm? Car B. Which will put out more power when the pedal is floored? They'll be the same.

OK, now car C and car D have the same engine and gearing. Car A weights 1000kg, car B weighs 500kg. Which car is more powerful? They're the same. Which will go faster at a given engine output? Clearly, car D.
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote


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
Fisher 800c static,crackle skiman762 Tubes / Valves 2 9th April 2009 03:59 PM
Fisher 800c neg bias problem Glowin Plates Tubes / Valves 10 26th September 2008 08:39 AM
fisher 800c intermitant hum slhoward Tubes / Valves 1 28th May 2007 04:16 PM
fisher 800c modifications slhoward Tubes / Valves 1 15th May 2007 11:25 PM
Fisher 800C FM Stereo problem Glowin Plates Tubes / Valves 5 2nd April 2004 10:46 AM

New To Site? Need Help?

All times are GMT. The time now is 01:04 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2