Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki 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

Nobsound EL34 DIY with left channel hum
Nobsound EL34 DIY with left channel hum
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 9th November 2018, 10:35 AM   #41
DF96 is offline DF96  England
diyAudio Member
Join Date: May 2007
Originally Posted by ricaputo
My back ground is digital where a gnd is a gnd.
Is that true? What about ground bounce? Do you only work on low speed logic?

I am not used to having to run grounds a certain way as if everything is a antenna.
No antennas, just impedance. If you make 'separate' circuit loops share a ground then their currents will produce voltages across the impedance of whatever you call a ground connection. The circuit loops are not separate.

I do not understand reservoir capacitor or -ve. So I isolated the 330uf cap with the 47uf cap. Also ran CT to this point.
The reservoir capacitor is the first big capacitor in the PSU - the one nearest the rectifier. The -ve is the negative terminal. You need to learn some words. I have no idea what you mean by 'isolated'.

There are no instructions at all for circuits or gnd's.
I thought you showed us a circuit which included instructions for grounds? Maybe I am confused with another thread.
  Reply With Quote
Old 9th November 2018, 11:28 AM   #42
Burnedfingers is offline Burnedfingers  United States
diyAudio Member
Join Date: Nov 2002
Your a little harsh aren't you. Isn't Diyaudio a place to learn? The poster asked for help and my opinion is he should get it without any negativity that is associated with other audio forums that I will not mention here.

I'm happy you got your problem solved and in the process you learned and will have a better idea of how to do your next project. I learned something also.... I always isolated the input jacks from the chassis and used a 10 ohm resistor from RCA jack to ground. Its always worked for me but now I will use a smaller resistor and see what difference it makes for me. I also never paid too much attention as to the order I soldered my grounds to my buss bar. I will now pay attention to that. However, I haven't had a noise problem possibly caused by the order I placed my grounds on my buss bar.

So, your thread in my opinion was a win, win. Your problem was solved and information was exchanged/shared.

Last edited by Burnedfingers; 9th November 2018 at 11:39 AM.
  Reply With Quote
Old 9th November 2018, 08:02 PM   #43
6A3sUMMER is offline 6A3sUMMER  United States
diyAudio Member
Join Date: Jun 2016

Most of the digital circuit boards of one company I worked at had at least one (1) 0.1uF capacitor for every 2 high speed logic ICs, and sometimes one capacitor for each individual high speed logic IC.

The capacitor was connected [directly] across the 5V supply logic + IC pin to the logic IC - (ground) pin and ground plane of the circuit board. The purpose was to provide a low impedance power supply at the highest bandwidth of the high speed ICs. A 1,0,1,0,1,0 pattern on a logic IC is a square wave. A good looking square wave has at least 10 times the frequency of the square wave fundamental frequency. The power to that high speed logic IC has to be very low impedance at those frequencies.

Just running a trace from +5V to several high speed logic IC does not provide a low impedance at high frequencies. The inductance of the trace has to high of an impedance at the highest frequencies on the circuit board. A high speed transition from high to low, or low to high has a very high slew current. This current has to come from the + and - pins of the IC (and from the 0.1uF capacitor).

I hope that explains the concept that a ground is not a ground, especially when it is at a distance. Inductive reactance (impedance) gets higher as frequencies go up, and as distances go up.
  Reply With Quote


Nobsound EL34 DIY with left channel humHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Help With Left Channel Hum Monjul Tubes / Valves 6 2nd November 2018 11:15 AM
Nobsound EL34 Class A Single-ended Tube Amplifier Stereo HiFi Amp Kit? HarryY Tubes / Valves 18 27th August 2018 11:15 PM
SSE left channel dead.... neonthecat Tubelab 23 30th April 2010 04:15 PM
Can I have the sub woofer channel and the left and right channel as one? Boscoe Chip Amps 7 21st February 2010 06:56 PM
K-502 Left Channel is out udailey Tubes / Valves 3 21st March 2008 06:12 PM

New To Site? Need Help?

All times are GMT. The time now is 10:07 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio