DIY Audio Projects Forum
http://diyaudioprojects.com/Forum/

Vertical 6EM7 Portable Amp
http://diyaudioprojects.com/Forum/viewtopic.php?f=9&t=5134
Page 4 of 17

Author:  mwhouston [ 22 Sep 2015, 06:52 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

You may not have a proper earth to each channel or a common earth to,both channels.

Author:  wdecho [ 22 Sep 2015, 07:16 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

I did build it like my SS builds with a common earth for both channels. I can easily separate the grounds for each channel but will that cause ground loops. I made a star ground common to everything in the audio path with the chassis ground separate with the switch if I wanted to connect the chassis to the audio ground which I have not needed to do.

Author:  mwhouston [ 22 Sep 2015, 07:22 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

Don't seperate the earths.

Author:  wdecho [ 22 Sep 2015, 07:26 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

mwhouston wrote:
Don't seperate the earths.


I do not quite follow what you mean then about a common earth. What do you suggest I do.

Your help is much appreciated. Tube circuit builds are new to me.

Author:  mwhouston [ 22 Sep 2015, 07:58 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

Don't make any changes until some can make a suggestion.

Author:  wdecho [ 22 Sep 2015, 09:06 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

Problem solved. On the pot I had tied the audio ground lugs together and sent one wire to ground. I separated the common ground and connected 2 separate wires and sent them to ground. The pot I used has another ground separate from the 3 lugs for audio which I thought was not necessary but I ground them also and now if I pull one input the speaker has no sound. I suspect the tied to lugs to ground was the problem. Lesson learned, success.

Author:  mwhouston [ 22 Sep 2015, 09:29 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

That's what I eluded at. Floating grounds.

That will be £4/10/3 thank you.

Lol.

Author:  wdecho [ 22 Sep 2015, 11:18 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

Both the leads go to ground so what if you just tie them together and send one wire to ground, that was my thinking. Putting two separate wires to ground fixed the problem but I really do not understand why this is so but the amp that original sounded mighty good sounds even better. I general use two single pots on my builds, that way you have some balance control but I did not know how this amp was going to sound so I went with a dual that I had. I thought it might be the volume control that somehow was causing the problem but I was expecting to replace it with 2 singles. All is good now.

Author:  wdecho [ 22 Sep 2015, 15:13 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

I think I understand what was happening now. I connected the grounds on the pot as 1 going to 2 then ground. If I had connected ground between 1 and 2 I believe it would have been good to go but as I had it 1 was going to 2 then ground. Does this make any sense?

Author:  mwhouston [ 22 Sep 2015, 18:37 ]
Post subject:  Re: Vertical 6EM7 Portable Amp

You may still have a high resistance ground. Check with a meter.

Page 4 of 17 All times are UTC - 6 hours [ DST ]
Powered by phpBB® Forum Software © phpBB Group
http://www.phpbb.com/