DIY Audio Projects Forum
 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

DIY Audio Projects Forum

Welcome to the DIY Audio Projects Message Forum. Use these forums to discuss Hi-Fi audio and to share your DIY Audio Projects. Registration is free and required to post messages and view the file attachments. Registration will only take a minute and registered users do not see any advertisements. After you have completed the online registration process, check your email (including spam/junk folder) for the verification email to activate your account. New members are under moderation - so your posts will not be visible until approved by a moderator. See the Read Me 1st, Forum RULES and Forum FAQ to get started on the forum.

It is currently 15 Oct 2018, 11:24

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 12 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Non-metal Chassis
PostPosted: 04 Nov 2013, 08:56 
Offline

Joined: 05 Jun 2012, 13:10
Posts: 196
Location: Darboy, WI, USA
I've seen a few builds on here that do not use a metal chassis. Personally, I'd like to work in wood. It just seems to be a bit more forgiving. They can have their own hurdles, however.

Is there any safety concerns to consider when you don't have a large chunk of metal? What would I have to exclude/include to the build? Should there be a ground plate or can I run a buss or bare ground lead?

In my head, it's no different to replacing the metal chassis grounding points with a bit of wire in a non-metal build.

Thoughts? Concerns?

I did a search to find any other relevant topics but didn't come up with much, so if this has been covered, links will appreciated.

_________________
Thanks,
Ross in Wisconsin


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 06 Nov 2013, 19:16 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4565
Location: Winnipeg, CANADA
Hi Ross,

What sort of electronics are you looking to enclose? Tubes are special and so are high gain electronics. Shielding is likely one item you may need to add.

Here are a couple of threads with some info:
viewtopic.php?f=14&t=1565
viewtopic.php?f=14&t=2346
viewtopic.php?f=14&t=557

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 06 Nov 2013, 21:47 
Offline

Joined: 05 Jun 2012, 13:10
Posts: 196
Location: Darboy, WI, USA
Sorry, I meant to refer to tube power amps and tube preamps. Thanks for the links, Gio. I will take a look through them.

_________________
Thanks,
Ross in Wisconsin


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 06 Nov 2013, 21:55 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4565
Location: Winnipeg, CANADA
You can use wood (not MDF) with tubes. Heat tends to build up easier so you have to give ventilation good consideration. I like to use aluminum tape on the inside for heat protection and for shielding.

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 06 Nov 2013, 22:00 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3813
Location: Arizona, USA
Hi, I have used all wood and all plexi chassis from time to time. There are no particular safety concerns that would not already apply to any sort of tube gear. The main issue is noise (EMI) pick up and hum pick up. You may need to shield some sub assemblies in metal enclosures. Any circuit that has gain of over about 10 or deals with signals much below 0.5 volts is likely to need shielding. Power amps usually will not, but preamps other than low gain line stage ones probably will.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 07 Nov 2013, 08:39 
Offline

Joined: 05 Jun 2012, 13:10
Posts: 196
Location: Darboy, WI, USA
Thanks guys. Yeah I would probably make an all wood (pine or oak for now) chassis. For the aluminum foil tape or small metal enclosure, do you ground them all together back to the star ground?

I suppose you have to watch out for strips that touch each other multiple times and make for a ground loop?

_________________
Thanks,
Ross in Wisconsin


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 07 Nov 2013, 09:02 
Offline
User avatar

Joined: 08 Aug 2009, 03:11
Posts: 2229
Location: Chilliwack, BC
My experienc with all wood chassis....

Heat...
Cool...
Heat...
Cool...
[some time]
Heat...
Cool...
*CRACK!*

So, I put the things that heat up on aluminum and have wood all around.

So Gio, why not MDF? I've repaired/modded commercial gear in all MDF boxes and they seem just fine :confused:

Cheers!

_________________
-= Gregg =-
* Ratings are for transistors - tubes have guidelines*
Home: GeeK ZonE
Work: Classic Valve Design


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 07 Nov 2013, 09:32 
Offline
Project Author
User avatar

Joined: 04 Jun 2008, 20:59
Posts: 3813
Location: Arizona, USA
Yes the shields should go to the star ground and not touch each other unless that is the path to the star ground. Ground loops have ruined many otherwise good projects. For shielding some things I have found that you can get cast metal boxes either designed for component use or from the hardware store for use in electrical systems. The ones for electrical systems often have mounting feet. Look in the early Forewatt project - I used one in the first version to house the power transformer. That is an all wood design and the mounting feet makes the boxes easy to use in all wood chassis. In that particular build I didn't shield the audio as the gain was so low. Later versions do as it does help shield from EMI. I had a problem with nearby electrical gear that forced the change.

Good listening
Bruce

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 10 Nov 2013, 11:28 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4565
Location: Winnipeg, CANADA
Geek wrote:
So Gio, why not MDF? I've repaired/modded commercial gear in all MDF boxes and they seem just fine

I find that MDF really traps heat. Prob fine for a very open guitar chassis but most hi-fi chassis are pretty closed up.

Cheers

_________________
[ DIY Mains AC Power Cable Cord ] - [ Gobo LM1875 Amp Kit ] - [ Tang Band D4-1 Horn Speaker Kit ] - [ Monoblock Push-Pull KT88 Tube Amp Kit ]


Top
 Profile  
 
 Post subject: Re: Non-metal Chassis
PostPosted: 12 Nov 2013, 08:46 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 18:23
Posts: 4944
Location: Australia
The only time a had a problem in a nonmetal box was with a phono preamp. I could not get enough shielding to stop hum. I use a bituminised heavy sticky Al foil to line most builds, metal or not. Even with this AC mains hum got in when the device was battery powered.

Amps and preamps (line level) should have no problems. Still line them with foil.

_________________
Projects: "Lagoon" - tube preamp with cathode follower | "retro-Oatley 6J6" - 6J6 push-pull headphone amp with OPTs | "retro-Hiraga" - Jean Hiraga Le Monster
Website: retro-thermionic


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 12 posts ]  Go to page 1, 2  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
DIY Tube Projects :: DIY Tube Amp Kits :: DIY Speaker Projects :: DIY Solid State Projects :: DIY IC / Op-amp Projects :: DIY Phono Projects :: DIY Cable Projects :: Hi-Fi Audio Schematics
© diyAudioProjects.com - Terms of Service - Privacy Policy