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 03 Dec 2020, 21:39

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 1694 posts ]  Go to page Previous  1 ... 55, 56, 57, 58, 59, 60, 61 ... 170  Next
Author Message
PostPosted: 16 Jan 2011, 05:55 
Offline

Joined: 18 Sep 2010, 12:48
Posts: 81
KrammeAcoustics wrote:
santik wrote:
what make DC offset?

what would cause it?

Hi santik

I have to understand your question right :geek: ...is it the NP-100v12 you're referring to ? If it is, you don't need to think about DC offset, because this amplifier has an AC coupled output electrolytic capacitor, which makes it unnecessary to think about DC offset ( it's not possible to measure any DC, only amplified AC is leaded through ).

For an amplifier with DC coupled output = no electrolytic capacitor, it's a different matter. There it's a must to have a DC offset adjustment. It's important to adjust to the lowest possible voltage, to avoid DC running through the coil, of the loudspeaker ( the coil can be damaged, if high DC are constantly, running through it ). Typical allowed values, for modern amplifiers = 10 - 30 mV.

Some simplified WIki about DC-offset.

A must reading:
http://www.tubecad.com , John Broskie shows schematics, in an "easy to understand" illustrated way.
( thanks to John, you make everything understandable ). :thumbsup:



The C3 is to remove DC... that I know...

But why I get about 10mV on right channel?
And 5-8 on left...

What would it be, C3 degrading? And if so why the measurements not same for both channels?


Top
 Profile  
 
PostPosted: 16 Jan 2011, 06:44 
Offline
User avatar

Joined: 24 Jun 2010, 00:48
Posts: 788
Location: Christchurch, NZ
Hi Santik,

A small DC offset is ok as long as it's under 50mV.
Both channels won't be exactly the same because of tolerances in components.

_________________
Kind Regards,
Dinesh

Some of my diy audio projects:


Top
 Profile  
 
PostPosted: 16 Jan 2011, 15:22 
Offline
User avatar

Joined: 31 Dec 2008, 15:34
Posts: 441
santik wrote:

The C3 is to remove DC... that I know...

But why I get about 10mV on right channel?
And 5-8 on left...

What would it be, C3 degrading? And if so why the measurements not same for both channels?

I've just tried to measure my own build, with a multimeter and for both channels it shows 2 mV for 1 sec. it falls back to zero after 1 sec. ( this measurement is caused by the multimeter, the amplifier shortly, sees the multimeter, as a load ).

Your build should not leak DC continuously ...if it does, somethings probably wrong, with the electrolytic capacitors.


Top
 Profile  
 
PostPosted: 17 Jan 2011, 08:25 
Offline

Joined: 17 Apr 2010, 16:07
Posts: 39
Location: Huddersfield ,West Yorkshire,UK
roggom wrote:
Thanks Koog,

Will post pics when I finish it. Will be around spring or so.


if you noticed there is alot of unused screw terminals on the brd files and finished board these where options so i could cut the power supply tracks to the diff modules to isolate if required for trouble shooting

i just updated my amp pic to reflect the updates i did :smoking:

Image

Regards

Koog

_________________
Homebuilthifi Projects
runawaybrainz.blogspot
Head Amp On 555 Delay all in one
NP-100v12 - 12AU7 / IRF510 HeadAmp


Top
 Profile  
 
PostPosted: 18 Jan 2011, 11:16 
Offline
User avatar

Joined: 07 Aug 2010, 06:24
Posts: 44
Location: India
O_o NYC! this a self etched board?

_________________
"Problems cannot be solved by the same level of thinking that created them" -Albert Einstein


Top
 Profile  
 
PostPosted: 18 Jan 2011, 13:24 
Offline

Joined: 15 Jan 2011, 10:53
Posts: 41
Location: Darmstadt, Germany
Hi there,

I finished my amp last year but had'nt got the time to take pictures. Now here they are:

Image

Image

Image

Image

Image

I integrated the delay circuit from http://diyforums.org/MAX/MAXe12.php. The board is about 85 x 56 mm in size. Right now I power it from a 12 V sealed lead acid battery but I plan on doing a power supply based on the lm317 circuit mentioned in this thread.
I have to thank Mr. Gomez for the circuit and the great tutorial. This was my first take on an amp and it sounds awesome!

- Ferdinand


Top
 Profile  
 
PostPosted: 18 Jan 2011, 19:20 
Offline

Joined: 14 Jan 2011, 23:28
Posts: 20
Location: Black Forest, Colorado
koogar wrote:
i just updated my amp pic to reflect the updates i did

Wow.
Very nice work in every respect.


Top
 Profile  
 
PostPosted: 18 Jan 2011, 19:25 
Offline

Joined: 14 Jan 2011, 23:28
Posts: 20
Location: Black Forest, Colorado
ferdinandkeil wrote:
I finished my amp last year but had'nt got the time to take pictures.
The board is about 85 x 56 mm in size. Right now I power it from a 12 V sealed lead acid battery but I plan on doing a power supply based on the lm317 circuit mentioned in this thread.
I have to thank Mr. Gomez for the circuit and the great tutorial. This was my first take on an amp and it sounds awesome!

Nice work.
You managed to pack the basic amp plus the delay circuit on to a 85 x 56 single sided board.


Top
 Profile  
 
PostPosted: 19 Jan 2011, 14:48 
Offline

Joined: 14 Jan 2011, 23:28
Posts: 20
Location: Black Forest, Colorado
My Son and I built this one to teach my Son how to design and etch a PCB and to learn how to solder.
A couple of mistakes along the way but we fixed everything and it works great

Next step will be to design and build a more complex variant and put into an enclosure.

Thanks for sharing the circuit Rogers :thumbsup:

Regards,
BB


This post has a file attachment. Please login or register to access it. Only Registered Members may view attached files.



Top
 Profile  
 
PostPosted: 19 Jan 2011, 16:44 
Offline
Project Author
User avatar

Joined: 03 Aug 2008, 20:22
Posts: 386
Location: Denver, Colorado
Ferdinand, Great job, I see you have everything packed in there very nicely, also great work on the etching and the ground plane.

BB, Wonderful, quality time with your son and tube amp basics, this was the inspiration for the amp and the posting.

Nothing like the glow of a triode to exemplify a successful build.

Rogers


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 1694 posts ]  Go to page Previous  1 ... 55, 56, 57, 58, 59, 60, 61 ... 170  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 7 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