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 11 Dec 2018, 07:40

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 14 posts ]  Go to page 1, 2  Next
Author Message
PostPosted: 05 Jan 2009, 22:07 
Offline
Project Author
User avatar

Joined: 03 Aug 2008, 20:22
Posts: 386
Location: Denver, Colorado
I have built up quite a collection of headphone amps and now venturing into higher voltage/wattage amps. My workbench/home office now has a variety of sources and amps, but one DIY item that was missing was an EQ of some sort. I have a few preamps, but I really did not want to add any more gain and noise to an already congested system. I found an answer in a simple but genius tone-control by Tony van Roon http://www.uoguelph.ca/~antoon/tutorial ... xtor5.html.
Image

I drew the amp up in Tina and sim'd the outputs and made only a few minor changes. I replaced the electrolytics with Poly film, R5 to 1K, and C2 to .068u for a little more bass.

The tone control sits in between two switch boxes (back to back) so that I have three sources to a switch box, tone control, switchbox, the amps. This gives me max flexibility to listen to any of the sources on any of my amps.

Since the control is passive it will attenuate about -20db at the baseline and the pivot point is around 800Hz. I get about +15 db of boost and -10db of cut. Now all I need to do is get through a song without knob tweaking :).

BTW: The volume pot is 50K (audio) and is before the input. Both bass and treble pots are (audio) log, radio shack 271-1732


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



Top
 Profile  
 
PostPosted: 05 Jan 2009, 23:54 
Offline
Editor
User avatar

Joined: 28 May 2008, 21:53
Posts: 4575
Location: Winnipeg, CANADA
Very nice Rogers. Looks like a Radio Shack enclosure and board.

TINA TI is very handy and I am staring to get the hang of it. I have been using the software to look at line level BSC. The advantage of the line level BSC over a speaker level BSC is that you don't need an inductor and a large wattage resistor.

_________________
[ 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  
 
PostPosted: 06 Jan 2009, 00:03 
Offline
Project Author
User avatar

Joined: 06 Jun 2008, 20:12
Posts: 972
Location: Houston, TX
I have so many projects I want to do. One is to build tone controls. This one is really nice. Minimum of parts to get the sound dirtied up.
Does it sound pretty clean? Can you tell its there if everything is set flat?
Ri

_________________
DIY Lightspeed Passive Attenuator


Top
 Profile  
 
PostPosted: 06 Jan 2009, 12:44 
Offline
Project Author
User avatar

Joined: 03 Aug 2008, 20:22
Posts: 386
Location: Denver, Colorado
Very clean, the only thing is the -20db loss, not a show stopper considering my RIAA stage and pre stage in the Magnavox can make up for the loss. I made a small change that raises the bass a little, but the original design would be completely flat. The controls will raise the high and low rolloff, the mids remain unchanged to an extent.
Attachment:
passive_Tone_control.zip

Gio, this is another Radio Shack project, Caps were sourced at a local electronics shop, as they have some obscure but not unobtainable values.

There is an active version that has a transistor and I played around with changing the transistor with a 12au7 and it is promising, but I will stick with the passive version.
Image
Attachment:
Active_Tone_control_tube.zip

Attachment:
ACTIVE_TONE_CONTROL_TUBE.PNG

Rogers


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



Top
 Profile  
 
PostPosted: 06 Jan 2009, 18:37 
Offline
Project Author
User avatar

Joined: 14 Oct 2008, 17:35
Posts: 901
Location: Dartmouth, Nova Scotia
I like that design, it is the simplest one I have ever seen, and best of all it does not use any transistors to boost the signal, so audio quality will stay unchanged with high quality components.

_________________
My Mini 12AU7 Tube Preamp, Pioneer SX-D7000, JVC XL-V221BK, JBL L80T, DCM TF700


Top
 Profile  
 
PostPosted: 06 Jan 2009, 18:47 
Offline
Project Author
User avatar

Joined: 03 Aug 2008, 20:22
Posts: 386
Location: Denver, Colorado
Thanks,
One note on using the Tina-Ti sim, I believe the pots are linear in the simulation vs. log audio, so 50 percent is not flat. The passive 9% is flat 1% is max cut and 99% is max boost.I will look online for a log pot model.


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



Top
 Profile  
 
PostPosted: 07 Jan 2009, 01:34 
Offline
Project Author
User avatar

Joined: 03 Aug 2008, 20:22
Posts: 386
Location: Denver, Colorado
One more addition, if -20db is too much attenuation I added a 2k feedback loop to bump the gain up to baseline -10db and the curve remains stable. If you use a volume pot the loop goes between the center pin and the output.


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



Top
 Profile  
 
PostPosted: 08 Jan 2009, 22:39 
Offline

Joined: 26 Aug 2008, 20:57
Posts: 415
Location: Atlanta
Here are a few more tube types:

http://home.comcast.net/~stphkeri/tone_control.html


Top
 Profile  
 
PostPosted: 04 Jul 2009, 08:29 
Offline

Joined: 04 Jul 2009, 08:26
Posts: 1
Hello! Am I right to assume this is for 1 channel and you would build 2 of these for a stereo tone control network? Peace. Robert


Top
 Profile  
 
PostPosted: 04 Jul 2009, 16:09 
Offline
Project Author
User avatar

Joined: 03 Aug 2008, 20:22
Posts: 386
Location: Denver, Colorado
Yes that is correct, most DIY schematics are drawn with one channel and you just repeat for second channel. One the same pcb or by making dual mono pcb's.

I have been using this as my primary passive pre/tone control for abour 6 months. It is controlling a magnavox 6v6 tube amp. Not super fancy but simple and sounds good. Here are some more pics as I had issues with my flickr account.

Remember this a passive pre so the overall volume will be less, but you can definatley tweak the highs and lows. I added an almost defeat switch for rocking out. :headphones:

The only change I would do is use a Blue velvet volume pot as the radio shack pot gets dirty sometimes, just have to cycle the pot a little, will hit it up with some faderlube someday.

Rogers


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



Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 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 9 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