How to use the almost Group buy Diyaudio CCS circuit - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

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
Reply
 
Thread Tools Search this Thread
Old 6th December 2008, 01:02 PM   #1
diyAudio Member
 
Join Date: Nov 2002
Default How to use the almost Group buy Diyaudio CCS circuit

This thread is dedicated to those of us that have our names on the list awaiting the receipt of our Darwin awards.

Some like me haven't used CCS boards and are scratching our heads in wonderment trying to figure out just what the hell is happening on this magic board or possibly perf board for some.

The idea of actually trying to use the board came about for me when I purchased a Dynaco Stereo 70 amplifier with a GSI board which had a circuit that used several LM334-Z of which I haven't been able to get running or keep running correctly because of blowing out components in the circuit. Having said to hell with purchasing some components that cost less than $1 ea and then spending about $8 to ship them I figured I would see what merit this design would bring. Isn't that what DIY is all about?

I will mention that this work is a result of planet10 contacting Morgan Jones about using a 317 for a CCS and as a result pinkmouse came up with a circuit for the constant current sources with input and assistance from SY, EC81010, & Gregg-the Geek.

Now I will start out the list of stupid questions.

1.) How does one figure which board/circuit design to use?
2.) Does one have to use a B+ supply which is high voltage of say
400 volts DC?
3.) Is there a way to use a smaller less lethal supply and use less
costly parts one might have on hand?
4.) Just how hard does the reference string have to run? The info
suggests 5mA. Is it possible to run it less without any dimmenishing results?

These are just a few of the stupid questions that I can come up with before having my second cup of coffee.

Documentation on the CCS boards

http://homepage.mac.com/tlinespeaker...-CCS-beta3.pdf
  Reply With Quote
Old 6th December 2008, 01:17 PM   #2
diyAudio Member
 
Join Date: Nov 2002
So second cup of coffee in hand and more stupid questions.

Looking at the amplifiers driver board and at the power supply in General.

Here is what I have in the way of supplies.

1.) I have the original supply that fed the on board CCS circuit which looks to be a negative supply of around aprox 9-10 volts roughly which is a result of the 6.3volt AC winding being rectified and filtered.

2.) I have on hand a bias supply which is negative filtered supply of 80 volts off the first cap and a resistive drop to -70 volts off the second cap.

3.) I have B+ of roughly 400VDC

Which supply can be used and why?

So the result is yet another stupid question...

Is a bigger supply better?

Do I use the 400 VDC supply?

Do I use the bias tap off the transformer and make a smaller positive supply?
  Reply With Quote
Old 6th December 2008, 01:40 PM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
I assume you're using the CCS as a long tail for the input stage.

If you've got the 9V supply, it's a better bet than the bias rail. Reason is that the bias supply is only half-wave filtered, lots of ripple, and drawing extra current from it will only make things worse (and might take the power transformer closer to saturation because of the offset between the two halves of the secondary). The 400V B+ is an excellent source for the bias string since it will require a large dropping resistor, minimizing the effects of PS ripple on the CCS's reference voltage.
__________________
The more you pay for it, the less inclined you are to doubt it.- George Smiley
  Reply With Quote
Old 6th December 2008, 01:42 PM   #4
diyAudio Member
 
Join Date: Nov 2002
The 9 volt supply is half wave rectified also. The supply circuit on the board I have is not as shown in the schematic.

9 volt supply ... not a good bet then
Attached Images
File Type: jpg picture 011.jpg (55.8 KB, 366 views)
  Reply With Quote
Old 6th December 2008, 01:58 PM   #5
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
From the somewhat unclear schematic, it looks like it could be a full-wave. Either way, at least there's some Zener regulation so ripple won't be a problem, and since you're not asymmetrically loading the power transformer, you won't have any saturation issues, either..

Here's a quick drawing of my suggestion; R2 could be 200k or so.
Attached Images
File Type: gif ccs for joe.gif (4.4 KB, 359 views)
__________________
The more you pay for it, the less inclined you are to doubt it.- George Smiley
  Reply With Quote
Old 6th December 2008, 02:09 PM   #6
Svein_B is offline Svein_B  Norway
diyAudio Member
 
Join Date: Oct 2005
Half-wave rectifier for the -9V will be OK if you use largish caps of 1000uF or more in a CRC supply.
What is more important than the ripple of the B- supply, is a clean supply for the CCS reference as indiocated by SY's diagram.

See also my thread here with a study of CCS performance vs. B+ and B- supply ripple.
LTP with CCS - IM Distortion

I used only a couple of mA for the reference string.


SveinB
  Reply With Quote
Old 6th December 2008, 02:27 PM   #7
diyAudio Member
 
Join Date: Nov 2002
So, in the interest of no negative supply ripple why not just eliminate the -9 and go to ground?
  Reply With Quote
Old 6th December 2008, 04:10 PM   #8
Svein_B is offline Svein_B  Norway
diyAudio Member
 
Join Date: Oct 2005
The CCS will require some volts to operate. If you connect to gnd, you will need to elevate the grids, and add an input cap. Not desirable.

Ripple on the negative voltage is not a major concern. Remember the CCS appears to be a very large resitor of several MegOhms, thus providing good PSRR.

SveinB.
  Reply With Quote
Old 6th December 2008, 06:12 PM   #9
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
What Svein said- the CCS needs some voltage headroom to operate.
__________________
The more you pay for it, the less inclined you are to doubt it.- George Smiley
  Reply With Quote
Old 6th December 2008, 08:20 PM   #10
diyAudio Member
 
Join Date: Nov 2002
Ok, so I will hook the "In" to the -9volts, the return to the B+, and the out to the cathodes.
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
is there a canonical LM3875 diyaudio.com circuit? travis Chip Amps 10 4th October 2007 06:31 PM
diyaudio moderator vs diyaudio member Leolabs Everything Else 6 18th June 2006 08:19 AM
Trouble with speaker protection circuit (Randy Slone's circuit) whalefat Solid State 3 13th April 2005 10:13 AM


New To Site? Need Help?

All times are GMT. The time now is 04:33 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2