Building Elvee's Circlophone: Documentation, Parts, Accessories, & beginner friendly - Page 5 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 15th May 2012, 09:09 AM   #41
diyAudio Member
 
Join Date: Jul 2011
Hi Elvee/Daniel,

I would like to build a circlophone with Sanken 2SC2922s. Elvee says here that they are very good choices provided the layout is good and the compensations are in place. Can you tell me which of the available board designs are the best for using these devices? If none are suitable, can you tell me what modifications I need to make to make them work? Would I need to use a specific driver?

The On Semi devices would be cheaper, but I am fascinated by these devices and they are easily available here through element14.
  Reply With Quote
Old 15th May 2012, 01:32 PM   #42
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by ImmortalZ View Post
Can you tell me which of the available board designs are the best for using these devices? If none are suitable, can you tell me what modifications I need to make to make them work? Would I need to use a specific driver?.
Powerflux's version looks like a good candidate for fast devices:
♫♪ My little cheap Circlophone© ♫♪
Good drivers among those listed are suitable. Be careful not to use fakes, there are so many around....
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  Reply With Quote
Old 16th May 2012, 04:52 AM   #43
diyAudio Member
 
Join Date: Jul 2011
Thanks Elvee. Time to go about DIYing the PCB. I'll post results in this thread soon.
  Reply With Quote
Old 27th May 2012, 08:44 AM   #44
abetir is offline abetir  Philippines
diyAudio Member
 
Join Date: Nov 2010
Location: Easternmost Region V
I guess this is the correct thread for posting messages with regards to build in progress...

After replacing parts and following terranigmas correction (terranigma has a keen eye on spotting details (eagle eyes!..) Here's my build so far, DC-offset measured at 01.8mv but the lowest was 00.6mv... but at times changing and the highest was about 02.00mv. At + rail collector voltage was at 21vdc and at - rail base & emitter voltage was at 21vdc. At phase-splitter I replaced the 2N5551 with BC547 but they seem to be fine none got shorted...hmm..strange though I decided to replace the 12v zeners for 0.5watts just to confirm if the 1 watter zeners was also creating problems. VAS trannie warms a bit after about 20mins but BD drivers are getting hot even with the heatsink around I think they won't survive. I used 2SC5200 for the output (they remain cold to touch) I think I'm sensing bias problems, can the 10k offset be increased? Could the 2SC5200 creates the problem?

Now I may have to ask a noob question did I measure the output voltages right? and how do I properly measure the idle current, sorry I am not so familiar with quasi's. Was it across R10 & R56?
Attached Images
File Type: jpg top.jpg (413.0 KB, 366 views)

Last edited by abetir; 27th May 2012 at 08:51 AM.
  Reply With Quote
Old 27th May 2012, 09:54 AM   #45
abetir is offline abetir  Philippines
diyAudio Member
 
Join Date: Nov 2010
Location: Easternmost Region V
Terranigma, the corrected cap 8n2 (822) is it correct? I think it should be 821pf.
Attached Images
File Type: jpg offset_test.jpg (463.9 KB, 340 views)
File Type: jpg front_output.jpg (410.5 KB, 322 views)
File Type: jpg BD_front.JPG (573.2 KB, 325 views)
File Type: jpg BD_back.JPG (552.4 KB, 288 views)
  Reply With Quote
Old 27th May 2012, 10:56 AM   #46
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
I've updated post #1 with the means to check the idle current (it is located in with the resistors).

Did you use a gray Philips BD139 (COB=6pF) for Q5 Q6? Surely those will work better than fake Hitachi devices and don't expect any sort of reasonable results or temperatures until you remove the fake devices. Why not start out with 2N3019's or 2N1893's for Q5, Q6 to absolutely assure that this section is working as expected?

Are you testing with output devices connected? I ask because you will need some outputs prior to power up, else the amp will overheat quickly. I got some BD911 and some MJE3055 for smoke tests. If no smoke then I can put on the MJL21194's later.

The MBR735's need shoulder washers and thermal pads if you want to mount them onto the heatsink--the PCB is arranged that way to help hold the heatsink stable. The authentic Philips BD140's have those soft copper leads and those need the added help to hold up the driver heatsink.

Well, I hope this helps.
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.
  Reply With Quote
Old 27th May 2012, 11:30 AM   #47
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by abeteer View Post
. . . 821pf.
When the capacitor reads 821 it is 820pF, but if it reads 822 it is 8200pF.
Ah, well, like this chart that was hung on the wall near the desk:
Click the image to open in full size.
(click image to enlarge)
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.
  Reply With Quote
Old 27th May 2012, 12:14 PM   #48
diyAudio Member
 
terranigma's Avatar
 
Join Date: Feb 2007
Quote:
Originally Posted by abeteer View Post
I guess this is the correct thread for posting messages with regards to build in progress...

After replacing parts and following terranigmas correction (terranigma has a keen eye on spotting details (eagle eyes!..) Here's my build so far, DC-offset measured at 01.8mv but the lowest was 00.6mv... but at times changing and the highest was about 02.00mv. At + rail collector voltage was at 21vdc and at - rail base & emitter voltage was at 21vdc. At phase-splitter I replaced the 2N5551 with BC547 but they seem to be fine none got shorted...hmm..strange though I decided to replace the 12v zeners for 0.5watts just to confirm if the 1 watter zeners was also creating problems. VAS trannie warms a bit after about 20mins but BD drivers are getting hot even with the heatsink around I think they won't survive. I used 2SC5200 for the output (they remain cold to touch) I think I'm sensing bias problems, can the 10k offset be increased? Could the 2SC5200 creates the problem?

Now I may have to ask a noob question did I measure the output voltages right? and how do I properly measure the idle current, sorry I am not so familiar with quasi's. Was it across R10 & R56?
Good to see measure healthy offset values. That heatsink looks very fit and nice! It means that you can connect a test speaker and begin to play some music. I see you are using wires for easy testing power transistors. I suggest you to keep those wires short as much as possible.

Are you sure that BD140's won't survive? That's right, they are getting hot but it wouldn't be a problem if temperature stood still for enough amount of running time. Those stain on metal plates at BD140's should be removed due to sufficient heat transfer.

As I mentioned earlier, I suggest you to use slower device for output. You can't be sure that 2sc5200 is causing a problem or not if you don't observe output with oscilloscope. For example, 3mhz BD249C's are very suitable transistors for circlophone. I tested Bourns brand of BD249C (they were made in Philippines) and their sonic behaviour was outstanding.

According to Elvee's latest experiments, low pass filter capacitor's value is 8.2 nF. See the C4's value of 3rd picture at related post.

Last edited by terranigma; 27th May 2012 at 12:36 PM.
  Reply With Quote
Old 27th May 2012, 12:32 PM   #49
diyAudio Member
 
danielwritesbac's Avatar
 
Join Date: Nov 2007
Quote:
Originally Posted by terranigma View Post
Those stain on metal plates at BD140's should be removed due to [in]sufficient heat transfer.
Thanks!
Q9, Q11: Yes, Philips BD140's that have been corroding since 1987 need some black sandpaper (like 600 grit, very fine grain) to "lap" the thermal interface surface and shine it up, thus removing most of the corrosion. Then they do need some thermal paste (and pads). Thermal paste, such as Arctic, will prevent future corrosion.

Q5, Q6: If TO126 size (Philips BD139, Toshiba 2SC3421) are used at Q5, Q6, they might be more comfortable with some little heatsinks, such that free aluminum circle from the bottom of the beer can or some TO126/TO220 economy size little heatsinks, or even some recycled metal will do. Huge heatsinks aren't required at Q5, Q6, but plastic devices need some means to get the heat out of them. The exception is 2SC5171 since it is a physically large TO220, doesn't need a heatsink at Q5, Q6.

Quote:
Originally Posted by terranigma View Post
As I mentioned earlier, I suggest you to use slower device for output. You can't be sure that 2sc5200 is causing a problem or not if you don't observe output with oscilloscope. For example, 3mhz BD249's are very suitable transistors for circlophone. I tested Bourns brand of BD249C (they were made in Philippines) and their sonic behavior was outstanding.
Concur. I believe that Elvee also ran some of the BD249C's on his own amplifier. These outputs are also suitable: 2N3055, MJ15015, MJ802, MJL21194, MJW21196, MJ21194, MJ21196, MJ15022, MJ15024, MJ15003. Surely you can find some?

Edit:
I'm trying to say: "Stable first, postpone trying unusual parts until later."
__________________
Tools, Models & Software for DIYClipNipper boostLM1875 TurboPowerful TDA7293 kitTDA7294 pt2pt ♦ My post has opinion.

Last edited by danielwritesbac; 27th May 2012 at 12:52 PM.
  Reply With Quote
Old 27th May 2012, 05:07 PM   #50
Elvee is offline Elvee  Belgium
diyAudio Member
 
Elvee's Avatar
 
Join Date: Sep 2006
Quote:
Originally Posted by abeteer View Post
DC-offset measured at 01.8mv but the lowest was 00.6mv... but at times changing and the highest was about 02.00mv.
That is perfectly normal for discrete devices: it is equivalent to less than 1°C difference between transistors, and random variations caused by draughts for example reach easily that level.
Quote:
but BD drivers are getting hot even with the heatsink around I think they won't survive. I used 2SC5200 for the output (they remain cold to touch) I think I'm sensing bias problems, can the 10k offset be increased? Could the 2SC5200 creates the problem?
The quiescent dissipation in the drivers is ~1W, and increase with signal, so nothing abnormal.
If you have doubts about the 2SC5200, try a slower device, TIP3055 or BD249.

About the low pass capacitor, I advise against actually using 8.2nF: it was meant as an illustration with a test signal, but for actual use, such a high value could cause excessive roll-off if the source impedance is much larger than 470 ohm.

Anyway, normal audio signals do not contain 10ns maximum amplitude edges.
__________________
. .Circlophone your life !!!! . .
♫♪ My little cheap Circlophone© ♫♪
  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
Building an AMP of a commecial piece but with top-notch parts Oystein Solid State 3 9th July 2009 10:22 AM
Beginner speaker building help Telemin Multi-Way 3 16th June 2009 12:23 AM
Beginner - Building a bass guitar cabinet richmoore1998 Multi-Way 3 27th December 2008 02:31 PM
Building a headphone amp from parts Smokehouse Bob Headphone Systems 13 13th August 2007 03:26 PM
speaker building (beginner) larksp Multi-Way 37 26th April 2007 03:41 PM


New To Site? Need Help?

All times are GMT. The time now is 09:37 PM.


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