Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Doug Self Preamp from Linear Audio #5
Doug Self Preamp from Linear Audio #5
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 7th June 2019, 08:58 PM   #1331
Hicoco is offline Hicoco  France
diyAudio Member
 
Join Date: Feb 2018
Location: Provence
Doug Self Preamp from Linear Audio #5
Quote:
Originally Posted by Carl_Huff View Post
The bubbles at the top are the rail voltage adjustment pots and the large bubble at the bottom is where you select input AC voltage. Once assembled you will have a premium grade series regulated adjustable power supply
Quote:
Originally Posted by Carl_Huff View Post
Ha, ha ... Yes! I should proofread what write.

Here is an example: TO-220 Silicone Insulator 10 pcs.
Yes i have silicone between, may be not enough grease..i will put little more.
  Reply With Quote
Old 7th June 2019, 09:43 PM   #1332
diyralf is offline diyralf
diyAudio Member
 
diyralf's Avatar
 
Join Date: Aug 2016
On youtube there was a test. Silicon has a catastrophic thermal conductivity. Mica is first choice! Moreover a good piece of mica costs 10 cent.
  Reply With Quote
Old 8th June 2019, 02:45 PM   #1333
Mark Tillotson is offline Mark Tillotson
diyAudio Member
 
Join Date: May 2018
Location: Cambridge UK
Thermal pads like silpad are a composite of silicone and a good heat conductor as filler. The silicone rubber can conform to the surfaces of device and substrate, the filler particles increase the thermal conductivity. Mica cannot conform to the surface as well, but has a reasonable bulk thermal conductivity. Diamond film would be really good for this, if it was affordable, as it has extreme thermal conductivity (better than metals).

diyralf we are not talking about silicon.
  Reply With Quote
Old 12th June 2019, 06:43 AM   #1334
Hicoco is offline Hicoco  France
diyAudio Member
 
Join Date: Feb 2018
Location: Provence
Doug Self Preamp from Linear Audio #5
Quote:
Originally Posted by Carl_Huff View Post
Hmm, did you put a dab of thermal grease under the BD139/BD140 devices and their heatsinks?

It sounds to me that you are not getting a good thermal couple between those transistors and their respective heatsinks.

Please note that some BD139/BD140s have an exposed metal mounting surface that must be electrically isolated from it's respective heatsink using a mica or silicon insulator.
I changed the SK 104-2 ( External Length - Metric 25.4mm) with SK104-6 ( External Length - Metric 63.5mm) heatsinks and the temperature drops of 10℃ on each side. But now i am too hight for my 1U chassis....i am curious to now if they are any other option than to change the heatsinks.. Carl, did you check for any oscillation on your boards ?? Thanks




  Reply With Quote
Old 12th June 2019, 05:38 PM   #1335
Carl_Huff is offline Carl_Huff  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Bakersfield, CA
Quote:
Originally Posted by Hicoco View Post
Carl, did you check for any oscillation on your boards ?? Thanks
I have been using this power supply in projects for at least the last six plus years. I cannot remember oscillations ever being a problem. How confident are you that the NE5534s are good?
__________________
Best Regards,
Carl Huff
  Reply With Quote
Old 12th June 2019, 05:44 PM   #1336
Hicoco is offline Hicoco  France
diyAudio Member
 
Join Date: Feb 2018
Location: Provence
Doug Self Preamp from Linear Audio #5
Quote:
Originally Posted by Carl_Huff View Post
I have been using this power supply in projects for at least the last six plus years. I cannot remember oscillations ever being a problem. How confident are you that the NE5534s are good?
I guess they are.... i bought them 2 week ago from Digikey...what is the best way to be sure they are good ??
  Reply With Quote
Old 12th June 2019, 05:53 PM   #1337
Carl_Huff is offline Carl_Huff  United States
diyAudio Member
 
Join Date: Dec 2004
Location: Bakersfield, CA
Quote:
Originally Posted by Hicoco View Post
I guess they are.... i bought them 2 week ago from Digikey...what is the best way to be sure they are good ??
Coming from Digikey I expect they are. What makes you think that you have oscillation? Can you see it on an oscilloscope?
__________________
Best Regards,
Carl Huff
  Reply With Quote
Old 13th June 2019, 08:54 AM   #1338
Hicoco is offline Hicoco  France
diyAudio Member
 
Join Date: Feb 2018
Location: Provence
Doug Self Preamp from Linear Audio #5
Carl, may be this is the answer....
The NE5534AN (PDIP-8) is obsolete. They sent me the NE5534AP (PDIP-8).
Looking at the datasheet of both, the Operating Supply Voltage range are different:
NE5534AN : From +/- 3 V to +/- 20 V
NE5534AP : From +/- 5 V to +/- 15 V
what is your thought?
i didn't check with an oscilloscope.
  Reply With Quote
Old 13th June 2019, 09:57 AM   #1339
diyralf is offline diyralf
diyAudio Member
 
diyralf's Avatar
 
Join Date: Aug 2016
The NE limit is +-22V. +-15..20V is standard.
  Reply With Quote
Old 13th June 2019, 01:55 PM   #1340
bobberner is offline bobberner  United States
diyAudio Member
 
Join Date: Dec 2018
Location: Allentown PA USA
Doug Self Preamp from Linear Audio #5
What is the approximate total cost to build one of these preamps? I saw the BOM and looks like quite a few parts.
  Reply With Quote

Reply


Doug Self Preamp from Linear Audio #5Hide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Doug Self's New Preamp Construction and Pictures redjr Analogue Source 190 30th May 2018 07:34 AM
What does preamp PSU oscillation look like for linear regulators? shredhead Power Supplies 59 28th March 2015 10:16 PM
Doug Self Elektor phono preamp: SA1085 substitute? tcpip Analogue Source 9 26th September 2013 01:11 PM
OLDSCHOOL CAR AUDIO-ORION/US AMPS/LINEAR POWER/PLANET AUDIO TUBES NIB mclsound Swap Meet 7 26th July 2013 11:10 AM
4th Ed. of Audio Power Amplifier Design Handbook (Doug Self) nickds1 Solid State 4 9th November 2006 01:02 PM


New To Site? Need Help?

All times are GMT. The time now is 10:10 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki