My_Ref Fremen Edition RC - Build thread - Page 24 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

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 27th August 2012, 08:19 PM   #231
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
I'm using a 3A slow blow and haven't had any problems.
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."
  Reply With Quote
Old 27th August 2012, 11:28 PM   #232
diyAudio Member
 
lehmanhill's Avatar
 
Join Date: Jan 2008
Location: Chelsea, Michigan
I'm using the same as Bob. I have Randy Slone's old book on building power amps. He suggests using both a fuse on the mains side of the transformer, plus one for each rail on the transformer side of the smoothing caps. I've done that in the past, but I'm not sure there isn't a negative effect on sound due to the impedance of the fuse and extra wiring. This time, I just used the mains fuse.

Any other thoughts?

Jac
  Reply With Quote
Old 28th August 2012, 12:23 AM   #233
Reality first!
diyAudio Member
 
ClaveFremen's Avatar
 
Join Date: May 2005
Location: Milan, Italy
Quote:
Originally Posted by lehmanhill View Post
Any other thoughts?
A fuse fuse on hot/phase is needed for safety.

Value used for gainclones are good also for the My_Ref (FE or not).

They're different for 110V (3A slow blow) and 230V (2A slow blow) for two modules in a single enclosure.
__________________
Dario
ClaveFremen "Bailando Salsa en el Sietch"
  Reply With Quote
Old 28th August 2012, 02:22 PM   #234
romvise is offline romvise  Italy
diyAudio Member
 
Join Date: Jan 2007
Location: Turin
I'm waiting for a pair of lm318 for solve the problem of first channel, but unfortunately today after one hour of listening, the second channel has stared to playing some bad intermittent distortion.
When I power on the unit, the relay switch on and off after a pair of second.
I've tried to measure DC offset but the value is variable.

Have you any useful tips?

Roberto
  Reply With Quote
Old 28th August 2012, 02:30 PM   #235
Reality first!
diyAudio Member
 
ClaveFremen's Avatar
 
Join Date: May 2005
Location: Milan, Italy
LM3886 temperature?
__________________
Dario
ClaveFremen "Bailando Salsa en el Sietch"
  Reply With Quote
Old 28th August 2012, 04:08 PM   #236
romvise is offline romvise  Italy
diyAudio Member
 
Join Date: Jan 2007
Location: Turin
No, the chassis was near cold and also the chip, but I've found T101 smoking on the pit of the middle leg, I think was dust! after clean DC offset look stable on 5.5mV.

What do you think about the transistor, could it be alive?

Last edited by romvise; 28th August 2012 at 04:29 PM.
  Reply With Quote
Old 29th August 2012, 09:23 AM   #237
romvise is offline romvise  Italy
diyAudio Member
 
Join Date: Jan 2007
Location: Turin
Yesterday I've pluged to mains the unit and today all was in order so I connect it to speaker, and all is ok!

Today I've also received the LM318M for the other channel, but I've found a surprise...
The chip don't have the pin orientation sign!!
So I've 50% of possibility to install it in the right way... and maybe I've also to consider Murphy's law...

Roberto
Attached Images
File Type: jpg t_SO8Photo.jpg (17.8 KB, 276 views)
  Reply With Quote
Old 29th August 2012, 09:33 AM   #238
Reality first!
diyAudio Member
 
ClaveFremen's Avatar
 
Join Date: May 2005
Location: Milan, Italy
Quote:
Originally Posted by romvise View Post
The chip don't have the pin orientation sign!!
So I've 50% of possibility to install it in the right way... and maybe I've also to consider Murphy's law...
It's not so... you have the dent:

Click the image to open in full size.

BTW it's strange... are you sure that distrelec shipped natsemi part?

Can you see the natsemi logo on chip?
Attached Images
File Type: jpg LM318M.jpg (187.5 KB, 538 views)
__________________
Dario
ClaveFremen "Bailando Salsa en el Sietch"
  Reply With Quote
Old 29th August 2012, 11:24 AM   #239
romvise is offline romvise  Italy
diyAudio Member
 
Join Date: Jan 2007
Location: Turin
Thanks Dario, I've found the dent with a lens.
I've bought two National LM318 and, I've just noticed, one has the round sign and the other the dent, both are MWAB LM318M with National logo.

I've substituted the LM318, but DC offset is always 60mV and sometime on start the relay don't wake up. So, the story is unvaried and maybe the problem is elsewhere.
  Reply With Quote
Old 31st August 2012, 09:08 PM   #240
diyAudio Member
 
Join Date: Sep 2002
Location: California
Default C12 position

Well I am finally soldering up the boards. A quick question though. C12 is not a polarized cap correct? That being said is there a preferred installation? I have the Amtrans 73778. In looking at the schematic, polarized cap installations are clearly marked with a + as is the circuit board. However, I noted o's on some of the other cap diagrams on the board. What is this? Clearly a newbie here. Thanks.

Paul
  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
My_Ref Fremen Edition - Beta build/Fine tuning ClaveFremen Chip Amps 1523 1st December 2013 11:16 AM
My_Ref Fremen Edition - need help on PCB evaluation ClaveFremen Chip Amps 450 23rd October 2013 03:38 PM
Last My_Ref Fremen Edition RC boards for sale ClaveFremen Swap Meet 3 4th December 2012 01:04 PM
Hx-Home Edition and Hx Mini Edition will be released December, 24th destroyer X Solid State 54 3rd September 2012 03:44 PM
Canton ERGO RC-1 (frequency room compensation) for RC-L - Schematic wanted tiefbassuebertr Multi-Way 2 20th September 2010 11:20 AM


New To Site? Need Help?

All times are GMT. The time now is 05:03 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