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

Solid State Talk all about solid state amplification.

Amp for sub...Recommendations
Amp for sub...Recommendations
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 23rd September 2019, 10:23 AM   #1
ubergeeknz is offline ubergeeknz  New Zealand
diyAudio Member
 
Join Date: Aug 2018
Default Amp for sub...Recommendations

So I've acquired an old JBL Digital 12 sub which has a built in amp. The amp is dead. The driver is good. The amp uses a module S53AMI which I'm pretty sure is blown (it's been removed from the main board) - The rest of the board seems okay.

So what I have is a +-42vdc supply, all the necessary filters, and a 4 ohm driver. There's also +5v and +-15v on the board. The transformer seems to have a good heft to it. I would guess 150 or 200VA at least. What's a good amp to build, or module, to fit here? Or is it possible, and worthwhile, to repair these modules? Recommendations please!

1569230404291.jpg1569230419564.jpg1569230432223.jpg
  Reply With Quote
Old 23rd September 2019, 10:28 AM   #2
Fenalaar is offline Fenalaar  Norway
diyAudio Member
 
Join Date: Apr 2011
A Hypex UCD180 module would be usable here, as long as you have +-42V. It runs on voltages from 30 to 49 volts.

DIYclassd.com

You'll need a spot of free space of 65x25mm on the rear plate to attach the heatsink, though.

Johan-Kr

Last edited by Fenalaar; 23rd September 2019 at 10:31 AM.
  Reply With Quote
Old 23rd September 2019, 10:37 AM   #3
ubergeeknz is offline ubergeeknz  New Zealand
diyAudio Member
 
Join Date: Aug 2018
The hypex looks ideal! I would love an option at around half that price, but I'm probably dreaming Amp for sub...Recommendations we shall see

BTW. It's a ported box. So a bit of airflow/cooling shouldn't be an issue.
  Reply With Quote
Old 23rd September 2019, 11:12 AM   #4
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
When R9 goes open circuit the amplifier output section stops working as there is no 6volt supply to the FM modulator.
__________________
Support for Fender, Marshall and all Valve Equipment; Audio Innovations, Audiorama FU29, Quad and Leak. www.jonsnell.co.uk
  Reply With Quote
Old 23rd September 2019, 11:19 AM   #5
ubergeeknz is offline ubergeeknz  New Zealand
diyAudio Member
 
Join Date: Aug 2018
Quote:
Originally Posted by JonSnell Electronic View Post
When R9 goes open circuit the amplifier output section stops working as there is no 6volt supply to the FM modulator.
I'm guessing wrong thread?
  Reply With Quote
Old 23rd September 2019, 11:26 AM   #6
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
The amp uses a module S53AMI that module uses a feed from the power to set up the FM oscillator.
This is a JBL Digi 12. See service manual.
__________________
Support for Fender, Marshall and all Valve Equipment; Audio Innovations, Audiorama FU29, Quad and Leak. www.jonsnell.co.uk
  Reply With Quote
Old 23rd September 2019, 11:39 AM   #7
ubergeeknz is offline ubergeeknz  New Zealand
diyAudio Member
 
Join Date: Aug 2018
I see! I could always check if that's the issue and not the module... I can see a cap blown across the output, so it got abused at some stage. Worth a try. Thanks.
  Reply With Quote
Old 23rd September 2019, 11:50 AM   #8
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
diyAudio Member
 
JonSnell Electronic's Avatar
 
Join Date: Dec 2012
Location: The Jurassic Coast, England. GB
My pleasure, let's hope it isn't terminal.
__________________
Support for Fender, Marshall and all Valve Equipment; Audio Innovations, Audiorama FU29, Quad and Leak. www.jonsnell.co.uk
  Reply With Quote
Old 24th September 2019, 09:28 AM   #9
ubergeeknz is offline ubergeeknz  New Zealand
diyAudio Member
 
Join Date: Aug 2018
Quote:
Originally Posted by JonSnell Electronic View Post
My pleasure, let's hope it isn't terminal.
Suffice to say, genius advice.

R9 was very high (and no wonder the heat which it puts out, I replaced it with 2 x 1k 2W in series and they still stunk for a while) and R46 low (5 ohm instead of 47) so I replaced both, put the module back in and low and behold... Life!

Unfortunately there is something oscillating in the input stage, putting a high frequency square wave to the input. There's also a square wave on the output, so the amp seems to work... Already checked all resistors around the opamps, and they seem okay. I've run out of time for tonight ... Any ideas on what might be worth a check, would be most welcome.

Attachment 783223
Attached Files
File Type: pdf jbl_digital_12_bu120e_pa_2000_sch.pdf (35.8 KB, 16 views)
  Reply With Quote
Old 24th September 2019, 09:40 AM   #10
tmuikku is offline tmuikku  Finland
diyAudio Member
 
Join Date: Sep 2004
Location: Savo, Finland
Send a message via ICQ to tmuikku
My old prosumer mixing console oscillated badly on the EQ section every once in a while. Some of the poti were losing contact turning the filter circuit into an oscillator. Not sure if this could be the case here. Anyway, extruding poti will take a hit sooner or later
  Reply With Quote

Reply


Amp for sub...RecommendationsHide 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
845 SET amp recommendations kinku Tubes / Valves 79 1st February 2019 10:04 AM
CD recommendations royd55 Tubelab 2 28th July 2014 01:41 PM
HT Sub Recommendations Lonely Raven Subwoofers 4 25th June 2013 03:18 AM
Kit Recommendations? bassnkeys Solid State 0 17th July 2011 06:11 AM


New To Site? Need Help?

All times are GMT. The time now is 10:40 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