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

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Crown IC150A mods
Crown IC150A mods
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
Thread Tools Search this Thread
Old 6th February 2004, 12:37 AM   #1
tony9409 is offline tony9409  United States
diyAudio Member
Join Date: Feb 2004
Location: NC
Default Crown IC150A mods

I'm upgrading my quad405 with newer op amps and got to looking at my Crown IC150A noticing it uses an LM301A in the phono section and a LF356 on the main board. Are there mods for the Crown to improve it ? Could I just swap those op amps for OPA134 chips or do I need to do other mods.

  Reply With Quote
Old 6th February 2004, 01:26 AM   #2
dshoaf is offline dshoaf
diyAudio Member
Join Date: Apr 2001
Location: Santa Cruz, CA
Default Old tantalum's too...

This pre amp came out when tantalum caps were considered all the rage. Crown ended up replacing quite a few of them when they became leaky - specifically I remember the output side of the phono preamp board seemed to prone to this symptom.

Something to think about. I've been through one wife and well onto another since I've had one of those in my system (1977).

Can't speak to any other mods, though.


  Reply With Quote
Old 6th February 2004, 10:44 PM   #3
tony9409 is offline tony9409  United States
diyAudio Member
Join Date: Feb 2004
Location: NC
Thanks, When the caps are leaky what does it do ? does it stop the signal or make the sound scratchy.

  Reply With Quote
Old 19th May 2004, 05:56 AM   #4
BlackBLOOD is offline BlackBLOOD  Bulgaria
diyAudio Member
Join Date: Apr 2004
Location: Varna,Bulgaria
Hi All.
I`m thinking of bridging a Quad405 amp by inverting the second amp.

Is there someone who already made something like that?
Can someone give mi scemathik or something?

Sorry for posting hire.I`m not allowed to make new theard...
  Reply With Quote
Old 27th May 2004, 12:12 AM   #5
dmfraser is offline dmfraser  United States
diyAudio Member
Join Date: Dec 2003
Location: Orange County, CA

If you don't have it already, the schematic for the IC150A is posted ae www.schematicsforfree.mattsoft.net in the Files/Audio/Products/Pre-amps section.
Dan Fraser
  Reply With Quote
Old 25th December 2004, 08:38 PM   #6
Blue is offline Blue  Cayman Islands
diyAudio Member
Join Date: Nov 2004
Location: Grand Cayman
All you dablers thinking of upgrading a 405 should check out...


but Blackblood? you could apply the input mod to one side only as it is non inverting, the standard amp being inverting.

could make an interesting variation.

Regards Blue

More like blown since the hurrican..........
  Reply With Quote
Old 25th December 2004, 08:43 PM   #7
SY is offline SY  United States
On Hiatus
SY's Avatar
Join Date: Oct 2002
Location: Chicagoland
Crown IC150A mods
The only really worthwhile mod of the IC150 is to gut it and build a new preamp in the case- you could retain the raw supply, jacks, and the switching. An IC-based preamp using modern ICs, caps, regulators, and the like could easily fit in there. A 797-based phono amp and a unity-gain buffer line stage would be ideal. If you're ambitious, you could incorporate a tone-tilt control.
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 25th December 2004, 09:22 PM   #8
Brian Beck is offline Brian Beck  United States
diyAudio Member
Brian Beck's Avatar
Join Date: Dec 2004
Location: South Florida, USA
Boy, I couldn't agree more with the "gut and start over" posting. My first "high end" preamp was an IC150 many, many moons ago. It wasn't until I heard a dead-stock Dynaco PAS 3X that I realized what damage the Crown was doing to music. I never looked back and have used tubes ever since for my main rigs. But back to your question: If I found an IC 150 (A or not) for cheap today, I'd buy it for the pretty chassis, knobs, etc. You might be able to salvage the power supply transformer, but if I recall correctly this part was pretty dinky. Then you can employ some nice opamps, of which there are many to choose from today, along with better passive components and power supply. it really would be a redesign and probably require a new PC card design. It would be a lot of work, but maybe worthwhile. Or, you could consider tubes....
  Reply With Quote
Old 8th April 2013, 06:04 AM   #9
boxcar is offline boxcar  United States
diyAudio Member
Join Date: Feb 2011
Location: buffalo ny usa
Crown IC-150 and Crown IC-150A are two different birds, being an Authorized Crown repairman of-the-day. Tony asks about the IC-150A. Brian responds w/a IC-150 history. Again...two different birds. (No denegration intended to any party).

Best regards,
  Reply With Quote
Old 9th April 2013, 03:29 AM   #10
ticknpop is offline ticknpop  Canada
diyAudio Member
Join Date: May 2005
Location: toronto
Crown IC150A mods
Same answer for both 150 and 150 A - gut it and start over -
  Reply With Quote


Crown IC150A modsHide 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
Crown sa 20 Newpaltzwonder Solid State 5 25th May 2011 10:12 AM
crown xls 602 galush Parts 1 4th June 2009 01:40 PM
crown xls 602 amp galush Solid State 0 6th April 2009 04:41 PM
Crown Com-Tech 210 Power Amplifier Crown Com-Tech 210 tyler477 Solid State 1 31st October 2008 04:24 AM
QSC/Crown and the like Madmike2 Solid State 4 3rd May 2005 10:38 AM

New To Site? Need Help?

All times are GMT. The time now is 10:21 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio