Audiokarma.org
Audiokarma Featured Sponsor

Go Back   AudioKarma.org Home Audio Stereo Discussion Forums > DIY


We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 05-09-2013, 03:59 PM
futureman's Avatar
futureman futureman is offline
AK Member
 
Join Date: Jan 2008
Location: NE Ohio
Posts: 765
Op amp rolling in a Kenwood Basic C2

I have a Kenwood C2 on its way to me, and I was thinking of a full recap. One can buy a recap kit for this unit online for about $16 (all Nichicon caps).

While I'm at it, I was considering replacing the original op-amps (NJM4560). I've read that the power supplied in this unit is greater than the +/-18V of these op amps, so replacing them with something like NE5532s (+/-22V) would be desirable. Does this seem right/advisable, or is there some other consideration I may be missing here?
__________________

Main system: Thorens 160 w/ Nagaoka MP 200 - Onkyo TX 6500 MK II (as tuner) - Kenwood L-07C II - Magnavox 9302 w/Edcor OPTs- Denon DCD 1520 - Electro-Voice Interface C-IIs w/EQ

Reply With Quote
  #2  
Old 05-09-2013, 05:41 PM
sKiZo's Avatar
sKiZo sKiZo is offline
Audio Puree-ist
 
Join Date: Apr 2009
Location: 42.96░N 85.67░W (Elev. 620 ft)
Posts: 6,039
If you've got viable alternatives listed as compatible, hey, go for it. You may ... or may not ... be pleasantly surprised. Only suggestion I'd make is to socket the chips so you have an easy fallback position.

I recently rebuilt a Carver H9AV holographic generator and had some fun with new tech op amps to replace the old school items available back in the day. Burr Brown hadn't even been born back when those were made - I would have used more of those, but those BrownDogs ain't cheap. Settled for real TI P3s instead of the Malaysian knockoffs elsewhere. Added some bypass caps in strategic locations, and a bit of this and that. Magic moment firing it up the first time, and many many grins since.

BEFORE >>



AFTER >>



I mean ... like ... what's the worst that could happen?

ZzzzZZT! Oh, the humanity ... film at 11 ...
Reply With Quote
  #3  
Old 05-09-2013, 05:48 PM
futureman's Avatar
futureman futureman is offline
AK Member
 
Join Date: Jan 2008
Location: NE Ohio
Posts: 765
Hey, that looks really nice. Apart from basic recapping I have not done very much. So I am not sure what it means to socket the op amps. Could you give me a brief explanation?
__________________

Main system: Thorens 160 w/ Nagaoka MP 200 - Onkyo TX 6500 MK II (as tuner) - Kenwood L-07C II - Magnavox 9302 w/Edcor OPTs- Denon DCD 1520 - Electro-Voice Interface C-IIs w/EQ

Reply With Quote
  #4  
Old 05-09-2013, 06:02 PM
static14's Avatar
static14 static14 is offline
AK Member
 
Join Date: Sep 2009
Location: Franklin, MA
Posts: 842
these are sockets for op amps



instead of soldering in a new op amp you solder in a socket for it that way you can insert and remove op amps with having to break out the soldering iron they make for a really simple way to quickly change them out, or "roll" as its called!
Reply With Quote
  #5  
Old 05-09-2013, 06:05 PM
futureman's Avatar
futureman futureman is offline
AK Member
 
Join Date: Jan 2008
Location: NE Ohio
Posts: 765
Ah! Makes perfect sense. Thanks.
__________________

Main system: Thorens 160 w/ Nagaoka MP 200 - Onkyo TX 6500 MK II (as tuner) - Kenwood L-07C II - Magnavox 9302 w/Edcor OPTs- Denon DCD 1520 - Electro-Voice Interface C-IIs w/EQ

Reply With Quote
Audiokarma
  #6  
Old 05-09-2013, 06:49 PM
sKiZo's Avatar
sKiZo sKiZo is offline
Audio Puree-ist
 
Join Date: Apr 2009
Location: 42.96░N 85.67░W (Elev. 620 ft)
Posts: 6,039
... and might I suggest, go with the gold pin sockets. They don't cost a lot more, and they're a lot easier to get into them lil holes in the board. Flex-locs (the ones with the skinny bent pins that grip the holes) are the work of the devil in retrofit projects.

Speaking of which, you'll also want to head on over to Rat Shack and get one of their desoldering tools ...



Best $15 you'll ever spend for this type of job. Let it heat up, squeeze the bulb, drop it on the pin, and let the bulb go when the solder pools. Clean as a whistle.

Little tip ... you'll have a few clean looking pins that will stick to the board. Doesn't take a lot of solder to make them fight you. That RS tool comes to the rescue once again. Just drop the tip over the pin and wiggle it a bit - you'll feel it pop loose. From there, just carefully pry the old chip off the board.

You can probably tell by now why sockets are a good thing. Besides making it easier to roll op amps, they also keep the soldering heat away from the chips themselves, so less chance of forping those ...
Reply With Quote
  #7  
Old 05-10-2013, 01:49 PM
nerdorama's Avatar
nerdorama nerdorama is online now
AK member
 
Join Date: Nov 2004
Location: Seattle area
Posts: 1,416
If you don't already have it, you can download the C2 service manual from the AK database here:

http://akdatabase.org/AKview/thumbnails.php?album=2

On the schematic, it shows the opamps being powered by at 18.6V by a discreet regulator using zeners as the reference. Probably could replace the zeners with a 15-16 volt version and reduce the output to +/-15V is newer opamps won't stand the 18V supplies.

Keep us posted.
Thanks,
John
__________________
De gustibus non est disputandum
VPI Scout, Denon DL-304,Wright WPA-200, DIY tube pre and amp, ADS 910, Lynn Olson ME2, Apogee Centaur Minor, Stax SR-X
Reply With Quote
  #8  
Old 05-10-2013, 02:06 PM
futureman's Avatar
futureman futureman is offline
AK Member
 
Join Date: Jan 2008
Location: NE Ohio
Posts: 765
Thanks. I may simply replace the caps and hear how things sound before tackling op amps.
__________________

Main system: Thorens 160 w/ Nagaoka MP 200 - Onkyo TX 6500 MK II (as tuner) - Kenwood L-07C II - Magnavox 9302 w/Edcor OPTs- Denon DCD 1520 - Electro-Voice Interface C-IIs w/EQ

Reply With Quote
  #9  
Old 05-18-2014, 05:35 PM
Smallies Smallies is offline
AK Member
 
Join Date: Mar 2013
Location: ME
Posts: 339
My solder sucker is mangled. Went to the Shack and they've incorporated it into a $35 package kit so I just bought a $10 iron and boy am I in misery right now. and somebody stole or threw away my op amps.
__________________
Polk monitor 5.2 new 6503's Sonicaps, Acurus Ls-11, JBL 6260, Shotguns, beer, Dragonfly DAC, YouTube madness, Spotify
Reply With Quote
  #10  
Old 05-20-2014, 07:09 AM
jhoyt's Avatar
jhoyt jhoyt is offline
Cognitively Dissonant
 
Join Date: Dec 2006
Location: Wichita, KS
Posts: 5,842
It's been a few years since I've been inside a C2, but I seem to remember that the op amps were the SIP-9 variety, where the new ones you'll be using are DIP-8. So you'll need an adapter, recommended is the Brown Dog series.
__________________
We don't need another manufactured rebel
We don't want your twisted doctrines of despair
If your music's saying nothing
Save it for the dentist chair

- Steve Taylor

My audio gear
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

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


All times are GMT -5. The time now is 12:12 AM.



Friends of Audiokarma
We appreciate your help in keeping this site going.
Stereo Repair World
Herbies Audio Lab
Vintage Home Audio
Amps and Sound
Pro DJ Headphones - click here
Organ Donor Parts
Wargos Electronics
Parts Connexion
Sonneteer
Take Five Audio
Sound Stage Direct
Audio Salon
AudioClassics
Audience AV
AV Solutions
Simply Speakers
Tone Arm Audio
BD Enterprise
Musical Paradise
Howard Products
Classic Sound Repair
FM DX Antenna
McIntosh Cabinets
Siliconray
BOI Audio Works
Vinyl Magic Record Cleaner
Amplifiedparts
Grant Fidelity
RSL Speakers
Yesterday's Audio
Urban Antigue Radio
DeWick Repairs
Many Moons Audio
Vintage Electronics Repair
The Tube Store
Politicalchat.org
Audio Doctor
Antique Radio Classifieds
MCM Electronics
Videokarma.org
   
   
Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
ęCopyright 2002-2014 AudioKarma.org, All rights reserved.