Tapeheads Tape, Audio and Music Forums
High quality analog audio tape for professionals and enthusiasts alike.

Go Back   Tapeheads Tape, Audio and Music Forums > Service, Restorations, Helpful How-Tos, Parts and Manuals, Ads and More! > Pacific's Restorations

Pacific's Restorations You can see all of Pacific's vintage gear restorations here.

Donate to Tapeheads!
Reply
 
Thread Tools Display Modes
  #1  
Old 08-03-2012, 10:32 AM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
Kenwood 600 Supreme restoration (and nudies!)

I've had a 600 in the lab for the last week or so. The owner wanted a full restoration, so it's been thoroughly gone through. EDIT: more units below, keep reading!

These are absolutely beautiful integrateds, both cosmetically and electronically. Full dual-mono everything, class-A prestages, a nice (if oddly complicated) power supply, FET differentials and direct-coupled power stage with no caps in the signal or feedback paths. Very sweet and smooth-sounding, with excellent detail and speed.

There are a lot of things to do to these, and they are damn annoying to work on. Since the power supply is the one thing that is easy to work on, I started with that. Why the rest of the amp isn't made this way, I simply don't understand. But it isn't.



This supply got a full recap, replacement of regulators, error drivers and zeners, "carbon glue" cleanup and tweaking of gains to bring voltages to where they belong.



I always seem to forget to take "before" photos, and I did again this time, too. Suffice to say that the amp was dirty inside, with a lot of "sticky dust" that doesn't just blow out. The main filter caps on these always tend to be bad, but this one's were still all right. However, since the unit was apart and this was the opportunity, the customer and I agreed that it made sense to go ahead and change out the filters, since it's difficult.

And look at that BEAUTIFUL precision attenuator! Oh, the stuff of dreams.



I ended up using some snap-in parts because I don't really like what's available in the screw-terminal department. These are better parts with a ripple-current rating of 11 amps each. They're slightly smaller in diameter than the parts they replace, so I glue some foam to the new parts to make them fit in the clamps correctly. You can just see it between the clamps and the parts. Oh, and see the output relay on the board in the center left? Guess what you have to do to change it? Yup. Remove those capacitors. Oh. You want to remove the capacitors? Remove the transformers.



All the other boards were recapped and serviced as well. The power stage boards were serviced, drivers replaced (those funky-can 2SA810s and their counterparts are time bombs), new sealed Bourns bias and offset pots were installed, and a few other various and sundry items were addressed.

Then it was time for BeautyMaker. This customer wanted the outer case redone, so along with the usual, she got some new paint, too. I've developed a method that duplicates the factory "splatter paint" effect quite nicely, and that was done here. So a little paint and polish, and voila!







After a 12-hour burn-in, she is ready to go back. Hate to do it, though, I'd just like to keep her!



NOTE: The volume knob is quite gouged up on the front. It's not easy to see because of the lighting, but it's there. I'd like to find a replacement for this customer. So if y'all wouldn't mind keeping your eyes peeled, I'd appreciate it.

Photos are copyright 2012 by Pacific Stereo. Absolutely NO unauthorized use or copying is permitted, and specifically, NO EBAY USE is permitted.
__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net

Last edited by Pacific Stereo; 09-21-2016 at 08:37 AM. Reason: added info
  #2  
Old 08-03-2012, 12:16 PM
goodrat's Avatar
goodrat goodrat is offline
Serious Tapehead
 
Join Date: Mar 2012
Posts: 556
Very Nice! Excellent job!

So how does it sound?
  #3  
Old 08-03-2012, 12:29 PM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
Quote:
Originally Posted by goodrat View Post
So how does it sound?
Absolutely delightful. Would keep it if I could.
__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net
  #4  
Old 08-03-2012, 02:41 PM
ke4mcl's Avatar
ke4mcl ke4mcl is offline
Miami Space Transit Planetarium 11/1966-8/2015
 
Join Date: Apr 2011
Location: miami, fl
Posts: 10,925
thats soooo not fair!!!

this guy's got mountains as a backdrop! not fair at all i tell you!
__________________
Home taping isn't killing music, it's dying of natural causes!
  #5  
Old 08-03-2012, 03:41 PM
Nakdoc's Avatar
Nakdoc Nakdoc is offline
Highly Biased
 
Join Date: Nov 2008
Location: Nashville, TN
Posts: 6,523
Good job! Did this one have double sided boards? When I encounter the early feedthru types I often have to add hardwire jumpers.
  #6  
Old 08-03-2012, 09:22 PM
VintageSteve's Avatar
VintageSteve VintageSteve is offline
Wish I was sailing....
 
Join Date: Jul 2009
Location: La Conner, WA
Posts: 1,330
As always, a superb looking restore! (Is that leaky capacitor gunk on the power board?)
__________________
Land-locked sailor, tape tinkerer
  #7  
Old 08-04-2012, 08:50 AM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
No double-sided boards in this one. The stuff on the power boards is the carbonized glue, though this one did have several leaking small capacitors in various places.
__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net
  #8  
Old 08-04-2012, 02:41 PM
DaveInVA's Avatar
DaveInVA DaveInVA is online now
audiophool deluxe
 
Join Date: Oct 2008
Location: Damnville, VA
Posts: 8,528
Very nice! I like the flagship Kenwood stuff. I have a 7002 kicking around here somewhere along with its matching tuner.


Dave
  #9  
Old 08-04-2012, 03:09 PM
Socal Sam's Avatar
Socal Sam Socal Sam is offline
Serious AudioHead
 
Join Date: Sep 2008
Posts: 3,692
PS, nice work as usual on all your stuff. Very impressed with the wide range of gear you do. Keep it up!
  #10  
Old 08-09-2012, 02:49 PM
NAD613's Avatar
NAD613 NAD613 is offline
Serious Tapehead
 
Join Date: May 2008
Location: Bismarck, ND
Posts: 2,276
Nice work! There sure were some nice looking integrated amps back in the 1960s-70s.
  #11  
Old 07-23-2014, 04:44 PM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
Well, just putting another one of these in burn-in. This one had mondo leaky main filter capacitors, as ugly as they come. It also had a problem I have seen only once before, and that's self-destruction of the detent mechanism for the precision attenuator. This causes the VC to lock up at various points in its rotation, very scary.

Alps put the detent mechanism in the MIDDLE of the attenuator instead of at the end, so service is well-nigh impossible. This control is so rare that one does NOT want to disassemble it under any circumstances.

It's now fixed, but it's a nerve-wracking feeling, because one can't just go out and get another one of these. The detent function is gone, but that's a small price to pay.

I'll have to see if I have any new photos of this one worth putting up. She sure sounds nice, though!

EDIT: Here are the caps.





One thing I just don't like about these is how hot they run the pass transistors in the power supply. Hard to see, but if you look you'll see added heat sinks on the four devices at the top. This is different than the earlier one in the thread.

__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net

Last edited by Pacific Stereo; 07-23-2014 at 05:09 PM.
  #12  
Old 07-23-2014, 06:48 PM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
And the last track before she goes to the load resistors is...

Peter Murphy - Indigo Eyes.
__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net
  #13  
Old 07-24-2014, 01:07 PM
Trekmaster Trekmaster is offline
TapeHeads.Net Member
 
Join Date: Apr 2014
Location: Washington State
Posts: 18
Very cool been awhile since I've seen any new restore pics. I notice you don't have any restore pics of a 950 hint hint
  #14  
Old 07-24-2014, 08:29 PM
HKken's Avatar
HKken HKken is offline
Serious Tapehead
 
Join Date: Jan 2014
Location: Columbus, OH USA
Posts: 221
Beautiful! The Supreme series was awesome!
__________________
HK CD491, Pioneer CT-F900, Sony Walkman MZ-R70, Sony Discman D-25, Rega P2, Tascam DR100 MkII, Kenwood KA-907 integrated amp, Kenwood KT-815 tuner; Denon AVR-3803 receiver, Denon DVD-2910, NHT SB3 spkrs, NHT SB2 spkrs, Pinnacle Baby Boomer
  #15  
Old 07-24-2014, 08:31 PM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
Quote:
Originally Posted by Trekmaster View Post
Very cool been awhile since I've seen any new restore pics. I notice you don't have any restore pics of a 950 hint hint
<sigh> The world it turns, from sun to sun, and Pacific's work is never done...
__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net
  #16  
Old 11-20-2015, 03:03 PM
Pacific Stereo's Avatar
Pacific Stereo Pacific Stereo is offline
Sendust for brains
 
Join Date: Feb 2010
Location: Somewhere in paradise!
Posts: 11,705
I had one of these come in for some additional work. This is the second Kenwood I have run across with switches and controls so dirty that my standard treatment just isn't enough. The trouble is that it is impossible to know this until trouble crops up again. After a year and a half, this owner wanted them gone through again. This time, I have modified the procedure and expect a good outcome.

One of the things I do not like about the 600 is how hot they run the power supply pass transistors. Even with the additional heat sinks, they are too hot to touch for longer than abut three seconds. That's just too hot in my book, even though I know what the specifications say. I took some additional measurements and made some calculations, and the devices are indeed safe, but that doesn't mean I have to like it. So what do we do when we don't like something? We change it!

Since we have some convenient metal right next to the supply, it makes a lot of sense to move the devices there.



They're connectorized, so that the board can just be popped out, just like before.



The paint under the devices was removed. And now they run cool as cucumbers. I like that. She's back in burn-in, and expect to have good news to report to her owner tomorrow, as the switches and controls are once again working very nicely.

Love the way this amplifier sounds. It's got something... something about it.
__________________
pacificstereo.net "Make your own kind of music!"



I RESTORE VINTAGE AUDIO AND VIDEO GEAR. Master technician for Concept, Quadraflex, Calibre, Pioneer and Sony. Endorsed by Richard Schram for Concept product restoration. Factory technician for both Yamaha and JVC. Sonics consultant for Denon. Pacific Stereo store manager, service manager, Central Service lead tech, liquidator at our demise. Pacific Stereo curator. Infinity IRS dealer. Music buyer for one of the first CD retailers in the USA. Authorized servicer for virtually every brand on the planet at one time or another. Music addict. Mastering & recording engineer, weaned on a Neve (no other console sounds like a Neve!). Industry-respected ears. Head Tapehead.

Need vintage audio & video repair and restoration, or unobtanium semiconductors and parts? Ask me! And do visit the website: pacificstereo.net
  #17  
Old 11-20-2015, 07:44 PM
HKken's Avatar
HKken HKken is offline
Serious Tapehead
 
Join Date: Jan 2014
Location: Columbus, OH USA
Posts: 221
Nice work, PS!
__________________
HK CD491, Pioneer CT-F900, Sony Walkman MZ-R70, Sony Discman D-25, Rega P2, Tascam DR100 MkII, Kenwood KA-907 integrated amp, Kenwood KT-815 tuner; Denon AVR-3803 receiver, Denon DVD-2910, NHT SB3 spkrs, NHT SB2 spkrs, Pinnacle Baby Boomer
  #18  
Old 11-20-2015, 11:13 PM
S10LAKE's Avatar
S10LAKE S10LAKE is offline
Serious Audio Nut/TapeHeads Member & Supporter
 
Join Date: Jul 2015
Location: Sun City/Menifee, CA.
Posts: 314
Great work PS!

I can't wait for you to go through my Pioneer SX-1980

Steve
__________________
RTR- TC-880-2, GX-400D-SS, 747, 747dbx CASS Dragon, 1000ZXL, TC K7II, TC K8B, TA-2066 TABLES - PX-2, PF1000 ELCASET - EL-5x2 and EL-7, MAG LOAD RCA 1YB-11 COND- Pro 7000 REC. SX-1980, QRX9001, QSD 1, HDVD PRE AMPS - CA-7x2 8-TRK - CR-80D-SS, GXR-82D, CR-81D, MDS -MDS JA555ES DCC - DD-92, DCC900 DAT - DTS-2000ES, DTC-700 VHS - VCR-953 LD - CLD-99, LD-870 CD - DCD-1015, SACD - SCD 777ES SPKRS - B&W 800, SP5500 PHONES - HD-600, HD-800, Bose QC3, QH-44 REC CLNR Nitty Gritty Mini Pro-2
Reply


Would you like to see your company or site here?  CONTACT US
For more Tapeheads affiliates and links, see the Links and Resources page.


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

Similar Threads
Thread Thread Starter Forum Replies Last Post
Concept 12.0D restore (and nudies!) Pacific Stereo Pacific's Restorations 16 10-16-2017 09:22 PM
BGW Pro 250D Nudies Eminence1963 Receivers, Amps, and Preamps - Solid-State 3 06-22-2013 03:56 AM
McIntosh MC75 Nudies! Socal Sam Tube Gear - Preamps, Power and More! 2 11-02-2009 11:27 AM
Kenwood Supreme 700M/700C BroonsBane Receivers, Amps, and Preamps - Solid-State 27 05-20-2009 02:24 PM


All times are GMT -7. The time now is 04:08 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright 2016, Tapeheads.Net. All rights reserved, no use of any element incorporated into this site without express written permission.