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

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Old 05-03-2014, 11:30 AM
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Pacific Stereo Pacific Stereo is offline
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Rotel RX-1603 receiver restoration... what a beauty!

It's time for another one. This is the very first time I have laid eyes on one of these beauties, and it might be yours, too. This was Rotel's answer to the monster receiver category, and it is spectacular. So to whet your appetite, here's a teaser!


No, I promise she won't tip over and tumble down the mountain. Let's start with a look at before. Here she is on the bench, ready to be evaluated.


And here's a look at the top of the unit with the cover on.


Notice something interesting? Ooooo! Yes, the input jacks are in the middle of the unit, in a recess. The reason for this will become clearer as we go on. On the back there is nothing but output jacks and an IEC power inlet (modified from the stock configuration by someone, previously). Let's take the cover off.


Now you can see the gorgeous toroidal power transformer and some of the construction. Yes, a little crowded inside, but not difficult to work on. The first thing we'll do is the power supply.


Thankfully, there's nothing esoteric going on in this supply and it's pretty routine to service. We do the usual recap with 105-degree parts, and change the zeners. Pass transistors are just fine and we leave those alone. A little spiffier, now.


In the following photo, you'll notice the surge board to the left of the transformer. It got overhauled and serviced as well. Where are the photos? Sheesh, I don't know. It's really easy to forget to take photos of stuff when you're working.

Moving on... The next places to work on are the amplifier stages. Here's a look at one side.


Notice something? Remember when I said this receiver was straightforward to service? This receiver literally comes apart in the middle! That's right, the front panel section, tuner, and line stages detach from the power supply and power stages. I have never seen anything like this before. But it sure made flipping this 72-pound beast around on the bench a LOT easier. Fantastic.

So we inspect one of the amp stages first.


It gets new caps, a nice Wima film input cap, some new semiconductors (not all are changed) and new bias, offset and overload adjustment pots. Also, new gain-matched differential transistors (left center) get coupled together for better tracking with temperature.


Part of this section of the unit is the speaker output board. It looks like this:


Somehow, there's no "after" photo (sigh), but this board got one new relay (contacts on the other two just needed to be spiffed up), new caps and new drive transistors for each relay, since they run in saturation all the time and can lose beta and become weak. No beta means no clickey, even if all is well.

All right, so now, on to the front half. All of the line-level boards are on this side of the receiver. Here's the volume control/tone/filter board before.


This is an interesting design, they attenuate volume TWICE (see the four sections to the VC on the left?)

This one gets Wima, Wima, Wima on the label, label, label, some other film and 105-degree caps along with a local zener diode. Switches and controls were pretty bad. They were intensively cleaned and treated. There was also some bad solder (microscopically bad!) on the mode switch connections in the center that only manifested after (you guessed it) I had reinstalled the board. Take it apart, put it together. Take it apart, do something else, put it together again. Lather, rinse, repeat. Man, that's the story of my LIFE!


Like many units of this era, it has a mic input. Why anyone would want this on a receiver is beyond me. Can you say, "Feedback destroyed my speakers in less than 0.3 seconds!" (or is it, "Dingo ate my baby!")? I knew you could! This unit goes a step beyond just an input and adds a switchable mixing function. Pull the control out, and the mixer is switched in. Here's before:


And after:


Because this function will never be used, I change only the electrolytics and leave the tantalums in there. They're not in the signal path when the switch is not engaged.

After that, we do the input and MPX board (Input and MPX? What? Yes, Rotel splits the tuner section into an IF board and the rest of everything put on the input board. It's odd, but it works nicely). Once again, close-ups are missing, but you can see the board in this photo, it's the one closest to the flywheel.


Speaking of the flywheel, on almost all of these receivers, that mechanism has to be taken apart, old grease removed and new grease applied. This one was no different, and that was done. Tuning action is now deliciously smooth, whereas before it was noisy and scrunchy (is that a word?).

Now I do have photos of the AM and FM IF board. Here's before:


And after:


While I was working on the unit, I noticed something interesting. See this label?


Normally, these are riveted to units. But this one had screws. And removing those screws revealed...


A-HA! Surprise, surprise, surprise! While this unit is labeled for US-only power, this one is actually a GenEx model with variable input power. I don't know if this is true for all samples, but my guess is that Rotel decided it was cheaper to not make a bunch of units for different markets. Perhaps someone who owns a 1603 can verify if their unit is like this.

One of the things I always do is inspect the power switch and deal with it. In this case, because of the surge control, the power switch was just fine. I did, however, refurbish it and use the unused contacts to reset the clock. This one has many years left in it. So, no photos of burned-up contacts, this time.

Normally on these units one of the things I do is change the bulbs, since they're all old and near the end of their lives. But Rotel did something interesting. They used a BUNCH of bulbs and ran them at a relatively low voltage. That means they are still babies and do not need to be changed. And who needs blue-coated bulbs when you can just do this?


Illumination is very uniform. And I love the color of the tuning scale and meter backgrounds. After a 12-hour burn-in, she looks like this on the bench:


Sonics are first-rate. This receiver has an effortless quality to her, smooth and natural, and able to bark quite nicely when required to do so. Rated at 180 WPC at eight ohms, she makes every bit of this and then some. I really like the way she sounds. And the FM stage is just superb. She has one of the most sensitive front-ends I have ever run across. Even with my ST-1020A turned all the way down, she would still make a signal. And with some tweaking, I was able to get mono FM distortion down to about 0.05% and stereo distortion to about 0.09%. That's very uncommon.

She had quite a bit of corrosion on her, on the rack handles, on the plastic-chrome buttons for speakers and functions, on hardware, etc. And you have to be really careful, because it's easy to clean/polish too much and make something look like chrome that isn't supposed to. So I worked her very carefully to strike the balance between yuck and just wrong. The owner has never laid eyes on this unit, so he will not have a baseline to compare against, but that's OK.

And here are the results.




See the bigger binding posts? This unit had clobbered speaker connectors on the C output. I did not have exact replacements, but I did have a very nice set of posts that fit nearly perfectly. So I put those in the A position, and moved the old wimpy connectors to the C position. The only disadvantage to this is that the new posts stick out beyond the bumpers on the back, so the unit now cannot be set on its back.


I know someone who is going to be very, very happy with his new girl. Truth is, I wish I could keep this one, I'd really like to.


All photos, copyright 2014 Pacific Stereo. All rights reserved, no use without written permission. I better not see these on eBay!
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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; 06-02-2014 at 07:02 PM. Reason: Forgot a section
  #2  
Old 05-03-2014, 02:09 PM
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retrokeeper retrokeeper is offline
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WoW!!! What a Monster!! I've always liked Rotel,never could afford it back then,but read some reviews and had a sense they were a "sleeper" ready to roar when needed,and it sound like you found that out.She is truly a beauty,I always liked how they did the "slanted down" dial design thingie on their receivers...easy to spot in the thrifts,that you found a truly unique receiver!! Rob
  #3  
Old 05-03-2014, 02:19 PM
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I had a 603 and could only dream of 1603
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Old 05-03-2014, 02:21 PM
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impressive looking. looks to me like that amp section was designed to be sold as a standalone amp for a separates system. the main chassis has cutouts where a normal sized PSU can go.
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Old 05-03-2014, 02:52 PM
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Just beautiful!
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Old 05-08-2014, 12:56 PM
Trekmaster Trekmaster is offline
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Outstanding as always PS!
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Old 05-08-2014, 04:25 PM
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Wow, that's pretty full on.

Roughly, how many hours involved in this restoration?
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Old 05-08-2014, 04:33 PM
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Far, far more than the customer paid for, that's for sure!
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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
  #9  
Old 05-10-2014, 02:36 PM
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Pacific, you do good work man. I have never seen one of these receivers. The $64,000 question is:

Rotel RX1603 or Pioneer SX1980?
The Rotel has the Kenwood KR9600 beat on the inside, and the big Sansui's beat on the outside.
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Old 05-11-2014, 08:04 AM
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Pacific Stereo Pacific Stereo is offline
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I think I like the Rotel better than I like the 1980. I definitely like the way it sounds, a lot. Also, the FM is better. The quartz-lock business on the 1980 is an unnecessary complication with little benefit, and the output devices for the Rotel can be had without issue and without either having to spend a fortune for original devices or dealing with subs and mods.
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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
  #11  
Old 05-11-2014, 03:01 PM
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Pardon my French, but what a f*cking fantastic receiver. In terms of build quality, looks, serviceability...man, why couldn't they all be built like this?

Looks like it could take a beating - but now that it's in such nice shape, I certainly hope it never does. Good work, Pacific.
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Old 05-13-2014, 01:53 PM
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That's one impressive receiver. I like the change in the illumination you did removing the blue filter. I was wondering with these units do you swap out the power supply caps or leave the originals assuming no known issues? Curious because on an older SA-900 I recapped I replaced the Power supply cap. Not sure if I'd attempt it myself on some of the larger caps on equipment I've seen.
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Old 05-13-2014, 03:49 PM
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Pacific Stereo Pacific Stereo is offline
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The illumination is not changed, the blue filter remains. But between them running the bulbs at a low voltage and the cream color of the bezel, it's quite orange.

A lot of folks change the main caps as a matter of course, but in my experience, unless I see or measure a reason to do so (or the customer has requested it), I do not change them.
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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
  #14  
Old 05-14-2014, 09:49 AM
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Gorgeous piece, and a tank! What did that thing weigh?
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Old 05-14-2014, 10:37 AM
nickblaze nickblaze is offline
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Pacific, thanks for posting all the good images. The new owner will be thrilled. My uncle used to jam out to 101 WRIF Detroit rock radio in his garage. The vintage Rotel RX 1203. Same orange illumination. Those rack handles made it so easy for him to transport.
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Old 05-14-2014, 10:53 AM
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Mmmm It is not Pioneer, But i could definitely live with that particular unit

Nice work (as usual).

Thank you for showing us.

PC
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Old 05-15-2014, 06:42 AM
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Rotel still makes fine equiopment but that receiver is a gem. Nice job on the restoration.
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Old 05-31-2014, 08:12 PM
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WOW!

Just come across this.....

I own one that has also been restored and everything I read on the net I have to say is true about this particular receiver, it is just awesome!.......except when you come to move it!!!

ATB Tase
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Old 06-02-2014, 07:07 PM
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Reports from the customer indicate a very happy camper. He loves his new 1603 and will be sending me some photos of the unit split up with the kit. When I have them, you'll see them!
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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
  #20  
Old 06-18-2014, 05:17 PM
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That is quite a beast, and I have seen the split configuration. It's very clever.

I had a Rotel Quad Receiver in my ignorant youth. Wish I kept it. It was a very modest one, but it was reliable and sounded good. Also liked the green illumination back then.
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