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New member and new Accuphase C-200 owner...

cube-tube

Super Member
Hello all, I am new here and just purchased a mint looking C-200 and have been lurking around here via Google searches to find out what I can about this preamp before it arrives on Monday. Through a little reading, I see that Echowars is the man to see about these great old preamps.

The C-200 I am getting is coming with the original user's manual as well as the service manual. I'm assuming and hoping that the service manual and preamp match up properly. As far as the history on this particular preamp is concerned, I have no clue. For all I know, it could already have been totally recapped and everything (boy, wouldn't that be nice) but I highly doubt it. I only say this because it comes with the service manual. Was it normal practice for Accuphase to include these with their gear?

From doing a little research, I see that there are a few different versions of this preamp under the same "C-200" name. The one I'm getting has the normal pair of stereo outputs plus a single mono output. Others I have seen have dual stereo outputs. Also, I have seen some that have the innards rearranged some. I have seen some with the input selector using a long aluminum rod connected to the actual switch which is mounted near the rear of the unit, and others that have the switch mounted right to the front panel. Board and component layout on these are also slightly different which they would need to be for the selector switch to be mounted near the rear of the unit. I'm hoping mine uses the latter with the input selector towards the rear as that would typically promote less noise due to shorter internal wiring from the RCA's to the switch and so on. Obviously, I have yet to see the interior of my C-200.

The Accuphase C-200 will be replacing my loved yet very limited (input wise only) KingRex Pre-Amp. I figure as long as the C-200 sounds at least as good as the KingRex, I'll be happy. Yes, it really is that good sounding of a little preamp. If the C-200 ends up sounding even better, that I'll be that much happier!

The reason for replacing the KingRex is simply due to the fact that it only has two inputs. The problem with that is that I have three turntables that I want to use and no way of playing them at the moment, well, unless I want to unplug and swap them around with my Music Hall mmf-phono pack, but this is a pain in the neck to do.

Since I got back into vinyl after quite a few years without, I jumped in head first this time around and bought not just one TT, but two, a Denon DP-55K and Luxman PD277. I then acquired an old idler wheel ELAC Miracord 40A from my parents.

Before the KingRex was pulled out of the closet, I was using an old Technics SU-8099 which had slews of inputs plus two phono inputs, MM and MC. This worked out fine with the Miracord being connected to the mmf-phono pack and into one of the other inputs on the Technics. All I had to do to listen to another TT was select the proper input. To make a long story short, the Technics died a couple months back, so I haven't used my TT's since. That sucks!

I resurrected an old dead Baldwin 6L6 PP amp that my brother had sitting at his place for the last couple of years. The original 3-section electrolytic caps dried up in it and he just packed it away. So I put all new lytics in it, bought some NOS coin-base Russian 5881's (6N3C-E), a NOS Phillips 5U4G and a mint but used Admiral 5U4G, and a NOS pair of RCA 5751's. I also installed a new heavy duty power toggle switch to replace the cheesy, half melted, tiny toggle switch. It's an excellent sounding amp, easily surpassing just about every amp I've owned or used in the pass! It powers my NHT 2.9's very nicely and can get them quite loud when I twist the noise knob! LOL Living in an apartment, I don't do that as often as I'd like however... :sigh:

At any rate, I have been reading through the various C-200 threads on here to get the scoop on my preamp so I know what needs to be looked at and taken care of when I get it. I'm sure that if I have any questions that I can't seem to find on my own, I'll get some good quality help here. :thmbsp:
 
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Well hello Echowars! I'm sure I will too. Like I said, if it sounds as good as my KingRex, I'll be happy, but if it sounds even better, I'll be extremely happy. :thmbsp:

BTW, I have a quick question for you or anyone really... How long of a run did the original C-200 have, and how can you tell the model year of a particular C-200?
 
My Orion Blue Book says '76 to '85. I doubt its accuracy for that. More like '76 to '79 or '80.

Kenwood SN's are meaningless as far as date of manufacture, and I suspect that the early Accuphase gear are the same in that regard.
 
Really, '76? I thought the C-200 was one of the first pieces to be sold in the states back in '73. Not saying mine is that old, but thought that the age would range from '73 on up to whatever. Just curious more than anything else.

Speaking of which, my C-200 should be showing up sometime soon today when FedEx comes around! Woo-Hoo, I'm excited! :banana:
 
I got in the C-200 and opened it up. It's a true virgin, and super clean inside. It looks like brand new!

I have a question, what is the first board on the left? This is the only board that I see a potential problem of two resistors (R1 & R4) that look like they got extremely hot at some point and quite possibly are fried.

Here's the pic of the board. Since it takes so long to upload my images, I'll post the rest in a bit, but for now I want to know about this particular board. I think it's part of the PS circuit.

Many many thanks in advance!!!

p292185413-5.jpg
 
Resistor rot. Not uncommon on early Accuphase stuff. The board is the power supply board. The failed resistors are R1 and R4, 9.1K, 1/2W.
 
Resistor rot. Not uncommon on early Accuphase stuff. The board is the power supply board. The failed resistors are R1 and R4, 9.1K, 1/2W.

Would it be a good idea to replace these two resistors with 1W resistors, or keep with the .5W ones?
 
Okay, here's the promised pics. The first batch are just random shots of the unit. The second batch which will be in the next post is of all the boards in order from left to right.

p389138453-4.jpg


p792443357-4.jpg


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p732442477-4.jpg


p683619743-4.jpg


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Now for the boards...

PS Circuit...
p831299338-4.jpg


Headphone Amp...
p784929913-4.jpg


Filter Output Amp (1)...
p854251963-4.jpg


p967333373-4.jpg


Filter Output Amp (2)...
p722467927-4.jpg


p613182830-4.jpg


Tone Control Circuit...
p674689813-4.jpg


Equalizer Amp (1)...
p1015333352-4.jpg


Equalizer Amp (2)...
p577292967-4.jpg
 
1W resistors are a good idea. Mount them a few mm off the board to help dissipation.

Thanks EW!

I was reading in another thread that you posted in, that you liked using the "original style" resistors in gear such as Accuphase to keep the appearance looking stock, but I'm not too concerned with that. I want it to be reliable and safe for a very long time, even when it's time for me to pass it on to someone else... If that ever happens.

So 1W resistors it is then! :thmbsp:
 
After looking at the PS board a little more, I think it might be a goo idea to also replace both R11 & R12 as the board shows slight signs of heat around those two resistors. In the service manual it calls for 560 ohm 2W, but on the actual board as you can see they are 330 ohm, though I have no clue how many watts they are.

Any thoughts?
 
Scat says 560 1W, and the BOM says 560 2W. Those resistors on the board look like 1W jobs (older 2W resistors were pretty large...a modern 2W resistor is about the size of those older 1W resistors).

I don't see anything wrong with R11 & R12 on the PS board. Soldering & de-soldering on these boards should be kept to a minimum. I'd leave them be.
 
I understand about doing as little soldering as possible, and that's exactly what I want to do, but if you're material says 560 ohms at 1W/2W and mine has 330 ohm 1W, wouldn't it be a wise idea to go ahead and just change them out for the 560 ohm 2W?

As I said already, they have begun to discolor the board which leads me to believe they're getting a bit too hot. Since this is the PS board, it's the hart and soul of the preamp and should be as safe and stable as possible. At least that's how I see it. :dunno:
 
There are many engineering changes that aren't reflected in the basic service manual. Unless you were in the repair business and an authorized Accuphase service provider, you'll probably never see a complete collection of the factory changes made to the C-200 in the years it was around. The point is that those resistors in your preamp are original, and if you're hell-bent on replacing them, then you really, really need to match what is on the board, as opposed to what you see on the schematic.

The only 1, 2, and 3W power resistors I like for the Accuphase are the Panasonic metal film jobs at Digikey. Page #1959 of the current catalog.
http://dkc1.digikey.com/US/EN/PDF/US2010/Complete.html
 
There are many engineering changes that aren't reflected in the basic service manual. Unless you were in the repair business and an authorized Accuphase service provider, you'll probably never see a complete collection of the factory changes made to the C-200 in the years it was around. The point is that those resistors in your preamp are original, and if you're hell-bent on replacing them, then you really, really need to match what is on the board, as opposed to what you see on the schematic.

The only 1, 2, and 3W power resistors I like for the Accuphase are the Panasonic metal film jobs at Digikey. Page #1959 of the current catalog.
http://dkc1.digikey.com/US/EN/PDF/US2010/Complete.html

"Hell-bent", huh? Sounds like you're upset with me for wanting to replace those 330 ohm resistors. I truly appreciate your concern and all, but if I'm going to be in there replacing resistors and caps, I might as well replace those two while I'm at it.

I have absolutely no problems sticking with the values already there. Though I do want to go to a higher wattage resistor, 2, 3 or 5 watt. If the body of the resistor ends up being too long, I can always mount them at an angle like I did when I overhauled an old cheap Chinese tube headphone amp a while back.

Angle them like this...
p1032010577-4.jpg
 
Any suggestion as to where I can buy a couple of the (565-2805-ND) 22000uF 6.3v caps?

Seems as though everyone is either out of them or you have to buy a large quantity, and I only need two.
 
Digikey, or Mouser, or Newark...

Digikey is my favorite because I like the interface.

http://search.digikey.com/scripts/DkSearch/dksus.dll

A quick search yields about 20 or so possible contenders of good repute.

Keep in mind that the voltage can go upwards. My search was limited to 25v or less. There are many more at higher voltage and those would be okay too, but they would be larger and more expensive.

Other factors for consideration would be Lowest ESR, Cap size, longest life rated at highest temperatures. There may be others I am not aware of.

I found this little blurb on Audiogon (message board comment only, take with grain of salt): "Message me if you want I have a great tech that was trained on these older Accuphase units by the factory. A word of caution as some of the caps and resistors were specially matched for the circuts and should not be replaced."
 
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I might swallow the part about the caps (and the reference here is certainly meant to refer to the original polyester film caps), but not the part about the resistors. These old Accuphase units have lots of problems with resistors falling apart, and replacement of bad ones is necessary. The modern Yaego 1/2W carbon film make a pretty close match to the originals.

As for the replacement for the original 10,000µf 6.3V electrolytics, the Digikey part referred to in Post #18 is NLA. Newark sells a 27,000µf 6.3V Nippon Chemi-Con, #66K7008, that should properly fit the clamp.
 
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