Recap a Yamaha C-2X preamp

shanyau

New Member
I have compared the mc phono out (using Audio Technica OC9 with a Linn lp12) of the C-2X with my friend's Plinius preamp (very old model and bought very cheap from ebay), within a minutes, we can tell the Plinius is better in all aspect, just more musical.
A little bit disappointed of this highly regarded preamp.

I'm thinking of recapping the C-2X to see if it can improve the sound, can anybody tell me which capacitors have to be repplaced?
What are their values? I'm thinking of Blackgate.

Also, recently I've got a Yamaha MX-1 to drive my NS-1000M, it's just so good and a great perfomer and value for money.

Shan
 
From what I can gather, the C-2X was made in the mid 1980s. It probably has Op-amps in the audio path which might be candidates for upgrades. If you are seriously considering doing the recap, you will need to get a service manual to get a better idea of how the circuitry is mapped out. This can help you decide where to use Black Gate caps to best effect. You can get a reproduction of the service manual here:

http://www.vintageaudiomanuals.com/-XYZ-.htm

can anybody tell me which capacitors have to be replaced

In most cases I would take the approach of replacing all of them if it's practical, with the exception of a few hard to find values especially if they are not in critical locations such as the digital display circuitry. In the end this is one big experiment, so there is no guarantee that you will be satisfied with the upgrades of the C-2X as far as the MC phono section goes.

The first step would be to clean all the switches, pots and contact points with deoxit. This includes the selector switches (ie the MC/MM switch). It is quite possible that your preamp is sounding duller than it should because of an accumulation of dirt. Once it has been cleaned up, it might sound better than your initial impressions gave it credit.
 
Do you have the turntable plugged into Phono 1? Phono 2 is for Moving Magnet cartridges only. Do you have the Phono Selector on MC Amp? The recommended load impedance for the AT-OC9ML/II is 20 ohms. I couldn't find the recommended load impedance for the AT-OC9ML. The standard load impedance on my C-2a on Phono 1 on MC AMP is 50 Ohms. Looks like you have an impedance mismatch. Have you tried the Phono Selector on the 100 Ohm selection? The 100 Ohm position is for a low impedance high output MC cartridge.
 
Can't comment on the comparison between the Plinius and the C-2x, but everyone else who has posted here has been quite pleased with the phono-stage on not just the C-2x, but most of the Yamaha preamps (CX-1, CX-1000, C-85, etc.), so suspect something amiss with yours or your setup. Had my C-2x cleaned, recapped the phono-stage with Black Gates and voltages set by EW a few months ago. To my ears, it is an excellent sounding phono stage and I have no complaints. And, think some of the op-amps mentioned above are Yamaha proprietary, so you may have a problem if you try to replace them. I have the service manual and schematic in .pdf. If you want a copy, send me a PM with your e-mail address.
 
B-2,

When you say recapped with black gates you mean the power supply, right? I think the C-2x already use film caps throughout the audio stages, and electrolytics in the power supply. Very good point about matching the cartridge load - this is the biggest reason for preamps to sound drastically different.

I do not think there are op-amps in this preamp. Any ICs will be Yamaha specific ICs, and these are usually just dual or quad ultra-low noise FETS.
 
Yamaha B-2 said:
Had my C-2x cleaned, recapped the phono-stage with Black Gates and voltages set by EW a few months ago.
As stated. the phono-stage, only. Doesn't matter the type of cap, once it is 20+ years old, IMHO, it is suspect. Especially the small signal caps.

The ICs in the phono-stage are NJM2041S. Here is a link to the info. http://www.sierraic.com/pnresults.asp?navpart=NJM2041S

A 'low-noise', off-the-shelf, op-amp. Not Yamaha proprietary.
 
shanyau said:
I have compared the mc phono out (using Audio Technica OC9 with a Linn lp12) of the C-2X with my friend's Plinius preamp (very old model and bought very cheap from ebay), within a minutes, we can tell the Plinius is better in all aspect, just more musical.
A little bit disappointed of this highly regarded preamp.

I'm thinking of recapping the C-2X to see if it can improve the sound, can anybody tell me which capacitors have to be repplaced?
What are their values? I'm thinking of Blackgate.

Also, recently I've got a Yamaha MX-1 to drive my NS-1000M, it's just so good and a great perfomer and value for money.

Shan
I'm not sure which Plinius preamp you listened to but I'm not surprised that you liked it. Plinius make very good equipment.
Checking the 2003 Orion Blue book, the only older Plinius Pre that they list is the M12 from 1991, $3995 list, $1302 used.
If your friend got one of these cheaper than a C-2x then he was very lucky.
It doesn't mean that the C-2x is not good, just that its in a completely different category.

David
 
packrat said:
Well that's certainly different from my C-2 - I think - now I'll have to check again! Thanks for the correction!
Believe the C-2's claim-to-fame (my words) is that it is a completely discrete components piece of gear. Has no ICs in the signal path.
 
Thanks for the response to my questions.
Don't get it wrong. The C-2X is very good, just not as good as the Plinius (model is Plinius 2B, 1980 product, my friend get it at ~A$250).
It could be an impedance matching issue.
Anyway, I would like to recap it.
My friend is ordering some cap from oversea tomorrow, so if anyone can tell me what are the values of the caps that could be replaced, please let me know. I don't have the time to open it up and check.
I have more time in Christmas, I am planning to compare the phono stage of the C-2X with my tube-based pre-pre amp from AudioExperience Concerto plus with the Solo setup.
Shan
 
Hi All,

my first post here. Looks like a good forum.

This morning i bought myself a Yamaha C-2x for £57 (about $110). I bought it for use with my Sony TA-N9000ES' using SACD. I couldn't find a TA-P9000ES and when i looked at this Yammy it seemed like the build was pretty good.

How good is it as a pre amp? Is it anything like close in performance to the TA-P9000ES or TA-E88/86 or something similar. Was it worth what i paid for it?

I'll be looking to recap it seeing as its a 1983 unit. Has anyone done any more significant mods to it?

Ben
 
Welcome to AK!!

My opinion is that it is superior to any of the 'ES' model Sony preamps (I've owned the TA-E90ES and understand it is at least the equal of the other 'ES' models). And, upon listening to my TA-E86B, I found the sound slightly less reticent from the C-2x. The problem with the vintage Yamaha preamps is that they have any number of propiretary parts in them. And are quite a hassle to get into to work on. The phono-stage on mine has been recapped with Black Gates (nothing else was recapped) and it is the best sounding phono-stage inside of a preamp that I've heard in this system. And, sounds better than the Jolida JD-9A stand-alone tube phono preamp I recently tried. Give all the controls and switches a good cleaning, set the voltages and recap what you can. Is a superb vintage preamp. And, they have have been selling for $300+ in the U.S., so you've done well by our standards. Keep us posted on any recapping you may do and the results. There are a couple of Yamaha Preamp threads in the Vintage forum. You can do a search on C-2x and they will probably come up. Good luck and enjoy your stay at AK.
 
Heck, yes, you got a steal of a deal!
I had the C-2x that Yamaha B-2 has now, and it had an excellent phono section to start with.
I now have a mid-90s CX-2 that is great, and an older C-80 that remains an excellent performer.
 
The C-2x is not a pre that hangs on the street corners; I think it is safe to call them rear and one of the best Yamaha ever did. The going rate on the continental Europe is 300-450€ if fully working, you're score is almost criminal :)

packrat: The only reason I can think of that made Yamaha use the C-2x name is some home market name tradition, curse I don't think they have much in common except the name. The matching amp is the B-2x witch has absolutely nothing in common with the B-2.

Take a look inside the C-2x: http://audiokarma.org/forums/showthread.php?t=61618&page=2
here the C-2; C-2a; CX-1 and CX-1000 scroll down a bit: http://audiokarma.org/forums/showthread.php?t=54348
 
The build of the C-2x looks very impressive indeed. Quite pleased with my purchase. It should arrive this coming week.

Its a little scratched on the top but i'll sort that out easily.

I'm hoping to start voluntary work with a high end hifi modifying company that is based locally. I'd love to take this along and see what could be done for some mods.

Its a 1983 pre amp so all electolytics could do with replacing really.
 
Just don't let them fumble too much around; it is a reference class pre. But as mentioned by B-2, BG's in the phone section is a good place to start then maybe replace old caps.

I know alex say early 80's, but all the data I can find sayes yhe C-2x is from 1985.
 
C-2x arrived

Hi All,

i got my Yamaha C-2x today. Its alot bigger and heavier than i thought it would be. :D

When i got it out of all the bubblewrap i noticed the last owner must have been a keen smoker. It stank! So i've spent the day stripping it right down and have had all the panels, knobs and everything non electrical into warm soapy water and given a really good clean. Its got the best casing i've ever seen on an amp. Nice thick aluminium.

Next i gave the boards a really good clean and decided to make a list of capacitors to replace the old ones. I got through around 10 or so when i realised the words "black gate" written on the side of them. Someone has already black gated the thing!

There are a few that weren't black gates but i'll be replacing all the old ones with the best i can afford.

I had a listen and it sounded abit harsh so my ears. Maybe it needs warming up or something? Or maybe its the 8 original large red caps that need replacing?

Anyway, i'm knocked out by it. Even though it needs abit of work it totally flattened my Sony TA-E9000ES processor for music. No contest.
 
Hi there,

i want to fit new caps to where the originals are still in place at least. Can't do any harm, can it?

I'll get plenty of pics of the innards with the covers off each section.

I had a look at the phono stage (which has also been black gated already) and its an amazing looking thing. I don't use vinyl anymore but i'm tempted to go back to it after seeing that phono stage.

I think there's something wrong with the pre amp though. I can't get past -40dB without it sounding harsh and frankly too loud, overdriven. Maybe its not suited to my power amp.

Does anyone have any specs on this or better an owners/service manual?
 
Yes, welcome in the club. It will be difficult to find an upgrade after the C-2x.

Pics are a must! Especially the replaced caps! And about replacing the red caps, think twice. With BG's you talk more than $1000, I would look elsewhere for upgrades and fixing.

One of the things you shall notice is the stereo perspective and feeling of the room, it is just really good. Do a search and read some of the other threads about the C-2x.

----EDIT----

What input do you use for the CDP? (do use AUX or DAT).
 
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