C-2X RCA upgrade

stoutblock

"If it sounds good, it is good." Duke Ellington
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I really like my C-4 and C-85 preamps and always wanted a C-2X. Thanks to fellow AK'er Justrideit I was able to pick one up. I decided to do an RCA upgrade similar to the one I recently did to my C-85. As nice as these preamps are, the POS RCA terminals are the weak link and often cause connectivity issues along with an occasional dislodged ground sleave. Such was the case with Mark's.

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I decided to use external threaded terminals on this modification (I used internal on the C-85). This will allow easier dis-assembly of the back panel if that were ever to be required in the future. I have to warn you though, once you get this all together, you will not want to tear it apart!

From Parts Connexion I purchased "Connex" jacks "Tiffany" style, inside chassis mount dsigned for a mounting hole of 12mm (perfect dia for the holes in the Yamaha back plate) .

I decided to use 21 AWG VH Audio's UniCrystal OCC (Ohno Continuous Cast) Copper wire with "AirLok" insulation. It is really tight in the C-2X and this wire is great to work with. It has superb dielectric performance for such a thin insulation. I took careful attention to not mar the solid copper wire surface.

On the C-85 I found out you need to ground the terminals just like Yamaha did in order to avoid any hum feedback. The back plate in particular needs to ground to the PCB at the same location as the stock mechanical screw connection.

The RCA spacing on the Yamaha is tight so you will need to very slightly trim the insulation grommets on the terminals in order to fit it all together. This takes a few trial fit ups to get it right. I'm also adding a FURUTECH Gold lug IEC connector (easy on the dual voltage version of the C-2X)

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In order to keep things tidy I joined the grounding lugs prior to assembly. The phono connections each had their own ground to the PCB so that's the way I did it. I made a little solder jig to get the spacing right.

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I did a test fit to determine the wire length and then removed the back panel to complete all the wiring to the new terminals.

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Connecting the wire to the PCB is strait forward but not for the impatient among us.

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Yes it is tight. Just remember you are having fun and just think, no more POS RCA terminals!

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It looks just fine. If all the empty stock screw holes bother you, just remember these preamps need better ventilation anyway! You can see the one (white) ground wire I will attach to a chassis screw on the rear panel.

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I never listened to the stock C-2X setup (due to damaged RCAs) but will rotate it into my system later today and let you know my conclusions.
 
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Looks good Martin..:yes: Much better than the OEM crimp style phono jacks.
 
I spent a couple of hours listening to it today. This is a fine pre-amplifier by any measure. It has that classic Yamaha sound which is to say it really does not have a sound. Dead quiet backgound. It is one of those pre-amplifiers that makes you feel like you are in the music rather than the music is around you.

It probably does not immerse you in the sound stage as much as my First Sound line stage but it is darn close. Considering the price of the First Sound that is impressive!

Compared to my C-85 I have to say it is very similar sounding when both are set flat. The C-2X seems to have a little more forward upper mid range. Listening to the new RAM CD Paul's voice definitely comes forward.

The C-85 with its loudness contour adjustment and parametric tone controls can be dialed into my room with better precision. Given more time tweaking the C-2X I may change my mind. When they are both set flat the C-2X may have an overall fuller sound.

I listened to some Jim Hall on vinyl. With a Dynavector 10x5 on my Music Hall 7 and the C-2X set at 100ohms, it was quite impressive. More time is needed spinning for sure.

The C-2X sounds great, and is built very well. The controls have a nice feel to them. The C-85 in comparison has the newer Yamaha feel (cheaper) but for the price the C-85 is a sleeper.

Music Hall Maverick > Music Hall DAC25.3 > Yamaha C-2X > Yamaha M-2 > Soliloquy 6.5
 
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I had a couple of guys ask me where this post went. I guess you cannot do a search on "C-2x"? Anyway, I found it for them.

I have to report that after 5 months this pre is a very fine sounding device! I am using it now with a rebuilt B-2 and they were simply made for each other. I've also upgraded to the Dynavector 20x2 cartridge and have no complaints with the MC phono stage.
 
Necropost.
Does the C-2x have the vertical RCA PCB board that fits in the Molexy type connectors like the C-2a does? I'm seriously considering doing this, but I'm not an electronics tech. I've recapped an integrated with 43 caps in it (and know how to not die), and can fabricate anything but don't get the electronic schematics. So, I'm wondering where all the wires connect to, LOL. I've got my C-2a apart, and took a cap inventory, as well as troubleshooting dodgy phono jacks. It looks like someone has already been there, and hacked around trying to fix RCAs. To me, your solution is really the only one that makes sense but for space issues the PCB might have to go? I'm lost at that point trying to figure out where to connect the wires, make sure its grounded and add back in the few little caps on that board. Also, it looks like the RCAs for the phono inputs 1 and 2 are different than the others? All of them have connection strips down the sides, inside the jack, but the two sets of phono don't.

Love your plug mod. My old HH Scott 420a I just recapped had a removable tail and it's the coolest.
 
I need to repost pictures to this old thread. The C-2x has a different setup than the C-2 and C-2a. The RCA lugs are soldered directly into the PCB and it is really crowded in there compared to the other C series (which are bad enough).
 
The C2x is a different best to the C-2 or C-2a. They share an outward similarity but that is where it ends. The C2x is a different circuit executed with the best parts. I actually wasn't overly fond of the line stage of the C2x. I felt that it 'oversmoothed' everything. I loved the phono stage of the C2x. I basically used it as a phono stage. Not as a preamp. It is a very suave sounding preamp. Maybe a little too 'tailored' sound.

Preamps weren't the Japanese strong suit in my opinion. They had a ton of good to great power amps. They had just a smallish number of great preamps.

The RCAs in the C2x sucked.
 
The C2x is a different best to the C-2 or C-2a. They share an outward similarity but that is where it ends. The C2x is a different circuit executed with the best parts. I actually wasn't overly fond of the line stage of the C2x. I felt that it 'oversmoothed' everything. I loved the phono stage of the C2x. I basically used it as a phono stage. Not as a preamp. It is a very suave sounding preamp. Maybe a little too 'tailored' sound.

Preamps weren't the Japanese strong suit in my opinion. They had a ton of good to great power amps. They had just a smallish number of great preamps.

The RCAs in the C2x sucked.

I agree with the "oversmoothing" of the sound in the C2x. It's not bad but it just seems to take the sparkle off the top end. The B2x however is an excellent amplifier. I'll probably keep the pre around just to have the B2x/C2x combo available but I doubt I'll use it much. The C2a is similar sounding but I've heard once gone through it's very nice (more projects for later on).
 
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