Yamaha C-4 pre

jeffe

Super Member
I'm still wondering why my preamp runs so warm. It is noticably warmer than my M-4 amp. Anyone out there running a hot C-4?
 
It is normal, my C-2x and CX-1000 does the same there is no ventilation so the heat can't get out. But if you look careful at the picture (C-2x), you can see that the cap's are rated at 85 degrees Celsius (big red ones). They are made for a "little" heat.
 

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My Yamaha C-4 also gets comparatively warmer than my other preamps, solid state and valve. It hasn't given me a problem yet, so, I think it's normal.
 
I had a c4 and it didn't seem to run any warmer than my other preamps. I'm sure you've checked all your connections but something doesn't sound right. Nice little preamp the c4 especially the on off switch for the 2nd set of pre-outs.
 
It does run hot. . .But then theres hot and theres HOT. . .No piece of electronics should run HOT while many do run hot. . .

Clear as mud. . . by hot I assume you mean warm to touch. If you can lay your hand on the hottest spot and leave it there with no discomfort thats hot. . .<115F while HOT would be >120F :smoke:
 
Last night I was playing my C-2x/M-80 pretty loud for an hour or so and the C-2x did not get too warm. Nothing to worry about, anyway.
 
I have a C-4, and yes the top gets pretty warm. This is normal for this model and nothing to worry about.

Bill from Indy
 
I have a C4 also. After it was on for 6 hours, it was warm but not uncomfortable to touch. It is a really good pre-amp.
 
Oh...I have one of these C-4s on its way to me...I'm also hoping that Mr. Merrylander will be able to revive a C-2 that I purchased (sight unseen!) from Glenn (Yamaha B-2). I think that the C-4 will look nice nearby an A-1! I will follow this thread to learn more about the C-4. I'm looking forward to a side-by-side test of the C-2 and C-4.
 
More on heat and the C-4...

While I haven't used it yet for listening, I have been cleaning up a very nice C-4 that I'm going to try out for a while (while waiting for another pre-amp). I actually picked this up on ebay (some say e-prey) for very little money (late night auction and not many bidders!--someone else got an M-4 from this seller for 75 bucks!--it looked very nice) with all the original boxes, manuals and even cords!

Internally, it's like some other Yamaha pre-amps...upside down circuit board design mostly accessible from the bottom. What's curious is that there are circuit boards all across the top of this unit right in front of the two venting panels at the top. Hence, I don't really see how this unit "breathes". Perhaps this is why this unit runs "hot"...there seems to be very little opportunity for what heat that's generated internally to get out. Thoughts?
 
Your wish is my command...

the-real-mandak said:
It would be nice with some pictures. As usual, naked is preferred :)

Photo attached! Apologies for the glare at the upper left--not the best photo!

This is the bottom looking towards the top...note the power supply and CBs all across the top (with the vents behind!). There are also vents on the bottom...but last I knew...heat rises!...perhaps play this preamp upside down? :D
 
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I always reflect on these nudes.

Most of the Yamaha preamps have a family resemblance.Then there is the C2x.
Kind of like a family of fair skinned freckled red heads,with a brother who has olive skin and different features. :smoke:
 
Well, well, well...the C-4 works!

The C-4 is back together again, and I will conduct some proper tests later, but the ol' CDP sounds very nice through the B-2, C-4 combination (I hope to compare a C-2, C-4 & a mystery pre-amp...forthcoming...still ether-ware until I get it). Although I had to listen QUIETLY this morning...it seems that the B-2 has lost little or none of its beautiful clarity running through the C-4. The pots, switches and lights all work again and this C-4 is all aglow. I will check back on the "heat" issue with this one.

I'm also looking forward to opening the B-2 up a bit later...hmm...what will it be...Little Feat...Steve Hackett...Zony Mash...Allan Holdsworth...hmm... :music:
 
I was just looking at the manual online for the C-4, and it wasn't clear to me if it allowed you to run two amps at the same time. I see that it has two sets of pre-outs, but the manual says to select a or b, not and/or. The M-4 that I picked up cheap was dropped off at my tech's shop yesterday, so I should know in a few days what the humming problem is that scared off the other eBay buyers. In the meantime, I'm trying to decide what Yamaha Pre-Amp to mate the M-4 with. I'm leaning towards the C-4, for the matching looks, but am open to finding a newer model as well. What's the consensus on the best bang for the buck Yamaha Pre? I'm in the under $150 shipped budget category.
 
The C-70 comes to mind as a HUGE bargain, and it was the TOTL preamp in 1982-83.
For a little more, the C-80 is an excellent sounding control amp.
 
There are a couple C-80s up for auction now, that I'm watching. I'll keep an eye out for the C-70. How does the C-65 compare with these two? There is one locally that I might be able to get for a decent price.
 
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