View Full Version : Yamaha c-70 preamp


Autobot
05-14-2009, 03:24 PM
Ok everyone Just bought a C-70 it should be here next week.
I cant find a owners manual for and there is in not one in the AK database either any help in that area would be appreciated.

So already have a C-4 which I like a lot but curiosity got the best of me so I did a buy it now on E-Bay for 199.00 free shipping.

If any of you have any experience with it let me know your thoughts likes dislikes and such.

I will post my thoughts as soon an I have it setup next week.

What I do like about it is the dual preouts something I like about the C-4 because I have one going to the main amps and the other to the sub amps with the subs firing in reverse
but on the C-70 already one set in reverse so I will just need to set the subs to normal so the preamp will do the reverse phase.
here are some pics from ebay not great pics but pics for now.

stereofanboy
05-14-2009, 09:14 PM
I've had the Kenwood KC-208, the Yamaha CX-600, and the C-70. While the Kenwood was nice, the CX was unimpressive, the C-70 sound quality ruled.

tubed
05-15-2009, 12:17 AM
Aside from them being nice quiet preamplifiers, those two are the only Yamahas that come without the varible loudness contour.

budgetaudio6
05-15-2009, 01:19 AM
Thats a nice preamp there. You will like it.
I like the one i have .
I use it connected to 4 amps/Amp sections in recievers. For some pics yu can find a few in my sig line. No nudies in there thogh. just front side pics....I need to learn the upload function of images. As it is now i gotta enter every letter and number of the tag...time consuming tho it is...

Autobot
05-15-2009, 07:23 AM
Thank you for all your replies.
I dont know why I suddenly opted to get the C-70 I really love the C-4 but I guess I cant help but want to try it out.
The C-70 seems to be a little more rare compared to some of the other C models yeah with the exception of the C-1.
I have not found many reviews on it and still have not found a users manual but found the service manual.
This should be fun comparing the C-4 to the C-70.

audiozaz
05-15-2009, 09:07 AM
Nice unit there!

C85 owner myself! Variable loudness works like a charm on this one. Too bad your does not have it, but then again maybe you're in that camp!

Loudness or no loudness, I'm sure you will enjoy this fine piece of gear!

az

Autobot
05-19-2009, 03:39 PM
Hit the Jackpot :thmbsp:
The seller indicated in the description that it was "Like New" and I thought yeah OK whatever.
Got it unpacked and the first thing I noticed was that not only did it look new, it was new!
Brand new
and I don't mean it had been cleaned up to look like new
I don't believe it had ever been used, there were no visible marks on any of the RCA's.
It still had that brand new electronics smell...y'all know the smell.
I took the top off and looked inside no dust no dust anywhere the inside looked and smelled factory fresh and when I plugged it in when it got warm I could smell the new electronics.
I guess they must have bought it new and wrapped it up tightly and put it away since 1983 that's the inspection date on the back.

Now on to the sound....
Listened mostly Vinyl LP's which is my primary medium.
Lets put it this way my beloved C-4 is getting wrapped up tight and put in the closet.

The C-70 I am thinking is must have been a flagship reference model.
Comparing it to the C-4:
There is a day and night difference in the sound in fact I have never heard such a sound the
Parametric EQ is very precise and I did not think that was a feature that I would really find useful after all I have a really good professional EQ sitting in the closet.
But with the C-70 I was able to isolate the vocals and bring them forward but it does not diminish or exaggerate the other frequencies.
For example on the C-4 , if I were to turn up the Treble I would just get more treble but then the voice may get a little thin sounding but with this unit I can narrow or widen the treble adjust the rollover and wow the vocals are clear and realistic with out making the top air Disappear.
The bass extension is fast and articulate and deep.

Dead quiet operation with more air and detail than I thought my system was ever capable of...And just to think I thought the C-4 was the cats meow.
Dont get me wrong the C-4 is still a fine unit and it served me very well but the C-70 is well just sounds *better to my ears.

Oh the CD sounds unbelievable too.
Still need to try the MC section out as well.
And I will add actual pics of it soon.

*Disclaimer fine print blah blah :blah:
In my house with my system
performance results may vary

budgetaudio6
05-20-2009, 12:54 AM
i find that my phono section has a bit of static...enough to shut off the amp(m70) when i turn the volume knob...do you notice that in yours as well?

Autobot
05-20-2009, 07:54 AM
i find that my phono section has a bit of static...enough to shut off the amp(m70) when i turn the volume knob...do you notice that in yours as well?

Hello Budgetaudio6,
I have not heard any static or noise with the Phono section its perfect.
And I am not running the M-70 amplifier.
But like I posted earlier the preamp is indeed new and unused, not NIB but definitely NOS.
I am so taken by the sound I am still trying wrap my head around it.
I really thought the the parametric EQ would be an annoyance, well.. for an Obsessive Compulsive that I am, I was worried that I would not be able to find the right setting and constantly be fiddling with it.
But once I got it set to sound correct in my environment I played record after record and did not feel the need to mess with it at all.
Even if I switch to HD-Radio or Played a CD the EQ still sounded correct
Where on the C-4 I always felt like I needed to reduce the Treble everytime I would Play a CD or listen to HD-Radio.

Your C-70 might need some minor work done,
may want to contact
Avionic (http://www.audiokarma.org/forums/member.php?u=14955)
http://www.audiokarma.org/forums/image.php?u=14955&dateline=1232163930&type=thumb
He knows a lot about Yamaha's.

So stoked right now! Up till I got the C-70 I really thought the C-4 was it and that I would never replace it heck I was contemplated getting another one just for backup parts.
But while I was browsing Ebay looking at a super clean C-4 I found the C-70 suddenly out of the blue and on a whim and since it was a "buy it now" Ebay I just jumped on it and there for for a while I had the "buyers remorse" because I did not really NEED another preamp, but decided to try the C-70 anyway and man am I glad I did. :yes:

When I got home yesterday I could not wait to play records and also tested the MC section with my Audio-Technica OC9 ML/II and it sounded wonderful through the Yamaha MC section.
But then I put the Shure V15VxMR Sound-Smith re-tip back on because it makes beautiful music I do like the OC9 MC but the Modified Shure will reach way further into the music and pick up detail the OC9 just mulls over altogether.

budgetaudio6
05-20-2009, 10:49 AM
nos for a c-70 is certainly a great deal. considering how much certain places charge for new NOS.
i thought as well that i wouldnt be able to dial in the parametric eq as well. but some times i turn up the mids a bit, and i like the fact that just small frequency bands can be adjusted...

Autobot
05-20-2009, 07:38 PM
http://gallery.audioreview.com/data/audio//500/medium/100_1094.JPG
Super Size it
http://gallery.audioreview.com/showphoto.php?photo=5129&size=big&cat=500&ppuser=239881


http://gallery.audioreview.com/data/audio//500/medium/100_1091.JPG
Super Size it
http://gallery.audioreview.com/showphoto.php?photo=5126&size=big&cat=500&ppuser=239881

http://gallery.audioreview.com/data/audio//500/medium/100_1093.JPG
Super Size it
http://gallery.audioreview.com/showphoto.php?photo=5128&size=big&cat=&ppuser=239881

budgetaudio6
05-21-2009, 01:12 AM
how well does it drive your QSC amps? WIth my C-70 i split the signal out to 4 amps...doesnt seem to affect the sound...

Autobot
05-21-2009, 09:17 AM
how well does it drive your QSC amps? WIth my C-70 i split the signal out to 4 amps...doesnt seem to affect the sound...

Hello budgetaudio6,
I also have mine split 4 ways too.
2 QSC amps are bridged mono and then I have two Subs with a plate amp for each one.
Can not hear any degradation in the sound either.
As to how well does it drive those amps, it does so with absolute authority.

The C-4 did a good job as well but with the C-70 I actually had to dial back on all 4 amps.
OMG the C-70 is detailed the resolution, imaging and sound stage is off the hook.

budgetaudio6
05-21-2009, 11:19 PM
sweet...is it true that the preamp operates in class a? i ...read it on here some where and yes it runs warm...i was quite surprised that it does...if your interested in seeing my m70 i think its on the 3rd or 4th page in my link...and what amps in use are listed....:)

Autobot
05-22-2009, 09:39 AM
sweet...is it true that the preamp operates in class a? i ...read it on here some where and yes it runs warm...i was quite surprised that it does...if your interested in seeing my m70 i think its on the 3rd or 4th page in my link...and what amps in use are listed....:)

Already look over at all your pics you have quiet a nice setup :thmbsp:

See my signature all that is underlined are links.

Here is a site but its in Japanese http://page.freett.com/knisi/c-70.htm
then I ran one of those web page translators...http://babelfish.yahoo.com/translate_url?doit=done&tt=url&intl=1&fr=bf-home&trurl=http%3A%2F%2Fpage.freett.com%2Fknisi%2Fc-70.htm&lp=ja_en&btnTrUrl=Translate
does not work very good.
So I sent it to my friend who can read Japanese and here is what he emailed me after he read it:

"I can read Japanese just fine thanks to my occupation. But when it comes to technical terms, it might as well be a medical text in Latin."

But here are some of the key factors I picked up:

· Preamp’s operates in Class A biased circuitry. (something the translator misses)

· Independent phono-amp sections for both MM and MC. (Instead of MM section with added head-amp).

· New phono section design called “Real Time Equalizer”.

And yeah does it run hot that's something I noticed it runs a lot hotted than the C-4.

Oh and that the power cord is oxygen free!

Here is the translated part of the Class A..like I said it translats but not too good.

being something to which, with the electric current which does not have the completely same strain is supplied, escaping even in the pure A class bias circuit it to be possible, in
It becomes the [tsu] it is without either influence of the electric current strain which originates in the gm curve of the element, the question to which purer A class operation becomes possible

budgetaudio6
05-22-2009, 10:01 AM
When i first saw the combo i almost didnt get the preamp...i finally gave in and went back for it from the cash refister...im so glad i did...i didnt really have a whole lot of money then but i had enough to budget for it...just enough....whew!

Autobot
05-24-2009, 09:12 AM
When i first saw the combo i almost didnt get the preamp...i finally gave in and went back for it from the cash refister...im so glad i did...i didnt really have a whole lot of money then but i had enough to budget for it...just enough....whew!

The Brochure has been uploaded to the Yamaha Database
Everything you ever wanted to know about Yamaha's line up for that years lineup very nice and a nice read.
Printed up color copies and sat and read while listening to the wonderful audiophile quality sound of my C-70.
I wondered why this thing sounded as good at low volumes as it did at high.
Now I know, why is because the C-70 has a variable gain volume control they call it "Varigain" cool

ryuuoh
05-24-2009, 08:53 PM
My C-50 has many of the features of the C-70. It sounds very good. I think it's worthy of consideration at a lower price.

avionic
05-24-2009, 09:50 PM
I'm just guessing but... It sounds like you like the C-70...Good find,NOS..:thmbsp:

Autobot
06-10-2009, 02:38 PM
Well its been 3 weeks and I just cant get enough.
I play records as soon as I get home till I go to bed and play them all day on the weekends.
Thought I just freaking out because it was new to me but I think its just because the C-70 is just that good.

centaurus3200
06-10-2009, 06:51 PM
totally agree about the C-70.

the C70 is a fricken bargain. sounds better than the following preamps i've had in my system. especially the phono section (i'm using a Scott Thompson modded Technics SL-1600MK2 with a VDH retipped Spectral MCR Signature cartridge:

- McIntosh C11
- McIntosh MX110
- Precision Fidelity C4
- Dynaco PAS-3
- MFA Magus C
- Conrad Johnson PV2a
- Quad 34

i also had a MINT C-80. hated it...

i blame the crappy variable loudness control in the C80. can't switch it out. make the thing sound veiled and harsh at the same time.

see ya,
Robby

Autobot
06-10-2009, 07:51 PM
totally agree about the C-70.

the C70 is a fricken bargain. sounds better than the following preamps i've had in my system. especially the phono section (i'm using a Scott Thompson modded Technics SL-1600MK2 with a VDH retipped Spectral MCR Signature cartridge:

- McIntosh C11
- McIntosh MX110
- Precision Fidelity C4
- Dynaco PAS-3
- MFA Magus C
- Conrad Johnson PV2a
- Quad 34

i also had a MINT C-80. hated it...

i blame the crappy variable loudness control in the C80. can't switch it out. make the thing sound veiled and harsh at the same time.

see ya,
Robby

How cool I just replied to your post on Audio Asylum I came across it today and posted a pic and a comment.
but yeah man I really like the C-70 it sucks the music from the grooves and pours it into my ears.

dkelley
08-26-2009, 11:11 PM
I just wanted to say, now that I've just gotten a c-70 (and m-70, t-70 and many other matching devices), I think I'll put that translated japanese quote about class A stuff on my recording studio's website.

Should bring in a few laughs from the smarter prospective clients, and a few questions from the rest :-)

by the way, anybody know if the m-70 is actually class A up to 25 wpc continuous and then switching to class AB as needed over that range? I've read that on here a few places, however an m-80 owner who's read the m-80 and m-70 manuals thoroughly (and I've read the m-70 pdf as well) verified that the m-80 actually says it's class A up to such n such wpc continuous, then after that goes into class AB, where the m-70 doesn't actually claim to be class "anything" at all.

"being something to which, with the electric current which does not have the completely same strain is supplied, escaping even in the pure A class bias circuit it to be possible, in
It becomes the [tsu] it is without either influence of the electric current strain which originates in the gm curve of the element, the question to which purer A class operation becomes possible"

the-real-mandak
08-27-2009, 06:34 PM
The M-70 is "only" class AB, it is of the X-Power breed. Look up the B-6 if you would like to know more about this.

BartK
11-17-2009, 07:16 AM
Thank you for all your replies.
I dont know why I suddenly opted to get the C-70 I really love the C-4 but I guess I cant help but want to try it out.
The C-70 seems to be a little more rare compared to some of the other C models yeah with the exception of the C-1.
I have not found many reviews on it and still have not found a users manual but found the service manual.
This should be fun comparing the C-4 to the C-70.


Where did you find the service manual? Do you have a link for it?

I just picked up a C-70 and need the manuals. Couldn't find the user manual either, but the user manual for the C-50 (one step down, same line, same year) is available in the library on Yamaha's own web site.

avionic
11-17-2009, 08:30 AM
http://sportsbil.com/yamaha/c-70-om.pdf
http://www.vintageaudiomanuals.com/

Martin.Ca
11-17-2009, 12:30 PM
Aside from them being nice quiet preamplifiers, those two are the only Yamahas that come without the varible loudness contour.

Yeah, and the C-2 (http://www.audio-extasa.eu/images/Yamaha%20C-2%20Preamplifier%200c.jpg)

BartK
11-18-2009, 03:21 PM
http://sportsbil.com/yamaha/c-70-om.pdf
http://www.vintageaudiomanuals.com/


Thank you.:thmbsp:

brutal
11-18-2009, 06:14 PM
C-2a also sans loudness.

http://amp8.com/tr-amp/yamaha/jpeg/c-2a-e.jpg

the-real-mandak
11-18-2009, 07:29 PM
And the C-2x.

Martin.Ca
11-18-2009, 11:36 PM
Oddly enough, I never used the loudness feature, when my Yamahas have it.

Bigyank
03-27-2010, 10:33 AM
I have had my eye on a C-70 now to mate with my M-70 (and possibly an M-45 as well) for a while. A question about the PRE OUT INVERT jacks. Still only used for a single amp connection or 2 in mono? Sorry for the cut and paste hack from the OM. :D

http://i165.photobucket.com/albums/u60/bigyank_19320/Yamaha%20C70/C70_PreOuts.jpg

Yank

brutal
03-27-2010, 12:53 PM
I have had my eye on a C-70 now to mate with my M-70 (and possibly an M-45 as well) for a while. A question about the PRE OUT INVERT jacks. Still only used for a single amp connection or 2 in mono? Sorry for the cut and paste hack from the OM. :D

Yank

Either actually. Read the manual and you'll see the inverted out can be used in a single stereo amp configuration to augment bass response, or used to bridge 2 common ground stereo amps into a dual mono config.

Analog King
05-22-2010, 08:37 AM
How the hell do you hook up FOUR power amps to a C-70??

ZeroG
05-22-2010, 12:31 PM
I love my C-70. But I'm on the hunt for another preamp that has a remote. All I want to do is be able to adjust volume.

Is there some way to set it, open up the volume then bypass it through another preamp that has a volume control?

I think I'm arguing with the laws of nature and physics here.....

Then again, there's always one of those remote controlled motorized belt and pulley systems. Anyone channeling Rube Goldberg these days?

brutal
05-22-2010, 12:42 PM
How the hell do you hook up FOUR power amps to a C-70??

You could use four mono amps if you can deal with the phasing. Although a splitter was likely used.

I love my C-70. But I'm on the hunt for another preamp that has a remote. All I want to do is be able to adjust volume.

Is there some way to set it, open up the volume then bypass it through another preamp that has a volume control?

I think I'm arguing with the laws of nature and physics here.....

Then again, there's always one of those remote controlled motorized belt and pulley systems. Anyone channeling Rube Goldberg these days?

You can slave to another pre using rec out, but them you're introducing the other pre sonic signature and additional circuitry into the mix.

I recall Yamaha made a volume control that had remote. It was a passive device but I think the only time I've seen mention of one around here was, of course, Mark B buying or looking at one. That also means it was probably pricey.

[edit] I just remembered, MVS-1 is the passive pre.

Bigyank
05-22-2010, 01:23 PM
I love my C-70. But I'm on the hunt for another preamp that has a remote. All I want to do is be able to adjust volume.

Is there some way to set it, open up the volume then bypass it through another preamp that has a volume control?

I think I'm arguing with the laws of nature and physics here.....

Then again, there's always one of those remote controlled motorized belt and pulley systems. Anyone channeling Rube Goldberg these days?

Though more in a styling queue to the C-65 is the CX-830 if you like remote control for volume and source.

Yank