C80 vs C60?

geartech

certifiable open reel nut
I just got a C80 control amp, and was looking around at power amps Yamaha made that kinda match this, M80, M60, M40 etc. Seems to be the 1984-85 timeframe. Then I noticed there was also a C60 pre amp, and that it seemingly looks identical to the C80. The C40 is different, less features. What's the difference between a C80 and C60 control amp?
 
Thanks avionic... it looks like the Invert jacks on the preamp out are about the only difference. "The invert terminals allow operation of one power amp for each channel - or rephasing for fuller bass reproduction". Interesting...
 
does the invert jacks mean you can take an amp that is not bridgeable and the pre-amp does that for you? ( any amp?) Just not sure exactly what this feature does...

...as it's the only difference between the C-60 and the C-80...seems like it could come in handy for bi-amping.
 
Well, not sure I would have thought of this, but here is what the manual states:

When using a separate power amplifier for each channel, make the alternate hookup in Fig 1. This allows you to run ordinary stereo amplifiers (those without inverting pre outs) monaurally. Power amplifiers' supply capacity limits their bass response. When a strong bass note enters both channels of the power amp, total demand for power is high. The PRE OUT INVERT jacks can solve this problem. The hookup as shown in Fig2 operates the power amp's left and right channels out of phase, greatly reducing the demand on the power supply and in many cases dramatically improving bass reproduction. Be sure to reverse the connections to one speaker as shown, to bring output back into phase.
 

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does the invert jacks mean you can take an amp that is not bridgeable and the pre-amp does that for you? ( any amp?) Just not sure exactly what this feature does...

...as it's the only difference between the C-60 and the C-80...seems like it could come in handy for bi-amping.

Yes.As long as the amplifiers are common ground.
 
I've used my C-80 to run both of my P2201 amps in mono and it worked great. I'm now running each amp in stereo again, but have them setup with one channel inverted as shown. Also works well. It does seem to give the amps just a hair more headroom when dealing with heavy bass but not a huge difference overall.

I do love the potential to run those amps in mono again if I need to, for an amazing amount of power output. When you bridge you're not just combining the power output of both sides of the amp, but you are effectively creating a 4-ohm load even when powering an 8-ohm speaker. Some amps can nearly double their power output into 4-ohms, so when bridging you are potentially talking about quadrupling your power output into an 8-ohm speaker vs it's traditional stereo output, not just doubling it. Of course in practice you are limited by your powersupply. My P2201's do 200-230wpc into an 8-ohm speaker when in stereo, maybe a smidge more due to running one side inverted. In mono it would probably be good for 600-700wpc into that same 8-ohm speaker.
 
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Well, not sure I would have thought of this, but here is what the manual states:

When using a separate power amplifier for each channel, make the alternate hookup in Fig 1. This allows you to run ordinary stereo amplifiers (those without inverting pre outs) monaurally. Power amplifiers' supply capacity limits their bass response. When a strong bass note enters both channels of the power amp, total demand for power is high. The PRE OUT INVERT jacks can solve this problem. The hookup as shown in Fig2 operates the power amp's left and right channels out of phase, greatly reducing the demand on the power supply and in many cases dramatically improving bass reproduction. Be sure to reverse the connections to one speaker as shown, to bring output back into phase.

Fig.1 is how I'm running a pair of Yamaha B-6 amplifiers with a C-85 control amplifier.
 
Is there a modern day equivalent? Sounds like it could be very useful for the right application. Also instead of a monster amp you could use 2 smaller ones to great effect.
 
Is there a modern day equivalent?
Of what ? Normal and inverted pre-amp outs ? Probably..I have no ideas - I deal with strickly vintage discreet solidstate gear.
 
I've used my C-80 to run both of my P2201 amps in mono and it worked great. I'm now running each amp in stereo again, but have them setup with one channel inverted as shown. Also works well. It does seem to give the amps just a hair more headroom when dealing with heavy bass but not a huge difference overall.

I do love the potential to run those amps in mono again if I need to, for an amazing amount of power output. When you bridge you're not just combining the power output of both sides of the amp, but you are effectively creating a 4-ohm load even when powering an 8-ohm speaker. Some amps can nearly double their power output into 4-ohms, so when bridging you are potentially talking about quadrupling your power output into an 8-ohm speaker vs it's traditional stereo output, not just doubling it. Of course in practice you are limited by your powersupply. My P2201's do 200-230wpc into an 8-ohm speaker when in stereo, maybe a smidge more due to running one side inverted. In mono it would probably be good for 600-700wpc into that same 8-ohm speaker.

Would this be true about the power?
I think bridging doubles the voltage capability, but the available current is unchanged. The amp(s) still see the same load but output becomes more a function of available current and thus the amps are less capable at lower impedances than before although power will be higher. (to quadruple power, voltage AND current must be doubled, which necessarily is when voltage is doubled into a load and the inputting device can produce double the current. This is why headlamp bulbs are so sensitive to voltage drops; their wattage is a second power of voltage)
 
understood and true.
A speaker of twice the resistance outputs half the power at the same voltage. (power/W=VxI; load=R/resistance)
If you double the voltage across a load, you quadruple the power dissipated.
I think in many cases that bridging average amplifiers is a good way to burn them out unless your speakers don't have any low impedance dips!
 
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How Does it Work?
A bridge tied load (BTL) amplifier applies a normal signal to one terminal of the speaker, and an inverted signal to the other. If a single amp is capable of producing 20V RMS across the speaker, this equates to P = V2 / R, so in this case, 20^2 / 4 = 100W.

When connected in BTL, the same speaker "sees" 20V at one terminal, and an inverted 20V signal on the other - a total of 40V RMS (I shall leave the proof of this to the reader :) Using the same formula, 40^2 / 4 = 400W - four times the power. But ... each amp now sees only half the load impedance (think of an imaginary centre tap in the voice coil, connected to ground). The amplifier must be stable into 2 ohms, or this method will not work. Of course, you can use an 8 ohm speaker and still get 200W if the amplifier cannot drive 2 ohms safely.
Rod Elliot..
 
So what's the answer to the OP's question.
Which is better....the C-60 or C-80 ??
Or better yet, perhaps I should ask: Would the C-60 or C-80 offer any improvement in sound quality over a C-2 using 2 P2200 amps to bi amp a pair of XPL200's ??
 
so what's the answer to the op's question.
Which is better....the c-60 or c-80 ??
Or better yet, perhaps i should ask: Would the c-60 or c-80 offer any improvement in sound quality over a c-2 using 2 p2200 amps to bi amp a pair of xpl200's ??

c80..
 
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