What do I get besides 3db?

Tomster

New Member
I'm pretty happy with a single MC225 in stereo driving the mid/high part of my 20 year old Legacy Audio Focus (98db 10-400 WPC). An MC250 handles the base (horizontal bi-amping).

I never turn the volume up beyond half way, so I don't need more volume.

What would I get out of using 2 mono MC225s to double up on the mid/high. I hear terms like 'headroom' and so on. The only thing I don't love about this system is percussion. Just doesn't sound genuine. I've got RCA splitters that I would attach to one of the RCA outputs of the C20 (the other output being used for the MC250). Hope that works. That's how I'd run 3 amps off it.

If it is just going to be louder, I won't bother.
 
Don't put three amps on a speaker that only has two pairs of binding pots ( I think that's how your post reads). You have plenty of power for 98db efficient speakers unless you have a pretty large room or like to make your neighbors mad. If the bass is not tight enough, you should try a direct coupled McIntosh amp in the place of your MC250, as it should give you more punch and tighter bass.
 
I would leave the one Mc225 for the mid and highs and increase the power to the bass. Mc amps are generally not the best in controlling the woofers for bass. A more substantial SS amplifier with a little better damping factor would produce tighter bass and more authority in the low end.
 
Thanks guys. But I don't think my explanation was clear. I'm just debating whether or not to run 2 MC225s as monoblocks, one to the mid/high posts on each speaker. Will continue to let the MC250 drive base on both speakers (although I know I could beef that up).
 
I have run two 225s in full range to Heresys. I have never really done a specific comparison to differences in the sound between running one in stereo and then both in mono. I like the sound when they run in mono. I’ve also been using one to run Belles. I’ll be glad to hook the other up again and give a listen.

Not sure why you’d need an RCA “Y” cord - you’d run the left channel to on MC225 and the right to the other. You’d continue using the other output. When running the MC225s in mono, they are strapped and you just need one channel going to each ...
 
If you don't like your percussion the C-20 has to go. A C-29 or 30 would be the next choice, followed by C-37, or some thing from the C-40 series. Then if you are still un happy the 225 and 250 will be the next to go replaced by 7100 for the top and 7200 for the bottom. After that comes a MC 162 for the top and keeping the 7200 for the bottom. Then maybe a MA 7900 for the top and a 7200 for the bottom and for get about a separate pre- amp. I would be using an electronic crossover by passing the appropriate passive crossover components in order to reduce intermodulation distortion. Mc 225 is a fantastic tube amp, but depending on the impedance curve of your speaker some tricky things can happen that a 225 may not like. Its not that the amp is bad, it just the way speakers and amps with low damping factor inter-react. Another choice would be a Mc 7104 with 4 channels, that are usually very under priced or a MC 205. Yes you would have an extra channel, but HT amps can usually be found at bargain basement prices.
 
If you don't like your percussion the C-20 has to go. A C-29 or 30 would be the next choice, followed by C-37, or some thing from the C-40 series. Then if you are still un happy the 225 and 250 will be the next to go replaced by 7100 for the top and 7200 for the bottom. After that comes a MC 162 for the top and keeping the 7200 for the bottom. Then maybe a MA 7900 for the top and a 7200 for the bottom and for get about a separate pre- amp. I would be using an electronic crossover by passing the appropriate passive crossover components in order to reduce intermodulation distortion. Mc 225 is a fantastic tube amp, but depending on the impedance curve of your speaker some tricky things can happen that a 225 may not like. Its not that the amp is bad, it just the way speakers and amps with low damping factor inter-react. Another choice would be a Mc 7104 with 4 channels, that are usually very under priced or a MC 205. Yes you would have an extra channel, but HT amps can usually be found at bargain basement prices.

Yup...I was also thinking of recommending the 7100. An MC754 would work nice on the bottom and somewhat match the looks of the MC225.
 
Thanks guys. But I don't think my explanation was clear. I'm just debating whether or not to run 2 MC225s as monoblocks, one to the mid/high posts on each speaker. Will continue to let the MC250 drive base on both speakers (although I know I could beef that up).

Seems like a lot of expenditure and complexity for improvements which may or may not occur.

Perhaps try running the MC250 alone as in normal stereo with regular single wiring to the speakers. You might be surprised.

Also double check speaker connections for correct phase.
 
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I was recommending various degrees of improvement, from the least expensive just replace the pre-amp to the the next to the most expensive. An integrated amp with a separate bass amp using an electronic crossover. The best solution is to scrap the entire system and buy new. But where is the fun in that?
 
Seems like a lot of expenditure and complexity for improvements which may or may not occur.

Perhaps try running the MC250 alone as in normal stereo with regular single wiring to the speakers. You might be surprised.

Also double check speaker connections for correct phase.
I did try that for awhile when the MC225 lost a tube. The MC250 didn't hold a candle to the MC225. Lost the beauty in everything from voices to symphonies.
 
All interesting ideas for improving a system, but the question on the table is this: Add a 2nd MC225 or not? What will I get out of it?
 
All interesting ideas for improving a system, but the question on the table is this: Add a 2nd MC225 or not? What will I get out of it?
Have you tried playing your current MC225 in mono through one channel to see if you can detect an audible improvement? Do you have a manual that describes the process of setting the amp up for mono? As I've mentioned, the closest experience I have to the setup you are proposing is using my 2 225s in mono to power 1978 Klipsch Heresys. The biggest difference in sound for me has come by using the MX110X rather than the C20. In what area are you located?
 
Have you tried playing your current MC225 in mono through one channel to see if you can detect an audible improvement? Do you have a manual that describes the process of setting the amp up for mono? As I've mentioned, the closest experience I have to the setup you are proposing is using my 2 225s in mono to power 1978 Klipsch Heresys. The biggest difference in sound for me has come by using the MX110X rather than the C20. In what area are you located?
I haven't tried that. Should do. I am familiar with how to strap it. I'm in NYC.
I like the idea of swapping the MX110X for the C20. I'll try that first. Thanks!
 
I haven't tried that. Should do. I am familiar with how to strap it. I'm in NYC.
I like the idea of swapping the MX110X for the C20. I'll try that first. Thanks!
I don't know your speakers, but at that sensitivity, I'd also see how the system sounds with just the 225. Do you have an MX110?
 
I asked your location as I would have loaned you a 225, but NYC is too far to drive ... LOL
Thanks Indiana Drew. I appreciate your thinking of it. My 2nd system has both an MX110z and an MC225. I can swap the C20 for the MX110, but if I cannibalize the MC225, that 2nd system is going to be pretty quite!

I do love my system as is, so just tweaking here. Since no-one is telling me to expect wine and roses with the 2nd MC225, I think I skip that step and just try the MX110. Will be giving it a workout this weekend and let you know!
 
Thanks Indiana Drew. I appreciate your thinking of it. My 2nd system has both an MX110z and an MC225. I can swap the C20 for the MX110, but if I cannibalize the MC225, that 2nd system is going to be pretty quite!

I do love my system as is, so just tweaking here. Since no-one is telling me to expect wine and roses with the 2nd MC225, I think I skip that step and just try the MX110. Will be giving it a workout this weekend and let you know![/QUOTE]
If you decide you love the MX110 with it, and want another, let me know ...

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Hmmmm . . .

Moving from a single stereo power amplifier to a pair of the same power amplifiers used as mono blocks typically results in a larger, deeper, soundstage with greater stereo imaging. There are a number of use here at AK that do just that, including myself.

Now, the MC225 seems to be a special power amplifier. I can hook mine up to a pair of mis-matched speakers stacked one atop the other facing the wall and my fiance' comes running into the room to hear it. It's something that I've never been able to explain about the MC225. I've had several over the years but never two at a time so I never did try them mono. But, I have done this with MC240s to great satisfaction.

So, you owe it to yourself to try it. I'd likely use the MC225s full range on each speaker in an effort to remove all other variables.
 
I may be missing something, but if you have 2 MC225 (even if you don’t want to perminantly dedicate both to one system) why not just hook them up in the proposed configuration and see how you like it. I also agree with damacman that you might like the dual 225s used in full range, mono. I have no experience with bi-amping so I may be missing some vast improvement your setup offers, but I’d swap the MC225 with the MC250. Of course if your speakers no longer have the crossovers, I guess I see the dilemma.
 
. . . The only thing I don't love about this system is percussion. Just doesn't sound genuine. . .

. . . The MC250 didn't hold a candle to the MC225. Lost the beauty in everything from voices to symphonies.

All this discussion assumes all of this 50-year-old stuff is working correctly and sounding up to par and in spec. Has this equipment been properly restored?
 
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