MC75 Reiussed, Did I Made the Right Chioce?

Well I can see your having a Merry Christmas or whatever you celebrate. I've had my MC40 mono blocks for about a year now and smile every time I turn them on. These amps are keepers for sure, I may play around with other stuff here and there but these stay.

BillWojo
 
ClaytonD said:
Nah, he doesn't need to spend that kind of money. His speakers doesn't even need 75 Watts, let alone double that! So, he's got plenty. I'd imagine using the entire 75 watts with his speaks would be ear bleeding judging by their sensitivity. He's fine :) Might I add that two 275's would be way over 10 grand. :dunno:
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First off I'm fully aware of the price of mac equipment...specifically the mc275s

His speakers can handle far more power, and really would benefit from it, but in fact two mc275 fall short when calculating head room. The Tannoy Turnberry are rated at 340watt 91db having head room for that speaker full capability would be using a 400+ watt amp. One can listen to a 75watt amp @ up to 25watts before the loss of head room and covering transient peaks in the music with those speakers. However overall performance at all volumes is given up with that combo, big drivers need power for speed and control for great bass response. Even tho OP states above that the Sony TA-N77ES @ 200+watts was better in that regard.
 
4-2-7 said:
First off I'm fully aware of the price of mac equipment...specifically the mc275s

His speakers can handle far more power, and really would benefit from it, but in fact two mc275 fall short when calculating head room. The Tannoy Turnberry are rated at 340watt 91db having head room for that speaker full capability would be using a 400+ watt amp. One can listen to a 75watt amp @ up to 25watts before the loss of head room and covering transient peaks in the music with those speakers. However overall performance at all volumes is given up with that combo, big drivers need power for speed and control for great bass response. Even tho OP states above that the Sony TA-N77ES @ 200+watts was better in that regard.
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Just because his speakers can handle 340 watts, doesn't mean he needs a 340 watt amp. Besides, how can you even listen to that much wattage in one room without becoming deft? Hmm. I don't believe you need the same or more wattage amp than the speaker is capable of handling to have "better sound".:no:
 
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ClaytonD said:
Just because his speakers can handle 340 Watts, doesn't mean he needs 340 Watts. Besides, how can you even listen to that much Wattage in one room without becoming deft? Hmm. I don't believe you need the same or more wattage than the speaker is capable of handling to have "better sound".:no:
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I suggest maybe doing some reading on clipping and transient peaks in music, maybe?
 
4-2-7 said:
I suggest maybe doing some reading on clipping and transient peaks in music, maybe?
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1. Most people play their music at around 10-20 Watts (of course the loudness also depends on speaker sensitivity, but I guess that is averaged out)

2. The power has to go up 10 times to double the perceived loudness of the sound.

In other words, unless you want to go deaf, you shouldn't need anything greater than 20 watts (75 watts in this case).
 
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ClaytonD said:
1. Most people play their music at around 10-20 Watts (of course the loudness also depends on speaker sensitivity, but I guess that is averaged out)

2. The power has to go up 10 times to double the perceived loudness of the sound.

In other words, unless you want to go deaf, you shouldn't need anything greater than 20 watts (75 watts in this case).
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First off no one listens @ WATTS, watts have nothing to do with what we hear, thats measured in decibel levels. Amp wattage output means little till you have the speaker efficiency per meter and their output handling capability. You seem to think that if someone has a high watt amp that their system plays loud or that's the reason for it, and thats not the case.
 
@ClaytonD
I need a sticky for this....

One of the main points to consider about amplifier power ratings as it relates to sound pressure levels developed by speakers is dynamic range. No one purchases a MC601 or MC1.2Kw to push a continuous 600 watts or 1200 watts into speakers. What the additional power ratings allow an amplifier to deliver is unclipped and undistorted musical peaks. Nearly all well designed speakers thrive on "clean"power but will fail quickly with clipped output from amplifiers. Reserve output power is essential to accurately reproduce the complex wave forms of music.

Music is not a constant tone and volume is not a constant level unless you are amplifying test tones. Music is a continuous stream of peaks and valleys with an average level that is typically consistent. It is not unusual for momentary peaks in a musical performance to rise above the average level by 10 to 12 decibels. These same peaks are often fleeting but require substantial output power to reproduce without clipping the waveforms. We know that for every 3dB rise of input signal the output power will double. Using this information it is easy to understand why an amplifier with plenty of power becomes necessary. As an example lets say you are enjoying a performance at an average level of 25 watts output and a sudden crash of drums or blast of horns generates a 12dB peak above your average level. 3dB above 25 watts would require 50 watts, 6 dB above 25 watts would require 100 watts, 9dB above 25 watts would require 200 watts, and 12dB above 25 watts would require 400 watts of reserve power in order to faithfully reproduce the peak level of 12dB above your average listening level without clipping the output signal. Knowing this, it doesn't seem like such a stretch to have 400, 500, 600, or even 1200 watts on tap.


Another point to take into consideration is almost all speaker manufacturers measure speaker sensitivity at a distance of 1 meter on axis (39.37 inches) directly in front of the speaker. These measurements are most often taken with the speaker placed inside an anechoic chamber where it is completely silent and there is no reflected sound for the microphone to hear. That's not exactly real world conditions that represent a typical end user. In addition, for each added meter of distance from the initial measurement point the audio level typically drops by 3 decibels. Looking at this another way, picture yourself listening to 96 decibels with one watt of amplifier power while sitting in front of a speaker at a distance of 1 meter. Moving your seat away from the speaker to 4 meters distance without increasing the amplifier output you will now be hearing an 87 decibel sound level. At this 4 meter distance you will need to increase the amplifier output to 8 watts to achieve the same volume level at your ears as was present when you were seated only 1 meter in front of the speaker. Move back 1 additional meter to 5 meters distance from the speaker and the amplifier power requirement will double to 16 watts for a 96 decibel sound pressure level at your ears. Even though a highly efficient speaker that produces 96dB with 1 watt at 1 meter is selected, mating it with an amplifier of 25 watts output can be a detriment or not depending on the distance you place your seat from the speakers and at what sound pressure level you commonly enjoy. Remember this, there needs to be sufficient power reserves (headroom) on tap to reproduce the dynamic differences above average level. If it takes 2 watts to sustain your desired average listening level at your selected seating location, you will still need something on the order of 30+ watts available to handle the dynamic range that is present in many recordings.

Changing the speaker efficiency to 86 decibels at 1 meter with 1 watt the perimeters differ dramatically. If you wish to listen at an average level of 95dB at a distance of 4 meters with this speaker, you will need 64 watts of output power not including reserve power for dynamics. To faithfully reproduce a 12 dB peak above 95dB average level with this speaker you will need 1024 watts, something a MC1.2KW amplifier can deliver in stride, as can a MC601 on momentary peaks. Both of these amplifier's power ratings are considered by many to be exorbitant but in fact they are necessary with this particular arrangement.

Both of these scenarios are examples of how speaker sensitivity, listening distance, and amplifier power ratings correlate into delivering satisfying listening experiences. It is clear that having additional amplifier power is an asset to reproducing undistorted, unclipped music, thereby protecting our speakers from the damage caused by inadequate power. One needs to consider speaker sensitivity, listening distance from the speakers, typical average music levels required and necessary headroom before deciding on amplifier output power.

The original 16 ohm Altec A7-8 Voice of the Theater speaker had a sensitivity of 101dB at 3 feet with 1 watt. This is the kind of sensitivity one needs to look for when planning to use low output amplifiers. It is all about the proper mating of amplifier power to speaker sensitivity and the sound pressure levels you wish to achieve at your listening position. These things must be considered to take full advantage of any particular sound system.

I hope it helps you understand the relationship of input versus output power and why high powered amplifiers may be necessary, particularly as it applies to your speaker's sensitivity and your common listening levels.
 
4-2-7 said:
To tell the truth I'v never seen tubes like that.
I would use my high speed grinder, or pneumatic disc sander.
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My statement was pretty straight forward for anybody to understand. Not sure why you continue to copy and paste things from the internet without giving a technical description yourself.

4-2-7 said:
"clean"power but will fail quickly with clipped output from amplifiers. Reserve output power is essential to accurately reproduce the complex wave forms of music.
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To me, "clean" power doesn't equate to 100,000,000,000,000,000,000 watts for a speaker. That's just audiophile nonsense. If a speaker is rated at 100 dB sensitive, you only need 20 watts. But even at that in a normal sized room, your ears will become permanently damaged. Also, HF clipping is NOT the cause of blown speakers with low-powered amps. Rather, it's a phenomenon called volume compression. The result is the same (a low-power amp, driven too hard, can blow a speaker with a high enough power rating as to make you think it'd be safe) but the mechanism is a lot more complex than just HF clipping.

Anyways, you'll never even pump out 75 watts through a speaker in a house, so I don't see any reason for the OP to have more wattage for "cleaner power". o_O..
 
Those tubes almost look like they were made to be printed circuit board mounted. Post your pictures on the tube forum, somebody there may be able to help you.

BillWojo
 
BillWojo said:
Those tubes almost look like they were made to be printed circuit board mounted. Post your pictures on the tube forum, somebody there may be able to help you.

BillWojo
Click to expand...

Does it mean I have make some kind of adapter for them to work? The pin arrangement is the same right?
 
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