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MA5300 Run with No Load/Speakers

MORTIS

MORTIS

Alien Member
I'm planning on getting an MA5300 for a 2nd smaller system. For an indefinite period of time I will be using it as a headphone amp with no speakers.
The MA5300 is a direct coupled amp, so I'm wondering if it will be safe for it to run with no load.

Also, when I do eventually hook up some speakers I'll be wanting to hook up a sub as well. The MA5300 has no 2nd set of pre-outs, and my sub has only RCA inputs. Is a 'Y' connector between the bridged outputs/inputs the only way to hook up this sub? I'm pretty sure it is, but I'm wondering if this method compromises the signal quality or output voltage.

MA5300-Back.ashx
 
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UncleBingo: Thank you. I'm sure the 'Y' splitter will provide signal to both the power amp section of the MA5300 and to the sub, however I'm concerned whether either will receive adequate voltage in order to achieve their maximum performance.

I appreciate any other advise or opinions from any of the many excellent tech-heads here on AK.
 
You may have to adjust the level of the sub. A lot depends on the relationship between the input impedance of the subwoofer and the power amp input impedance. Hook stuff up with the power off and then try it. You don't want to be messing with the power amp inputs with a live unit. You could harm your speakers with a powerful transient.
 
Definitely would not plug/unplug anything from the outputs/inputs while amp is powered.
I've already used the sub with the MA7000 which has a 2nd set of preamp outputs. It worked great, but using a 'Y' splitter on the 5300 I'm thinking it could affect output impedance and voltage to amp and sub.
 
I am trying to think if I EVER measured a Mac preamp that could not output at least 7 volts....I would be concerned about over loading the input of a mass market sub before the voltage would "run out" from a McIntosh preamp.
 
c_dk: thank you. Do you think the signal quality could be compromised at all from splitting the pre-output to amp and sub?

By the way, the MA5300 preamp output voltage, according to the manual, is 1.4V unbalanced (8V Maximun).
My MA7000 preamp output voltage is 2.5V unbalanced (8V Maximun). I was using the balanced outputs which are 5.0V balanced (16V Maximun)
 
When Holman etal were establishing the pro THX standards for pro system interchangeability they set 1.4 volts as their benchmark......that is 2 times 1 dB volt, .707 volts rms.

You have to remember that when a pro system goes down you are making no money or worse yet refunding money so having amps that are quickly interchangeable with the same input sensitivity and gain is paramount.

Your unit can output 8 volts rms so typical Mac overkil even though they spec it at the pro level which was a step back for them from the days gone by when they used 2.5 volts as their input spec.

We would custom make up y cables for such purposes.....a 6 inch leg and whatever the client needed to get to the sub......whatever wirewound cable you desired just bring your checkbook.
 
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Thanks c_dk, that's very helpful. Do you also agree with UncleBingo that the amp will be fine if run with no load?
 
I actually seriously considered the MHA150, and yeah it has a sub output, but then for a number of reason I decided on the MA5300; well until recently when I discovered the 5300 has no 2nd set of pre-outs.

I decided against the MHA150 because it has only a bass boost option, not the usual bass and treble. It also lacks a phono section and I really don't want to buy a separate phono pre. And last, even for the smaller system, I really don't want less than 100wpc. I'm sure the MHA, typical of Mcintosh, has a very healthy 50wpc but that's just my personal hangup about minimum headroom and speaker options.
MHA150-Back.ashx
 
So do you mean that's further confirmation that SS amps are fine running with no load?
I wondered about that but also wondered if something about the design of the MHA allowed for operation with no load. I didn't want to assume it applied to all SS amps.
 
MORTIS said:
So do you mean that's further confirmation that SS amps are fine running with no load?
I wondered about that but also wondered if something about the design of the MHA allowed for operation with no load. I didn't want to assume it applied to all SS amps.
Click to expand...
All Solid State amplifiers can run all day with no load on them. There is absolutely no danger to the amplifier at all doing this.
 
Hi Mortis,

Did you ever purchase the MA5300? I don't see it in your signature ..

If so, are you happy with it? I am contemplating one as well. Or an MHA100/150 for my desk at work.

Thanks!
-Matt
 
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