MC250 help needed

Re: MC250 help needed

Postby mijknahs » Sun Feb 26, 2012 9:45 am

I've always played the MosValve (and other power amps with presence control) with the presence totally OFF. The added presence sounds artificial (too bright) to me.
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Re: MC250 help needed

Postby Pete B. » Sun Feb 26, 2012 10:45 am

One thing I discovered is that the Dual Showan Reverb Pre-amp'd to the MosValve 962 is a good match.
I had been running the Moss with the Alembic F2B pre-amp and Lex 'verb forever.
I'm gonna put the Moss in a 2-space rack by itself now, and use it with the DSR (for non-Mac-cessible outings).
I kinda hate those little "clicks" in the volume knob on the 962 (the volume I need is "between" clicks)... But I like being able to taylor the treble with the Presence knob for very low volume Jerry tone but with the DSR at 5-6.
I just set up another 1x12 cab and am going to run in Stereo (dual-mono) with the Moss and MC250.
Funn Stuff!
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Oh yeah, one other thing with the Moss... Is there an easy way to re-tension the internal 1/4" jack tip-connector-thingie without opening up the chassis?
The Channel A and B 1/4" inputs slide right in and are like barely making connection.
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Re: MC250 help needed

Postby TRG » Sun Feb 26, 2012 11:29 am

mijknahs wrote:I've always played the MosValve (and other power amps with presence control) with the presence totally OFF. The added presence sounds artificial (too bright) to me.


That's good to know! I've used a Fender twin combo amp for the past 10 years, so I'm a newbie with a rackmount rig. The MosValve was new to me this fall as well and really didn't know where to "homebase" that presence setting.

So I've learned alot over the past couple of days with regard to both the MosValve and the mac. Thanks guys!
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Re: MC250 help needed

Postby mijknahs » Sun Feb 26, 2012 4:07 pm

Pete B. wrote:Oh yeah, one other thing with the Moss... Is there an easy way to re-tension the internal 1/4" jack tip-connector-thingie without opening up the chassis?
The Channel A and B 1/4" inputs slide right in and are like barely making connection.


The only way is to open it up and re-tension the "thingie" (tip connector) by bending it a bit. That reminds me that I need to open mine up an shoot some contact cleaner in the gain pots because they are very scratchy.
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Re: MC250 help needed

Postby JonnyBoy » Tue Mar 20, 2012 3:15 pm

Make sure you don't have the mono switch on. All my macs differ in color noticably and they are a little darker sounding amps than other ss amps. Having my mono switch on screws up the tone when run in stereo.
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Re: MC250 help needed

Postby TRG » Fri Jun 22, 2012 6:26 am

So I thought I'd ressurect this thread since this question is also related. Our band was practicing the other night and someone inadvertently kicked out the speaker cables from the mac...so I started playing the first song without a speaker load. It was only a minute or two until I realized what had happened and shut everything down, but did I do damage to the mac?

Any Mac users out there know if the MC250 can handle being on without a speaker load? I know it's a definite no no for tube amps, but wasn't sure if the same holds true for SS amps. Everything seems ok, but from what I've been reading it sounds like I could've done some serious damage to the Output Transformer ...I'm just not sure how I can tell...?

Thanks!
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Re: MC250 help needed

Postby SarnoMusicSolutions » Fri Jun 22, 2012 8:45 am

Fortunately, solid state amps like the MC250 don't care at all if there's no load. Zero risk there. It's only with tube power amps that we run the risk when there's no speaker load. What happens with a tube amp is that having NO speaker load is basically showing a VERY VERY VERY high impedance load since air is a very high value resistor. The output transformer can then become unstable and oscillate at inaudibly high frequencies and at extremely high power levels to the point of actually burning out the transformer. So anyway, for tube amps, never run them unloaded. With transistor amps, it just doesnt matter at all.


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Re: MC250 help needed

Postby TRG » Fri Jun 22, 2012 10:00 am

SarnoMusicSolutions wrote:Fortunately, solid state amps like the MC250 don't care at all if there's no load. Zero risk there. It's only with tube power amps that we run the risk when there's no speaker load. What happens with a tube amp is that having NO speaker load is basically showing a VERY VERY VERY high impedance load since air is a very high value resistor. The output transformer can then become unstable and oscillate at inaudibly high frequencies and at extremely high power levels to the point of actually burning out the transformer. So anyway, for tube amps, never run them unloaded. With transistor amps, it just doesnt matter at all.


B


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