Pro Audio PA Amps - Bargains to Be Had?

Now that you know what speed you need the fans, you can measure the voltage after the Zalman little control devices. From that you can work out a simple resistor value to achieve the same.

Like this you can do away with all the extra stuff and just put some resistors in line with the fans.

Hmm yes, except if I ever really do want to welly it and it does redline, with the fan mates (or that fancy schmancy controller) in, I can just wack up the dial
 
Hmm yes, except if I ever really do want to welly it and it does redline, with the fan mates (or that fancy schmancy controller) in, I can just wack up the dial

What a statement that would make if you ever have your mates around for a bake-off..."Hang on lads, she's red lining here...better turn the fans up."

Great to see MC2 helping out with your tinkering too. :)
 
I fitted the twin heat sensors last night and its enabled me to properly tweak the fan speeds, you can really fine tune them and keep the temperature at sensible levels and an even temperature on both channels. Knowing the actual temparature of the heatsinks on each side has proved to be very useful in getting it just so.

I think I'm there with this now. I can't hear the fans even after running the setup at full blast and then dropping the volume to zero. You literally have to get your ears up against the grill to hear a whisper. On the current setting, its not just silent, but I found it impossible to trip it into the first headroom reduction stage, even cranking it to proper party levels. Time to drop the pots down the back and forget about them or follow Tenson's suggestion regarding resistors.

I also discovered that lid off it runs about 6 degrees cooler, which suggests that the gubbins between the inlet at the front and the fans is restricting the airflow and a ventilated lid would allow the fans to run even slower, or give a bigger margin before potentially redlining.

I absolutely love what this amp is doing. Its got rock solid bass, great levels of detail, its not harsh, never hardens, imaging is fine. It's actually quite similar to the KaT88 at lower volumes, just with proper bass and the ability to go loud as well, should you want it.

I never thought I'd say it, but I think its the final piece of my personal jigsaw, at least so far as power amps and speakers are concerned. All that remains is a nicer fascia.
 
Last edited by a moderator:
Hahahhah

Been lurking for a bit....reading this thread.

Well i took the plunge and bought a mc750....(prob paid to much £550...but its in ex condition....so wtf)

I am having a bit of a system shuffle so have quite a bit of kit on dem etc.

After spending a month with following amps:

Sugden a21 se
Pathos something (£2700)
s/h Musical fidelity kw500
EAR somthing power amp (2-3K?)
Naim 250/ pre something
Esotoric Audio integrtaed

I finished up liking an old Audio Analogue integrated .......Its a bit big and weighs about 60kg.....but it controls my martin logans a treat.

My source is a Krell ikid (don't knock it till youv heard it:cool:) and a fully sorted garrard 301

So......i put the mc750 in and used the krellikid as the pre.
HaHhahahhahh.................so thats what the bass is supposed to sound like!!!!:D
maybe MC2 could tell martin logan how to make an amp. I ditched the £4k ml speakers with active woofers ....cause they sounded lumpy and crap in my room....these are the £3k passive version....and there is NO comparison using the mc750.
They are very revealing though! Its really easy to tell a 320 rip against a 256 etc.

hahhahh i am still laughing...lost a bit of "hifi" air around the top end but.........
Cant wait to fix me valve pre and try it through the mc750 and i will probably mod the fans eventually.....


Might even look at some different speakers from the pro side....although me rooms only 18ft X 11ft so i have to be careful.

Any suggestions for a passive sub? low low low not boom boom boom?

good thread ....learned a lot.
 
:DAnother one sees the MC2 light!:D
At this rate the 2nd hand prices will start to climb;-)
Get yours now folks.
Cooky
 
Keep up chaps,the hippy was using PA amps over 25 years ago for his hifi duty's ,OK so i was using pa speakers as well, but 9 foot stacks and 2.5kw 3 way active was a bit much for the living room.
 
hahha

:DAnother one sees the MC2 light!:D
At this rate the 2nd hand prices will start to climb;-)
Get yours now folks.
Cooky

Yeh............the really funny thing ....hifi buffs (incuding me:o) will not believe how good until they try.....which most never will!! i don't mean as good I mean better....Hahahahha

Any ideas for a smallish passive sub (i will buy another MC2 for it)
 
As your using a pa amp why not go with a pa sub,i likes eaw sb528 but they aint that small:JPS:
SB528zR.jpg
 
so in all seriousness, just how good a pair of speakers would you use with this MC750 amp? Would it be a suitable partner for my focal 1007be's?

what kind of preamp would best suit it, to perhaps add a little midband warmth to the system.

with my cyrus III/PSX-R i find the tonal balance and soundstaging excellent, but i suspect a bit more grip and grunt would suit the focals well.

im very curious about this route
 
speakers

so in all seriousness, just how good a pair of speakers would you use with this MC750 amp? Would it be a suitable partner for my focal 1007be's?

what kind of preamp would best suit it, to perhaps add a little midband warmth to the system.

with my cyrus III/PSX-R i find the tonal balance and soundstaging excellent, but i suspect a bit more grip and grunt would suit the focals well.

im very curious about this route

Well my Martin Logans are about 3k (thats 2k for marketing and hype included :D:D) and I tried the mc750 with the 4.5k pair. As it happens I have a good hifi dealer who happens to be moving shops so I have had a lot of kit for about a month. The MC2 is ...in my opinion better than the other amps in a lot of areas....as i said ....it loses a bit of air around the top end ....but the dynmics and directness is in another league. I have spent years trying to get a tight bass sound that still sounds realistic ..........now I have it. Be warned though .....if its a bad recording ....you know very quickly and you start to here sample splices etc!!!!
oh and i would presume the mc450 is more than adequate for mmost domestic apps.....................my mc750 only ticks over with a very difficult electrostatic load.
 
interesting... is it worth running these amps via balanced (e.g. are they truly balanced in operation, or just offering the sockets for convenience?)

i picked my cyrus III/PSX-R as its slightly on the warmer side of neutral, i take it these amps are just pretty straight down the line tonality wise?

any mainstream amps you can compare it to tonaly? e.g. something like audiolab 8000M monoblocks for neutrality?
 
xlr

I am running my krell ikid as a preamp which has xlr socket outs.......which i had presumed were balanced.

I think you will get a bit of a shock compared to the cyrus kit!!! (i had a straightline once which was a little thinner than the III....liked it)

I have had audiolabs and found them quite cold sounding. The MC2 is no colder, much more presence and has a huge amount grip (its not a heavy sound though)...........it lacks a touch of sparkle at the top end on my electrostatics ....but with a berylium tweeter I would think this would not be a problem. I really can hear a massive difference........one of the things i am noticing is that some recordings are starting to make a bit more sense..........difficult to describe..............very direct , especially with vocals.

makes it even more funny when i think some of the other amps were near to 4K!
 
i may need to try it... the berylium tweeter kind of relies on a system with an extended and clean top end though, but then perhaps it may balance off who knows. I may need to try one of these.

I have a spare original cyrus pre kicking about, which has XLR outputs on it.
 
Back
Top