Realistic Mach 2 mods
- Thread starter bre's dad
- Start date
jameselmer66
Active Member
Love my vintage 'Shack stuff
Dollar short and a day late with this thread but here it goes. I just acquired a pair of Mach 2's. The woofers were recently refoamed but I did notice one of the midrange needs refoamed also. I was 18 when Mach 2's came out in 1985 and drooled over them at the local Shack. Now I have them and was really dissapointed with their sound at first. They didn't come with the original tweets but some Dayton titanium domes. Which sound alright but they aren't horns. Still looking for some baby butt crack horns by the way...But the muddy and boomy sound was intolerable. I swear these things are tuned at about 50hz. So I hooked them up to my H/K AVR 240 which has bass management, hooked up a sub set my crossover on the H/K at 60hz. Turned the sub up only quarter way and all of a sudden no muddyness. Smooth transition between sub and Mach 2's. Which to me proves the theory that the crossover points are out of whack. Midrange was always a little "honky" on these speakers. IMO. But I am a stickler for wanting vintage stuff to be original. So the original mids will stay.:thmbsp:
Dollar short and a day late with this thread but here it goes. I just acquired a pair of Mach 2's. The woofers were recently refoamed but I did notice one of the midrange needs refoamed also. I was 18 when Mach 2's came out in 1985 and drooled over them at the local Shack. Now I have them and was really dissapointed with their sound at first. They didn't come with the original tweets but some Dayton titanium domes. Which sound alright but they aren't horns. Still looking for some baby butt crack horns by the way...But the muddy and boomy sound was intolerable. I swear these things are tuned at about 50hz. So I hooked them up to my H/K AVR 240 which has bass management, hooked up a sub set my crossover on the H/K at 60hz. Turned the sub up only quarter way and all of a sudden no muddyness. Smooth transition between sub and Mach 2's. Which to me proves the theory that the crossover points are out of whack. Midrange was always a little "honky" on these speakers. IMO. But I am a stickler for wanting vintage stuff to be original. So the original mids will stay.:thmbsp:
Big Tuna
Too Much Power!
Bre, try reversing the phase of the wiring to the mids. Sometimes the reverse phase cancels out the coloration. I've done that trick both ways, wiring reverse where they are in phase and wiring in phase where they are reversed. You should notice a difference. I would also check the sub-enclosure that is behind mid and make sure it is totally sealed. I have seen way too many that have not been sealed, adding heavy muddiness to the midrange, even with ported cabs, it still will color the mid. Put your hand on bass port and plug it, push on woofer and watch midrange cone closely. If it moves, your sub-enclosure is leaking. If there is no sub-enclosure behind mid and it is a sealed back style, check the terminal plates and make sure they are not allowing air to enter behind cone.
bre's dad
I drank what?!?
That was one of the first things I did and didn't notice much difference. I do agree the crossover points are screwed up. Recapping the crossovers & replacing the midrange drivers proved fruitless, as far as cleaning up the midrange. Recapping did bring out more brilliance in the highs but that was about the only difference I noticed. I had the woofers refoamed and that did tighten up & bring out the bass some.
jameselmer66
Active Member
Thanks for the tweeter find.:thmbsp: I saw maybe about 2 inches of batting around the woofer interior section. Adhered to the interior walls. I will try some more and see what happens.
Wigwam Jones
Caesar non supra grammati
I will be watching this thread with interest. I refoamed my Mach 2's after getting them. Don't care for them. They sound like ass. I have not recapped yet, hoping some big brain will do the heavy lifting and I can benefit from the work!
Big Tuna
Too Much Power!
Now that stinks, lol! My Mach 2's sounded pretty dang good to me, and that was with just with low volume playing because mine need new surrounds. I think they are kinda picky with what they like to power them. I played mine thru my Marantz 2385.
One thing puzzles me though. Every time I hear someone say a particular speaker sounds like crap, they never say what they were powering them with, or give any specifics as to the health/age of their amplifier.
jameselmer66
Active Member
You are so right. When I first hooked my Mach 2's up they sounded like crap but after some tweaking and proper speaker placement they sound pretty good and definitely will rattle the windows. I am pushing them with an H/K AVR 240 but am anxious to get my Concept 2.0 back from my brother on loan and see what the difference in sound is between a modern AVR and old 2 channel. The Concept is only 20 watts per but has an enormous amount of headroom and the Mach 2's are efficient at 94 dbl.
Wigwam Jones
Caesar non supra grammati
The tube amp Squidward built for me. My Luxman L-580 integrated amp. And a few other vintage SS receivers. CD player.
Copa1934
My ears are bleeding
I wish I didn't have so many projects going on at once. DCM-600, Mach One (4029), Mach Two (mids left to repair), Pioneer 99 (mids), several receiver's, and I still haven't realigned the tape guide on my Pioneer 900 tape deck. Oh yeah, my Dual 1019 (recent acquisition) still needs general service. Almost wish I was retired, or wealthy enough not to have to work, just so I can play.
None of the speakers I have owned thus far could match my Two's of HT work, none. Based on the many posts I've read that compare them, good and bad, with other brands and models I'm pretty certain nothing ever will, at least not that I'll be able to afford any time soon.
For music, however, I still prefer my Mach One's and my VA Haydns. Until the Two's are fully service I have RTR-200's that are serving admirably.
Geez, almost forgot the 5 vintage cars I haven't even begun working on.
I'll agree and to also add a third piece of missing information- what type of music do they listen to the most on a given speaker?
I have ported Mach Two's and I have some acoustic suspension Fisher XP-65's and they're like night and day on my recapped and tweaked Scott's. I like the diversity. I wouldn't get rid of either ones.
Wigwam Jones
Caesar non supra grammati
I'll agree and to also add a third piece of missing information- what type of music do they listen to the most on a given speaker?
I have ported Mach Two's and I have some acoustic suspension Fisher XP-65's and they're like night and day on my recapped and tweaked Scott's. I like the diversity. I wouldn't get rid of either ones.
I listen to all kinds of music, except rap and opera. I don't play it loyd anymore, I enjoy lower listening levels; not so low you could have a conversation, but low enough so you could hear a car if it crashed into your garage.
I also have a couple sets of Fisher XP speakers; XP-7 and XP-56. Good stuff. I tend to like my BA A60, Klipsch KG2, and my KLH 6. I like acoustic suspension speakers, but potted are good too. I don't have perfect ears or high demands; just not liking my Mach 2. They're supremely meh.
But I'd love to give the another chance with a custom crossover network. Sorry for voicing anything negative guys, I wasn't expecting a kind of Spanish Inquisition.
Wigwam Jones
Caesar non supra grammati
Note; loud not loyd, and ported not potted. that's my iPod spellcheck again. Argh!
aidynphoenix
Super Member
got a pair. 
BrokenHill
Well-Known Member
There is definitely the synergy thing going on with the Mach two's, I had a couple
of Fisher 400 tube amps and they both sounded like crap on the Mach two's
but with other speakers they sounded great, I have a 9303 magnavox console
amp and using a Eico HF-85 preamp together and they sound excellent with the
Mach two's.
I have a Marantz 1060 amp and it does not sound all that great on the Mach two's,
now my Hafler DH-500 with a SAE mark nine preamp sound unbelievably great
with them.
Here is what I have done to my Mach two's, replaced the foam surrounds on the
woofers and that did help tighten up the bass, had to fix the brace inside the cabinet
to keep it from vibrating and buzzing, two years later I recapped the crossovers and
used Axon Polypropylene caps, that helped a lot, cleaner more detailed sound.
About a year later I blew out one of those funny looking fuses on the crossover
board and had no mid range from one speaker at all so I used some wire to bypass
the fuse just to get it working for now and I noticed the midrange opened up a lot
and the speaker sounded much better so I took out the other fuse in the other
speaker for the mid range and it sounded better too, so now both speakers have no
fuses for the midrange.
I know I risk blowing out the midrange speakers but they sounded so much better
with them out I will just take that chance, I have driven them fairly hard with Hafler
and so far nothing has happened to them and it's been about a year since I took
them out.
It seemed like the fuses were just holding them back from getting more juice to them
and having a negative effect on the music imaging.
I have owned these speakers since 1990 and have noticed before that some amps
sound very good with them and others are just not a good match for them. (synergy)
of Fisher 400 tube amps and they both sounded like crap on the Mach two's
but with other speakers they sounded great, I have a 9303 magnavox console
amp and using a Eico HF-85 preamp together and they sound excellent with the
Mach two's.
I have a Marantz 1060 amp and it does not sound all that great on the Mach two's,
now my Hafler DH-500 with a SAE mark nine preamp sound unbelievably great
with them.
Here is what I have done to my Mach two's, replaced the foam surrounds on the
woofers and that did help tighten up the bass, had to fix the brace inside the cabinet
to keep it from vibrating and buzzing, two years later I recapped the crossovers and
used Axon Polypropylene caps, that helped a lot, cleaner more detailed sound.
About a year later I blew out one of those funny looking fuses on the crossover
board and had no mid range from one speaker at all so I used some wire to bypass
the fuse just to get it working for now and I noticed the midrange opened up a lot
and the speaker sounded much better so I took out the other fuse in the other
speaker for the mid range and it sounded better too, so now both speakers have no
fuses for the midrange.
I know I risk blowing out the midrange speakers but they sounded so much better
with them out I will just take that chance, I have driven them fairly hard with Hafler
and so far nothing has happened to them and it's been about a year since I took
them out.
It seemed like the fuses were just holding them back from getting more juice to them
and having a negative effect on the music imaging.
I have owned these speakers since 1990 and have noticed before that some amps
sound very good with them and others are just not a good match for them. (synergy)
I keep thinking about this. Someday I'll find a schematic. :yes:
That's me, anymore, as well.
I believe those are nothing more than light bulbs that effectively limit current as volume increases. The questions would be is this current limiting important for the longevity of the mid's? Or, is it simply a "feature" of the Mach II sound (i.e. the louder the volume the less linear the mid range levels)? I don't know much about these when it comes to design- I've never studied them. So, if it's the latter, and you like the sound, I wouldn't worry about bypassing the lamps. If it's the former, I would replace the lamps asap, particularly if you do any serious 'cranking'.
Brian
BrokenHill
Well-Known Member
Years ago when I used to crank those speakers extremely loud I had the grill
off one night and the inside lighting turned way down, I noticed there was a glow
coming from inside the Mach two bass port tube so yes I do believe it is some
kind of light bulb that limits the current, it also holds back the mid range speakers
performance.
Today I only drive them moderately with the Hafler DH-500 and because it such
a clean sound with very low distortion it seems to not be a problem for the mid
range speakers, normally I am just driving them with the 9303 Maggie at lower
volume levels so I am not too concerned about blowing them out.