Copa1934
My ears are bleeding
Hope you'll do a post when the time comes. Any change to the networks while you're at it?
Realistic Mach 2 mods
- Thread starter bre's dad
- Start date
The cabs will be a step or two above anything I've built so far. Think thick & beefy. The networks will depend on whether I keep the Pyle mids or use the RS domes.
DonQuixote99
just give me some truth
Nice work. Good fit with the baffle.
thankyou 
does anyone have the resistance of teh pots that make up the L pads for the tweeter and mid? keen to know if they are linear or log as well. guessing linear in this application, and havent had time to bust out the multimeter for a look.
I've also drawn the crossover PCB in eagle and will etch up a board to replicate it - its very expensive here in AU to get boards done (actually everything is expensive now) so will look a bit average, but, will work just the same
i have to wind my own chokes too, to get the right mH values. but thats OK - its an indoor sport at the moment as its so bloody cold here (for us anyway) - has been a long cold winter.
also does anyone have the mach1 box specs. keen to build a pair of those as well
does anyone have the resistance of teh pots that make up the L pads for the tweeter and mid? keen to know if they are linear or log as well. guessing linear in this application, and havent had time to bust out the multimeter for a look.
I've also drawn the crossover PCB in eagle and will etch up a board to replicate it - its very expensive here in AU to get boards done (actually everything is expensive now) so will look a bit average, but, will work just the same
i have to wind my own chokes too, to get the right mH values. but thats OK - its an indoor sport at the moment as its so bloody cold here (for us anyway) - has been a long cold winter.
also does anyone have the mach1 box specs. keen to build a pair of those as well
cnh2
Super Member
What do you think about PExpress Daytons as mid-driver replacements for Mach IIs?
http://www.parts-express.com/dayton-audio-ds135-8-5-designer-series-woofer-speaker--295-426
I picked up a set of Mach IIs a couple of weeks ago, HT maybe? The seller had the original mid-drivers (which I have, they need a refoam--any ideas on the kit?). He had replaced the mids with the Daytons above-they sound OK for what they are. Again, I don't know what the original mids sound like but I have them.
I have NOT heard original Mach IIs so I have no idea what they should sound like over all-the highs are fairly detailed and mildly but not overly bright with good dispersion, the mids are reasonably clean but a tad muddy, the bass-see below.
He also refoamed the original 15" drivers but glued the foam to the outside rather than the inside of the woofer? Will that cause a big problem or can I just leave them like that for a while. The bass seems to be what I would expect from 15"ers in a smaller cab, not as deep as it could be but OK.
Thanks!
http://www.parts-express.com/dayton-audio-ds135-8-5-designer-series-woofer-speaker--295-426
I picked up a set of Mach IIs a couple of weeks ago, HT maybe? The seller had the original mid-drivers (which I have, they need a refoam--any ideas on the kit?). He had replaced the mids with the Daytons above-they sound OK for what they are. Again, I don't know what the original mids sound like but I have them.
I have NOT heard original Mach IIs so I have no idea what they should sound like over all-the highs are fairly detailed and mildly but not overly bright with good dispersion, the mids are reasonably clean but a tad muddy, the bass-see below.
He also refoamed the original 15" drivers but glued the foam to the outside rather than the inside of the woofer? Will that cause a big problem or can I just leave them like that for a while. The bass seems to be what I would expect from 15"ers in a smaller cab, not as deep as it could be but OK.
Thanks!
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so tonight i put the drivers inside my case.
wow what a difference. the 'mud' has gone.
the lower end of the bass is not there, it rolls off alot sooner, and, doesn't have that thundering mach2 (mud) bass - its much more tight and punchy as expected with the sealed cabinet. mids and highs are alot cleaner. note that this test was done with the 'standard' crossover complete with light globes still in it. i would have etched the board tonight except i don't have the stuff i need.
wow what a difference. the 'mud' has gone.
the lower end of the bass is not there, it rolls off alot sooner, and, doesn't have that thundering mach2 (mud) bass - its much more tight and punchy as expected with the sealed cabinet. mids and highs are alot cleaner. note that this test was done with the 'standard' crossover complete with light globes still in it. i would have etched the board tonight except i don't have the stuff i need.
still havent etched boards. slack. I got a Pyle PDMR5 mid range driver. it has a sealed back on it, and, has little to no driver excursion. 92dB. T/S params seem to be as rare as hens teeth, so i thought for 42 bucks AUD i'd give it a shot.
this thing is bloody fantastic. i don't like midrange. i like this midrange. it is clear, non muddy, bloody lovely. the thing fits in the stock hole and the holes for the most of it line up for the screws.
i still have the globes in the crossover so have to jumper them. i've found a place here in AU who wind coils too who are very cost effective so will drop a few bucks on some coils and get that board done. i've modelled the params too of the crossover in LTSpice and will change the 0.6mH coil for 1mH to smooth out the curve of the midrange as it looks pretty awful when graphed out (whether it will sound better - yet to be determined)
this thing is bloody fantastic. i don't like midrange. i like this midrange. it is clear, non muddy, bloody lovely. the thing fits in the stock hole and the holes for the most of it line up for the screws.
i still have the globes in the crossover so have to jumper them. i've found a place here in AU who wind coils too who are very cost effective so will drop a few bucks on some coils and get that board done. i've modelled the params too of the crossover in LTSpice and will change the 0.6mH coil for 1mH to smooth out the curve of the midrange as it looks pretty awful when graphed out (whether it will sound better - yet to be determined)
DonQuixote99
just give me some truth
Very interesting. Keep reporting!
Copa1934
My ears are bleeding
Dang. Can you post images of the readings you've done? I still have Mach One drivers (no cabinets) and have waited for such a project. Look forward to more posts. If you can, please compare to other speakers you have or have access to. Something to "gauge" by, if you will.
Keep on keeping on.
hi there.
i didn't think anyone was reading actually
sure will keep posting stuff up. i don't have anything to take readings per se ; i don't have any gear to read stuff, i use my ears, best measurement gear i have got, sorry. if there is something that reasonably cost effective to make/build/buy happy to see if i can source something, but everything is bloody expensive over here now
only other speakers i have to compare these against are a pair of marantz ls20. these are apparently quite rare? i had the 15's refoamed as they were falling to bits, and, they are a beautiful sounding speaker. i love them to bits. the bass from the marantz ls20 far surpasses the mach2, in that it is much deeper than the mach2, but the high end and (now) mid on the custom mach2 is better than my ls20. note something i omitted to mention is that i had to use the L-pad to dial down the midrange as it was too loud (so its set to half) but it is sooooooooo much nicer.
i can drag the graphs out of LTspice if you like and show them here with the 0.6mH to the 1.0mH inductor if you would like too?
i have been doing some research as well on ports, a 3" port for the mach2 based on the 90 litre enclosure volume should be ~ 182mm long. note that my marantz ls20 also use the same dia of port (some people are not to keen on the mach2 port diameter due to its small size) however the ls20 has 2 of them
i didn't think anyone was reading actually
sure will keep posting stuff up. i don't have anything to take readings per se ; i don't have any gear to read stuff, i use my ears, best measurement gear i have got, sorry. if there is something that reasonably cost effective to make/build/buy happy to see if i can source something, but everything is bloody expensive over here now
only other speakers i have to compare these against are a pair of marantz ls20. these are apparently quite rare? i had the 15's refoamed as they were falling to bits, and, they are a beautiful sounding speaker. i love them to bits. the bass from the marantz ls20 far surpasses the mach2, in that it is much deeper than the mach2, but the high end and (now) mid on the custom mach2 is better than my ls20. note something i omitted to mention is that i had to use the L-pad to dial down the midrange as it was too loud (so its set to half) but it is sooooooooo much nicer.
i can drag the graphs out of LTspice if you like and show them here with the 0.6mH to the 1.0mH inductor if you would like too?
i have been doing some research as well on ports, a 3" port for the mach2 based on the 90 litre enclosure volume should be ~ 182mm long. note that my marantz ls20 also use the same dia of port (some people are not to keen on the mach2 port diameter due to its small size) however the ls20 has 2 of them
Mods M II
Hello everyone,
First sorry for my English but I used my Google translation.
In short, I read with great interest that thread. I learned many things and above all I could get a feedback on several mods.
Fiare you I will share mine, I do not still have the sound I want, but I'm getting there and I have some tracks.
To start my Mach Two have been completely refurbished to the level of suspensions.
The filter is of origin, but after reading the mods here and there, I decided to change it completely. As I am "lazy" and I find 2 Monacor filters for 19 euros (22 dollars) 1000Hz and 5000Hz in cut 12dB.
In fact the only thing that bothers me a bit in this filter is the cut from low to 1000Hz..
I will prefer a cut to 650 / 700Hz. Having said this Clipping for a test for me, especially for the top of the band. I must say that I replaced the original Technics medium by a dome midrange Altai 2 ". It is a medium that Sono sounds pretty sweet, over my use remains Hifi sound level. Clipping is the Optimal 650Hz -5000Hz, so being even higher in low cut than is recommended and so I just may avoid distortions which is very good. For the top it is recommended 5000Hz which just falls. The top would MD500 a dome midrange Ditton 66 first name !!. Breaking 500Hz / 5000Hz.
It is a medium that Sono sounds pretty sweet, over my use remains Hifi sound level. Clipping is the Optimal 650Hz -5000Hz, so being even higher in low cut than is recommended and so I just may avoid distortions which is very good. For the top it is recommended 5000Hz which just falls. The top would MD500 a dome midrange Ditton 66 first name !!. Breaking 500Hz / 5000Hz.
For the tweeter my test will be made with the original one but quickly replaced by a dome tweeter. Indeed during my research I listened to a pair of dome tweeter brand Heco / Grundig vintage (model KHC25 / 4)
I think that will transfigure these speakers. These tweeters actually sound good with beautiful and rich harmonic finesse at the top.
I need to make changes as they are 4Ohm and filter Ohms..à least 8 to find the model with 8 Ohms Heco or to Audax course reasonably priced dome ... but that goes well with medium.
Here, I'll post the latest results of this configuration.
I will use the attenuators that of the High, the middle one will be used for low. Indeed my medium is only 89dB. so it does not need to attenuator. This will be used for low frequencies because the 38 "will be too much performance and so will be too strong.
Seeya
Graffy
Hello everyone,
First sorry for my English but I used my Google translation.
In short, I read with great interest that thread. I learned many things and above all I could get a feedback on several mods.
Fiare you I will share mine, I do not still have the sound I want, but I'm getting there and I have some tracks.
To start my Mach Two have been completely refurbished to the level of suspensions.
The filter is of origin, but after reading the mods here and there, I decided to change it completely. As I am "lazy" and I find 2 Monacor filters for 19 euros (22 dollars) 1000Hz and 5000Hz in cut 12dB.
In fact the only thing that bothers me a bit in this filter is the cut from low to 1000Hz..
I will prefer a cut to 650 / 700Hz. Having said this Clipping for a test for me, especially for the top of the band. I must say that I replaced the original Technics medium by a dome midrange Altai 2 ". It is a medium that Sono sounds pretty sweet, over my use remains Hifi sound level. Clipping is the Optimal 650Hz -5000Hz, so being even higher in low cut than is recommended and so I just may avoid distortions which is very good. For the top it is recommended 5000Hz which just falls. The top would MD500 a dome midrange Ditton 66 first name !!. Breaking 500Hz / 5000Hz.
It is a medium that Sono sounds pretty sweet, over my use remains Hifi sound level. Clipping is the Optimal 650Hz -5000Hz, so being even higher in low cut than is recommended and so I just may avoid distortions which is very good. For the top it is recommended 5000Hz which just falls. The top would MD500 a dome midrange Ditton 66 first name !!. Breaking 500Hz / 5000Hz.
For the tweeter my test will be made with the original one but quickly replaced by a dome tweeter. Indeed during my research I listened to a pair of dome tweeter brand Heco / Grundig vintage (model KHC25 / 4)
I think that will transfigure these speakers. These tweeters actually sound good with beautiful and rich harmonic finesse at the top.
I need to make changes as they are 4Ohm and filter Ohms..à least 8 to find the model with 8 Ohms Heco or to Audax course reasonably priced dome ... but that goes well with medium.
Here, I'll post the latest results of this configuration.
I will use the attenuators that of the High, the middle one will be used for low. Indeed my medium is only 89dB. so it does not need to attenuator. This will be used for low frequencies because the 38 "will be too much performance and so will be too strong.
Seeya
Graffy
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Copa1934
My ears are bleeding
Welcome to this glorious thread, if you will. You're suggestions sound pretty good.
One of the things we've been trying to accomplish is getting the most of the factory drivers. A couple challenges are the (smallish) size of the cabinet and the other the midrange. Many would agree dropping the x-over for the woofer is a good idea, but that again makes the midrange the weak link. Not sure I entirely agree since my T/S tests show the midrange can easily go below 600hz. Whether or not this would be wise given the high crossover point for the Tweeter is debatable, but I think most would conclude that it would be quite a stretch for a low end midrange.
This thread just won't die. That's a good thing, by the way.
I just picked up a pair of Mach Two's to refurbish. I'm planning to copy RickeyM's mods with a new Pyle PDMW5 Mid and his cap changes. One question though, how have folks handled jumping the bulbs? Did you desolder the whole bulb and bracket, or leave them and add a wire jumper from one point to another, and if so exactly where? Thanks.
DonQuixote99
just give me some truth
My approach was to remove the bulbs, and solder a jumper from one side of each bracket to the other.
What type of wire did you use, 18ga copper strand?
DonQuixote99
just give me some truth
That will work. I'm sure whatever you have handy will work fine.
I actually used 10 ga solid copper, I believe, just because I happen to own a ton of it....
I actually used 10 ga solid copper, I believe, just because I happen to own a ton of it....
cdmccul
New Member
ROLL CALL!!!
Hi all, I'm new here. I've been active in the past on other forums (car based stuff) but I've been lurking here for some months. Like many of you, I saw and drooled all over Mach speakers at the local Radio Shacks, while playing with the remote control cars while my dad was buying serious stuff (resistors, bread boards, pots, and the like). I remember looking at the Radio Shack catalog, and seeing the giant Mach II speakers. It had the same appeal that adult magazines had... wow. Anyway, I digress.
Fast forward 3 decades, three houses, and two children later, and here I am at a local recurring junk sale poking through the newest batch of garbage hauled in from the scourges of the last bits of an auction... They always have really obscure things there - a chainsaw with no case, chain, twisted bar... a pile of terrible records, with ONE gem in the bunch (Jackson 5 stuff) BUT NO RECORD in the sleeve. A chandelier missing one globe... And now this time a pile of 1970s and 1980s speakers. A pair of Cerwin Vega's with one of the woofers replaced with a generic sits there with a sold tag... but behind that, looking abandoned and forlorn, is a big beefy real wood box, and its twin behind that.... yup, Mach IIs. $40, and they were mine. I didn't even hesitate and look at the condition, I wanted them. It was like meeting a centerfold.
Brought them home to find they have the typical foam rot on the woofers, but the cones are in good shape, dust caps not dented or damaged, and the spiders held the cones in place. With gentle even pressure, they had no rubbing. The mids were just showing cracking in the surrounds behind the grills. The L-pads felt smooth. The cabinets had seen some water at some point - I'm sure they were in someone's basement - the bottom corners were just swollen, and the big speaker grills had some wicking marks in the cloth. The drivers show no water damage at all, and the cabinets are solid otherwise.
Hooked them up and gently increased the volume. No scratching or rubbing, but didn't drive them long. Just ran them long enough to find that one tweeter didn't make any sound, but all the others were ok. I opened the cabinets to find that they were clean on the inside, no infestations, no water damage on the inside to speak of (sure, the moisture from the outside corners I know is there, but you couldn't see it on the inside). The light bulbs were all in tact, and no obvious damage to be found on the crossovers. I'm assuming the tweeter died from a crossover cap going bad possibly. I knew that old crossovers often need re-capping, so I started searching. I found this thread.
I will post up pictures in the coming days, but I just wanted to see who was still reading this. I have decided I'm going to follow the re-capping and re-coiling process done by RickyM, and I'm going to use the Realistic Mids 40-1281(a) to keep the speakers all "Realistic" and less Frankenspeaker. Maybe Copa and/or Ricky have some long term feedback? I can't wait to re-foam my woofers and bring this big pair of knockers back to the home theater.
Hi all, I'm new here. I've been active in the past on other forums (car based stuff) but I've been lurking here for some months. Like many of you, I saw and drooled all over Mach speakers at the local Radio Shacks, while playing with the remote control cars while my dad was buying serious stuff (resistors, bread boards, pots, and the like). I remember looking at the Radio Shack catalog, and seeing the giant Mach II speakers. It had the same appeal that adult magazines had... wow. Anyway, I digress.
Fast forward 3 decades, three houses, and two children later, and here I am at a local recurring junk sale poking through the newest batch of garbage hauled in from the scourges of the last bits of an auction... They always have really obscure things there - a chainsaw with no case, chain, twisted bar... a pile of terrible records, with ONE gem in the bunch (Jackson 5 stuff) BUT NO RECORD in the sleeve. A chandelier missing one globe... And now this time a pile of 1970s and 1980s speakers. A pair of Cerwin Vega's with one of the woofers replaced with a generic sits there with a sold tag... but behind that, looking abandoned and forlorn, is a big beefy real wood box, and its twin behind that.... yup, Mach IIs. $40, and they were mine. I didn't even hesitate and look at the condition, I wanted them. It was like meeting a centerfold.
Brought them home to find they have the typical foam rot on the woofers, but the cones are in good shape, dust caps not dented or damaged, and the spiders held the cones in place. With gentle even pressure, they had no rubbing. The mids were just showing cracking in the surrounds behind the grills. The L-pads felt smooth. The cabinets had seen some water at some point - I'm sure they were in someone's basement - the bottom corners were just swollen, and the big speaker grills had some wicking marks in the cloth. The drivers show no water damage at all, and the cabinets are solid otherwise.
Hooked them up and gently increased the volume. No scratching or rubbing, but didn't drive them long. Just ran them long enough to find that one tweeter didn't make any sound, but all the others were ok. I opened the cabinets to find that they were clean on the inside, no infestations, no water damage on the inside to speak of (sure, the moisture from the outside corners I know is there, but you couldn't see it on the inside). The light bulbs were all in tact, and no obvious damage to be found on the crossovers. I'm assuming the tweeter died from a crossover cap going bad possibly. I knew that old crossovers often need re-capping, so I started searching. I found this thread.
I will post up pictures in the coming days, but I just wanted to see who was still reading this. I have decided I'm going to follow the re-capping and re-coiling process done by RickyM, and I'm going to use the Realistic Mids 40-1281(a) to keep the speakers all "Realistic" and less Frankenspeaker. Maybe Copa and/or Ricky have some long term feedback? I can't wait to re-foam my woofers and bring this big pair of knockers back to the home theater.
DonQuixote99
just give me some truth
Hey CD, welcome to AK. Sounds like this isn't the first set of old speakers you ever delved into.... The Mach 2's should be excellent restored as you plan, for HT mains. Enjoy!