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Mach One 4024, 4024A, 4029 Information and Upgrades!

TransduceLuv said:
Too cool, say are yours the 4029's ? seems the newer 4029s are a 4 ohm vs the older what I have 4024s are 8 ohms woofers.read through the thread at 4:00 this morning and perhaps I missed if this was said. the crossover is going to be different in that case.

The lovely marantz...way to go. I have a few put away 2270 and an older intergrated in one of those pretty wood cases.

I did switch the machs over to the ss sumo setup and they sounded better.
good guess is the impedence is a bit tough on the el 34 monoblocks. just fooling round checking all the old tubes may even of been distortion from them.

Now I am really interested in enclosure, the design this acousta reed setup is nice idea to correct phase and back wave problems. man would it be nice to see the inside of the large cabinets. I know what a folded horn sub can do.:thmbsp:
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I have the 4024a,s but VL dealt with the differences and decided the same crossover could be used for the 4029, 4024 and the 4024a,s All the caps are the same , the coil values will be the same the only difference is the 4024a has a .2mh coil, a 3.0mh coil and a 1.4mh coil. The 4029 has a .3mh coil, a 2.7mh coil and a 1.0 coil. If you have the 4029 all you need to change is the .3mh if you have the 4024 you need to change all three
 
Testing Questions Answered

TransduceLuv said:
Hello, nice project good work.

Has anyone seen the crossover response graphs 4024 stock vs the modded 4029 (not A's)
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Somewhere in this thread, near the front, you can find pictures and values on the 4024 crossover. It is the same as the 4024a. Same parts and values.

Love to see the waterfall graphs too. This is sort of funny was fooling around with few old tube amps swapping tubes and biasing them, pulled out machs to use with them.
thought oh these suck. but could be much better with a decent crossover upgrade.
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No waterfall graphs. Transient and group delay are however, very good.

So to my surprise and delight this thread has been very amusing.

I have to know what is that amp in your avatar? tubes and mirrors>
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Avatar Image, one of the tube amps we manufacture!

In your pdf where you say a bit about speaker placement floor vs stands, what kind of room was it ? cement floors or ? in room gain was how much? why I ask is recently we moved from a old house with raised foundation and wood floors to a newer slab foundation , miss the wood floors and the way it made gear sound. Is it safe to say that the crossover gave a 5 db increase at 20-40 hz by shifting the crossover points or was it largely due to the 3.5 holes cut to increase cabinet volume?
ADD A PASIVE RADIATOR?
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First, passive Rad would kill transient response in upper frequency response compared to Acoustic Loading. It was a testing lab, 100' x 100' x 50'. Did not measure room gain, only ground plain with diffraction effects.
 
videolady201 said:
Just some info for those who want to know. None of the Mach 1s were ever 4 ohm. None of them were ever even 6 ohms. The 4029 woofers are marked 6 ohm but that is the DCR of the driver. You can look at any ad all the way up to where they stopped selling the Mach 1s. You can do this at: www.radioshackcatalogs.com. You will see that all Ads for the 4029 model says 8 ohms, all Ads for the 4024 and the 4024a also says 8 ohms. I have tested all these drivers and they are all 8 ohms.!:yes:
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Opps, somebody tell parts express they screwed up? nah I'll measure mine here soon. See what you have done made want to work.. heehe..
Nice job. the bit about the foam correction on the mid horn is the ****..
i did it today wow..

Now if I could get some help with the hand made gene cherwinsky woofers to recone them...pre vega massive magnets. god I love this old stuff.

One of these days I want to buy a pass to an audio lab , call it spring camp for old women like me that need to know , what its like to be a audio engineer
Vanc.. Bob, James, and all the audio gods that taught them american sound is still the de facto thanks to these fine men.

And once again VL.. wow .. amazing work.. with real conviction.

So when can we talk about heils? :tears:
 
videolady201 said:
Somewhere in this thread, near the front, you can find pictures and values on the 4024 crossover. It is the same as the 4024a. Same parts and values.



No waterfall graphs. Transient and group delay are however, very good.



Avatar Image, one of the tube amps we manufacture!



First, passive Rad would kill transient response in upper frequency response compared to Acoustic Loading. It was a testing lab, 100' x 100' x 50'. Did not measure room gain, only ground plain with diffraction effects.
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No I agree massive work you have done,, I just wish to get my hot hands the test equipment. ding bat.. no way.that's me.

So my friend.. as a Qc engineer for 30 years, no wonder I contest but love it..
Not a bad thing ? to hate overseas crap?

I support folks like you and me.:yes:
 
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Lemme add that VL's work is on target and well worth following the steps in altering the Mach's circuity mods and cab's interal dimensions- proofing the woofer cone is a must. Simply moding the internals and altering the coils will satisfy most Mach loyalists.
Anyone loving their machs should not skip this thread. Anyone putting machs in bad light owe it to themselves to land a pair and perform the tweaks outlined throughout this thread.
Thanks again VL for stepping up to the plate and squashing the Ivy Leaguers and think-tankers...
 
HomeBody said:
Lemme add that VL's work is on target and well worth following the steps in altering the Mach's circuity mods and cab's interal dimensions- proofing the woofer cone is a must. Simply moding the internals and altering the coils will satisfy most Mach loyalists.
Anyone loving their machs should not skip this thread. Anyone putting machs in bad light owe it to themselves to land a pair and perform the tweaks outlined throughout this thread.
Thanks again VL for stepping up to the plate and squashing the Ivy Leaguers and think-tankers...
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Considering that i am a novice in anything audio except for my love for music, this journey with VL has not only greatly improved my Mach 1,s but has been given me an inside view to reproduction of sound. In doing all of the mods listed i have a better understanding of what a crossover should do and why. As homebody mentioned the information on this thread regarding these speakers is priceless, cant wait for tier 2.
 
Resistive Port

RickeyM said:
Hi VL. Since the Mach One's cabnet is considered small fo the woofer, have you considered adding these http://www.scan-speak.dk/flow.htm to the cabinet? Parts Express has discontinued them but Scan-Speak still shows them on their website.
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I am not interested in these ports for a few reasons. However, anyone can add these at will and post their results. The reason I would not use them are as follows:

1..They do not add any extension to the response and pull more current from your amp.
2..They unload the driver at lower frequencies, (below Fc).
3..They cut the low end response another 6db. AR systems roll off at 12db an octave and the AV systems roll off at 18db.
4..Group delay and transient response is slightly worse with them.
5..They change over a period of time, depending on the amount of dust in the room.
 
Resistive/Aperiodic Vent Info

Here is a little info on them for those who may want to read up on them!
 

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Just an observation, after finishing all the recommended mods on my 4024a,s (which by the way sound great ) I noticed while playing some Eurithmics at a concert like volume, i could here a slight vibration coming form the speakers at Annie Lennox's higher notes. Listening intently it sounded like the vibration was coming from the tweeter. I removed the tweeter from the plastic horn and installed a little silicone where they meet before putting it back together. I didn't use much in case i needed to separate in the future, Also i installed a little strip of ice shield over the side of the magnet and plastic on both sides. After reinstalling there is no more sound distortion. Has anyone else noticed this?
 
unwinding it up on the mach mods

I made the following unwraps to the three coils in the 4024a.

woofer 3.0mh down to 2.7 10 turns off equals 2.695mh

mid 1.4mh down to 1.0 20 turns off equals .997 mh

tweet .20mh to .15mh 32 turns off equals .148mh

Hope this helps the 4024a owners.

Thanks to all who spent hours and hours of time. I completed all the mods posted thus far. There is a huge difference on the low end. No more farting. The mid horn is no longer distorted. I did knock a few pictures off the wall when testing. One the glass broke. You have to test them right?:thmbsp:
 
4024a owner here. Guess I'm next for the upgrades! Really glad you folks have published your success with the upgrades. Thanks!!! VL rules!
 
I think that the next weekend coming up, I might try the foam fix on the midrange drivers. I have been noticing lately that the midrange is a little distorted, so I'm sure the foam is rotted.

My question is, what material would I use? I have some foam sealing tape that I use for wrapping linesets on refrigeration piping. It's about 1/16" thick and is sticky on one side. It has a very smooth outer side though, so I don't know if this would work properly.

Also, the white thing in the center that was added, I am not too sure what that is. But I would like to try it.

I'd also like to replace the capacitors in the crossover, but I am not sure what to go with. Can't really decide as I don't have experience with the different cap names.
 
All I can say is avoid Electrolytics, but only due to the fact you don't want a repeat of what is already happening to vintage speakers, ie cap deterioration. As for the others, there are many posts regarding styles of caps. If you go to Erse they have very good descriptions. Basically different caps affect the "liveliness" of the drivers, such that mids and highs become brighter. Each manufacturer does it's best to explain the characteristics of each of it's products. Hope that helps.
 
One of my woofers seams to be glued/sealed into the front, has anyone have the same experience and how do I remove it?

The other one removed easily, but showed a pronounced 7dB peak around 600Hz and the near response drops fast beyond around 700Hz.
I guess the super glue will remove that peak.
 
I would suggest polypropylene capacitors (but not Solen).

The large cap across the woofer is less affected than the midrange and tweeter caps
and a mylar type may be substituted with little impact on sound.
Electrolytics can easily vary by 20% in value.
 
I am just going to buy these....

http://www.mcmelectronics.com/product/310-315

http://www.mcmelectronics.com/product/31-2025

http://www.mcmelectronics.com/product/31-2035

They are Electrolytic, but i bought the replacements for the stock caps a while back before the new crossover design... i bought SOlens, they were expensive, in hind sight i should have waiting for VL to finish his work, but i was anxious.. :)

I will probably be dead when these Electrolytic caps go bad.. :)

Unless VL states NOT to buy Electrolytic, i will buy them ...
Plus MCM has all 3 values in stock, parts-express does not have the 14 uF

VL ??

have a great day..
 
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