Realistic Mach One Speaker Crossover Rebuild

[RailroadJim]

Hello to everyone else interested in the Mach One Speakers from RadioShack from 1975 to 1984
From 1975 to 1981 it was the 4024 series from 81 to 84. It was the 4029.
Now let’s get down to business
I am trying to understand and rebuild a cross overs in my 4029s’ . These are the best speakers I have ever heard in my life so I want to try and hear them again I know it’s possible and I know the information is out there but I can’t find it.
I would like to return the speakers to the original specifications .
On the cross over is that I’m looking at it is not clear the specific values on the capacitors or the inductors .
If anyone has any kind of advice, as to the components, I can put in that will give the beautiful sounding Lowe’s and make the speaker sound reasonably near what it once was, I would gladly like to hear from this person

 

[Copa1934]

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

Alright.. After becoming a bit frustrated over searching countless threads from here and other websites, I STILL Cannot find the Information I'm looking for. So, if you all could kindly please post Any and All information you have about the different versions of Realistic Mach One Speakers...

audiokarma.org

 

[malden]

@RailroadJim , why do you think they still don't sound like they did when new? Are all of the drivers functioning? I've recapped older speakers than yours and there was no change in the sound.

 

[RailroadJim]

Hello Malden , When hooked up to my 100 W receiver , and the volume is turned up to three or four perhaps you can hear in the speaker some kind of static I would describe it as, and do not confuses with cracking,

 

[maxhifi]

The 50uf and 22uf capacitors need to be replaced. The yellow one is metal film and wont suffer from age. While it is true often a recap makes no difference, those specific gray colored capacitors in 1970s Radio Shack speakers age poorly, and replacing them is a good idea.

Crackling however is probably not related to the capacitors. For this issue I'd first check the L pads, some cleaner spray may be beneficial.

 

[RailroadJim]

Thanks so much Maxhifi / Jim

 

[maxhifi]

Thanks so much Maxhifi / Jim

Sorry I meant 10uF and 22uF, made a mistake in my response. Just use electrolytic speaker crossover capacitors from a vendor like parts express. I bought the capacitors for my Mach Ones at a local electronics store. The key is they must be bipolar electrolytic capacitors, designed for crossovers.

 

[RailroadJim]

Got it Thanks / I just want to fix the speakers so things are sounding like they were when I first got them . Thanks

 

[SmileyFaceEQ]

Easiest way to re-populate the caps is the hook and loop method.

 

[maxhifi]

Easiest way to re-populate the caps is the hook and loop method.

Yes, and it really has no down side.

 

[RailroadJim]

What do you mean by the hook and loop method ? Thank you in advance.

 

[RailroadJim]

Easiest way to re-populate the caps is the hook and loop method.

Respectfully, what do you mean by the hook and loop method?

 

[RailroadJim]

The 50uf and 22uf capacitors need to be replaced. The yellow one is metal film and wont suffer from age. While it is true often a recap makes no difference, those specific gray colored capacitors in 1970s Radio Shack speakers age poorly, and replacing them is a good idea.

Crackling however is probably not related to the capacitors. For this issue I'd first check the L pads, some cleaner spray may be beneficial.

Hi Max, I really appreciate the input that might be OK for the 22 µF and 50 µF bipolar resistor’s but what about the rectangular resistors ? First, I don’t recognize the labeling.
Could you tell me what they are and what to replace them with?
I appreciate your help so much and actually everyone that has responded to me so quickly in this forum I will be coming back here in the future with other questions but for now I would love to hear my Realistic Mach Ones again

 

[SmileyFaceEQ]

Just google it. Effectively trim out the old caps and leave the entire length of the original caps leads intact. Make a loop on the end of the wire with your pliers. Place in the new cap lead through the loop and make a j hook and the solder the leads. Use hot glue to position and secure the new cap. Similar to the top example in the image.




The yellow caps are film and do not need to be re-populated. Only the grey caps. The white things are resistors and should be fine as new unless there is soot signs of heat and even then they may measure in spec.

 

[RailroadJim]

Oh OK hook and loop just refers to a method replacing the original capacitors. OK great..
No, what about the rectangular capacitors?

Just google it. Effectively trim out the old caps and leave the entire length of the original caps leads intact. Make a loop on the end of the wire with your pliers. Place in the new cap lead through the loop and make a j hook and the solder the leads. Use hot glue to position and secure the new cap. Similar to the top example in the image.

View attachment 2924615


The yellow caps are film and do not need to be re-populated. Only the grey caps. The white things are resistors and should be fine as new unless there is soot signs of heat and even then they may measure in spec.

ok Thank you so much for your information and help

 

[newclassA]

Hello to everyone else interested in the Mach One Speakers from RadioShack from 1975 to 1984
From 1975 to 1981 it was the 4024 series from 81 to 84. It was the 4029.
Now let’s get down to business
I am trying to understand and rebuild a cross overs in my 4029s’ . These are the best speakers I have ever heard in my life so I want to try and hear them again I know it’s possible and I know the information is out there but I can’t find it.
I would like to return the speakers to the original specifications .
On the cross over is that I’m looking at it is not clear the specific values on the capacitors or the inductors .
If anyone has any kind of advice, as to the components, I can put in that will give the beautiful sounding Lowe’s and make the speaker sound reasonably near what it once was, I would gladly like to hear from this person

Pictures look like of a 4024a not 4029

 

[RailroadJim]

Pictures look like of a 4024a not 4029

Yes , you are correct. The crossover pictured is that of a 4024A . Thanks ! See photo attached. And if there is someway to edit the original post, let me know. Thanks

 

[Lavane]

The 50uf and 22uf capacitors need to be replaced. The yellow one is metal film and wont suffer from age. While it is true often a recap makes no difference, those specific gray colored capacitors in 1970s Radio Shack speakers age poorly, and replacing them is a good idea.

Crackling however is probably not related to the capacitors. For this issue I'd first check the L pads, some cleaner spray may be beneficial.

Is the yellow film cap in these speakers polypropylene, or Mylar? I've run across some of those flattened film caps that were mylar. Not the best choice in the sig al path.

 

[maxhifi]

Is the yellow film cap in these speakers polypropylene, or Mylar? I've run across some of those flattened film caps that were mylar. Not the best choice in the sig al path.

Not sure, but IMO in a Radio Shack speaker, if it's what it came with and it's good (i.e. not technically defective), I'd leave it alone.

 

[RailroadJim]

Hello to everyone else interested in the Mach One Speakers from RadioShack from 1975 to 1984
From 1975 to 1981 it was the 4024 series from 81 to 84. It was the 4029.
Now let’s get down to business
I am trying to understand and rebuild a cross overs in my 4029s’ . These are the best speakers I have ever heard in my life so I want to try and hear them again I know it’s possible and I know the information is out there but I can’t find it.
I would like to return the speakers to the original specifications .
On the cross over is that I’m looking at it is not clear the specific values on the capacitors or the inductors .
If anyone has any kind of advice, as to the components, I can put in that will give the beautiful sounding Lowe’s and make the speaker sound reasonably near what it once was, I would gladly like to hear from this person