Magnavox D8443 Power Blaster Upgrade

[Lasonic TRC-920]

Enjoyed your video on the teardown Chris,also dug the vintage Scorps!Looking forward to more vids.Keep up the good work.

Thanks ralrein1, I have a long way to go, but I am searching for parts, making purchases and gearing up.

I have been using speakers from a company called Tang Band out of China. The build quality is really good, their subwoofer hit REALLY hard and I've been looking at 4" these mid drivers

As I sit back and look at people projects, sometimes I think that they are going overboard. Massive speakers with magnets that match the cone size, 150 watt amps. I went down that path with the Louder Blaster project. But this time around I want to keep it more realistic.

First, it has to run on batteries, second it has to be able to be carried. I don't want it weighing 50 pounds.

This radio was 3-5 watts from the factory. Radio's that are 12w-15w are solid in the boombox world and 30 watt boxes are the top of the field.

So, with that said, I'm looking for quality speakers, but not necessarily speakers with HUGE magnets and small efficient amps

 

[jimmyjimmy19702010]

Thanks ralrein1, I have a long way to go, but I am searching for parts, making purchases and gearing up.

I have been using speakers from a company called Tang Band out of China. The build quality is really good, their subwoofer hit REALLY hard and I've been looking at 4" these mid drivers

As I sit back and look at people projects, sometimes I think that they are going overboard. Massive speakers with magnets that match the cone size, 150 watt amps. I went down that path with the Louder Blaster project. But this time around I want to keep it more realistic.

First, it has to run on batteries, second it has to be able to be carried. I don't want it weighing 50 pounds.

This radio was 3-5 watts from the factory. Radio's that are 12w-15w are solid in the boombox world and 30 watt boxes are the top of the field.

So, with that said, I'm looking for quality speakers, but not necessarily speakers with HUGE magnets and small efficient amps

I think you're on the right track with regards to the amp power output required in a project like this. 15-20 watts RMS per channel is plenty if you stick with high sensitivity, 4 ohm speakers.

 

[Lasonic TRC-920]

I think you're on the right track with regards to the amp power output required in a project like this. 15-20 watts RMS per channel is plenty if you stick with high sensitivity, 4 ohm speakers.

Did you have a look at those Tang band? Your thoughts?

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[Lasonic TRC-920]

Chris, looks like that's a 2.1 amp. So perfect for you. 3-channel output. 2@15wpc and 1@30wpc. So you only need one amp.

To be honest, I didn't know I could run that amp as a stereo AND sub amp.

Are you sure?

That would be sweet BUT how would I have a separate sub woofer control?

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[jimmyjimmy19702010]

Did you have a look at those Tang band? Your thoughts?

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Sorry Chris but I've never tried that brand of speaker before. I had a quick EBay look and they sure look great.

True HiFi speakers that sound really nice are often designed to work with powerful AC amps where efficiency is not a huge concern. Speakers with 85-88 dB sensitivity just won't sound particularly powerful in your application - a nice sound but not loud and proud. - 90-95 dB speakers will take your breath away!!

 

[Lasonic TRC-920]

Sorry Chris but I've never tried that brand of speaker before. I had a quick EBay look and they sure look great.

True HiFi speakers that sound really nice are often designed to work with powerful AC amps where efficiency is not a huge concern. Speakers with 85-88 dB sensitivity just won't sound particularly powerful in your application - a nice sound but not loud and proud. - 90-95 dB speakers will take your breath away!!

Yes, high dB speakers are nice. Obviously cost is a consideration as well. The Tang Band speakers I have used are amazing. Their 4 inch subs hit super hard with 15w

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[jimmyjimmy19702010]

Sometimes you can get lucky with buying shelf speakers that can give you a predictable sound and you get a taylor made cross over network included.

I recently scored these Yamaha 3 ways that sound really nice - $10. They are going into a future project for sure.

 

[Superduper]

To be honest, I didn't know I could run that amp as a stereo AND sub amp.

Are you sure?

That would be sweet BUT how would I have a separate sub woofer control?

The smaller the driver, the more difficult it is to find them with high SPL figures. 88db out of a 4-inch driver imho is on the high end already. In fact, it's not very easy even to find 6.5" drivers with 90 or more.

As for the amp, I don't have any personal experience nor can I see how all the connections are labeled on that board. The eBay ad creater isn't very well versed in good english so it's sometimes a bit hard to figure out what they are trying to say. However, I did see the one on parts express and it looks like the one you show. Their description is a bit easier to understand amd unless they misspoke, it sounds clear to me that it will power 1 pair of speakers in at 15w and a 3rd output for sub at 30wpc hence 2.1 or 2+1. However, as with all these chinese stuff, there is no documentation since that must be more challenging than cloning these designs. Still, I did see this at the parts express description and it may answer some of your questions.

"There is an optional 2-pin connector for adding a standby feature, and a 3-pin connector with included jumper for regulating the bass volume (wiring harnesses not included). Add a 50k potentiometer (sold separately) to the 3-pin terminal to control the subwoofer channel's volume separately from the master volume control. When the jumper is placed between the middle and right pins, the subwoofer channel is controlled by the master volume. And when the jumper is placed between the middle and left pins, the subwoofer channel is shut off."

 

[Lasonic TRC-920]

The smaller the driver, the more difficult it is to find them with high SPL figures. 88db out of a 4-ohm driver imho is on the high end already. In fact, it's not very easy even to find 6.5" drivers with 90 or more.

As for the amp, I don't have any personal experience nor can I see how all the connections are labeled on that board. The eBay ad creater isn't very well versed in good english so it's sometimes a bit hard to figure out what they are trying to say. However, I did see the one on parts express and it looks like the one you show. Their description is a bit easier to understand amd unless they misspoke, it sounds clear to me that it will power 1 pair of speakers in at 15w and a 3rd output for sub at 30wpc hence 2.1 or 2+1. However, as with all these chinese stuff, there is no documentation since that must be more challenging than cloning these designs. Still, I did see this at the parts express description and it may answer some of your questions.

"There is an optional 2-pin connector for adding a standby feature, and a 3-pin connector with included jumper for regulating the bass volume (wiring harnesses not included). Add a 50k potentiometer (sold separately) to the 3-pin terminal to control the subwoofer channel's volume separately from the master volume control. When the jumper is placed between the middle and right pins, the subwoofer channel is controlled by the master volume. And when the jumper is placed between the middle and left pins, the subwoofer channel is shut off."

I picked this little amp up from parts express, so same one your referring too.

I will do some testing and get back with you.

A piece of me wants to build plastic enclosures for each of the 3 speakers, but not sure if it can be done, I might buy those Tang Band 4 inchers and start there.

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[jimmyjimmy19702010]

Yes, high dB speakers are nice. Obviously cost is a consideration as well. The Tang Band speakers I have used are amazing. Their 4 inch subs hit super hard with 15w

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If they sound nice and loud and sweet, then they should be a great choice. They look quality for sure!

I assume you are going to devote as much internal realestate to the 8 inch ported sub as possible. If you place an airtight cup behind each of the 4 inch drivers, their cones should be nicely protected from the movement of the sub.

That should take the pressure off the 4 inchers from having to produce big bass and leave that to the speaker that's more capable of producing those deeper frequencies.

If you didn't have the sub, then obviously a ported arrangement for the 4 inchers would be more appropriate.

I thought these little 4 inchers might work well (don't look as cool though):
https://www.ebay.com.au/ulk/itm/391089169349

 

[Lasonic TRC-920]

If they sound nice and loud and sweet, then they should be a great choice. They look quality for sure!

I assume you are going to devote as much internal realestate to the 8 inch ported sub as possible. If you place an airtight cup behind each of the 4 inch drivers, their cones should be nicely protected from the movement of the sub.

That should take the pressure off the 4 inchers from having to produce big bass and leave that to the speaker that's more capable of producing those deeper frequencies.

If you didn't have the sub, then obviously a ported arrangement for the 4 inchers would be more appropriate.

I thought these little 4 inchers might work well (don't look as cool though):
https://www.ebay.com.au/ulk/itm/391089169349

Those 4 inch speakers look good and I'm sure if they are powered by 15 real watts they will hit hard.
Yes, the goal is to give the 8 inch sub the most space, but it would I want to figure out the math on what 4 inch speakers need for their enclosure.
Can I find the perfect space for the 8 and two 4's? Is there enough room?
Here is a thought I have been running over....
A sealed enclosure for the 8 and a cabinet for each 4...

 

[kennerithmcguire]

Did you have a look at those Tang band? Your thoughts?

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The Tang bang are good if you have lots of power. 87db sensitivity will cost you in overall volume as well. Its just as easy to blow or clip the signal with an amplifier ( and blow a driver with distortion ) when under powered. I would double the wattage to a 50w by 50w amplifier. This will give you the headroom needed to push the the box with out distortion. That being said this will also need a larger power supply.

Another good spot to get speakers is to buy used speaker cabinets ( name brand - Vega - JBL - Klipsch - Polk ) and strip the cabinet of the cross overs and speakers. It's a win win - you will get better speakers cheaper with the 2nd order or 3rd order crossover that is complimentary to the speakers.

Just IMO - Love what you are doing. Looks like we are trying to solve very similar problems.

 

[blu_fuz]

I put (2) 8" Tang Band speakers in the rear deck of my car back in 2009 from parts express. Hell of a speaker for the money.

 

[Lasonic TRC-920]

The Tang bang are good if you have lots of power. 87db sensitivity will cost you in overall volume as well. Its just as easy to blow or clip the signal with an amplifier ( and blow a driver with distortion ) when under powered. I would double the wattage to a 50w by 50w amplifier. This will give you the headroom needed to push the the box with out distortion. That being said this will also need a larger power supply.

Another good spot to get speakers is to buy used speaker cabinets ( name brand - Vega - JBL - Klipsch - Polk ) and strip the cabinet of the cross overs and speakers. It's a win win - you will get better speakers cheaper with the 2nd order or 3rd order crossover that is complimentary to the speakers.

Just IMO - Love what you are doing. Looks like we are trying to solve very similar problems.

I have done that too, bought used cabs and strip them for parts, yard sale finds ROCK!

I'm still looking....nothing solid yet

I put (2) 8" Tang Band speakers in the rear deck of my car back in 2009 from parts express. Hell of a speaker for the money.

I haven't used any of their 8's. but certainly looking at them. Some of them can be pricey, but damn they hit hard!

 

[jimmyjimmy19702010]

Here are a pair of those 'cups' I was referring to. I salvaged these from a high end 1960s National Hi Fi speaker cabinet. The mids were 4 inch drivers - these steel cups with internal acoustic padding will work well in your application. Remember, you're not wanting bass from your mid speakers - that's not their job in this application.

One idea might be to isolate the mids, completely seal the cabinet from air leaks, load up your 8 inch sub of your choosing and try it out. If that sub can see enough air and the box is sealed, I'd be surprised if the Maggie didn't sound pretty darn nice without a casing spacer.

That's a 4 incher in the pic with the biggest magnet I've seen!!View attachment 26245View attachment 26246View attachment 26247View attachment 26248

 

[Lasonic TRC-920]

Here are a pair of those 'cups' I was referring to. I salvaged these from a high end 1960s National Hi Fi speaker cabinet. The mids were 4 inch drivers - these steel cups with internal acoustic padding will work well in your application. Remember, you're not wanting bass from your mid speakers - that's not their job in this application.

One idea might be to isolate the mids, completely seal the cabinet from air leaks, load up your 8 inch sub of your choosing and try it out. If that sub can see enough air and the box is sealed, I'd be surprised if the Maggie didn't sound pretty darn nice without a casing spacer.

That's a 4 incher in the pic with the biggest magnet I've seen!!

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Yes, I have seen those before. I also have some Cerwin Vega's that are completely sealed. They are the mids used on the AT-15 cabs. Here are some on eBay

And yes, if I could get the right volume on a sealed cabinet for that 8, it would be SICK!

I'll tell ya, you guys have ME all fired up about this...ha ha...I just have to do the damn work!

BTW, what are your thoughts of resistors for the mids and highs? Do you have any numbers I should be looking for to limit the frequency?

 

[kennerithmcguire]

Yes, I have seen those before. I also have some Cerwin Vega's that are completely sealed. They are the mids used on the AT-15 cabs. Here are some on eBay

And yes, if I could get the right volume on a sealed cabinet for that 8, it would be SICK!

I'll tell ya, you guys have ME all fired up about this...ha ha...I just have to do the damn work!

BTW, what are your thoughts of resistors for the mids and highs? Do you have any numbers I should be looking for to limit the frequency?

Are you looking to crossover at 6db - 12db or 24db per octave? Are you looking to use the least amount of components?

 

[kennerithmcguire]

Here are some great 4" mid speakers - you can also remove the tweeter and use it up top; http://www.amazon.com/JBL-GTO428-4-Inch-2-Way-Loudspeaker/dp/B003KN2TDK

4 1/2" Mid range - http://www.simplyspeakers.com/replacement-speaker-full-range-f-701.html

4" Mid Range - Full Range http://www.parts-express.com/tymphany-ne123w-08-4-full-range-woofer-speaker--264-1128

8" Subwoofer - Vifa - http://www.tymphany.com/transducers/transducer-search-results/transducer-detail/?id=631

8" Subwoofer from Cerwin Vega - Use an AT-8 cabinet E 708 - D2 - SE 200 - these cabinets run for about 80$ up to 125 each used

8" Infinity Subwoofer High excursion - http://www.amazon.com/gp/product/B002GHBUFY/ref=pd_lpo_sbs_dp_ss_2pf_rd_p=1944687722&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B0016GX21G&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1SFC1259HK660HYHX4NX

These are all good options for a real quick ass sound!

 

[kennerithmcguire]

Since you are adding a box for the subwoofer, have you thought of horn loading or manifolding the inner box? Horn loading might be more difficult....

If you manifold the drivers you could use 2 drivers staggered back to back firing in opposite directions - the box could actually be smaller than you would imagine and you wouldn't need to port it.

Similar to this picture from pro Electrovoice speakers... OK this has gone off the rails lol "Go big or go home" is what i always say.

 

[jimmyjimmy19702010]

At this early stage of development, I wouldn't bother with a complex crossover until you've confirmed your speaker selection, cabinet details etc. Just cap the tweeter and leave the mid and sub full range just to get things rolling. Test it, tweek it.

All the theory in the world can be quickly confirmed or denied the second you fire it up!