PROJECT: Louder Blaster

[bill]

its awesome. i would love to have something like that for a live pa for doing drop it and go guerilla electro sets.

some of the boxes i have are ok for that but cant handle a raw synth signal going into it. i think your box would be pretty close. it might suffer in the long term i am sure all that bass would shake it apart eventually.
seriously impressive tho. i think if someone marketed this kind of box to the right crowd they could make some cash.
i mean add a overdrive circuit to the audio in and you have a killer portable busking guitar amp.
just a great box man. really nice.

 

[Superduper]

Can I GLUE the heat sink to the IC's?

As per the power switch, Right now I have the amp wire "Power" to "Power", "Ground" to "Ground" and the "Amp On" switch running off the hot line I found for the power switch to the switch the amp on. What do you think about running the low voltage power from the switch to a relay and then running all the hot power through the relay?

As to gluing a heat sink to the IC............ NO. The IC's need to be sinked at the mounting tabs. The semiconductor substrate (internally inside the IC package) sinks heat directly to the tab which probably stretches throughout the underside of the module. That junction point generates a tremendous amount of heat and the ability of the heatsink to carry away the current will determine how much power the amp is capable of delivering at a sustained rate. Normally, the IC's will be bolted (screwed) onto a thick aluminum plate. In some equipment like home audio gear, you may see the amps bolted to a huge block with fins. In automotive amps, the IC's are frequently bolted to a piece of the chassis/case -- the collective of which functions as the heatsink as the heat travels throughout. That way, the heat is carried away from the cramped interior of the housing to the exterior and dissipated. So the proper way to affix a heatsink to the IC is a mechanical connection to the mounting tab with heatsink compound (grease) between the tab and heatsink.

As for the power switch issue -- I see what is happining now. The amp has an internal switching circuit. You have connected the standby wire to the boombox's power switch and that would be fine for the standpoint regarding the power switch. The only drawback to connecting it in that manner is that the amp will always consume power, even when powered off. A small amount of current is drawn to support the standby circuitry. The power draw will be low but keep in mind that it was designed for automotive applications which is frequently recharged and where it is expected that the battery is much larger than D cells. Remember that batteries stored in a boombox that gets completely discharged will begin to leak shortly thereafter. Therefore, a relay circuit that switches the amp completely on or off is more desirable in portable applications; so off that really means off is best. Of course to do this, both the power and standby wires will be connected together and powered by a relay.

Last suggestion: If you are sufficiently technically inclined to determine where to extract a low level signal source to power your new amp, you will produce cleaner power since you won't be multiplying distortion on top of distortion. Also, bypassing the internal amps might make more a more power thrifty installation instead of having both original and new amps working simulataneously. Don't know how much power you will save but in a portable device, every little bit helps. Good luck.

 

[steedums]

I'm not sure how much you're planning to run this on batteries, but on the 13.5 volt subject again:

Alkalines drop off from 1.5v pretty quick. 1.5 is just the peak voltage. All these boomboxes are built to run off a variable DC voltage from 1 to 1.5v/battery

 

[Lasonic TRC-920]

its awesome. i would love to have something like that for a live pa for doing drop it and go guerilla electro sets.

some of the boxes i have are ok for that but cant handle a raw synth signal going into it. i think your box would be pretty close. it might suffer in the long term i am sure all that bass would shake it apart eventually.
seriously impressive tho. i think if someone marketed this kind of box to the right crowd they could make some cash.
i mean add a overdrive circuit to the audio in and you have a killer portable busking guitar amp.
just a great box man. really nice.

Thanks to everyone for the comments on this project. Of course as fans of these we all want more power. I really think if a company put some effort out, they could make a really loud radio with full range. Maybe we will see it!

 

[Lasonic TRC-920]

Can I GLUE the heat sink to the IC's?

As per the power switch, Right now I have the amp wire "Power" to "Power", "Ground" to "Ground" and the "Amp On" switch running off the hot line I found for the power switch to the switch the amp on. What do you think about running the low voltage power from the switch to a relay and then running all the hot power through the relay?

As to gluing a heat sink to the IC............ NO. The IC's need to be sinked at the mounting tabs. The semiconductor substrate (internally inside the IC package) sinks heat directly to the tab which probably stretches throughout the underside of the module. That junction point generates a tremendous amount of heat and the ability of the heatsink to carry away the current will determine how much power the amp is capable of delivering at a sustained rate. Normally, the IC's will be bolted (screwed) onto a thick aluminum plate. In some equipment like home audio gear, you may see the amps bolted to a huge block with fins. In automotive amps, the IC's are frequently bolted to a piece of the chassis/case -- the collective of which functions as the heatsink as the heat travels throughout. That way, the heat is carried away from the cramped interior of the housing to the exterior and dissipated. So the proper way to affix a heatsink to the IC is a mechanical connection to the mounting tab with heatsink compound (grease) between the tab and heatsink.

As for the power switch issue -- I see what is happining now. The amp has an internal switching circuit. You have connected the standby wire to the boombox's power switch and that would be fine for the standpoint regarding the power switch. The only drawback to connecting it in that manner is that the amp will always consume power, even when powered off. A small amount of current is drawn to support the standby circuitry. The power draw will be low but keep in mind that it was designed for automotive applications which is frequently recharged and where it is expected that the battery is much larger than D cells. Remember that batteries stored in a boombox that gets completely discharged will begin to leak shortly thereafter. Therefore, a relay circuit that switches the amp completely on or off is more desirable in portable applications; so off that really means off is best. Of course to do this, both the power and standby wires will be connected together and powered by a relay.

Last suggestion: If you are sufficiently technically inclined to determine where to extract a low level signal source to power your new amp, you will produce cleaner power since you won't be multiplying distortion on top of distortion. Also, bypassing the internal amps might make more a more power thrifty installation instead of having both original and new amps working simultaneously. Don't know how much power you will save but in a portable device, every little bit helps. Good luck.

OK, Heat sink: I totally see what your saying and this I can create AND have space for! Question: heatsink compound (grease)??? What type of grease? Wheel Bearing Grease??? White Lithium???

Amp power to relay: This is an easy fix, power and switch power together to a relay switch that is turned on from the original switch. Believe it or not, the relay will be the first part I will have purchased for this project, other then the radio!

OK, now, getting the low line signal could prove to be an issue as this radio has no line out, so I'm not sure where to go looking. I agree power on top of power makes for a dirty out. Now, if I simply by pass the signal from the old amp and go to the new amp, but the old amp is still running, does it still eat the same amount of power?

Can I go looking for the low level signal for the tuner, cassette and line in on the back of the "Selector" switch? Then wire that to the new amp?

 

[MasterBlaster84]

Absolutely awesome Chris and what we dreamed our boomboxes could and should be.

With new amp technology such as the efficient and tiny ICE amps the possibilities for these boomers is only limited by $$$'s. Some of the big companies like Panasonic or Sony could really make an insane and real world useable boombox if they wanted to but that's not going to happen, we can dream.

 

[Lasonic TRC-920]

I'm not sure how much you're planning to run this on batteries, but on the 13.5 volt subject again:

[ Image ]

Alkalines drop off from 1.5v pretty quick. 1.5 is just the peak voltage. All these boomboxes are built to run off a variable DC voltage from 1 to 1.5v/battery

thanks for this info, anything i can get helps!

 

[blah blah]

badass bro, simply bad ass

 

[Superduper]

OK, Heat sink: I totally see what your saying and this I can create AND have space for! Question: heatsink compound (grease)??? What type of grease? Wheel Bearing Grease??? White Lithium???

None of those. Heatsink grease is specially manufactured specifically for use as a thermal transfer medium for use in heatsinks. The most commonly used variety uses silicone grease mixed with ceramic particles. I suspect it may even be available at your local radio shack. The compound fills in the microscopic surface imperfections and transfers the heat from the IC to the heatsink. So what you are looking for is a special grease specifically designed for heatsinks. Actually computer CPU heatsinking compound will work but is far too expensive for this application. Is the IC tabs still mounted to a substrate or did you remove everything bolted to the IC tabs?

Amp power to relay: This is an easy fix, power and switch power together to a relay switch that is turned on from the original switch. Believe it or not, the relay will be the first part I will have purchased for this project, other then the radio!

OK, now, getting the low line signal could prove to be an issue as this radio has no line out, so I'm not sure where to go looking. I agree power on top of power makes for a dirty out.

You would not want to take a signal from the line-outputs anyway, even if line-out RCAs were present. The reason is that the line-outs are fore of the preamp, and there would be no way to control either the volume, balance or tone using the boombox controls. Instead, tap the low line signal after the preamp. Typically, the last spot would be at your volume control. But the simplest location may be at your old amplifier module. Determine which chip is present and get a datasheet. The datasheet will identify which pin is used for the inputs and using shielded microphone cables, tap into that. To reduce intererence and hum, ground the shield wire in at least 1 end.

Now, if I simply by pass the signal from the old amp and go to the new amp, but the old amp is still running, does it still eat the same amount of power?

Depends how your mod is implemented. If you remove the solder from the power pin of the IC, it is essentially dead weight since it will behave like a failed amp. If you remove the line-level signal to the current amp, then it will consume quiescent current only (idle) and will behave as if it was powered on but doing nothing. Quiescent current of most amp IC's are typically in the 30 - 60mA range so, not much. Think of if you powered on a boombox but had the volume turned down to zero. It will consume power still but be very very thrifty. In fact, an amp powered up like this can probably be powered on for days or weeks before it drains down. The last scenario which is probably the simplest is to just leave the amp in there. The original output wires can then be bridged with a dummy but very high impedance load or just left open. Just a FYI -- the original amp outputs can be used to drive a VU meter too. With a very high impedance or open driven load, it will consume very little power.

As to having the current amp drive the high-level inputs to the new amp -- the amount of current drawn by the original amp will depend on the input impedance of the new amp.

Can I go looking for the low level signal for the tuner, cassette and line in on the back of the "Selector" switch? Then wire that to the new amp?

Once again, the selector switch is "fore" of the preamp and will present the same issue as noted above. To retain full normal use of the boombox controls, you will need to take the signal "aft" of the preamp. The amp module is the best location to draw the signal because the audio signal would've already been shaped by the preamp and appropriately throttled by the volume control. Take a moment to think about what I'm saying and I believe it will make perfect sense to you.

 

[Soundwave]

wow amazing project indeed....

 

[TRC-911]

I'm glad I let it go to you chris AWESOME JOB!!!!!!!!!!! thumbsup: thumbsup:

 

[Lasonic TRC-920]

I'm glad I let it go to you chris AWESOME JOB!!!!!!!!!!! thumbsup: thumbsup:

Thanks Chris.....Your old radio is stronger than ever!

Thanks Soundwave and everyone else for the support! Makes it fun to have the feed back!

Superduper,
I'm going to digest everything you have said, re-read it a few more times and then open it up and start work on the heat sink. I will look for that grease at radio shack and to answer your question, I have NOTHING on the IC right now, but I'm not powering it on any more until I work this technical issues out. First and foremost the large heat sink. I will post video when I get that worked out.

Then i will start looking for the signal as you described above. Of course I have no schematic on this radio. It's just an odd ball, so I am stumbling around a bit.

 

[Gluecifer]

PHENOMONAL!!

Geezum crow, Chris!! That's some of the best work (and documenting thereof!) I've ever seen.

You've done boomboxery proud, brother!! A trailblazer to be sure!!

Fatdog: This needs to be stickied for future generations!!


LOVE your work, Chris!! Looking forward to more.



Rock On.

 

[sony_apm_fan]

I want one

Me too!!!

Do you take Credit cards / paypal / kidneys????

Chris, that is one of the finest mod / upgrades ever seen. I wish I could hear her...wait...I can FEEL the bass from here!!!

 

[Radio raheem]

best mod i have seen in a long time bro.... there was a member on here Ned209 who used to do this sort of thing... you have done him and all of us proud.... prepare for incomming orders realy..

 

[oldskool69]

I'm lovin this project! This is something I have in the works for my Sears SR2100 series component box whenever I can get to it.

 

[Lasonic TRC-920]

PHENOMONAL!!

Geezum crow, Chris!! That's some of the best work (and documenting thereof!) I've ever seen.

You've done boomboxery proud, brother!! A trailblazer to be sure!!

Fatdog: This needs to be stickied for future generations!!


LOVE your work, Chris!! Looking forward to more.

Rock On.

Thanks Glue, I still have some technical hurtles to over come. But with the help of SuperDuper and others I think they can be over come. I am walking through this project slowly with the goal of REALLY having something that works proper for the long term.

More up dates to come!

I want one

Me too!!!

Do you take Credit cards / paypal / kidneys????

Chris, that is one of the finest mod / upgrades ever seen. I wish I could hear her...wait...I can FEEL the bass from here!!!

The way I party, I may be interested in a LIVER!

The bass is mind blowing. Once I get the heat sink worked out....I will have the chance to really lay into it.

best mod i have seen in a long time bro.... there was a member on here Ned209 who used to do this sort of thing... you have done him and all of us proud.... prepare for incomming orders realy..

Thanks allot man, I have heard of the great legendary Ned209. I think I need to do a site search.

I'm lovin this project! This is something I have in the works for my Sears SR2100 series component box whenever I can get to it.

I am the kind of person that thinks about something for a long time and try to work on much of the technical issues in my mind before diving in....But obviously, this was a big project for a back yard tinker-er. Thankfully I was in the wiring harness / electronics's industry for 13 years....so I can solder and create wiring harnesses. But there is so much more to a project like this then just stuffing a new amp in and hitting the streets with my "Raising Hell" cassette. But I'm not too far from that!

SO, this is what is next....

As strange as it may seem....I totally forgot that my bass player worked for Chow Communications, a company that makes industrial communication amplifiers for things like military jets, the Mars Rover and communication satellites (I know, I know, we just don't talk to much about that stuff!)

So we were talking heat sinks and he told me to bring in the amp and he would have his tech guy work up the math on it and have the machine shop would whip up a heat sink for me. He also has heat sink contact grease! So, in the next few weeks we will see what he can come up with.

That should fix that problem confidently.

 

[el cad]

Wow! Awesome work.

Very cool of you to do all the videos, so we all can see how you did it. You need need your own TV show. Maybe "This Old Boombox" for the PBS crowd.

808 notes? Is that like from a Roland 808? I've never heard that term before.

 

[MONOLITHIC]

EXCELLENT WORK, CHRIS!!!

Wish I had the patience and knowhow to undertake such a project but when it gets that deep, that technical stuff bores/scares the hell outta me... I'd rather pay somebody else to do it.

I have the General Sound version of that box. You almost couldn't have picked a better candidate for an upgrade 'cause there's a lot of space in there... A few years ago, I added MB Quart tweeters to mine... http://stereo2go.com/eve/forums/a/tpc/f ... 002405/p/2 ... but never got around to adding woofers. I did buy and still have those Goldwood woofers tho. Still, an amplifier upgrade might be good for those tweeters 'cause even tho there was an improvement in sound, overall, the box doesn't sound so hot.

Yeah, the true test of any so-called "BOOM"box is can it handle an 808 bass kick... That one can obviously handle it very well.

I get the feeling that's gonna be your main box, especially after it's 100% complete.

 

[Lasonic TRC-920]

EXCELLENT WORK, CHRIS!!!

Wish I had the patience and knowhow to undertake such a project but when it gets that deep, that technical stuff bores/scares the hell outta me... I'd rather pay somebody else to do it.

I have the General Sound version of that box. You almost couldn't have picked a better candidate for an upgrade 'cause there's a lot of space in there... A few years ago, I added MB Quart tweeters to mine... http://stereo2go.com/eve/forums/a/tpc/f ... 002405/p/2 ... but never got around to adding woofers. I did buy and still have those Goldwood woofers tho. Still, an amplifier upgrade might be good for those tweeters 'cause even tho there was an improvement in sound, overall, the box doesn't sound so hot.

Yeah, the true test of any so-called "BOOM"box is can it handle an 808 bass kick... That one can obviously handle it very well.

I get the feeling that's gonna be your main box, especially after it's 100% complete.

Hey Mono, would love to see pics of your GS. I have seen some other pictures of radios that are very similar. I love the layout and full sized tuner on this radio, but like you said, kind of an empty powerless box.

I'm really hoping to get this up and running at some point. And yes, this could be the out door radio I have in hand more then the others....I HOPE! We'll see.

Wow! Awesome work.

Very cool of you to do all the videos, so we all can see how you did it. You need need your own TV show. Maybe "This Old Boombox" for the PBS crowd.

808 notes? Is that like from a Roland 808? I've never heard that term before.

Thanks El Cad, An 808 note is a super low frequency bass note / sweep. That is that first note you hear in the video. It is really the lowest note the human ear can hear, close to 20 hertz but also a note very hard to reproduce. Older equipment wasn't designed to create those tones. But then again, older music didn't use them.