Another Car Audio Amp ( 5,000W - Mono ) :O

[dacflyer]

once again i am working on another car audio amp, this is the largest one i have worked on to date.
it is a Hifonics XXV Goliath 5,000WRMS @ 1ohm stable :O but they do make a 10,000W model also.
anyway this things requires a 500A external Fuze. Phuuuuu.

i am searching for a schematic for this or at least a IC id of the 10 different 8-pin in the preamp section.
i am having issues with a slight oscillation of noise in the pre-amp section.
i am not sure if this has been worked on before or not, because screws were missing from the bottom cover panel.
and logically looking some of the op amp ic's look different from the others.
personally when i replace them i always put in a ic socket.

[Janitor Tzap]

once again i am working on another car audio amp, this is the largest one i have worked on to date.
it is a Hifonics XXV Goliath 5,000WRMS @ 1ohm stable :O but they do make a 10,000W model also.
anyway this things requires a 500A external Fuze. Phuuuuu.

i am searching for a schematic for this or at least a IC id of the 10 different 8-pin in the preamp section.
i am having issues with a slight oscillation of noise in the pre-amp section.
i am not sure if this has been worked on before or not, because screws were missing from the bottom cover panel.
and logically looking some of the op amp ic's look different from the others.
personally when i replace them i always put in a ic socket.

I'm betting that the person who brought it to you must of dug it out of the garbage.
Or.......
It was sitting on a repair shelf, at some place.
Because the customer bailed when he found out what it was going to cost to repair.
Thus, this guy took it off this shops hands thinking you could fix it on the cheap!

Am I close?

Meanwhile.......
Lets have those IC numbers if you please.

Also, on an amplifier that is using that kind of power.
It would make sense that all the IC's are soldered down.
The heat being generated would cause the pins in sockets to spread.
Leading to intermittent connections.

Does this have a muffin fan built in?
If not, it should.


Signed: Janitor Tzap

[Bob Scott]

once again i am working on another car audio amp, this is the largest one i have worked on to date.
it is a Hifonics XXV Goliath 5,000WRMS @ 1ohm stable :O but they do make a 10,000W model also.
anyway this things requires a 500A external Fuze. Phuuuuu.

Did you double check the fuse value? I don't think that a modern car battery can supply 500 Amps at 14V. Using the formula P = I^2 * R, and a 2 Ohm load, that 500 Amp fuse won't blow until the output reaches 500,000 Watts RMS. Maybe it's a 50Amp fuse?

On the oscillation noise: Check for ground loops. If the amp was taken apart, there may be an insulating washer missing on a screw that holds the board down. With high ground currents you have to be careful with ground points. That's just one possibility. Another could be a bad compensation capacitor if the design does not use unity gain compensated op-amps.

[Janitor Tzap]

Did you double check the fuse value? I don't think that a modern car battery can supply 500 Amps at 14V. Using the formula P = I^2 * R, and a 2 Ohm load, that 500 Amp fuse won't blow until the output reaches 500,000 Watts RMS. Maybe it's a 50Amp fuse?

I came across a operators manual with spec's
http://www.maxxsonics.net/manuals/hifon ... Manual.pdf
500 Amp Fuse is right for this monster!


Signed: Janitor Tzap

[dacflyer]

the amp does play, but you hear almost like a high pitched hiss...no squealing..
but after a few min of heavy use the amp shuts down into protect mode.
i have isolated the preamp from the main amp, so this is how i know its in the preamp section..
its just hard to track down a soft failure. in a leaky ic chip.. in a OP amp.
there is several TL072CN , a few BA4558 and one 4556AD
these could have been in IC sockets, but i know it was designed not to be worked on.
there is over 30 clips that clamp down the transistors to the heat sink. and they are not easy to remove. then there's the massive gobs of heat sink grease...lol

i called the owner today..and he agrees to the repair cost..apparently i am the only one in town that repairs car amps..lol
he says this is the best amp he has ever owned for driving 2 18" subs. and even they are rated for
5KW.. they are from same Mfg. so it is all matched.... that's some serious $$ probably all worth more than the car itself..lol

[Janitor Tzap]

The TL072CN is a LOW NOISE DUAL JFET OP-AMP.
Here's where you can down load the data sheet.
http://www.datasheetcatalog.org/datashe ... s/2298.pdf

The BA4558 - Dual operational amplifier.
Here's where you can down load the data sheet.
http://pdf1.alldatasheet.com/datasheet- ... A4558.html

The 4556AD is a strange one.
I'm coming up with NJM4556A DUAL HIGH CURRENT OPERATIONAL AMPLIFIER.
Here's where you can down load the data sheet.
http://www.synthdiy.com/files/2008/njm4556a_e.pdf

Hmmm...........
The TL072CN LOW NOISE DUAL JFET OP-AMP's could be the problem.
I've run into noisy JFET's in some car stereo's.
It will produce similar hissing problem like you have described.

Note: The Troubleshooting part of the manual talks about hiss problems.

But don't rule out a defective electrolytic capacitor(s).
Do a visual inspection first, looking for bulged or leaking cap's.
If you can't see any physical signs of bad cap's.
Break out the ESR meter, and start working through the board,
concentrating on the pre-amp section.
There are still bad batches of cap's still floating around out there.

Well that's the best I can offer you Dac.


Signed: Janitor Tzap

[Edd]

.




In consulting of the PSSSSSZAPPPPPster's supplied referencing of the units manual . . . . .and in looking at ALL of the
associative/companion brand names used . . . .you will also see that they are in bed with "CRUNCH." . .remember CRUNCH ?
I see that in addition to the "4558"'s, that some TL FET front ended op amps are also being utilized.
My first dealing with the "Original" 4558 was back in '74 when I received a box of 6 preliminary engineering samples from
Raytheon.
Those units were a benchmark for flawless performance, as well as my later additional use of the Motorola versions
. . . .and even the current day Texas Instruments versions.

I think that you are already full versed on the potential flaws of the previous CRUNCH unit and its 4558 shortcomings
on the particular units which they were utilizing, I wouldn't be surprised to be seeing some variant KA4558 branded
units being used ?
I would suspect the present unit having a fault somewhere, with the preamp IC's being unstable and letting out
either a constant ultrasonic output or some bursts of same, in response to some audio notes being hit.
Your perception of "some hiss" within the high audio spectrum which you are actually hearing, may only be the
tip of the iceberg sticking up, where you can see it . . . . with a fierce accompanying level of ultrasonic signal which
the amp is mostly responding to and processing thru also .
(With its fierce current draw due to the sheer number and fast sine transitions of a higher frequency signal . . . . at
least on a s..l..o..w.. recurring bass signal, the system gets some rest between notes . . . not so with a continuous
30-100k sines per second having to be amplified.)

My personal troubleshooting procedure would be to pull out and connect up ye olde silly-scope to the driver stage
of each of the channels , thereby, observing JUST BEFORE the
QUASI_PUSH-PULL_DECA-PARALLELED_POWER OUTPUT TRANSISTOR_CLUSTERS
and use either 10 or 1 us hoz time base to see EXACTLY what unwanted HF signal is being outputted.
(The logic for monitoring at the driver versus the speaker output terminals . . . . .there is typically a hi freq snubber
L+C or R+C network shunted across those points, on its feed route to the speaker.)
The dastardly power consuming deed would have already have occurred by the amplification within the AF output stages.
Try with no signal input, as well as with different audio levels to see if it attaches high frequency signal onto the audio.
If this proves the source of the "parasitic signal" as being the fault; an increased current drain on the system would also be concurrent.
Upon confirmation of this type of problem, use the reverse of your last procedure used on the CA-RUNNN-CH unit .
Initially confirn that unwanted signal with your scope monitoring and then see if it is ALSO prevalent on the OTHER
channel. (IF THIS HAPPENS TO BE A STEE-RO unit, which I really don't suspect.)
While having the unwanted HF trash signal present, then move the scope to monitor the power supply lines to see
if HIGH ESR on a power supply electrolytic could be letting " trash" into the power lines that are feeding preamp IC
stages .
After confirmation of power supply electrolytic filtering as NOT being the fault, start at the stage just prior to the
driver and use a short leaded .1 ufd ceramic capacitor to bypass the INPUT of that stage to ground.
If the trash then dissappears, consider the HF trash origin to be occurring further towards the FRONT of the amp
and then move on to each earlier stage's INPUT and try the same bypassing to ground test.

Considering that the additional aspects mentioned by "The GREAT Scott" have been met, also delve into the
temporary test bypassing of each op amps input power supply buss RIGHT at the IC and ground plane with a short
leaded .1 ufd ceramic bypassing capacitor.

Now . . .go . . . seek, and hopefully . . .ye shall find . . . .

73's de Edd

[email protected]. . . . . . . . (Interstellar~~~~~Warp~~~~Speed)
[email protected]. . . . . . . . (Firewalled*Spam*Cookies*Crumbs)



The main reason that SANTA is so jolly . . .?
'cause he knows where all the bad girls live .




.

[dacflyer]

i been doing a lot of research tonight..the 3 different chips i listed earlier here seem to be related in one way or another..

i found this info on DIYAudio.com
the BA4558 & 4556AD seem to cross to the TL072CN as this is the better chip..and from what i have seen, it looks like this amp was repaired once before..and my guess is that the last shop used what they had on hand..
i am starting to think that all the preamps in this thing were all TL072's

Edd do you like to comment on this theory?

[Janitor Tzap]

i been doing a lot of research tonight..the 3 different chips i listed earlier here seem to be related in one way or another..

i found this info on DIYAudio.com
the BA4558 & 4556AD seem to cross to the TL072CN as this is the better chip..and from what i have seen, it looks like this amp was repaired once before..and my guess is that the last shop used what they had on hand..
i am starting to think that all the preamps in this thing were all TL072's

Edd do you like to comment on this theory?

Did you compare the circuits that the BA4558 & 4556AD's are in, to the circuits TL072CN's are in?
Please check the spec's on these Dual OP-AMP's.

For if the circuits are the same.....
Your theory holds some providence.

Time to be the detective.
I would delicately ask the customer if the unit was repair before.
If he says it has.
Then assume that the repair wasn't done right.

<RANT MODE>I really hate having to clean up the mess left by some guy trying to do a quick fix with parts that are not rated for the circuit.</RANT MODE>

The reasoning why the amplifier was originally built with the TL072CN's is a simple one.
The higher the wattage, the harder it is to keep out parasitic signals,
that get amplified more & more with each stage of the amplifier.


Signed: Janitor Tzap

[dacflyer]

the owner says that he bought this from a friend..and yes it was in the shop before once apon a time..
so that's why i am assuming the parts are not the correct ones..
the ic's are all in the preamp / tone amp section..
but without a schematic i am only guessing..but i am going to replace with
0-insertion low profile ic sockets..then next time, if it comes to that..you will not have to dissemble the whole unit to repair it..

[Dean Huster]

The uninitiated don't realize that about 3/4 of the circuitry in one of these car amps is not amplifier -- it's power supply just to get the higher voltages required to have that massive output power available. If all you have to work with is the 12v from the car, you're limited to just a few tens of watts and then only if you have really low speaker impedances. It's my opinion that any add-on amp in a car is pure foolishness. Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!Oooooooomm!-THUMP!!-THUMP!!

[Edd]

.




Mistah Flac Dyer:


Ohhhhhhh MAN . . .'dat DO be one Dreadfull Bedfull of amplifier. Look at that central cross bussing gauge of wire being used to route from the amps output over to its speaker terminals !
I also see that this unit is using large black block (Aromat ? ) cut out relays, interrupting the output audio.

Has the scoping of outputs for unwanted parasitics presence and grounding out of inputs revealed anything ?

Since you have the " METAL" . . . and all we have left here for referencing is a small pic . . . .of which I enhanced upon a bit, to see the better detail of the front end IC amps . . . but at a cost of some silver solarization of the non important top aluminum case.



Amps Photo Illustration:



The big buzz word now seems to be the " class D " connatation markings on the units case, suggesting that they are utilizing FETS in the power output stages "clusters" . . .which looks to be like 12 + 12 units lined up in a string, on either side of the heatsink / case.
Can you pass on their ID numbers being used, to see if they are NOT being conventional bipolar transistors as was encountered on the prior "CRUNCHSTER" unit.


That, along with possibly 10 + 10 sets of power FETS on either side of the unit for the power converter, along with a transforming to almost using "quasi-Litz " wire for the two large power toroids windings.
And, do I see triple paralleled Schottky rectifiers starting on the center just beside where the power FETS end ?
Looks like they have taken a page from the reliability/low esr book in the clustering of individual filter capacitors over at the right sides capacitor bank.

The power converter supply uses up the whole right half of the unit up to the placement of the cluster of 12 larger high voltage filter capacitors.
Also back to the center left of the amp portion, I am seeing 4 toroid donuts that might be associative with being a sub voltage power supplies . . .but most likely being associative with the inherent design of "class D' amplifier circuitry.
Should this unit have Power FET's hiding under those mounting clips of the power output semis.
Look see and pass on the part ID's of the power output semis.

I can just see the 8 pin op amps strung along the input side of the board just behind the adjunct small vertical "daughter boards" . . . now, is there any chance that they might ALSO have any 8 pin IC's mounted on them ?
I definitely remember the original Raytheon 4558's having a transistor differential pair input being used in their design . . . . . whereas on the more modern TL072, it is using FETS inputs instead.

You would have to pull the PCB for foil side chassis viewing, but can you ascertain all of the the 8 pin IC's that seem to still retain "virgin" factory flow soldering joints. That would at least confirm THEIR particular part number validity.




73's de Edd

[email protected] . . . . . . . . (Interstellar~~~~~Warp~~~~Speed)
[email protected]. . . . . . . . . (Firewalled*Spam*Cookies*Crumbs)



An ounce of application is worth a ton of abstraction..



.

[Bob Scott]

Break out the ESR meter, and start working through the board,
concentrating on the pre-amp section.
There are still bad batches of cap's still floating around out there.
Signed: Janitor Tzap

Hey Tzap,

This would be something new to me, working through a board with an ESR meter. I usually troubleshoot with a DVM and a scope. How do you find bad electrolytic caps with an ESR meter?

In my experience, they either go resistive (leaky) or lose capacitance when they get old.

[Janitor Tzap]

Break out the ESR meter, and start working through the board,
concentrating on the pre-amp section.
There are still bad batches of cap's still floating around out there.
Signed: Janitor Tzap

Hey Tzap,

This would be something new to me, working through a board with an ESR meter.
I usually troubleshoot with a DVM and a scope.
How do you find bad electrolytic caps with an ESR meter?

In my experience, they either go resistive (leaky) or lose capacitance when they get old.

ESR meter testers are easy to use.
I have a MAT Electronics Analog unit.
You place the probe ends on the suspect Cap, in-circuit or out, and read the meter.
The meter face has markings on it of resistance, and what range is considered Good, Fair, or Bad.

The CapAnalyzer 88A is a better meter.
You put it on to the cap in-circuit or out and you get a bad, good or fair indication immediately.

Sencore Z-Meter is the Best Unit I have ever used.
It will test not only for resistive changes in the cap.
But also Dielectric Leakage, Absorption, and give you the current value of the capacitor.

The MAT Electronics Analog unit.
Is cheap, right around $50, will test most capacitors.

The CapAnalyzer 88A.
Around $229, also will test most capacitors.

Sencore Z-Meter.
Expensive!!!!
Even the used good working units can go for over $1000!!!
But it will test ALL Capacitors!

I remember at the Vo-tech I went too.
I got to work on a portable tv that was popping the main AC fuse intermittently.
I suspected the 680uF 250V Filter Cap in the Main Supply.
But checking the Cap with a standard Cap Checker showed it was fine.
My instructor then told me to grab the Z-Meter, and test it with that.
I did, and found that the Cap was leaky, the Dielectric in it was slowly breaking down.
Thus, replacing that cap solved the problem.


Signed: Janitor Tzap

[dacflyer]

for some reason the pictures i posted earlier have gone bye bye, anyone have a clue as to why they went POOF ?

and why is this post so stretched wide for ?? crazy...

will return with more info later on for Edd...oh BTW the daughter board is all SMD's and the ID's have been sanded off of the IC's
Grrr. i do hope there is no problem with that board,

parts are ordered, waiting for them to arrive next week, all is on hold til then.. i'll get you the ID on the outputs in a while..