car amp repair man.....

[lucas569 10+ year member]

macs are heavy beasts, i had one back in the day and didnt really notice any real audible difference but then again i had ppi pro mos and soundstream reference series to compare to.

the good old days of QUALITY USA made amps //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

heck even with employee discount macs were pricey!

 

[amprepairman 10+ year member]

View attachment 26515402

this would be one of the 2 ss750.1's I got for $20.00 a piece broken off ebay

 

[amprepairman 10+ year member]

This amp and its matching partner will be my project amp's I have however pissed my son off because I decided to keep them as they are identical matches...

This is a good example of a cheap but really cool amp...It has many design features that I look for...(I wish it was a ZED!) but I'll work with it....

First off...for every fet in the power supply there is a output...many amps might have lets say 6 fets in the power supply and 10 outputs..just a example but I like the 1 for 1 deal myself....

The amps running 2SC5200/2SA1943 toshiba outputs...advertised collector current 15 amps a piece x 16 outputs=240 amps...wil it do it?...no...

but its a great starting point....these are a popular matched pair and I will prob stick with them but go with a matched set...

In the power supply we have 16 IRFz44N's...Real world good for about 40 amps a piece...for 640 amps...Will it do it...no...but its a great starting point as well...

So what Im gonna go for first is to find better caps..Probly ELNA GOLD (never had one fail) for audio...look around and see what my fet options are(not that the z44's are bad mind ya) but I want to see whats out there maybe try something new? ...and I'm gonna see if anyones got output transistors from the same batch..I need enough to do both amps mind you..Im gonna try for VBE within about 1millivolt and beta within 2% So I'll need to get about 200 of each figureing I need 32 of each hopeing 200 will give me enough to hopefully find matches.I use them alot day to day anyway so it doesnt bother me to buy so many at once...I need to get 100 at least anyway to get a decent price break...

Im gonna do some work on the board itself...someones been all over it with a cheap low wattage iron and it looks bad on the solder side...Im gonna clean it up and fill in all the high current traces and maybe I might line some of them with solder wick which is a copper braid we use in the service industry...I can make it look really good and Ive allready been warned about appearance!...I need functionality too though!So I'll go for both...

Also at one point the thermal sensor which should be mounted to the heatsink got bolted to the board itself...bad bad bad...So it was useless...

When I got it ..it took me all of five minutes to find the problem..It had one bad output..I simply clipped it off and powered it up..and it ran..its ok to do this in a multi output amp just for testing purposes...I unhooked the speaker lines and let it idle for about 2 to 5 minutes to see if anything got hot...under zero load you should get even heat up and no hot spots-I do this with no heat sink so that if theres a problem it'll show fast...You have got to be careful when you do this! I watch a current meter and my hands are all over the board the whole time its on...things can go tragically bad really fast if your not totally paying attention!

As Im doing this project I'll be posting pics along the way....

I will be using these amps in a full range old school passive crossover application...theres more than enough power for what Im doing and these amps are 1 ohm stable out of the box so Im not worried about that either...We call it equal power...

One amp per channel...350 advertised per amp at 4 ohms...I'll be running a single 10" 2-5 1/4"s and prob 2 tweets off each amp... I like the 10" for the tightness of the bass...I like quick responce and the 10 is the best woof made in my opinion..for sound quality anyway...I dont like 6 1/2s so I wont even go there...And most importantly...I NEVER use a speaker that isnt round.. no 3x5 5x7 6x9...trash!!! I have seen some 5x7 plates made by polk that used round drivers that were nice though...

Im gonna use MOREL speakers as I like the quality of them all around...I'm not going for ground pounding..Im going for SQ and enough power to make me stop turning it up way before I run out of power...Maybe not the 10..but all the other speakers are gonna hafta be morel...they got this internal 3" voice coil in a small package thats 300 watt capable...real world power too...I had 4 6" morels in the back deck of my 72 cutlass...untouchable mid bass...I loved them...

Anyway thats my goal...but Im just getting started so its gonna be a long road and keep in mind..I have my customer stuff too and it has to come first...

I hope everyone has a great christmas..Me?..I'll be fixing amps for the rest of the day...

Ho Ho Ho.....

 

[mrrbiggz 10+ year member]

Hey amprepairman...Welcome. This is one of the best threads Ive read yet. Thanks to all...Any who. I got a couple of questions, I currently run a kicker zx1500 for da lows its only 2 and 4ohm stable,, I got a DC lvl 3 15 with Dv2 upgraded coils which can go 4ohm or 1ohm..I can run da kicker @ 4ohm but its only rated 750.. what hapeens to the amp when it sees a 1 ohm load if its rated @ 2ohm's? Second, What do you think of the new Hifonics amps on ebay? Im thinkin of gettin a pair of them so I can have a matching set..Brutus and a Titan (lows and highs)Thanks

 

[amprepairman 10+ year member]

when you go against the manufacturers rating ...lower than allowed on ohm ratings...several things can go wrong...It might just go into protect...it might evenatually blow up and it might suffer heat damage and parts will eventually start falling out of it...I would come up with a sub configuration to run 2 ohms...the ultimate damage to your amps not worth it..it'll allso load down your electrical system in a matter not neccesary...once you start running in the 1 ohm world...your ******* the life right out of yout battery with the quickness....Me personally..I just wouldnt do it cause I hate fixin stuff cause I did just exactly what I was directly told(via instructions) not to do!...Which I was known for doing for years...good luck with whatever you decide! Let me know what you finally decide on...

 

[mrrbiggz 10+ year member]

yeah I hope to be doin my trunk soon...havin trouble gettin some questions answered regarding sub specs and box specs..But I'll def let ya know..

 

[amprepairman 10+ year member]

go to mcminone ..or google boxmaker or speaker box specs...be creative on google and you'll get the box maker calculator and it works for strange shape boxes as well...consider you need the specs off your speaker before you can begin

 

[amprepairman 10+ year member]

I would like to thank everyone whose posted on my thread...we are kickin *** and its pretty cool...so many visits in such a small amout of time...very nice....

 

[gunz4me2 10+ year member]

I am going to refurb an older Orion 280 GX that I am keeping as a backup for one of my systems. It has a couple of resistors that ran warm and I figure it could use a fresh set of electrolytic caps. The only downside is that I really want to choke the tech who seemed to use hot glue liberally:

 

[Louisiana_CRX 5,000+ posts]

I am going to refurb an older Orion 280 GX that I am keeping as a backup for one of my systems. It has a couple of resistors that ran warm and I figure it could use a fresh set of electrolytic caps. The only downside is that I really want to choke the tech who seemed to use hot glue liberally:

he didn't want parts to vibrate loose....

 

[amprepairman 10+ year member]

right...it was a act of preservation...Ive seen entire amps epoxy coated...great till it cooks....nothing a hammer and chisel cant fix though!

Replace the two large caps by the transformer too...that hot glue actually comes off pretty easy...just use a pick or something like that...its just time consuming...

 

[amprepairman 10+ year member]

I will be gone till monday but will still be answering emails...Have a great new years everyone....

 

[SicAudio 5,000+ posts]

You have a great New Years dude !!

 

[ABMughma 10+ year member]

sent ya an email just to let ya know

 

[amprepairman 10+ year member]

YEA! happy new years everyone....Lookin forward to a great year.....