Wicks' E46 M3 Build. Hertz 3-Way Set from Tony D!

[Wicks]

Looks amazing dude!. A trick I learned with glass is to brush a little resin over the tape and then put the Matt over it, the resin will hold it down since its sticky! Keep up the great work

Thanks!

Yeah I was thinking while I was writing up the post..."Man, I should have sprayed a light coat of spray adhesive or something similar on the tape to allow me to set the initial layer of cloth nice and smooth...."

Ohh well. Live and learn.

[SnowDrifter]

How is it that I've managed to miss this entirely too-sexy build until today? Wooaoaoaoaoawww!!

[Wicks]

How is it that I've managed to miss this entirely too-sexy build until today? Wooaoaoaoaoawww!!

Thanks for stopping by Dude

You've probably been busy running from all the Cap-Haters out there.

Moar updates on those caps!!

Stay tuned, the sexiness has only yet begun...

[simicblu]

dammm man great project, have been watching it almost from the beginning... keep up the awesome work can't wait to do something like that have some things on my mind

feet kicked up, waiting for the next update

[Wicks]

dammm man great project, have been watching it almost from the beginning... keep up the awesome work can't wait to do something like that have some things on my mind

feet kicked up, waiting for the next update

Well, thank you Sir!

You're next update is coming shortly.

[Kyblack76]

bout time.. slacky slack face...

[Wicks]

Disclaimer: Prepare yourself. Gratuitous amount of amp porn coming up!

I started this build last year originally wanting to do an all old school build but quickly realized that no old school amp would be able to push my XL12's so I altered the plan a little.

But an old school amp would work perfect for my Hertz High's.

I also needed an amp whose heatsink was more vertical then horizontal (due to the tight spaces in my trunk) which is hard to find nowadays.

It just so happens that my old school Rockford Fosgate Punch 200DSM fits all those requirements perfectly.

I bought the amp used from a friend in 1994 and it was built in 1993 which makes it a lot older then most of you on this forum...

I popped the board out, here's a walk-around:

Pic of the output FET's. IRF540's. Good for 100V and 33A each.

In case you're curious: These conduct alternately from the positive and negative power rail to the speaker outputs.

Pic of the Power Supply FET's. IRFZ40's. Good for 60V and 50A each.

In case you're curious: These pulse the 12-14V from your electrical system through the primary of the power supply toroid transformer.

They help turn DC voltage into AC which the toroid then can use to create a higher voltage AC.

Power Supply Rectifier Diodes. U1610/U1610R. Good for 16A each.

In case you're curious: These "rectify" that AC voltage that has been boosted by the toroid and turn it back into DC (power rails).

One rectifies for the positive rail and one for the negative.

Since its was a good 20 years old I wanted to refurb it since electrolytic caps tend to dry out and degrade with age.....or do they?

I went to Mouser.com and ordered up a bunch of different replacement caps to see which ones I liked best.

The amp was originally built with Nichicon brand caps (which most old school amps were) and they are great caps but it is possible for good caps to go bad after 20 years of intermittent use.

I have access to a nice LCR meter at work. An LCR meter can measure impedance, capacitance and inductance at various frequencies and is very handy in determining whether components meet their specifications or not.

Here are the old Nichicon's (from the power rails) on the LCR:

They're rated at 3300uF so to my complete surprise they are still well within initial specs (+/-20%).

(3mF = 3000uF).

Here's the best available replacement cap from Nichicon since that series of cap is no longer available.

As you can see, brand new, out of the bag and they measure ~2800uF and a slightly higher ESR (Equivalent Series Resistance).

Here's another brand (Cornell Dubilier 3900uF):

Here is a new cap from Panasonic which is rated at a higher base capacitance (3900uF):

You an see it takes a higher rated cap to even come close to that original rating of 3300uF.

Really justifies the saying: "They sure don't make 'em like they used to..."

[Omega5002]

I bet that 100 rms per channel rating is an understatement

[SnowDrifter]

Wicks.... You're doing that "thing" again. You know... Where you make me drool? lol

[Wicks]

Here are the 12V caps at the power input to the amp:

These are what cause that spark when you first connect your power wires to the amp as the caps charge up QUICKLY.

Here is what they measure:

I found some nice Nichicon "MUSE" replacements which are supposed to be great for music applications:

Similar capacitance but much better ESR!

Here's an angle shot with the power rail caps removed:

Looky what I found, a burnt power supply FET. Good thing I decided to refurb some parts.

Smaller caps, various power resistors and 12V input caps replaced:

Lining up the new power supply FET's. ST P75NF75's. Good for 75V and 80A each!

Output FET's yanked:

Output FET's lined up. IRF540's, similar as the originals. 100V and 36A each.

Output FET's soldered:

Refurb'd walk-around:

Hmmm, originally had a red power LED. Red means "bad"........lets swap that for a green one.