SPL Z1X-3000D

[Dr Zeus]

I'm sure this amp is very similar to others. I've seen similar design in Power Acoustic and PowerBass amplifiers.

All IRFZ46N fets in the PS are blown. I've got a large order of IRFZ48N coming in. Can I use IRFZ48N? Arrow is out of the IRFZ46Ns. Also, this amp is using what looks like around three 100 ohm resistors in paralel of the PS fet gates as the components leading to the gates measure up about 33 ohms. I clippe one of the 3 off the board as they are mostly burnt up anyways and it measures at 100ohms.

Two of the ten FB31N20D outputs are shorted so I'll need to replace all of them in this amp. I can likely test this amp with the 8 surviving pieces, but is there any alternate I can use for FB31N20D? One shop I work with seems to be repairing a lot of amps using this for outputs but can never really find a price better than about $2 a piece.

I was poking around, and it looks like the last repair job had messed with Q413 which is an A1023 driver - Whomever put this part in did a junk solder job and just touching this part made it break off the board. Theres another A1023 just next to this one, and by the design this amp has two PSs. Both supplies are fried.

[Perry Babin]

The 100 ohm resistors are not in parallel. They appear to be in parallel because the FETs are shorted.

You can use the Z48s but the gate resistors may be borderline. I'd reduce the value a bit.

The best price you can expect on the 31n20d is $1.50. Arrow generally has them for that price. If you call for a quote at Future, they'll likely match that price. Quotes are generally much less than the site's pricing.

[Dr Zeus]

OK I'll add 47 and 68 ohm resistors to the order. Thank you.

[Dr Zeus]

I got some 47 ohm resistors which I'll try using for IRFZ48s. My 68 ohm resistors were not ordered correctly and I got 1w instead of 1/4w so they are huge.

Can I use BD139/BD140 for the A1023/C1027 ps drivers?

[Perry Babin]

I use the 139/140 extensively for drivers and haven't had any problems with them.

[Dr Zeus]

I've got this amp working pretty will with degraded outputs. Im still trying to search for good prices for a bulk order of 31n20D, but today I started looking for something a little bigger and better...

This amp originally came with IRFZ46N but is now running with IRFZ48N due to what I had in stock. If the PS is upgraded and working correctly, can I also try outputs to suite for a more complete upgrade? Im looking at STF40NF20 to repalce the stock 31N20D as they are more cost effective and look like a better (40A vs 31A) part.

[Perry Babin]

With class D amps, the specs can be deceiving, especially if you're only looking at the amp rating. If you look at the other specs, you'll see increased turn on/off time as well as increased total gate charge and input capacitance. All of these can make a difference. Even if they work in one amp. You'll need to try them in multiple amps of the same make/model to determine if they're a suitable substitute.

Also consider that these are fully encapsulated. Although the power rating isn't as important in class D amps, it's still a factor. The rating on these is only 40w vs 160 for the non-encapsulated version (which seems to be in short supply). Of course, you wouldn't use a insulator but if the original transistors were using an insulator that was more efficient than the plastic used for encapsulation, the encapsulated ones may not be as reliable.

The difference in cost isn't significant and I bet if you call or email Debbie at Future, you'll get a much better price that what's on the site (if you buy 100 or more).

[brandes.cm]

Any idea what value the caps are under the post-it note? I am repairing this same model and don't have the value and would like to order some today.

cory

[Dr Zeus]

I'd have to go look at a spare amp, but if your amp is like this, there is one cap larger unlike the other 4 near the speaker terminal outputs. This is the 6th rail cap. If you can get the numbers off of that then you'll know what to order. Order and replace all 6 rail caps.

[brandes.cm]

I was looking to order today and the amp is at home, it can wait.