QSC part question

[Techknowman]

I’m working on a MX2000a.
I need to replace 2 Mosfet transistors in the unit.
The QSC part number is QD-000031-QD which looking on the web has been replaced with an IRFZ44N. Now QSC doesn't want that part used but gives no other good part number but the QSC part number.
There was mention of a IRF1407 but QSC really didn't support it.
Anyone have an idea what to replace this PITA with?
(Stepping up on soapbox)
I hate oem part numbers for standard semiconductors what a PITA.
Companies like this need to get over themselves; they buy a standard part and just re-label it. It cost them more money it costs the consumer more money and waists a lot of time doing this smoke and mirrors stuff. At least companies like Peavey aren’t a pain about it.
I can understand truly OEM parts but sometimes its just plain ridiculous.
(Stepping off soapbox)

[Jazz P Bass]

Many manufacturers are "kind enough" to "select" and or "grade" there replacement transistors.
To me, this is truly a service.
Plug & Play.
Peavey, Crown, Carvin, Yorkville & QSC come to mind.
It does suck if they relable a "standard" part.
The techs that I have dealt with at QSC have always been helpful, although there online order page is kind of funky.

[Techknowman]

I could understand parts like matched complementary pairs and such but most modern manufacturing techniques produce parts to really close tolerances that make grading or selecting really just a way of saying "a way to make more money"

[dkessner]

Disclaimer: I'm an electrical engineer, and I work for QSC. What I'm about to say is my own words and not at all the official word from QSC.

First, let's talk about what you're calling an "OEM Part #". This isn't a "Re-labeled" part. Simply put, everything that QSC sells has a QSC part # on it. Much in the same way that everything Best Buy sells has an SKU or bar code #. The entire accounting system is based on these QSC part #'s. Further, all parts that go into a product also has a QSC part #. Diodes, MOSFETs, chips. Even the shipping boxes and manuals have QSC part numbers. Most of the time the customer never sees these numbers, as they are used to track inventory, order parts to build things, etc.

You might ask yourself, "Why go through the bother of having QSC part numbers at all, and just use the manufacturer part # instead (like IRFZ44N)?" Well, because we might have approved two different manufacturers for the same part. Or the manufacturer might change their part #. Etc. Our purchasing department knows what manufacturer part #'s can be bought for a specific QSC part number and orders the parts accordingly-- The rest of the company doesn't need to know, or care, that the part was made by International Rectifier, Texas Instruments, or whoever.

Now QSC is just like all other electronics companies in this regard. Next time you buy something, look at the packing list carefully. You'll see part numbers specific to who you're buying from. Digikey is a great example of this.

Some companies try to hide this from you, with varying degrees of success. QSC chooses to leave the customer exposed to this, but for a very good reason. By making you order according to QSC part # you are assured of getting the correct part. Even if the manufacturer discontinues that part and QSC needs to buy from a different source you'll still get the right part.

If you bought QD-000031-QD you would not get a relabeled part The bag it's in might be marked with the QD number, but the part itself would not have the original markings removed and the QSC part number put on it.

Now, as for what part to get for your amp... I'll have to wait until Monday to look it up. It's Friday evening where I am, and I've earned a quiet weekend. I'm send you a private email asking for some more info, too.

-David K

[Enzo]

I'm sorry, doesn;t want it used? The IRFZ44 has been working in these amps for years and years, and NOW we have to stop using them? I have always used random IRFZ44s, and never a problem. They are not working in parallel with anything, they are used as commutators, turning powr rails off and on. Get some plain old 44s from Mouser and try them.


And get off that soap box. They are not doing that to be snarky. They spec a part number, their number for a particular component. If they later find something elose works better there, they change what is in their bin for that part. You order from them by their part number, you get the part they currently consider best suited.

I love peavey, but try an order one of those 5000uf 55v can caps they used to use everywhere. You'll get a 4700/63v.

[Techknowman]

Enzo, as usual you are right. I didn't think of that scenerio for stocking parts.
From what I saw on a QSC forum...

QSC Audio Forum • View topic - Mosfet replacement

Re: Mosfet replacement by Thanh Nguyen on Thu May 14, 2009 2:04 pm
If you don't have QD-000031-QD, please contact QSC distributor in your area to order it. Note that IFRZ44 is no longer in approved list for QD-000031-QD. Thank you.

Dkessner, i apologize for being an A#S. I think I woke of on the wrong side of the universe!
It does make sense to use a single part number for what could be many different equivelent parts.

P.S. I'm going to hide my soapbox from myself!