Cheaper alternative to AD MAT02 Transistor? - Gearspace.com
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Cheaper alternative to AD MAT02 Transistor?
Old 22nd November 2009
Cheaper alternative to AD MAT02 Transistor?

I bought an Ashly SC-50 today that I want to upgrade. From what I've gathered online from Jim Williams, I can replace all the resistors with Vishay/Dale RN55 series resistors, replace every cap and increase power supply capacitor values and add decoupling caps, use AD8597 for 301 and AD8599 for 4558 op-amps...so on and so forth.

However, Jim suggest replacing all LM394 transistor pairs with Analog Devices MAT-02 E, which are pretty expensive. This will already be a pretty expensive and time consuming upgrade, so is there a cheaper alternative?
Old 22nd November 2009
Well, actually, it's an obsolete product. So...what should I use instead? Is anything even made in the metal can TO-78 anymore? If not, am I stuck with the LM394?
Old 23rd November 2009 | Show parent
Lives for gear
🎧 15 years
I'm pretty sure the LM394 is on an end of life run. So once the stock at distributors is sold they will be rare.

Old 24th November 2009 | Show parent
Lives for gear
JohnRoberts's Avatar
🎧 10 years
The LM394 is not a bad part...

While you may better it with some modern technology, not cheaply or easily.

On a new design the THAT 300 series looks interesting (in dip or soic), but for your situation, unless they're busted why change them?

Old 24th November 2009 | Show parent
Gear Guru
They are available from NOS resellers. Prepare to pay $$$. The LM394 is also discontinued, thankfully. I've never found a worse sounding transistor pair, very dark and nasal sounding.
I've done some experimenting with the that arrays. They have low hfe's that will not allow them to sub the LM394. Even their MAT-4 copy won't work in those circuits, a 125 hfe won't even get you started, they fold at higher gains.

Jim Williams
Audio Upgrades
Old 24th November 2009 | Show parent
Thanks Jim, I think I can probably find some for sale on the prodigy pro website, $10 each seems to be the going rate.

As far as the RN55 resistors, do you remember what voltage and power rating you used in your SC-55? Does the tolerance make a big difference? Paying 8 cents instead of 58 cents for 50 or so resistors adds up, especially if I'm going to replace the op-amps and re-cap the whole thing.
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