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Old 18th June 2004, 08:55 PM   #11
K-amps is offline K-amps  United States
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Quote:
Originally posted by BobEllis
Thanks, guys. I'll try the MJ21195/96 mod Leach. Too bad the usual suspects don't have them in stock. Arrow shows a 10 week lead time. Digikey has the similarly spec'd MJ21193/94 in stock tho.

I had a Phase Linear 400 in college. My brother had it when it blew. At least my speakers were OK.

Slowhands, I appreciate your caution. I'll set the transformer primary to give 80 volt rails. If I blow the outputs I'll go with MOSFETs the next time.
How many pairs of 21195/96 do you want? I have many ....
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Old 18th June 2004, 08:57 PM   #12
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Quote:
Originally posted by markp
The MJL21195/6 are higher voltage devices so you should stick with them.
Yeah right! which is higher; Vce of 250v or Vce of 250v?

Your serve!
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Old 18th June 2004, 09:01 PM   #13
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Quote:
Originally posted by BobEllis
Thanks, guys. I'll try the MJ21195/96 mod Leach. Too bad the usual suspects don't have them in stock. Arrow shows a 10 week lead time. Digikey has the similarly spec'd MJ21193/94 in stock tho.

I had a Phase Linear 400 in college. My brother had it when it blew. At least my speakers were OK.

Slowhands, I appreciate your caution. I'll set the transformer primary to give 80 volt rails. If I blow the outputs I'll go with MOSFETs the next time.
I have used the 21193/94/95/96 in the said Adcom 555II with no issues at +/- 100vdc rails!

You can be as conservative as you want which is sometimes good, yet from your earlier post, I sense the primary reason or interest you had was high power for a sub-woofer... in that scenario, you are fine with the 21195/96's even 3 pairs, heck I am willing to wager that the 3 pairs will be fine with a 4 ohm woofer no problems at 90v rails.
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Old 18th June 2004, 09:08 PM   #14
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Quote:
Originally posted by K-amps


Yeah right! which is higher; Vce of 250v or Vce of 250v?

Your serve!
The SOA allows a higher voltage to be used on the 95/6 safely. Balls in your court.
They would not make two identical spec'ed transistors, would they?
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Old 18th June 2004, 09:30 PM   #15
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The 1 second SOA appears identical 3 amps at 80 volts for either device - perhaps they put in the wrong curve for the 93/94, or the 95/96 is more tolerant of short duration high current operation. At any rate, I'll trust your experience Mark. Thanks for the insight.

K-Amps, Please contact me off line robert.e.ellis (at) verizon.net, I'm interested in 6-10 pairs.
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Old 18th June 2004, 10:30 PM   #16
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Quote:
Originally posted by markp

The SOA allows a higher voltage to be used on the 95/6 safely. Balls in your court.
They would not make two identical spec'ed transistors, would they?
Mark:

Your statement was about absolute voltage not SOAR. It read something like this, "The MJL21195/6 are higher voltage devices so you should stick with them."

Correction: They are not higher voltage devices... they are the same voltage devices in the absolute sense. They might handle higher currents for a given unit of time but that does not make them higher voltage devices.

Now please be a man and own up to the mistake you made instead of refuting it ad nauseum and sucking both of us in a peeing contest that I do not wish to be part of. I make many mistakes too, we are all human....

Now to your next statement: "They would not make two identical spec'ed transistors, would they?"

Define similarly spec'ed? Mototrola is one manufacturer I know for a fact makes large quantity parts and then grades them by yeilds. This grading is done per batch (pre-labelling) by non-destructive testing. They can test the secondary breakdown structures of the device and then categorize the batch as having higher SOAR or lower SOAR devices. And label them either as a 93/94 or a 95/95 part. Now they could have labelled everything as 21193/94 but then they would'nt be taking advantages of some parts that offered better SOAR parameters.

I did suggest to BobEllis (before) your post that I'd recommend him to upgrade the Adcom to 2119X devices. So to answer another one of your antagonistic remarks, 4X 250 is better than 3X 250. As far as heatsink area is concerned, it's importance is more of an issue with lower impedances which BobEllis did not mention that he needed.

Lastly the GFA-555II's heatsinks are much larger than the older 555's and can easily handle one woofer.... making heatsinking an issue when it is not is festering a non-productive argument. As suggested by slowhands, secondary breakdown is more of a primary concern than thermal equilibrium of the heatsinks.

Since I have been on the forum, I have learnt not to assume the other guy is an ignorant moron, it has saved me many a troublesome situations. I do not consider you one either and think you have given some good suggestions to our friend, I just feel you were a little more antagonistic than you needed to be.

regards,

K-
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Old 18th June 2004, 10:41 PM   #17
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I don't think that the words 'identical' and 'similar' are the same. You are putting words into my mouth that don't have the same meaning and blaming me for being antagonistic. I never brought up heatsinks so why attack me about them?
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Old 18th June 2004, 11:00 PM   #18
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Mark,

My apologies, the heatsink remark was meant for djk,

cheers!
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Old 19th June 2004, 02:13 AM   #19
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My personal experience is that three pair of MJ21193/94 can deliver 600W/4R with proper heatsinking.

At 100V this part has 200W SOA for $2, a far cry from fragile, expensive lateral FETs ($10 for 125W SOA)
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Old 20th July 2009, 06:02 PM   #20
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Question Yamaha M2 for parts

Does anyone out there still have a Yamaha M2 to sell for parts? I am rebuilding mine (again), need outputs and drivers and some misc parts
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