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Old 14th November 2012, 09:01 AM   #2621
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Quote:
I figured I should start to work with 2n3055 (as they are cheap) and when the circuit is debugged and stable, to upgrade it to MJ15003 as most people recommend it.
Small warning:
I did something like that too. But with my relatively high rail voltages (about + and minus 20V) the Toshiba's 2n3055 where just outside their SOA. One channel repeatedly died on me.
After changing to the new transistors overything is ok.

MArco
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Old 14th November 2012, 10:40 AM   #2622
Mooly is offline Mooly  United Kingdom
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Quote:
Originally Posted by deduikertjes View Post
Small warning:
I did something like that too. But with my relatively high rail voltages (about + and minus 20V) the Toshiba's 2n3055 where just outside their SOA. One channel repeatedly died on me.
After changing to the new transistors overything is ok.

MArco
Perhaps they weren't genuine devices. 40 volts and a couple of amps (which is more than the JLH runs at) is well within a 2N3055's abilities as long as it is cooled sufficiently.
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Old 14th November 2012, 12:53 PM   #2623
AC439 is offline AC439  United States
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Quote:
Originally Posted by deduikertjes View Post
Small warning:
..... (about + and minus 20V) the Toshiba's 2n3055 where just outside their SOA. One channel repeatedly died on me.
After changing to the new transistors overything is ok.

MArco
I also first started with Toshiba 2n3055 bought from the "_bay" for prototype thinking they were fake. I paid $1/piece. But to my surprise, they did not sound bad at all. I ran them at +/- 25v for quite a while before changing them to MJ15003. The upgrade was a direct swap and no adjustment was needed.
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Old 14th November 2012, 03:26 PM   #2624
Jaap is offline Jaap  Netherlands
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Default Huh ?

Is something wrong with the siliconray PCB's ?
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Old 14th November 2012, 04:13 PM   #2625
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Jaap, if you're concerned by the discussions around the siliconray pcbs that I've started, it's just that it's my first diy amp, so I managed to fry it when I first powered it, and then after powering it second time.. and then after short circuiting some transistor with the test probe.. . no reasons to panic. I'll receive the replacement transistors tomorrow (or so I hope), and come back with the results, of more questions..
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Old 14th November 2012, 05:58 PM   #2626
AC439 is offline AC439  United States
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Originally Posted by Jaap View Post
Is something wrong with the siliconray PCB's ?
There is a discussion on their board. Error was mentioned but seems like was fixed in later version of the board:-

★★ Free PCB for JLH 2005 Class-A Amplifier

I don't use their board so I cannot verify this.
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Old 16th November 2012, 01:46 PM   #2627
Geoff is offline Geoff  United Kingdom
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Good news! TCAAS is now back on-line. It is being hosted by ESP (many thanks Rod) and can be accessed using the following link:

The Class-A Amplifier Site

or via the ESP index page (it's in the 'Articles & Information' section):

Elliott Sound Products - The Audio Pages (Main Index)
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Old 16th November 2012, 02:12 PM   #2628
Telstar is offline Telstar  Italy
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Thanks Rod!
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Old 16th November 2012, 04:26 PM   #2629
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an aside. I used Bourns TIP3055 in Rod Elliots P3 amp with +/- 42V rails with no issue. At least none I was aware of. They worked much better than the SMI types i trialled breifly, but even those didnt fail.
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Old 16th November 2012, 11:30 PM   #2630
paulb is offline paulb  Canada
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Originally Posted by Geoff View Post
Good news! TCAAS is now back on-line.
Good news indeed, and good to see your name here again Geoff! Time to dust off my JLH and put it back in service.
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