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Amp Internals 2
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ArthurG View Drop Down
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Points: 976 		Post Options Post Options   Thanks (0) Thanks(0)   Quote ArthurG Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 1:45am
Originally posted by M4trix M4trix wrote:

I have orgasms when I see amps with 2SA1295/2SC3264 in the output. Rugged, fast and powerful bipolar transistors ! Hug


+1000
Back in the days, when I compared 200V/15A class transistors from Motorola Toshiba and Sanken, the latter was clearly the best sounding. Motorola has nice mids but lacks on bass. Toshiba was lifeless sounding. But Sanken, yummy bass and lovely mids. It brings joy to the music Approve
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Points: 817 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 12:51pm
The transistor itself cannot "control or modify bass".
The schematic where is implemented can do, regarding Damping Factor of amplifier.
 


Edited by DjLeco - 16 October 2016 at 12:52pm
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Points: 7216 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 2:02pm
+1

Those Sanken transistors are wider than the normal TO-3P devices, so better thermal transfer. They also seem to be more robust, maybe a bigger/better die.

A while back I broke open a load of A1943/C5200's from various suppliers (mainly ebay types) to see how different the dies where. It was crazy. Most of them looked like crap. I really don't trust those devices anymore, especially when they come attached to some cheapo amp.    Ouch





Edited by Earplug - 16 October 2016 at 2:04pm
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Points: 11155 		Post Options Post Options   Thanks (0) Thanks(0)   Quote jbl_man Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 2:08pm
Completely agree....beware of buying budget devices on ebay,way to many fake parts being flogged off,as you say Earplug,break them open,rubbish inside.
Be seeing you.
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Points: 817 		Post Options Post Options   Thanks (0) Thanks(0)   Quote DjLeco Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 5:32pm
Left genuine MJ On Semi, right Fake Motorola.
 
 
Fake one:
 
 
 
Left good clone of 2SC5200, right Fairchild (2S)C5200
 
 
 


Edited by DjLeco - 16 October 2016 at 5:32pm
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Points: 7216 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 6:28pm
Originally posted by DjLeco DjLeco wrote:

Left genuine MJ On Semi, right Fake Motorola.
 
 
Fake one:
 
 
 
 


That white paste seems to be common in a lot of fakes. I forgot to say earlier that what kicked me off was finding some fakes among a lot of transistors I bought from my local electronics store. They assured me that they only buy from a proper (legitimate) distributor, but somehow fakes got into the stock, so who do you trust?

I use this circuit to test all power transistors now, but unfortunately it's not going to get them all, just the worst ones:
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Teunos View Drop Down
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Original on the right, fake on the left. fake silicon area only 50% of the genuine article.
The fake was PNP while the original NPNLOL
Also note the large amount of voiding in the solder under the fake one on the left that reduces thermal capability.


Edited by Teunos - 16 October 2016 at 6:38pm
Best regards,
Teun.
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Points: 445 		Post Options Post Options   Thanks (0) Thanks(0)   Quote M4trix Quote  Post ReplyReply Direct Link To This Post Posted: 16 October 2016 at 9:40pm
Speaking of which, the only seller I trust on ebay regarding Sanken and Toshiba transistors is Electronics Salon. Never had problems with his devices. He even smashed couple of his products and showed what he is selling. Thumbs Up Probably there are more honest sellers on ebay but I'm not willing to experiment.

http://stores.ebay.com/Electronics-Salon/High-Power-Bipolar-/_i.html?_fsub=272699419&_sid=804830199&_trksid=p4634.c0.m322
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Points: 7216 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 17 October 2016 at 5:08pm
More old-skool stuff. Amp made in Valencia:





Again, a bit scant on the output devices:











Rogue generator damage - fried soft-start:
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Points: 445 		Post Options Post Options   Thanks (0) Thanks(0)   Quote M4trix Quote  Post ReplyReply Direct Link To This Post Posted: 17 October 2016 at 11:41pm
What's that small PCB with a 14DIP socket and ribbon cables attached to it ?
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Points: 7216 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 8:57am
That's just a splitter for the cable going to the front panel - input signals and LEDs.



EDIT:  You can see how it works in the first photo above - large cable g£s to the front and 2 smaller ones to the modules.    Smile

EDIT 2: WTF - 'o+e' = '£' ???




Edited by Earplug - 18 October 2016 at 9:03am
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Points: 445 		Post Options Post Options   Thanks (0) Thanks(0)   Quote M4trix Quote  Post ReplyReply Direct Link To This Post Posted: 18 October 2016 at 6:09pm
So, they didn't have enough cable to reach the front panel. LOL Wink
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