Denon Output Transistors.

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Hi, I have a Denon AVC-A11SR (AVR 4802) amp that has blown a pair of output transistors. :(

MN1715 and MP1715, they are large plastic devices like the Sanken MT200 case. I have scrolled web without sucess. They are used in a number of their larger amps from the AVC-A1SE, AVC-1SR, AVC-A1VX etc as well as in the AVR's that match, so any help will be gratefully received.

I blew these driving a Quad ESL989 (rather hard) and on one of the Quads shut down's (thernal overload) the amp shut down as well. Now I have a QUAD 909 driving the ESL's as they handle the loads with out fail!!;)
 
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Thanks guys, always been a bit suspicious about buying components out of China. Thinking though that one.....um... the Amp originally came from there!!

I have checked the drivere and power supplies which in this case are ok.

I wrote the above from one brain lobe whilst thinking in an other. Ideally what I am looking for is a data sheet or just a description of them. I thought that they were a darlington as the earlier Denon amps used the MN15N - MN15P darlington combos. Comparing circuits between these amps the voltage acrss the base's are very close. These being 2.2Volst for the MN15x's and 2.4Volts for the MN/MP pairs.
I have tried unsuccessfully in fabricating darlingtons from differing discrete components but have always had problems setting the bais. (just proving that a little knowledge is dangerous!)

J
 
Yes I have. Not sure what service Denon offer down under but here they are a nightmare.

After numerous phone calls and email's I was given a phone number for an outlet that sold them. Only when I contacted them they wanted £55.00 plus postage per device, and to top it off they would have to order the part from the east after I paid up front for them!! grrrrrrrrrrrrrrrr
j
 
Thanks guys,
Have never used little Diode so thanks.

My original search was Sanken as they seem to be the main (only?) fabricator for the MT200 case but searching through their data base does not provide any clue to their real identify. They are not in their current or obsolete listing, I’ve even searched for matching Numerals with substitute Alpha characters but nothing matches. This did not surprise me as the earlier Denon models used MN15N / MN15P part No’s (which thanks to Jan Didden’s reply under the design & build forum too “unknown parts” identified them as SAP15x) are not listed by Sanken either.


Assuming that they are Darlington’s then there are only two pairs in Sanken’s catalogue the 2SB1750 / 2SD2401 and 2SB1648 / 2SD2561. Has anybody had experience with these?

I will continue with my search for data as I want to understand why the Quad ESL’s managed to destroy the original MN1715 / MP1715’s, then maybe I’ll be able to prevent this happening again if I drive them from the Denon.

I originally bought the Quad 909 to drive a pair of TL Sub’s in an effort to take the power of the lower octaves away from the ESL’s driving them into overload and protect the diaphragms in the process.

j.

 
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