The new series of Naim amplifiers has an unusual output device. From their website:
"A bipolar transistor with a specification combination of very high current, power rating and bandwidth was needed, far in excess of anything available to Naim before. A suitable output device was eventually developed after six years' collaboration with a semiconductor manufacturer.
"These outstanding components each provide up to 80 Amps and 350 Watts, negating the need to use parallel pairs of transistors (which always have a negative effect on sound). Additional 007 transistors are used in the fully regulated power supply, ensuring the very best performance."
My understanding is that Naim uses quasi-comp output stages, so I would assume that these are NPN only. This is still an extremely robust part. Does anyone out there have any more information on these parts?
"A bipolar transistor with a specification combination of very high current, power rating and bandwidth was needed, far in excess of anything available to Naim before. A suitable output device was eventually developed after six years' collaboration with a semiconductor manufacturer.
"These outstanding components each provide up to 80 Amps and 350 Watts, negating the need to use parallel pairs of transistors (which always have a negative effect on sound). Additional 007 transistors are used in the fully regulated power supply, ensuring the very best performance."
My understanding is that Naim uses quasi-comp output stages, so I would assume that these are NPN only. This is still an extremely robust part. Does anyone out there have any more information on these parts?
Naims own custom design
Not available I'm afraid, custom designed and manufactured for Naim exclusively, love to try them though!
RC
Not available I'm afraid, custom designed and manufactured for Naim exclusively, love to try them though!
RC
Does anybody know what package they are in? It would have to be pretty darned big to safely dissipate 350 watts.
Any guesses on the manufacturer?
Any guesses on the manufacturer?
I don't if this would be of any help .............
Transistors NA001 MJ15003 output transistors, BUV20 also good but expensive Farnell £3
Nait One Trannies
Try: BD711 - NPN & BD712 - PNP, both 12A @ 100V, 75W TO220 NPNs are numbered 003, PNPs numbered 004
ZTX384s may be replaced by BC182 or BC546. Also ZTX651Q & 751Q
NA005 BD743's will replace the NA005s- recommended by Naim.
ztx 653 npn used to replace ztx 652 N/A N/A N/A
Jam
Transistors NA001 MJ15003 output transistors, BUV20 also good but expensive Farnell £3
Nait One Trannies
Try: BD711 - NPN & BD712 - PNP, both 12A @ 100V, 75W TO220 NPNs are numbered 003, PNPs numbered 004
ZTX384s may be replaced by BC182 or BC546. Also ZTX651Q & 751Q
NA005 BD743's will replace the NA005s- recommended by Naim.
ztx 653 npn used to replace ztx 652 N/A N/A N/A
Jam
Charles,
From some review I learnt that the transistor has a house marking of NA001. A review is in issue #8 of Hi Fi+ (NAP500) might shed some light on the subject, sorry I do not have that issue.
From my post above, taken from some web site, it seems that the NA001 is a MJ15003 which makes it a Motorola TO-3 device..............but then again I could be wrong.
Regards,
Jam
PS The NAP500 is a bridged amp rated at 140W, may be the lower rail voltages....................., there is also the Motorola BUV20 which is more likely (higher ft )
http://www.alldatasheet.com/datasheet-pdf/pdf/MOTOROLA/BUV20.html
............or it might be some OEM Sanken device.
From some review I learnt that the transistor has a house marking of NA001. A review is in issue #8 of Hi Fi+ (NAP500) might shed some light on the subject, sorry I do not have that issue.
From my post above, taken from some web site, it seems that the NA001 is a MJ15003 which makes it a Motorola TO-3 device..............but then again I could be wrong.
Regards,
Jam
PS The NAP500 is a bridged amp rated at 140W, may be the lower rail voltages....................., there is also the Motorola BUV20 which is more likely (higher ft )
http://www.alldatasheet.com/datasheet-pdf/pdf/MOTOROLA/BUV20.html
............or it might be some OEM Sanken device.
Hi Jam,
Thanks for the detective work. The Naim website calls this part the "007", so I think it is different than the "001" Motorola part. I think I have issue #8 of Hi-Fi+ at work. I will look for it on Monday.
Thanks,
Charles
Thanks for the detective work. The Naim website calls this part the "007", so I think it is different than the "001" Motorola part. I think I have issue #8 of Hi-Fi+ at work. I will look for it on Monday.
Thanks,
Charles
With that power, they may just be using a new industrial package part. Since they like NPN devices, they don't need a compliment.
-Chris
-Chris
Why do you mean, that paralleling have negative impact in sound, Charles ? Have you some proofs for this statement ?
There have always been a handful of specialty semiconductor manufacturers who have built much larger discrete bipolar power transistors,
usually in metal and plastic modules with screw terminals. Alas,
my middle-aged brain refuses to recall a single name now! Often
these are multiple devices soldered in parallel on a heat spreader
that is bolted to an appropriate heatsink.
However, for the right price, the semiconductor die can be made
much larger for increased current and power dissipation. These are
usually employed in motor controllers and the like, and seldom
make it into consumer electronics.
An advantage is that two large devices can replace many paralleled
devices, and save some money on the simplified assembly. I can see
where Naim could have commissioned a special part for their design
at reasonable cost (to them), when manufactured in the thousands.
I guess my question is how fast these transistors would be.
But I'll continue to use paralleled transistors, thank you; far cheaper
and more available.
I had a look at Apex Microtechnology's site, but it appears they are
into large power ICs rather than discrete semiconductors.
usually in metal and plastic modules with screw terminals. Alas,
my middle-aged brain refuses to recall a single name now! Often
these are multiple devices soldered in parallel on a heat spreader
that is bolted to an appropriate heatsink.
However, for the right price, the semiconductor die can be made
much larger for increased current and power dissipation. These are
usually employed in motor controllers and the like, and seldom
make it into consumer electronics.
An advantage is that two large devices can replace many paralleled
devices, and save some money on the simplified assembly. I can see
where Naim could have commissioned a special part for their design
at reasonable cost (to them), when manufactured in the thousands.
I guess my question is how fast these transistors would be.
But I'll continue to use paralleled transistors, thank you; far cheaper
and more available.
I had a look at Apex Microtechnology's site, but it appears they are
into large power ICs rather than discrete semiconductors.
Yes, transistors for locomotives, it is righ thing, which catapult this firm into hifi heaven...😀 ( but still in quasicomplementary heaven...😀 )
Dimitri,
You maigt be right..........................but look at the maximim base current, you probably need an output device to drive these things.............😀
Regards,
Jam
You maigt be right..........................but look at the maximim base current, you probably need an output device to drive these things.............😀
Regards,
Jam
jam said:
That's easy to fix. These babies from ON are 300 W Darlingtons with hfe of min 400 @ 50 A Ic 🙂
www.elfa.se/pdf/71/07105208.pdf
dimitri said:
OK, Dmitri, you've solved the mystery. The NAP-250 uses the "007" transistors, and they are clearly TO-3 packages.
I'm used to using TO-264 packages, which stop at about 15 A and 230 W for modern high-speed designs. I was surprised to hear about devices with 5x the current and over 50% power dissipation, but as you and others have pointed out, the Naim transistors are not so unusual.
Thanks for your input, everybody!
dimitri said:
80A BUR51, BUR52 from ST, 60A BUX20 from Semelab
hFE=20-100, transition frequency 10Mhz
NAP-250
Dimitri,
you have e-mail!
Charles,
how come you are so keen to BJT output tranies, should it not be lateral FET's to make you post, or are we seeing Ayre with BJT's in the output soon? 😀
Cheers michael
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