What type of transistor is the NA009?


Just wanted to know what type of transistor is the NA009. Is it a JFet, bipolar…?

Anyone know???

MOSFET pretty sure. Someone will confirm.

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@NeilS interested to know also

Interesting question i don’t think Naim have ever said that much about them. Even the reviews of Statement amps do not go into that level of detail.

Yep. That’s why I thought I’d ask. There is never any mention anywhere???

The DR technology used in the Statement and the NAP250DR, NAP300DR, and NAP500DR was widely covered in the press. You might be interested in one of the most in-depth reviews from Martin Colloms for Hifi Critic, which is available to read online;

AFAIK it is similar in type to the outgoing 007, the main differences being materials (non-resonant epoxy and copper body and copper legs) used and that the 009 is precisely matched from single silicon wafers into NA009N and NA009P.

Thanks but where does it mention what type of transistor it is?

It doesn’t make specific mention of the type, so, as I wrote above, I would guess it’s similar to the outgoing 007 and 001, i.e. bipolar. However, I’m sure Naim can confirm one way or other for you.

A good one!


A long time ago I used to collect clips whenever Naim actually said anything. A quick search gave this:

Mr. Vereker in 1999 on the 250:
"I wanted a transistor which was very fast (rather than necessarily linear), without any storage time especially at low currents, and I wanted it to turn off at low currents.”

And this was once on the Naim website on the NA007:
"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.

The NAP 250 uses the same 007 transistors that were custom-designed for the NAP 500. 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."

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If they come in npn and pnp varieties, then they aren’t MOSFET!



Stephen Fry is bipolar. Could explain why he is more funny.

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Thanks :+1:t2:

Don’t Naim use NPN for both of a quasi complimentary pair, presumably for better matching? I seem to remember reading that somewhere.

I assume bipolar NPN and PNP for either side of the output AB push pull.

Every helpful, here’s a Pushme Pullyou complete with Dr Doolittle, who discovered it:

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According to Art Dudley, writing in Stereophile, Listening column #205:

“Other Naim characteristics include their use of quasi-complementary class-AB output stages—NPN transistors are used for both halves of the waveform, rather than the far more common approach of using NPN devices for one phase and PNP for the other—and Naim’s amps make extensive use of star grounding…”

Ok, thanks for clarification.

NPN transistors should switch faster than PNP ones all other things being equal.