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Old 05-04-2022, 04:20 AM   #1
dicky96
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Default What 'class' is this Hill Audio DX3000 Amplifier?

Hi guys, this is general query really

So I have a Hill DX3000 3KW audio amplifier here.

It has a topology/design like a class A/B but all the banks of output transistors (10 transistors in each 'side' of the channel) are NPN.

I was wondering what class this is. It doesn't fit the description of class A.
It also doesn't match class A/B or B amplifiers as all the examples I see have a complimentary output stage desigs (NPN/PNP) and clearly is not G, H or D

I looked for 'class A push pull' but that didn't tell me anything either

Here is the schematic. So what is it?


OOPS WRONG PIC - On moment

thanks
rich
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File Type: rar hill_dx1000_dx2000_dx3000_amp_sm.rar (17.89 MB, 29 views)
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Last edited by dicky96; 05-04-2022 at 04:22 AM.. Reason: WRONG PIC LOL!!!! one minute...
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Old 05-04-2022, 04:27 AM   #2
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Default Re: What 'class' is this Hill Audio DX3000 Amplifier?

Try this pic
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Old 05-04-2022, 09:19 AM   #3
eccerr0r
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Default Re: What 'class' is this Hill Audio DX3000 Amplifier?

Without looking at the schematic, likely Class AB.
AB can also be all NPN or all PNP power transistors.

---

Now after looking at the schematic, it indeed has a quite unusual design, but seems to fit just as well - still has all the characteristics of an AB design.

Last edited by eccerr0r; 05-04-2022 at 09:32 AM..
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Old 05-05-2022, 03:28 AM   #4
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Default Re: What 'class' is this Hill Audio DX3000 Amplifier?

Thanks eccerr0r
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Old 05-16-2022, 09:16 AM   #5
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Default Re: What 'class' is this Hill Audio DX3000 Amplifier?

@eccerOr
The manual you provided describes it on page 5 as a "Super A" sliding bias configuration. See the first paragraph in the Operation section.

Last edited by Erico1; 05-16-2022 at 09:17 AM.. Reason: added the page number to the reference source.
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Old 05-16-2022, 09:47 AM   #6
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Default Re: What 'class' is this Hill Audio DX3000 Amplifier?

The main characteristic of class B is evident in the design however - since only half of the transistors are on during a specific half of the waveform. Yes this design leaks like a class A but not as much as so due to the half waveform design, so it's tough to classify these.
I don't see any advantage of this over a traditional AB design, just costs more with ugly transformer coupling...
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Old 05-17-2022, 02:48 PM   #7
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Default Re: What 'class' is this Hill Audio DX3000 Amplifier?

I read an article that described it as an A+B type. The design is derived from Technics.
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