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-   -   What 'class' is this Hill Audio DX3000 Amplifier? (https://www.badcaps.net/forum/showthread.php?t=106096)

dicky96 05-04-2022 04:20 AM

What 'class' is this Hill Audio DX3000 Amplifier?
 
2 Attachment(s)
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

dicky96 05-04-2022 04:27 AM

Re: What 'class' is this Hill Audio DX3000 Amplifier?
 
1 Attachment(s)
Try this pic :)

eccerr0r 05-04-2022 09:19 AM

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.

dicky96 05-05-2022 03:28 AM

Re: What 'class' is this Hill Audio DX3000 Amplifier?
 
Thanks eccerr0r

Erico1 05-16-2022 09:16 AM

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.

eccerr0r 05-16-2022 09:47 AM

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...

Erico1 05-17-2022 02:48 PM

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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