Integrated Amplifier

[VJC]

Hi Guys, 

Can anyone please help me with a class A amplifier like Luxman 550 AXII or Sugden a21se maximum current output from the amp when playing music?

 

Thank you

Edited November 6 by VJC

[Hydrology]

Im sorry, could you elaborate on what the question is?

[Grizzly]

7 hours ago, Hydrology said:

Im sorry, could you elaborate on what the question is?

 

I think we're looking for either specified or measured current delivery of either amp.

[Snoopy8]

If high current is the criteria, why not get a Purifi Eigentakt powered integrated amp like this?

 

https://nadelectronics.com/product/m33-bluos-streaming-dac-amplifier/

 

And with Dirac Live room correction.

[VJC]

On 05/11/2024 at 10:13 PM, Hydrology said:

Im sorry, could you elaborate on what the question is?

Hi Hydrology, can you please help me how much max current output by Luxman 550 AXll while playing the amplifier?

 

Please refer attachment. Thank you

Edited November 6 by VJC

[VJC]

23 hours ago, Grizzly said:

measured current delivery of either amp.

Yes please Grizzly.

[Grizzly]

Just now, VJC said:

Yes please Grizzly.

 

From some cursory reading it doesn't appear that strong current delivery (ie into low impedances) is necessarily the strong suit of a proper class A amp. They are better paired with relatively easy to drive speakers, though not restricted to high sensitivity. Emotion over impact, if you will. If it was me I'd be looking to BBC monitor style or single driver "full range" speakers.

 

We may be putting the cart before the horse though- still best to settle on speakers that move you, then find the amp that pairs with them to really give you "the feels".

[Mendes]

2 hours ago, Grizzly said:

We may be putting the cart before the horse though- still best to settle on speakers that move you, then find the amp that pairs with them to really give you "the feels".

This is valuable advice.

What speakers are you looking to use/ do you have?

 

[sir sanders zingmore]

4 hours ago, Grizzly said:

 

From some cursory reading it doesn't appear that strong current delivery (ie into low impedances) is necessarily the strong suit of a proper class A amp. They are better paired with relatively easy to drive speakers, though not restricted to high sensitivity. Emotion over impact, if you will. If it was me I'd be looking to BBC monitor style or single driver "full range" speakers.

 

We may be putting the cart before the horse though- still best to settle on speakers that move you, then find the amp that pairs with them to really give you "the feels".

 

This is my understanding too. 
The audiophile world defines “high current” amps as those that double (or nearly double) their power as the impedance halves. 
As I understand it, Class A amps deliver the same power into different impedances and are therefore, not high current by that definition 
 Class A amps that quote any sort of “doubling” are actually not pure class A but are some kind of high bias A/B

(I may be completely wrong, but I’m pretty sure that’s what @Zaphod Beeblebrox once said and he knows a lot more about this stuff than I do)

[aussievintage]

4 minutes ago, sir sanders zingmore said:

As I understand it, Class A amps deliver the same power into different impedances

 

No I don't think that's right.   There may be a temperature limitation, but with big enough cooling systems, half the load should result approx. double the current, if the the devices and their power supply can handle it.    As for high bias class A/B, there is an argument to be made that most class A amps are really this.  In the end it doesn't matter at all, because we usually only listen to a small fraction of their capability, so most amps stay in the Class A region of operation.

[sir sanders zingmore]

4 minutes ago, aussievintage said:

 

No I don't think that's right.   There may be a temperature limitation, but with big enough cooling systems, half the load should result approx. double the current, if the the devices and their power supply can handle it.    As for high bias class A/B, there is an argument to be made that most class A amps are really this.  In the end it doesn't matter at all, because we usually only listen to a small fraction of their capability, so most amps stay in the Class A region of operation.

looks like I was wrong. I found the quote I was referring to and it’s even worse than I said:

 

 

On 4/3/2017 at 3:21 PM, Zaphod Beeblebrox said:

 

Oh dear, can 'o worms time. Here's the dirty little secret about Class A amps:

 

A Class A amp rated at 20 Watts @ 8 Ohms, will deliver:

10 Watts Class A @ 4 Ohms

5 Watts Class A @ 2 Ohms

2.5 Watts Class A @ 1 Ohm

 

https://www.stereonet.com/forums/topic/119510-class-a-solid-state-amplifiers/?do=findComment&comment=1802115

but it turns out that is for single ended only

 

On 4/3/2017 at 3:31 PM, Zaphod Beeblebrox said:

 

Nope. You nailed it in one. That said, there is no reason why a push pull Class A amp cannot deliver more power into lower impedances, provided the output stage and power supplies are suitably rated, but with single ended Class A amps, you're pretty much screwed: Lower impedances = lower power outputs.

 

so you are correct @aussievintage as long as it’s push pull Class A

[aussievintage]

3 minutes ago, sir sanders zingmore said:

so you are correct @aussievintage as long as it’s push pull Class A

 

ah yes, I was only thinking of push/pull.     Single ended solid state is not something I think of often.  For me single ended makes me immediately think of a nice triode, but then there is an output transformer with taps that make all loads equal  

[Grizzly]

Hooray, everyone is right!!

 

Kum Ba Yaaaaaah, m'lord......

[aussievintage]

5 minutes ago, Grizzly said:

Hooray, everyone is right!!

 

Kum Ba Yaaaaaah, m'lord......

 

You've started early...  

Edited November 7 by aussievintage

[andyr]

The rabbit hole is even more twisty than that, Trev!

 

Copying your post:

 

 

 

... I recently built two of the 40w-into-8ohms Class A amp which Hugh Dean designed for diyAudio - the 'Alpha Nirvana'.  (Actually, I built the 40w-into-4ohms version ... to power the 3ohm mids & 2ohm ribbons of my Maggies.)

 

This has +/- DC rails ... but behaves like a 'single-ended' design - in that the mosfets don't turn off.

 

The clipping tests I did (using a resistive load - and looking at the 1kHz output sine wave on my 'scope) showed the following:

• 3.7R load - 47w (voltage limited)
• 3.1R load - 52w (current limited - not voltage limited)
• 2.5R load - 42w (current limited)
• 2.1R load - 34w (current limited).

 

 

 

[sir sanders zingmore]

10 minutes ago, Grizzly said:

Hooray, everyone is right!!

 

Kum Ba Yaaaaaah, m'lord......

No, I was wrong

[Grizzly]

4 minutes ago, aussievintage said:

 

You've started early...  

 

On any given day, between 12 and 5.30am there is very little silliness in my life. Once my feet hit the floor, however, it's a different question entirely. This is quite off topic though, with apologies to the OP.

 

I do like to be silly though, keeps one young.

[Grizzly]

1 minute ago, sir sanders zingmore said:

No, I was wrong

 

Well, partially. As was I. Let's sing anyway.

[aussievintage]

20 minutes ago, andyr said:

 

 

 

... I recently built two of the 40w-into-8ohms Class A amp which Hugh Dean designed for diyAudio - the 'Alpha Nirvana'.  (Actually, I built the 40w-into-4ohms version ... to power the 3ohm mids & 2ohm ribbons of my Maggies.)

 

This has +/- DC rails ... but behaves like a 'single-ended' design - in that the mosfets don't turn off.

 

The clipping tests I did (using a resistive load - and looking at the 1kHz output sine wave on my 'scope) showed the following:

• 3.7R load - 47w (voltage limited)
• 3.1R load - 52w (current limited - not voltage limited)
• 2.5R load - 42w (current limited)
• 2.1R load - 34w (current limited).

 

 

 

 

I wish you hadn't muddied the waters with this.  It's SE with a reactive push-pull by the active constant current circuit.    Not a good example to use at all.

Edited November 7 by aussievintage

[rantan]

On 05/11/2024 at 10:26 PM, VJC said:

Hi Guys, 

Can anyone please help me with a class A amplifier like Luxman 550 AXII or Sugden a21se maximum current output from the amp when playing music?

 

Thank you

This thread has become needlessly complex to the point where I wonder if you are getting caught up in technicalities which you do not need?

Unless you have speakers which are VERY difficult to drive then a Luxman L550 AX II will do the job with ease and grace and you may be  very agreeably surprised at the result

I have the earlier version of your Luxman amp and I have used it with a wide variety of speakers ( with varying sensitivity and impedance ) over several years and never once did I have even a hint of a problem in my med-large room with any speakers I tried . The Sugden is slightly less able with more difficult loads but still sounds beautiful and should work  with most sensible specified speakers.

[rantan]

31 minutes ago, Grizzly said:

 

 Let's sing anyway.

 

"there's a lady who is sure all that glitters is gold and she's buying a stairway to heaven"

[Zaphod Beeblebrox]

1 hour ago, sir sanders zingmore said:

 

This is my understanding too. 
The audiophile world defines “high current” amps as those that double (or nearly double) their power as the impedance halves. 
As I understand it, Class A amps deliver the same power into different impedances and are therefore, not high current by that definition 
 Class A amps that quote any sort of “doubling” are actually not pure class A but are some kind of high bias A/B

(I may be completely wrong, but I’m pretty sure that’s what @Zaphod Beeblebrox once said and he knows a lot more about this stuff than I do)

 

Not quite.

 

Single ended (SS or valve) do exhibit such a characteristic. Push pull is different, though pentode valve amps tend to deliver approximately the same output power, regardless of load impedance. Triodes, OTOH, operate more like SS amps, in that they deliver more power into successively lower impedances. Within limits.

 

A SS Class A amp, like a Class A/B amp, may deliver higher powers into successively lower impedances.

 

NB: There is no amplifier in this universe that can deliver a perfect doubling of maximum power into half the output impedance. What happens is that, manufacturers will typically build a (say) 100 Watt amplifier, but rate it at (say) 50 Watts. Krell did it with the original KSA50 amplifier. The KSA 50 was actually a 75 Watt @ 8 Ohms amplifier. Then, as internal losses of the output stages increased, due to higher current requirements, the amplifier appeared to double it's output with each successive impedance drop.

[sir sanders zingmore]

1 hour ago, Grizzly said:

 

Well, partially. As was I. Let's sing anyway.

Sounds good. Can we drink too?

[gemini07]

On 05/11/2024 at 10:26 PM, VJC said:

Hi Guys, 

Can anyone please help me with a class A amplifier like Luxman 550 AXII or Sugden a21se maximum current output from the amp when playing music?

 

Thank you

 

I own a Sugden A21 SE Signature and may be able to help.

 

As you would know, the Sugden is a 'pure class A amp' capable of 30W. However, nowhere in any of the manuals, brochures, reviews or blogs have I seen any data on its current output. 

 

You really do need to specify what speakers you are looking to drive before any pre-emptive opinions can be made on amp suitability. The amp's effectiveness in driving your speakers is predominantly determined by the nature of your speakers and how loud you want to play music within the room you listen in.

 

My subjective experience with the Sugden is that it is a briliant integrated amp, easily the best I have owned (including a couple of Accuphase/s) and as good as, if not better than some Accuphase separates. 

 

I have used it with a variety of floorstanding and standmount speakers rated between 86 and 90dB sensitivity.