Emotiva XPA-1 vs Jungson 99D

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If anyone is interested I asked Emotiva support about increasing the bias further into class A and this is the response i received:

"First of all thank you for your interest in Emotiva. The XPA-1 is biased at roughly 10 watts before switching into class A/B mode. It is not able to be changed via a potentiometer, this is controlled by a section on the PCB and it is fixed. I hope this helps and please let me know if you have any other questions"

then I asked another question and got this response..

"The bias is set at 10 watts because it plays enough into class A mode to give is a smooth sound but not so high that it turns into a room heater. The bias could be increased by changing out some parts but we do not offer this as a service, they all come set with the same bias"

As these amps have massive heat sinks, I think they could have potential for better sound If the bias could be increased, but as Emotiva wont release the schematic, this makes pre-planning to do this a bit difficult.
 
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The fourier analysis says that the emotiva has very poor
power supply noises rejection...

So one has lots of THD at low level and low frequency,
while the other has less distorsion but a lot of power supply noise.

Wahab,
So do you think some small bypass capacitors across the big capacitors in the power supply could improve this?
Perhaps some Shottky or soft switching diodes?
 
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Where can you get this 2x200w/8R amp from and are they easy to build
for the non guru DIY builder ?

Perhaps there are one by there , although i didn t saw anything
which can be called high end these times...

As a clue, here a simulation of a FUNCTIONNAL amp that
display the kind of Thd figures that an amplifier sold for
a hefty price, or a build branded high end should have,
as a minimum..
 

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Wahab,
So do you think some small bypass capacitors across the big capacitors in the power supply could improve this?
Perhaps some Shottky or soft switching diodes?

No , this is the main noise and his harmonics that is at stake.(60HZ)
Since this kind of amp has surely vast numbers of big
capacitors, it s surely the amplifier itself
that is unable to reject these artefacts.
 
If anyone is interested I asked Emotiva support about increasing the bias further into class A and this is the response i received:

"First of all thank you for your interest in Emotiva. The XPA-1 is biased at roughly 10 watts before switching into class A/B mode. It is not able to be changed via a potentiometer, this is controlled by a section on the PCB and it is fixed. I hope this helps and please let me know if you have any other questions"

then I asked another question and got this response..

"The bias is set at 10 watts because it plays enough into class A mode to give is a smooth sound but not so high that it turns into a room heater. The bias could be increased by changing out some parts but we do not offer this as a service, they all come set with the same bias"

As these amps have massive heat sinks, I think they could have potential for better sound If the bias could be increased, but as Emotiva wont release the schematic, this makes pre-planning to do this a bit difficult.

Since they won't release the schematics what happens if the amp packs up ? Do Emotiva expect you to send it all of the way back to the US rather than get a local tech to repair it ?
 
frugal-phile™
Joined 2001
Paid Member
Since they won't release the schematics what happens if the amp packs up ? Do Emotiva expect you to send it all of the way back to the US rather than get a local tech to repair it ?

How much power do you really need? I bet Hugh Dean's NASKA blows the doors off both these amps sonically. And it is made in Australia.

dave
 
frugal-phile™
Joined 2001
Paid Member
Well, if you own a set of B&W800's then you need lots of power and current ;)

Not to worry on my account... the local hifi store has these and i find them underwhelming

The Jungson has power similar to the NASKA, and if the SS units rated power is like that of one of their tube units i have, then closer than the numbers would make you think.

dave
 
Not to worry on my account... the local hifi store has these and i find them underwhelming

The Jungson has power similar to the NASKA, and if the SS units rated power is like that of one of their tube units i have, then closer than the numbers would make you think.

dave

So what if I have Brand X speaker that is inefficient and requires lots of current and power to drive, then what ??
 
So the is the Jungson JA 99D a good integrated amplifier to buy ?

Form the reading I have been doing it has been mentioned that it can compete against $5000 upward amplifiers are these just bold claims or would any body know if they are even remotely true ?

TNT audio have stated it is one of the most cost effective well designed and beautifully built Chinese amplifiers on the market and had nothing but praise for the amplifier :confused:

Here is a link to the review from TNT audio Jungson JA-99D amplifier test on TNT-Audio - [English] :spin:
 
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