P801 Power Amp

Alan March wrote:
We do have a policy of continuous improvement. It's life in general. If you wait there will always be something better come along.

I totally understand, it's just that these are only around 3 months old, it would've been great to have implemented these Ultra Buffer improvements upon their release & like most manufacturers they typically wait for a couple of years or so to release improvements or release a MkII model.

Oniiz86 wrote:
I totally understand, it's just that these are only around 3 months old, it would've been great to have implemented these Ultra Buffer improvements upon their release & like most manufacturers they typically wait for a couple of years or so to release improvements or release a MkII model.

That may the old scenario with large companies, but not these days. The market is too competitive to wait for years. The advantage of small companies is that we can move quickly.

Also note I said "idea" for improvement. There many reasons that might not come to fruition.

Alan March wrote:
That may the old scenario with large companies, but not these days. The market is too competitive to wait for years. The advantage of small companies is that we can move quickly.

Also note I said "idea" for improvement. There many reasons that might not come to fruition.

1. When shall we see the new and improved board in the new amps? Shouldn't prudent customers wait for the new boards?

2. Also, since the 9040BA uses the OPA1632 differential amp to provide gain (14dB?) and we know the module has very low noise, shouldn't you have used the same diff-amp in your ultra-buffer board for maximum SINAD, while providing roughly the same gain of 14dB or less? For example, if SINAD is 130dB at 14dB for the chip, the combined amp will provide a SINAD of roughly 127dB, correct?

Oniiz86 wrote:
Oh, I thought at 21dB Gain his SINAD is 114dB with a noise level of 6.5 uV(A) & at 26.3dB gain his SINAD is 112dB with a noise level of 8.7 uV(A).

Whilst Boxem may be suitably proficient with his designs, I still don't appreciate the use of Hypex PSUs, he feels it is the only safe & suitable to utilise at this point in time, as far as I'm concerned, you Alan are the only game in town for the true discerning individual, your technical prowess is unparalleled when it comes to your Purifi designs 🙂

How can one have a gain option of 12dB if the amp module itself has a voltage gain of 14dB? Shouldn't this be the minimum available gain?

SmartOne_2000 wrote:
1. When shall we see the new and improved board in the new amps? Shouldn't prudent customers wait for the new boards?

2. Also, since the 9040BA uses the OPA1632 differential amp to provide gain (14dB?) and we know the module has very low noise, shouldn't you have used the same diff-amp in your ultra-buffer board for maximum SINAD, while providing roughly the same gain of 14dB or less? For example, if SINAD is 130dB at 14dB for the chip, the combined amp will provide a SINAD of roughly 127dB, correct?

1. Probably never. As I said, it was just an idea. Have to prove I can get it to work. Is it cost effective? Etc. Anyway, now I have thought about it further I have realised you wont get 2 more dB improvement in the 5 watt output SINAD of the 6525 because of the fundamental noise of the Purifi module. Potentially possible with the 9040.

You can wait for ever because I guarantee that sooner or later something better will come along....and then something else....

2. Thats a very confident statement. Do you have the circuit diagram or tests to show that's what the op amp is doing?

SmartOne_2000 wrote:
How can one have a gain option of 12dB if the amp module itself has a voltage gain of 14dB? Shouldn't this be the minimum available gain?

The data is for their 6525 based amp. This Purifi module has 12.3dB gain. So this result is either with a buffer at unity gain, or completely bypassed. I would suggest bypassed.

The 9040 module has 14.4dB gain.

As I have mentioned before, there are few pre amps / Dacs that can provide the 10.5 v rms voltage into a 1.5k load. Even less again with noise and distortion lower than a well designed input buffer. It's a pointless gain option.

Alan March wrote:
1. Probably never. As I said, it was just an idea. Have to prove I can get it to work. Is it cost effective? Etc. Anyway, now I have thought about it further I have realised you wont get 2 more dB improvement in the 5 watt output SINAD of the 6525 because of the fundamental noise of the Purifi module. Potentially possible with the 9040.

You can wait for ever because I guarantee that sooner or later something better will come along....and then something else....

2. Thats a very confident statement. Do you have the circuit diagram or tests to show that's what the op amp is doing?

1. The 4R 5W SINAD for both the 6525 and 9040 is already at 116 dB. The amplifiers' specs are 115dB/116dB respectively, so adding a 2dB improvement from the buffer will at most net you SINAD numbers of the modules themselves. It's a benefit-cost calculation you'll have to do and decide if it's worth it.

2. They refer to an OPAMP that directly takes in an audio signal, as configured below, and provides gain/input resistance as shown in Table 4.

SmartOne_2000 wrote:
1. The 4R 5W SINAD for both the 6525 and 9040 is already at 116 dB. The amplifiers' specs are 115dB/116dB respectively, so adding a 2dB improvement from the buffer will at most net you SINAD numbers of the modules themselves. It's a benefit-cost calculation you'll have to do and decide if it's worth it.

2. They refer to an OPAMP that directly takes in an audio signal, as configured below, and provides gain/input resistance as shown in Table 4.

277

1. 9040 module is -119.9dB, 6525 module is -116.6dB. Currently achieve 116dB and 115dB respectively ref 4.473v RMS (5 watts into 4 ohms). So very little further possible. You wont get to the modules stand alone figures. Might get another dB or so. I do like a challenge though 😉

2. No, that diagram is just a figurative indication of what the input looks like, and with with respect to impedance. Note the "equivilent to".

Alan March wrote:
1. 9040 module is -119.9dB, 6525 module is -116.6dB. Currently achieve 116dB and 115dB respectively ref 4.473v RMS (5 watts into 4 ohms). So very little further possible. You wont get to the modules stand alone figures. Might get another dB or so. I do like a challenge though;)

2. No, that diagram is just a figurative indication of what the input looks like, and with with respect to impedance. Note the "equivilent to".

I bet it would be nice to deliver an amp that delivers the theoretical specs of the module it uses at 5W into 4R. Serious bragging rights! 🙂
Both modules produce a SINAD of 125 dB at 100W. Your amp specs are 122 dB / 118 dB ... so there's still room for improvement;)

SmartOne_2000 wrote:
I bet it would be nice to deliver an amp that delivers the theoretical specs of the module it uses at 5W into 4R. Serious bragging rights! 🙂
Both modules produce a SINAD of 125 dB at 100W. Your amp specs are 122 dB / 118 dB ... so there's still room for improvement;)

We will see. Lots of other higher priority things to do 😀.

@SmartOne_2000 @Oniiz86

We have performed a forum software update this morning and I have seen a few weird things happen and posts disappear. Can you check if the forum working OK for you?

Thanks
Akan

@Alan March Hey Alan, all seems fine but yes I've noticed one of your posts that I had responded to has disappeared on the previous page.

Oniiz86 wrote:
@Alan March Hey Alan, all seems fine but yes I've noticed one of your posts that I had responded to has disappeared on the previous page.

Thanks. I might have to do a backup restore.

All seems ok on my end (I think).

SmartOne_2000 wrote:
Do you plan to make amps out of the new Nilai modules or the new Hypex NCx modules? If not, why not? Just curious!

^ bump