B'ASS Current Amplifier

[PeterSt]

Oh boy ...

2 months or so back, I blew something in my own NOS1a and I replaced it for two days with another NOS1a I had laying around and which was waiting for the B'ASS upgrade already;
What I noticed was that this NOS1a, being cold as stone, sounded quite nice right form its box. At that moment I had the idea that it was sounding possibly better than my own NOS1a, just because it sounded so good right from the start, thus cold from the box.

Two weeks ago we came back from a small vacation, and all the audio gear had been off for a week;
I noticed that nothing told me that all had been off for a week indeed. Maybe I got used to the car radio and found my home system infinitely better ?
It creaped on to me that the B'ASS possibly was related to this all. I mean, it could be that this device "made" all what requires warm up, did not really need that any more.


Yesterday something of the other way around happened;
Once again I blew something (I get better and better at that) and again I grabbed the same NOS1a still waiting for its B'ASS upgrade, instead.

Can anyone guess what I did "wrong" here ?


I couldn't at first either.
But after 15 minutes or so I started to think seriously whether I really had taken the same NOS1a as 2 months ago. Hmm ... I sure did. But why was it so super UNinterestingly sounding, flat-ish, no sparkle, no dimensions anywhere. Something must be wrong with it suddenly.
And then it came to me ...

Even two months ago I never thought of the fact that I had been replacing my own NOS1a with another one without removing the B'ASS from the chain. I just replaced out-going Interlinks (which I reach from the front side), never seeing what's at the end of them. Well, yesterday I did the very same. One difference : no B'ASS at the other end, because that now sits in my own NOS1a. So I removed the B'ASS together with my NOS1a, without really knowing / thinking about it.
OMG, what a difference !


This must have been the most objective "blindfolded" test ever.
Now, I don't want to debunk our own products which even are regarded the best in the world, but ... it still will be so that you are all listening to what I regard "bad sounding" these days.
You should start looking forward seriously !!

Peter

[PeterSt]

One small issue at this moment : I don't know what is happening in China, but the final PCBs required for the B'ASS/G3 are more than a week over due and the guys don't respond to my emails either.

[PeterSt]

Now let's pray a bit that it works.

[PeterSt]

Dear All,

It has been a hard week in trying to get the B'ASS right in its latest version as "G3" Gain Stage. But 5 days in a row is really sufficient to know that something must be wrong in the PCB.
It runs all right, but noise is not on par and for one of the channels even less than not so good. Chips on that channel reach 55C where the better channel remains at 35C, which probably is an indication that oscillation is going on because of that noise. Hard to tell what's first though.

FYI : It thus takes a full week to break down all the possibilities of error sources, thinking about building up a board bit by bit until errors occur. From then on you will know what step causes it to be wrong which does not mean you will know the cause. In this situation it is almost worse that I know that the concept works because the previous two boards worked fine, so you keep on trying. And so I think that something is wrong in the boards which starts with me myself possibly making a mistake in the layout of them, which would be a tough call (haha) but it has to be something. If we can find the error regarding this then nothing is lost (I now assume it can be fixed somehow) and when we can not find the error then it's possibly best to revert to the previous version (2.0). Anyway that will be three weeks of waiting again, because that version I had made in the amount of 10 only, while each channel requires 1, thus I'd have for five DACs which in the end is four because I use 2 boards myself.


Peter

[AlainGr]

Peter,

Please don't be so heavy on yourself. You said in another topic that you are obsessed with the best SQ possible and we know that you have achieved it in so many ways. I certainly consider myself very lucky to have all I already have because of your sense of perfection. Like we use to say here, "I won't complain with my mouth full already".

Take it easy on yourself (if you can)

Alain

[briefremarks]

Peter,

I want to second Alain's sentiments.  It has really been a most amazing experience to participate in your obsession with perfect sound, and this community which goes so much beyond customers and vendors.

I had some "audiophile" visitors over a couple of weeks ago, and they were literally shocked at what they heard; and this is with the LX521 speakers.

Ramesh

[acg]

Hi Peter,

Please take your time to make it right.  For me there is no real difference between waiting 3 more weeks or 3 more months.

Cheers,

Anthony

[juanpmar]

Hi Peter, no problem on my part either, take the time you need until you are satisfied with the SQ. That's the best guarantee for everyone.

Cheers,
Juan

[PeterSt]

Thank you so much for your warming words !

Again 11 days further I can now say that this little project (ahum) succeeded after all. And how !

After countable failures and things changed and what not, yesterday morning I thought of something that I wanted to have in this design and what slipped out of it because of space constraints : an isolated part (two actually) on the board for the ultra low voltage regulation. Why ? well, because none of the boards with the similar design (including those for the power amps which functioned as the base for the B'ASS/G3) wanted to work well with the regulation on-board. The kind of stupid thing is that v2 of the B'ASS (which I am using for 2 months or so by now) *does* work regarding this, although I can see habits of "instability". Anyway, this put my attention away from the culprit, which ended up to be quite similar to the power amp situations as well as v1 of the B'ASS. So ... that v1 version I used for about a year in a row, but with the regulation off-board. And nothing wrong with that.
And so a new v3 board was starting to develop yesterday and bit by bit it was tested, and made larger (for necessary components).

30 minutes ago it was full-fletched and the most extended usage (which is also going through the largest chain of components) now looks like this :

It may not tell you much, but to me this looks superb (this is 16/44.1 and balanced output) and the THD+N is not only 0.0002% better (mind you, this is still a few dB at that level) but it is foremost most stable. So let's say that with all this work to find out the source of the (about 10dB of) too much noise and with all the component testing and trialling, it is now more robust than the gain stage of the NOS1(a) ever was. You can just see it by the THD+N being rock steady in itself (it is not the one second 0.0001% higher as the next second).

Funny thing is also, that while what you see above thus is balanced (XLR) output, SE (RCA) output is hardly worse, if only not this longest chain is used. This is because this longest chain implies a higher 2nd harmonic (I see I never made a screenshot of that) meaning that it is higher than the others which are about all equal (see first picture above). But when *not* this longest chain is used, and actually the one proposed by me, all is equal to what Balanced output shows, and then to know that the signal output of SE is 6dB less. Again it may tell you nothing, but when new NOS1a's go out they need to comply to THD+N figures, and coincidentally that number for Balanced output (which is the measure) is now the same number but for the RCA output. So this is seriously better.

This I want to show you too :

as it meant a record for me on low THD+N (this is a 24 bit signal).

And how does it sound ? ... I don't know yet because we now need some other definite "fixtures" first plus this is a test board not containing my own SQ related chips (remember, yours too are pulled over from your momentary gain stage).
The fixtures are about the two now outboard ultra low noise regulators which a. must fit somewhere, b. must be fixated in a sturdy fashion not looking too much like a hobby-job (nothing is made for it in the case, obviousy) and which also involves some additional work. Apart from two additional PCB's, 4 more expensive capacitors are extra and I assume it is fine when the B'ASS costs 30 euros more because of it, including that extra labor.

Regards,
Peter

[Scroobius]

Specs look very nice Peter!!

[KnB]

Hi Peter,
Very promising
Happy you are spending all the needed, being a Phasure customer er is a privilege 
And the added 30€ is not worth mentioning, high expectations on the B'ASS and now even higher 

[PeterSt]

But ... I have another upgrade for 80 euros. I don't know whether you guys are up to that or whether it maybe becomes too much of it all ?

[KnB]

For me that's perfectly OK 
now, what is that all about?

[manisandher]

I don't know whether you guys are up to that or whether it maybe becomes too much of it all ?

Nah, never... just keep 'em coming

Mani.

[juanpmar]

80€?, mmmmm... I don't know, I don't know...
 
No Peter, it does not seem like much for the improvements we have been accustomed to. Let us know what it is!

Regards,
Juan